specialize inventory/storage indices

30 files changed, 973 insertions, 488 deletions

diff --git a/src/char/char.cpp b/src/char/char.cpp
index 965693b..c26fa64 100644
--- a/src/char/char.cpp
+++ b/src/char/char.cpp
@@ -359,7 +359,8 @@ AString mmo_char_tostr(struct CharPair *cp)
     // memos were here (no longer supported)
     str_p += '\t';
 
-    for (int i = 0; i < MAX_INVENTORY; i++)
+    for (IOff0 i : IOff0::iter())
+    {
         if (p->inventory[i].nameid)
         {
             str_p += STRPRINTF("%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d "_fmt,
@@ -376,26 +377,33 @@ AString mmo_char_tostr(struct CharPair *cp)
                     0 /*card[3]*/,
                     0 /*broken*/);
         }
+    }
     str_p += '\t';
 
     // cart was here (no longer supported)
     str_p += '\t';
 
     for (SkillID i : erange(SkillID(), MAX_SKILL))
+    {
         if (p->skill[i].lv)
         {
             str_p += STRPRINTF("%d,%d "_fmt,
                     i,
                     p->skill[i].lv | (static_cast<uint16_t>(p->skill[i].flags) << 16));
         }
+    }
     str_p += '\t';
 
     assert (p->global_reg_num < GLOBAL_REG_NUM);
     for (int i = 0; i < p->global_reg_num; i++)
+    {
         if (p->global_reg[i].str)
+        {
             str_p += STRPRINTF("%s,%d "_fmt,
                     p->global_reg[i].str,
                     p->global_reg[i].value);
+        }
+     }
     str_p += '\t';
 
     return AString(str_p);
@@ -953,10 +961,14 @@ static
 ItemNameId find_equip_view(const CharPair *cp, EPOS equipmask)
 {
     CharData *p = cp->data.get();
-    for (int i = 0; i < MAX_INVENTORY; i++)
+    for (IOff0 i : IOff0::iter())
+    {
         if (p->inventory[i].nameid && p->inventory[i].amount
             && bool(p->inventory[i].equip & equipmask))
+        {
             return p->inventory[i].nameid;
+        }
+    }
     return ItemNameId();
 }
 
@@ -1348,7 +1360,7 @@ void parse_tologin(Session *ls)
                                 cd.sex = sex;
 //                      auth_fifo[i].sex = sex;
                                 // to avoid any problem with equipment and invalid sex, equipment is unequiped.
-                                for (int j = 0; j < MAX_INVENTORY; j++)
+                                for (IOff0 j : IOff0::iter())
                                 {
                                     if (cd.inventory[j].nameid
                                         && bool(cd.inventory[j].equip))
@@ -1482,10 +1494,11 @@ void parse_tologin(Session *ls)
                     CharData *c = &cd;
                     Storage *s = account2storage(k->account_id);
                     int changes = 0;
-                    int j;
 #define FIX(v) if (v == source_id) {v = dest_id; ++changes; }
-                    for (j = 0; j < MAX_INVENTORY; j++)
+                    for (IOff0 j : IOff0::iter())
+                    {
                         FIX(c->inventory[j].nameid);
+                    }
                     // used to FIX cart, but it's no longer supported
                     // FIX(c->weapon);
                     FIX(c->shield);
@@ -1494,8 +1507,12 @@ void parse_tologin(Session *ls)
                     FIX(c->head_bottom);
 
                     if (s)
-                        for (j = 0; j < s->storage_amount; j++)
+                    {
+                        for (SOff0 j : SOff0::iter())
+                        {
                             FIX(s->storage_[j].nameid);
+                        }
+                    }
 #undef FIX
                     if (changes)
                         CHAR_LOG("itemfrob(%d -> %d):  `%s'(%d, account %d): changed %d times\n"_fmt,
diff --git a/src/char/int_storage.cpp b/src/char/int_storage.cpp
index 7a41f43..9527806 100644
--- a/src/char/int_storage.cpp
+++ b/src/char/int_storage.cpp
@@ -58,7 +58,8 @@ AString storage_tostr(Storage *p)
             p->account_id, p->storage_amount);
 
     int f = 0;
-    for (int i = 0; i < MAX_STORAGE; i++)
+    for (SOff0 i : SOff0::iter())
+    {
         if (p->storage_[i].nameid && p->storage_[i].amount)
         {
             str += STRPRINTF(
@@ -77,6 +78,7 @@ AString storage_tostr(Storage *p)
             // shouldn't that include 'broken' also? Oh, well ...
             f++;
         }
+    }
 
     str += '\t';
 
diff --git a/src/generic/array.hpp b/src/generic/array.hpp
index e6fefae..5e4dd67 100644
--- a/src/generic/array.hpp
+++ b/src/generic/array.hpp
@@ -24,18 +24,94 @@
 # include <cassert>
 # include <cstddef>
 
-template<class T, size_t n>
-struct Array
+# include "oops.hpp"
+
+template<class I, I be, I en>
+struct ExclusiveIndexing
+{
+    using index_type = I;
+    constexpr static size_t index_to_offset(index_type idx)
+    { return static_cast<size_t>(idx) - static_cast<size_t>(be); }
+    constexpr static index_type offset_to_index(size_t off)
+    { return static_cast<I>(off + static_cast<size_t>(be)); }
+    constexpr static size_t alloc_size = index_to_offset(en) - index_to_offset(be);
+};
+
+template<size_t n>
+using SimpleIndexing = ExclusiveIndexing<size_t, 0, n>;
+
+template<class I, I lo, I hi>
+struct InclusiveIndexing
+{
+    using index_type = I;
+    constexpr static size_t index_to_offset(index_type idx)
+    { return static_cast<size_t>(idx) - static_cast<size_t>(lo); }
+    constexpr static index_type offset_to_index(size_t off)
+    { return static_cast<I>(off + static_cast<size_t>(lo)); }
+    constexpr static size_t alloc_size = index_to_offset(hi) - index_to_offset(lo) + 1;
+};
+
+template<class E, E n=E::COUNT>
+struct EnumIndexing : ExclusiveIndexing<E, static_cast<E>(0), n>
 {
-    T data[n];
+};
+
+template<class I, size_t limit>
+struct InventoryIndexing
+{
+    using index_type = I;
+    constexpr static size_t index_to_offset(index_type idx)
+    { return idx.get0(); }
+    constexpr static index_type offset_to_index(size_t off)
+    { return I::from(off); }
+    constexpr static size_t alloc_size = limit;
+};
+
+template<class T, class I>
+struct GenericArray
+{
+    T data[I::alloc_size];
 public:
-    T& operator [](size_t i) { assert (i < n); return data[i]; }
-    const T& operator [](size_t i) const { assert (i < n); return data[i]; }
+    T *begin()
+    { return data + 0; }
+    T *end()
+    { return data + I::alloc_size; }
+    const T *begin() const
+    { return data + 0; }
+    const T *end() const
+    { return data + I::alloc_size; }
+    size_t size() const
+    { return I::alloc_size; }
+
+    T& operator [](typename I::index_type i_)
+    {
+        size_t i = I::index_to_offset(i_);
+        ALLEGE ("index in bounds", i < size());
+        return data[i];
+    }
+    const T& operator [](typename I::index_type i_) const
+    {
+        size_t i = I::index_to_offset(i_);
+        ALLEGE ("index in bounds", i < size());
+        return data[i];
+    }
 
-    T *begin() { return data + 0; }
-    T *end() { return data + n; }
-    const T *begin() const { return data + 0; }
-    const T *end() const { return data + n; }
+    friend bool operator == (GenericArray& lhs, GenericArray& rhs)
+    {
+        for (size_t i = 0; i < I::alloc_size; ++i)
+        {
+            if (lhs.data[i] != rhs.data[i])
+                return false;
+        }
+        return true;
+    }
+    friend bool operator != (GenericArray& lhs, GenericArray& rhs)
+    {
+        return !(lhs == rhs);
+    }
 };
 
+template<class T, size_t n>
+using Array = GenericArray<T, SimpleIndexing<n>>;
+
 #endif // TMWA_GENERIC_ARRAY_HPP
diff --git a/src/generic/array_test.cpp b/src/generic/array_test.cpp
new file mode 100644
index 0000000..7b5ffca
--- /dev/null
+++ b/src/generic/array_test.cpp
@@ -0,0 +1,159 @@
+#include "array.hpp"
+//    array_test.cpp - Testsuite for a simple bounds-checked array.
+//
+//    Copyright © 2014 Ben Longbons <b.r.longbons@gmail.com>
+//
+//    This file is part of The Mana World (Athena server)
+//
+//    This program is free software: you can redistribute it and/or modify
+//    it under the terms of the GNU General Public License as published by
+//    the Free Software Foundation, either version 3 of the License, or
+//    (at your option) any later version.
+//
+//    This program is distributed in the hope that it will be useful,
+//    but WITHOUT ANY WARRANTY; without even the implied warranty of
+//    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+//    GNU General Public License for more details.
+//
+//    You should have received a copy of the GNU General Public License
+//    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+#include <gtest/gtest.h>
+
+#include "../poison.hpp"
+
+
+TEST(Array, simple)
+{
+    GenericArray<int, SimpleIndexing<3>> a;
+    try
+    {
+        a[0];
+        a[1];
+        a[2];
+        SUCCEED();
+    }
+    catch (const AssertionError&)
+    {
+        FAIL();
+    }
+    try
+    {
+        a[3];
+        FAIL();
+    }
+    catch (const AssertionError&)
+    {
+        SUCCEED();
+    }
+}
+
+TEST(Array, inclusive1)
+{
+    GenericArray<int, InclusiveIndexing<int, 1, 3>> a;
+    try
+    {
+        a[0];
+        FAIL();
+    }
+    catch (const AssertionError&)
+    {
+        SUCCEED();
+    }
+    try
+    {
+        a[1];
+        a[2];
+        a[3];
+        SUCCEED();
+    }
+    catch (const AssertionError&)
+    {
+        FAIL();
+    }
+    try
+    {
+        a[4];
+        FAIL();
+    }
+    catch (const AssertionError&)
+    {
+        SUCCEED();
+    }
+}
+
+TEST(Array, negative)
+{
+    GenericArray<int, InclusiveIndexing<int, -1, 1>> a;
+    try
+    {
+        a[-2];
+        FAIL();
+    }
+    catch (const AssertionError&)
+    {
+        SUCCEED();
+    }
+    try
+    {
+        a[-1];
+        a[0];
+        a[1];
+        SUCCEED();
+    }
+    catch (const AssertionError&)
+    {
+        FAIL();
+    }
+    try
+    {
+        a[2];
+        FAIL();
+    }
+    catch (const AssertionError&)
+    {
+        SUCCEED();
+    }
+}
+
+TEST(Array, enum)
+{
+    enum class Blah
+    {
+        FOO,
+        BAR,
+        BAZ,
+        COUNT,
+    };
+
+    GenericArray<int, EnumIndexing<Blah>> a;
+    try
+    {
+        a[static_cast<Blah>(-1)];
+        FAIL();
+    }
+    catch (const AssertionError&)
+    {
+        SUCCEED();
+    }
+    try
+    {
+        a[Blah::FOO];
+        a[Blah::BAR];
+        a[Blah::BAZ];
+        SUCCEED();
+    }
+    catch (const AssertionError&)
+    {
+        FAIL();
+    }
+    try
+    {
+        a[Blah::COUNT];
+        FAIL();
+    }
+    catch (const AssertionError&)
+    {
+        SUCCEED();
+    }
+}
diff --git a/src/generic/enum.hpp b/src/generic/enum.hpp
index 5f075bc..1e83c24 100644
--- a/src/generic/enum.hpp
+++ b/src/generic/enum.hpp
@@ -29,62 +29,10 @@
 
 # include "../compat/iter.hpp"
 
-template<class T, class E, E max>
-struct earray
-{
-    constexpr static
-    size_t size()
-    {
-        return static_cast<size_t>(max);
-    }
-
-    // no ctor/dtor and one public member variable for easy initialization
-    T _data[size()];
+# include "array.hpp"
 
-    T& operator[](E v)
-    {
-        auto i = static_cast<size_t>(v);
-        assert (i < size());
-        return _data[i];
-    }
-
-    const T& operator[](E v) const
-    {
-        auto i = static_cast<size_t>(v);
-        assert (i < size());
-        return _data[i];
-    }
-
-    T *begin()
-    {
-        return _data;
-    }
-
-    T *end()
-    {
-        return _data + size();
-    }
-
-    const T *begin() const
-    {
-        return _data;
-    }
-
-    const T *end() const
-    {
-        return _data + size();
-    }
-
-    friend bool operator == (const earray& l, const earray& r)
-    {
-        return std::equal(l.begin(), l.end(), r.begin());
-    }
-
-    friend bool operator != (const earray& l, const earray& r)
-    {
-        return !(l == r);
-    }
-};
+template<class T, class E, E max>
+using earray = GenericArray<T, EnumIndexing<E, max>>;
 
 template<class T, class E, E max>
 class eptr
@@ -102,7 +50,7 @@ public:
     {}
 
     eptr(earray<T, E, max>& arr)
-    : _data(arr._data)
+    : _data(arr.data)
     {}
 
     T& operator [](E v) const
diff --git a/src/generic/oops.cpp b/src/generic/oops.cpp
new file mode 100644
index 0000000..95fdcad
--- /dev/null
+++ b/src/generic/oops.cpp
@@ -0,0 +1,45 @@
+#include "oops.hpp"
+//    oops.cpp - Stuff that shouldn't happen.
+//
+//    Copyright © 2014 Ben Longbons <b.r.longbons@gmail.com>
+//
+//    This file is part of The Mana World (Athena server)
+//
+//    This program is free software: you can redistribute it and/or modify
+//    it under the terms of the GNU General Public License as published by
+//    the Free Software Foundation, either version 3 of the License, or
+//    (at your option) any later version.
+//
+//    This program is distributed in the hope that it will be useful,
+//    but WITHOUT ANY WARRANTY; without even the implied warranty of
+//    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+//    GNU General Public License for more details.
+//
+//    You should have received a copy of the GNU General Public License
+//    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+#include <cstdlib>
+#include <cstring>
+#include <cstdio>
+
+//#include "../poison.hpp"
+
+
+static
+std::string do_asprintf(const char *desc, const char *expr,
+        const char *file, size_t line, const char *function)
+{
+    char *what = nullptr;
+    int len = asprintf(&what, "%s:%zu: error: in '%s', incorrectly alleged that '%s' (%s)",
+            file, line, function, desc, expr);
+    if (len == -1)
+        abort();
+    std::string out = what;
+    free(what);
+    return out;
+}
+
+AssertionError::AssertionError(const char *desc, const char *expr,
+        const char *file, size_t line, const char *function)
+: std::runtime_error(do_asprintf(desc, expr, file, line, function))
+{}
diff --git a/src/generic/oops.hpp b/src/generic/oops.hpp
new file mode 100644
index 0000000..231a4e4
--- /dev/null
+++ b/src/generic/oops.hpp
@@ -0,0 +1,43 @@
+#ifndef TMWA_GENERIC_OOPS_HPP
+#define TMWA_GENERIC_OOPS_HPP
+//    oops.hpp - Stuff that shouldn't happen.
+//
+//    Copyright © 2014 Ben Longbons <b.r.longbons@gmail.com>
+//
+//    This file is part of The Mana World (Athena server)
+//
+//    This program is free software: you can redistribute it and/or modify
+//    it under the terms of the GNU General Public License as published by
+//    the Free Software Foundation, either version 3 of the License, or
+//    (at your option) any later version.
+//
+//    This program is distributed in the hope that it will be useful,
+//    but WITHOUT ANY WARRANTY; without even the implied warranty of
+//    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+//    GNU General Public License for more details.
+//
+//    You should have received a copy of the GNU General Public License
+//    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# include "fwd.hpp"
+
+# include <cstddef>
+
+# include <stdexcept>
+
+# include "oops.hpp"
+
+
+class AssertionError : public std::runtime_error
+{
+    const char *_what;
+public:
+    AssertionError(const char *desc, const char *expr,
+            const char *file, size_t line, const char *function);
+};
+
+# define ALLEGE(desc, expr) \
+    if (expr) {} \
+    else throw AssertionError(desc, #expr, __FILE__, __LINE__, __PRETTY_FUNCTION__)
+
+#endif // TMWA_GENERIC_OOPS_HPP
diff --git a/src/generic/oops_test.cpp b/src/generic/oops_test.cpp
new file mode 100644
index 0000000..d16db04
--- /dev/null
+++ b/src/generic/oops_test.cpp
@@ -0,0 +1,50 @@
+#include "oops.hpp"
+//    oops_test.cpp - Testsuite for stuff that shouldn't happen.
+//
+//    Copyright © 2014 Ben Longbons <b.r.longbons@gmail.com>
+//
+//    This file is part of The Mana World (Athena server)
+//
+//    This program is free software: you can redistribute it and/or modify
+//    it under the terms of the GNU General Public License as published by
+//    the Free Software Foundation, either version 3 of the License, or
+//    (at your option) any later version.
+//
+//    This program is distributed in the hope that it will be useful,
+//    but WITHOUT ANY WARRANTY; without even the implied warranty of
+//    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+//    GNU General Public License for more details.
+//
+//    You should have received a copy of the GNU General Public License
+//    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+#include <gtest/gtest.h>
+
+#include "../poison.hpp"
+
+TEST(oops, okay)
+{
+    try
+    {
+        ALLEGE ("the sky is gray", true);
+        SUCCEED();
+    }
+    catch (const AssertionError& e)
+    {
+        FAIL();
+    }
+}
+
+TEST(oops, uhoh)
+{
+    try
+    {
+        ALLEGE ("the sky is falling", 1 == 0);
+        FAIL();
+    }
+    catch (const AssertionError& e)
+    {
+        ASSERT_STREQ(strstr(e.what(), "src/generic/"),
+                "src/generic/oops_test.cpp:42: error: in 'virtual void oops_uhoh_Test::TestBody()', incorrectly alleged that 'the sky is falling' (1 == 0)");
+    }
+}
diff --git a/src/map/atcommand.cpp b/src/map/atcommand.cpp
index d2f154f..f405f14 100644
--- a/src/map/atcommand.cpp
+++ b/src/map/atcommand.cpp
@@ -1371,7 +1371,7 @@ ATCE atcommand_item(Session *s, dumb_ptr<map_session_data> sd,
             PickupFail flag;
             if ((flag = pc_additem(sd, &item_tmp, get_count))
                 != PickupFail::OKAY)
-                clif_additem(sd, 0, 0, flag);
+                clif_additem(sd, IOff0::from(0), 0, flag);
         }
         clif_displaymessage(s, "Item created."_s);
     }
@@ -1388,9 +1388,7 @@ static
 ATCE atcommand_itemreset(Session *s, dumb_ptr<map_session_data> sd,
         ZString)
 {
-    int i;
-
-    for (i = 0; i < MAX_INVENTORY; i++)
+    for (IOff0 i : IOff0::iter())
     {
         if (sd->status.inventory[i].amount
             && sd->status.inventory[i].equip == EPOS::ZERO)
@@ -3118,7 +3116,6 @@ ATCE atcommand_char_wipe(Session *s, dumb_ptr<map_session_data> sd,
         if (pc_isGM(sd).overwhelms(pc_isGM(pl_sd)))
         {
             // you can reset a character only for lower or same GM level
-            int i;
 
             // Reset base level
             pl_sd->status.base_level = 1;
@@ -3139,7 +3136,7 @@ ATCE atcommand_char_wipe(Session *s, dumb_ptr<map_session_data> sd,
             clif_updatestatus(pl_sd, SP::ZENY);
 
             // Clear inventory
-            for (i = 0; i < MAX_INVENTORY; i++)
+            for (IOff0 i : IOff0::iter())
             {
                 if (sd->status.inventory[i].amount)
                 {
@@ -3678,7 +3675,7 @@ ATCE atcommand_chardelitem(Session *s, dumb_ptr<map_session_data> sd,
     XString item_name;
     int i, number = 0;
     ItemNameId item_id;
-    int item_position, count;
+    int count;
     struct item_data *item_data;
 
     if (!asplit(message, &item_name, &number, &character) || number < 1)
@@ -3697,11 +3694,11 @@ ATCE atcommand_chardelitem(Session *s, dumb_ptr<map_session_data> sd,
             if (pc_isGM(sd).overwhelms(pc_isGM(pl_sd)))
             {
                 // you can kill only lower or same level
-                item_position = pc_search_inventory(pl_sd, item_id);
-                if (item_position >= 0)
+                IOff0 item_position = pc_search_inventory(pl_sd, item_id);
+                if (item_position.ok())
                 {
                     count = 0;
-                    for (i = 0; i < number && item_position >= 0; i++)
+                    for (i = 0; i < number && item_position.ok(); i++)
                     {
                         pc_delitem(pl_sd, item_position, 1, 0);
                         count++;
@@ -3849,7 +3846,7 @@ ATCE atcommand_character_item_list(Session *s, dumb_ptr<map_session_data> sd,
         ZString message)
 {
     struct item_data *item_data = NULL;
-    int i, count, counter;
+    int count, counter;
     CharName character;
 
     if (!asplit(message, &character))
@@ -3863,7 +3860,7 @@ ATCE atcommand_character_item_list(Session *s, dumb_ptr<map_session_data> sd,
             // you can look items only lower or same level
             counter = 0;
             count = 0;
-            for (i = 0; i < MAX_INVENTORY; i++)
+            for (IOff0 i : IOff0::iter())
             {
                 if (pl_sd->status.inventory[i].nameid
                     && (item_data =
@@ -3961,7 +3958,7 @@ ATCE atcommand_character_storage_list(Session *s, dumb_ptr<map_session_data> sd,
 {
     Storage *stor;
     struct item_data *item_data = NULL;
-    int i, count, counter;
+    int count, counter;
     CharName character;
 
     if (!asplit(message, &character))
@@ -3977,7 +3974,7 @@ ATCE atcommand_character_storage_list(Session *s, dumb_ptr<map_session_data> sd,
             {
                 counter = 0;
                 count = 0;
-                for (i = 0; i < MAX_STORAGE; i++)
+                for (SOff0 i : SOff0::iter())
                 {
                     if (stor->storage_[i].nameid
                         && (item_data =
@@ -4188,8 +4185,7 @@ static
 ATCE atcommand_dropall(Session *, dumb_ptr<map_session_data> sd,
         ZString)
 {
-    int i;
-    for (i = 0; i < MAX_INVENTORY; i++)
+    for (IOff0 i : IOff0::iter())
     {
         if (sd->status.inventory[i].amount)
         {
@@ -4212,7 +4208,7 @@ ATCE atcommand_chardropall(Session *s, dumb_ptr<map_session_data>,
     dumb_ptr<map_session_data> pl_sd = map_nick2sd(character);
     if (pl_sd == NULL)
         return ATCE::EXIST;
-    for (int i = 0; i < MAX_INVENTORY; i++)
+    for (IOff0 i : IOff0::iter())
     {
         if (pl_sd->status.inventory[i].amount)
         {
@@ -4232,8 +4228,6 @@ static
 ATCE atcommand_storeall(Session *s, dumb_ptr<map_session_data> sd,
         ZString)
 {
-    int i;
-
     if (!sd->state.storage_open)
     {
         //Open storage.
@@ -4250,7 +4244,7 @@ ATCE atcommand_storeall(Session *s, dumb_ptr<map_session_data> sd,
                 return ATCE::EXIST;
         }
     }
-    for (i = 0; i < MAX_INVENTORY; i++)
+    for (IOff0 i : IOff0::iter())
     {
         if (sd->status.inventory[i].amount)
         {
@@ -4286,7 +4280,7 @@ ATCE atcommand_charstoreall(Session *s, dumb_ptr<map_session_data> sd,
         clif_displaymessage(s, "run this command again.."_s);
         return ATCE::OKAY;
     }
-    for (int i = 0; i < MAX_INVENTORY; i++)
+    for (IOff0 i : IOff0::iter())
     {
         if (pl_sd->status.inventory[i].amount)
         {
diff --git a/src/map/battle.cpp b/src/map/battle.cpp
index 99252e3..a653cac 100644
--- a/src/map/battle.cpp
+++ b/src/map/battle.cpp
@@ -1327,9 +1327,9 @@ int battle_is_unarmed(dumb_ptr<block_list> bl)
     {
         dumb_ptr<map_session_data> sd = bl->is_player();
 
-        int sidx = sd->equip_index_maybe[EQUIP::SHIELD];
-        int widx = sd->equip_index_maybe[EQUIP::WEAPON];
-        return sidx == -1 && widx == -1;
+        IOff0 sidx = sd->equip_index_maybe[EQUIP::SHIELD];
+        IOff0 widx = sd->equip_index_maybe[EQUIP::WEAPON];
+        return !sidx.ok() && !widx.ok();
     }
     else
         return 0;
@@ -1449,12 +1449,12 @@ struct Damage battle_calc_pc_weapon_attack(dumb_ptr<block_list> src,
     atkmin = atkmin_ = dex;     //最低ATKはDEXで初期化？
     sd->state.arrow_atk = 0;    //arrow_atk初期化
 
-    int widx = sd->equip_index_maybe[EQUIP::WEAPON];
-    int sidx = sd->equip_index_maybe[EQUIP::SHIELD];
+    IOff0 widx = sd->equip_index_maybe[EQUIP::WEAPON];
+    IOff0 sidx = sd->equip_index_maybe[EQUIP::SHIELD];
 
-    if (widx >= 0 && sd->inventory_data[widx])
+    if (widx.ok() && sd->inventory_data[widx])
         atkmin = atkmin * (80 + sd->inventory_data[widx]->wlv * 20) / 100;
-    if (sidx >= 0 && sd->inventory_data[sidx])
+    if (sidx.ok() && sd->inventory_data[sidx])
         atkmin_ = atkmin_ * (80 + sd->inventory_data[sidx]->wlv * 20) / 100;
     if (sd->status.weapon == ItemLook::BOW)
     {                           //武器が弓矢の場合
@@ -2010,8 +2010,8 @@ ATK battle_weapon_attack(dumb_ptr<block_list> src, dumb_ptr<block_list> target,
         // 攻撃対象となりうるので攻撃
         if (sd && sd->status.weapon == ItemLook::BOW)
         {
-            int aidx = sd->equip_index_maybe[EQUIP::ARROW];
-            if (aidx >= 0)
+            IOff0 aidx = sd->equip_index_maybe[EQUIP::ARROW];
+            if (aidx.ok())
             {
                 if (battle_config.arrow_decrement)
                     pc_delitem(sd, aidx, 1, 0);
@@ -2058,9 +2058,9 @@ ATK battle_weapon_attack(dumb_ptr<block_list> src, dumb_ptr<block_list> target,
 
         if (src->bl_type == BL::PC)
         {
-            int weapon_index = sd->equip_index_maybe[EQUIP::WEAPON];
+            IOff0 weapon_index = sd->equip_index_maybe[EQUIP::WEAPON];
             ItemNameId weapon;
-            if (weapon_index >= 0 && sd->inventory_data[weapon_index]
+            if (weapon_index.ok() && sd->inventory_data[weapon_index]
                     && bool(sd->status.inventory[weapon_index].equip & EPOS::WEAPON))
                 weapon = sd->inventory_data[weapon_index]->nameid;
 
diff --git a/src/map/chrif.cpp b/src/map/chrif.cpp
index 3a329f8..ff0adbd 100644
--- a/src/map/chrif.cpp
+++ b/src/map/chrif.cpp
@@ -625,7 +625,6 @@ void chrif_changedgm(Session *, const Packet_Fixed<0x2b0b>& fixed)
 static
 void chrif_changedsex(Session *, const Packet_Fixed<0x2b0d>& fixed)
 {
-    int i;
     dumb_ptr<map_session_data> sd;
 
     AccountId acc = fixed.account_id;
@@ -642,7 +641,7 @@ void chrif_changedsex(Session *, const Packet_Fixed<0x2b0d>& fixed)
             else if (sd->status.sex == SEX::FEMALE)
                 sd->sex = sd->status.sex = SEX::MALE;
             // to avoid any problem with equipment and invalid sex, equipment is unequiped.
-            for (i = 0; i < MAX_INVENTORY; i++)
+            for (IOff0 i : IOff0::iter())
             {
                 if (sd->status.inventory[i].nameid
                     && bool(sd->status.inventory[i].equip))
@@ -942,9 +941,8 @@ void ladmin_itemfrob_c2(dumb_ptr<block_list> bl, ItemNameId source_id, ItemNameI
         {
             dumb_ptr<map_session_data> pc = bl->is_player();
             Storage *stor = account2storage2(pc->status_key.account_id);
-            int j;
 
-            for (j = 0; j < MAX_INVENTORY; j++)
+            for (IOff0 j : IOff0::iter())
                 IFIX(pc->status.inventory[j].nameid);
             // cart is no longer supported
             // IFIX(pc->status.weapon);
@@ -954,10 +952,12 @@ void ladmin_itemfrob_c2(dumb_ptr<block_list> bl, ItemNameId source_id, ItemNameI
             IFIX(pc->status.head_bottom);
 
             if (stor)
-                for (j = 0; j < stor->storage_amount; j++)
+            {
+                for (SOff0 j : SOff0::iter())
                     FIX(stor->storage_[j]);
+            }
 
-            for (j = 0; j < MAX_INVENTORY; j++)
+            for (IOff0 j : IOff0::iter())
             {
                 struct item_data *item = pc->inventory_data[j];
                 if (item && item->nameid == source_id)
diff --git a/src/map/clif.cpp b/src/map/clif.cpp
index 2275023..2ae9825 100644
--- a/src/map/clif.cpp
+++ b/src/map/clif.cpp
@@ -673,20 +673,20 @@ void clif_set0078_main_1d8(dumb_ptr<map_session_data> sd, Buffer& buf)
     fixed_1d8.species = sd->status.species;
     fixed_1d8.hair_style = sd->status.hair;
 
-    int widx = sd->equip_index_maybe[EQUIP::WEAPON];
-    int sidx = sd->equip_index_maybe[EQUIP::SHIELD];
+    IOff0 widx = sd->equip_index_maybe[EQUIP::WEAPON];
+    IOff0 sidx = sd->equip_index_maybe[EQUIP::SHIELD];
     if (sd->attack_spell_override)
         fixed_1d8.weapon = sd->attack_spell_look_override;
     else
     {
-        if (widx >= 0 && sd->inventory_data[widx])
+        if (widx.ok() && sd->inventory_data[widx])
         {
             fixed_1d8.weapon = sd->status.inventory[widx].nameid;
         }
         else
             fixed_1d8.weapon = ItemNameId();
     }
-    if (sidx >= 0 && sidx != widx && sd->inventory_data[sidx])
+    if (sidx.ok() && sidx != widx && sd->inventory_data[sidx])
     {
         fixed_1d8.shield = sd->status.inventory[sidx].nameid;
     }
@@ -727,20 +727,20 @@ void clif_set0078_alt_1d9(dumb_ptr<map_session_data> sd, Buffer& buf)
     fixed_1d8.species = sd->status.species;
     fixed_1d8.hair_style = sd->status.hair;
 
-    int widx = sd->equip_index_maybe[EQUIP::WEAPON];
-    int sidx = sd->equip_index_maybe[EQUIP::SHIELD];
+    IOff0 widx = sd->equip_index_maybe[EQUIP::WEAPON];
+    IOff0 sidx = sd->equip_index_maybe[EQUIP::SHIELD];
     if (sd->attack_spell_override)
         fixed_1d8.weapon = sd->attack_spell_look_override;
     else
     {
-        if (widx >= 0 && sd->inventory_data[widx])
+        if (widx.ok() && sd->inventory_data[widx])
         {
             fixed_1d8.weapon = sd->status.inventory[widx].nameid;
         }
         else
             fixed_1d8.weapon = ItemNameId();
     }
-    if (sidx >= 0 && sidx != widx && sd->inventory_data[sidx])
+    if (sidx.ok() && sidx != widx && sd->inventory_data[sidx])
     {
         fixed_1d8.shield = sd->status.inventory[sidx].nameid;
     }
@@ -784,15 +784,15 @@ void clif_set007b(dumb_ptr<map_session_data> sd, Buffer& buf)
     fixed_1da.option = sd->status.option;
     fixed_1da.species = sd->status.species;
     fixed_1da.hair_style = sd->status.hair;
-    int widx = sd->equip_index_maybe[EQUIP::WEAPON];
-    int sidx = sd->equip_index_maybe[EQUIP::SHIELD];
-    if (widx >= 0 && sd->inventory_data[widx])
+    IOff0 widx = sd->equip_index_maybe[EQUIP::WEAPON];
+    IOff0 sidx = sd->equip_index_maybe[EQUIP::SHIELD];
+    if (widx.ok() && sd->inventory_data[widx])
     {
         fixed_1da.weapon = sd->status.inventory[widx].nameid;
     }
     else
         fixed_1da.weapon = ItemNameId();
-    if (sidx >= 0 && sidx != widx && sd->inventory_data[sidx])
+    if (sidx.ok() && sidx != widx && sd->inventory_data[sidx])
     {
         fixed_1da.shield = sd->status.inventory[sidx].nameid;
     }
@@ -1245,21 +1245,19 @@ int clif_buylist(dumb_ptr<map_session_data> sd, dumb_ptr<npc_data_shop> nd)
  */
 int clif_selllist(dumb_ptr<map_session_data> sd)
 {
-    int i, val;
-
     nullpo_ret(sd);
 
     Session *s = sd->sess;
     std::vector<Packet_Repeat<0x00c7>> repeat_c7;
-    for (i = 0; i < MAX_INVENTORY; i++)
+    for (IOff0 i : IOff0::iter())
     {
         if (sd->status.inventory[i].nameid && sd->inventory_data[i])
         {
-            val = sd->inventory_data[i]->value_sell;
+            int val = sd->inventory_data[i]->value_sell;
             if (val < 0)
                 continue;
             Packet_Repeat<0x00c7> info;
-            info.ioff2 = i + 2;
+            info.ioff2 = i.shift();
             info.base_price = val;
             info.actual_price = val;
             repeat_c7.push_back(info);
@@ -1359,7 +1357,7 @@ void clif_scriptinputstr(dumb_ptr<map_session_data> sd, BlockId npcid)
  *
  *------------------------------------------
  */
-int clif_additem(dumb_ptr<map_session_data> sd, int n, int amount, PickupFail fail)
+int clif_additem(dumb_ptr<map_session_data> sd, IOff0 n, int amount, PickupFail fail)
 {
     nullpo_ret(sd);
 
@@ -1367,18 +1365,18 @@ int clif_additem(dumb_ptr<map_session_data> sd, int n, int amount, PickupFail fa
     Packet_Fixed<0x00a0> fixed_a0;
     if (fail != PickupFail::OKAY)
     {
-        fixed_a0.ioff2 = n + 2;
+        fixed_a0.ioff2 = n.shift();
         fixed_a0.amount = amount;
         fixed_a0.name_id = ItemNameId();
         fixed_a0.pickup_fail = fail;
     }
     else
     {
-        if (n < 0 || n >= MAX_INVENTORY || !sd->status.inventory[n].nameid
+        if (!n.ok() || !sd->status.inventory[n].nameid
             || sd->inventory_data[n] == NULL)
             return 1;
 
-        fixed_a0.ioff2 = n + 2;
+        fixed_a0.ioff2 = n.shift();
         fixed_a0.amount = amount;
         fixed_a0.name_id = sd->status.inventory[n].nameid;
         fixed_a0.identify = 1;
@@ -1405,13 +1403,13 @@ int clif_additem(dumb_ptr<map_session_data> sd, int n, int amount, PickupFail fa
  *
  *------------------------------------------
  */
-void clif_delitem(dumb_ptr<map_session_data> sd, int n, int amount)
+void clif_delitem(dumb_ptr<map_session_data> sd, IOff0 n, int amount)
 {
     nullpo_retv(sd);
 
     Session *s = sd->sess;
     Packet_Fixed<0x00af> fixed_af;
-    fixed_af.ioff2 = n + 2;
+    fixed_af.ioff2 = n.shift();
     fixed_af.amount = amount;
 
     send_fpacket<0x00af, 6>(s, fixed_af);
@@ -1425,17 +1423,17 @@ void clif_itemlist(dumb_ptr<map_session_data> sd)
 {
     nullpo_retv(sd);
 
-    int arrow = -1;
+    IOff0 arrow = IOff0::from(-1);
     Session *s = sd->sess;
     std::vector<Packet_Repeat<0x01ee>> repeat_1ee;
-    for (int i = 0; i < MAX_INVENTORY; i++)
+    for (IOff0 i : IOff0::iter())
     {
         if (!sd->status.inventory[i].nameid
             || sd->inventory_data[i] == NULL
             || itemdb_isequip2(sd->inventory_data[i]))
             continue;
         Packet_Repeat<0x01ee> info;
-        info.ioff2 = i + 2;
+        info.ioff2 = i.shift();
         info.name_id = sd->status.inventory[i].nameid;
         info.item_type = sd->inventory_data[i]->type;
         info.identify = 1;
@@ -1444,7 +1442,7 @@ void clif_itemlist(dumb_ptr<map_session_data> sd)
         {
             info.epos = EPOS::ARROW;
             if (bool(sd->status.inventory[i].equip))
-                arrow = i;      // ついでに矢装備チェック
+                arrow = i;
         }
         else
             info.epos = EPOS::ZERO;
@@ -1458,7 +1456,7 @@ void clif_itemlist(dumb_ptr<map_session_data> sd)
     {
         send_packet_repeatonly<0x01ee, 4, 18>(s, repeat_1ee);
     }
-    if (arrow >= 0)
+    if (arrow.ok())
         clif_arrowequip(sd, arrow);
 }
 
@@ -1472,14 +1470,14 @@ void clif_equiplist(dumb_ptr<map_session_data> sd)
 
     Session *s = sd->sess;
     std::vector<Packet_Repeat<0x00a4>> repeat_a4;
-    for (int i = 0; i < MAX_INVENTORY; i++)
+    for (IOff0 i : IOff0::iter())
     {
         if (!sd->status.inventory[i].nameid
             || sd->inventory_data[i] == NULL
             || !itemdb_isequip2(sd->inventory_data[i]))
             continue;
         Packet_Repeat<0x00a4> info;
-        info.ioff2 = i + 2;
+        info.ioff2 = i.shift();
         info.name_id = sd->status.inventory[i].nameid;
         info.item_type = (
                 sd->inventory_data[i]->type == ItemType::_7
@@ -1515,7 +1513,7 @@ int clif_storageitemlist(dumb_ptr<map_session_data> sd, Storage *stor)
 
     Session *s = sd->sess;
     std::vector<Packet_Repeat<0x01f0>> repeat_1f0;
-    for (int i = 0; i < MAX_STORAGE; i++)
+    for (SOff0 i : SOff0::iter())
     {
         if (!stor->storage_[i].nameid)
             continue;
@@ -1527,7 +1525,7 @@ int clif_storageitemlist(dumb_ptr<map_session_data> sd, Storage *stor)
             continue;
 
         Packet_Repeat<0x01f0> info;
-        info.soff1 = i + 1;
+        info.soff1 = i.shift();
         info.name_id = stor->storage_[i].nameid;
         info.item_type = id->type;
         info.identify = 0;
@@ -1557,7 +1555,7 @@ int clif_storageequiplist(dumb_ptr<map_session_data> sd, Storage *stor)
 
     Session *s = sd->sess;
     std::vector<Packet_Repeat<0x00a6>> repeat_a6;
-    for (int i = 0; i < MAX_STORAGE; i++)
+    for (SOff0 i : SOff0::iter())
     {
         if (!stor->storage_[i].nameid)
             continue;
@@ -1568,7 +1566,7 @@ int clif_storageequiplist(dumb_ptr<map_session_data> sd, Storage *stor)
         if (!itemdb_isequip2(id))
             continue;
         Packet_Repeat<0x00a6> info;
-        info.soff1 = i + 1;
+        info.soff1 = i.shift();
         info.name_id = stor->storage_[i].nameid;
         info.item_type = id->type;
         info.identify = 0;
@@ -1837,8 +1835,8 @@ int clif_changelook_towards(dumb_ptr<block_list> bl, LOOK type, int val,
             EQUIP equip_point = equip_points[type];
 
             fixed_1d7.look_type = type;
-            int idx = sd->equip_index_maybe[equip_point];
-            if (idx >= 0 && sd->inventory_data[idx])
+            IOff0 idx = sd->equip_index_maybe[equip_point];
+            if (idx.ok() && sd->inventory_data[idx])
             {
                 fixed_1d7.weapon_or_name_id_or_value = unwrap<ItemNameId>(sd->status.inventory[idx].nameid);
             }
@@ -1849,20 +1847,20 @@ int clif_changelook_towards(dumb_ptr<block_list> bl, LOOK type, int val,
         else
         {
             fixed_1d7.look_type = LOOK::WEAPON;
-            int widx = sd->equip_index_maybe[EQUIP::WEAPON];
-            int sidx = sd->equip_index_maybe[EQUIP::SHIELD];
+            IOff0 widx = sd->equip_index_maybe[EQUIP::WEAPON];
+            IOff0 sidx = sd->equip_index_maybe[EQUIP::SHIELD];
             if (sd->attack_spell_override)
                 fixed_1d7.weapon_or_name_id_or_value = unwrap<ItemNameId>(sd->attack_spell_look_override);
             else
             {
-                if (widx >= 0 && sd->inventory_data[widx])
+                if (widx.ok() && sd->inventory_data[widx])
                 {
                     fixed_1d7.weapon_or_name_id_or_value = unwrap<ItemNameId>(sd->status.inventory[widx].nameid);
                 }
                 else
                     fixed_1d7.weapon_or_name_id_or_value = unwrap<ItemNameId>(ItemNameId());
             }
-            if (sidx >= 0 && sidx != widx && sd->inventory_data[sidx])
+            if (sidx.ok() && sidx != widx && sd->inventory_data[sidx])
             {
                 fixed_1d7.shield = sd->status.inventory[sidx].nameid;
             }
@@ -1954,7 +1952,7 @@ int clif_initialstatus(dumb_ptr<map_session_data> sd)
  *矢装備
  *------------------------------------------
  */
-int clif_arrowequip(dumb_ptr<map_session_data> sd, int val)
+int clif_arrowequip(dumb_ptr<map_session_data> sd, IOff0 val)
 {
     nullpo_ret(sd);
 
@@ -1962,7 +1960,7 @@ int clif_arrowequip(dumb_ptr<map_session_data> sd, int val)
 
     Session *s = sd->sess;
     Packet_Fixed<0x013c> fixed_13c;
-    fixed_13c.ioff2 = val + 2;
+    fixed_13c.ioff2 = val.shift();
     send_fpacket<0x013c, 4>(s, fixed_13c);
 
     return 0;
@@ -2007,13 +2005,13 @@ int clif_statusupack(dumb_ptr<map_session_data> sd, SP type, int ok, int val)
  *
  *------------------------------------------
  */
-int clif_equipitemack(dumb_ptr<map_session_data> sd, int n, EPOS pos, int ok)
+int clif_equipitemack(dumb_ptr<map_session_data> sd, IOff0 n, EPOS pos, int ok)
 {
     nullpo_ret(sd);
 
     Session *s = sd->sess;
     Packet_Fixed<0x00aa> fixed_aa;
-    fixed_aa.ioff2 = n + 2;
+    fixed_aa.ioff2 = n.shift();
     fixed_aa.epos = pos;
     fixed_aa.ok = ok;
     send_fpacket<0x00aa, 7>(s, fixed_aa);
@@ -2025,13 +2023,13 @@ int clif_equipitemack(dumb_ptr<map_session_data> sd, int n, EPOS pos, int ok)
  *
  *------------------------------------------
  */
-int clif_unequipitemack(dumb_ptr<map_session_data> sd, int n, EPOS pos, int ok)
+int clif_unequipitemack(dumb_ptr<map_session_data> sd, IOff0 n, EPOS pos, int ok)
 {
     nullpo_ret(sd);
 
     Session *s = sd->sess;
     Packet_Fixed<0x00ac> fixed_ac;
-    fixed_ac.ioff2 = n + 2;
+    fixed_ac.ioff2 = n.shift();
     fixed_ac.epos = pos;
     fixed_ac.ok = ok;
     send_fpacket<0x00ac, 7>(s, fixed_ac);
@@ -2087,7 +2085,7 @@ int clif_changeoption(dumb_ptr<block_list> bl)
  *
  *------------------------------------------
  */
-int clif_useitemack(dumb_ptr<map_session_data> sd, int index, int amount,
+int clif_useitemack(dumb_ptr<map_session_data> sd, IOff0 index, int amount,
                      int ok)
 {
     nullpo_ret(sd);
@@ -2096,7 +2094,7 @@ int clif_useitemack(dumb_ptr<map_session_data> sd, int index, int amount,
     {
         Session *s = sd->sess;
         Packet_Fixed<0x00a8> fixed_a8;
-        fixed_a8.ioff2 = index + 2;
+        fixed_a8.ioff2 = index.shift();
         fixed_a8.amount = amount;
         fixed_a8.ok = ok;
         send_fpacket<0x00a8, 7>(s, fixed_a8);
@@ -2104,7 +2102,7 @@ int clif_useitemack(dumb_ptr<map_session_data> sd, int index, int amount,
     else
     {
         Packet_Fixed<0x01c8> fixed_1c8;
-        fixed_1c8.ioff2 = index + 2;
+        fixed_1c8.ioff2 = index.shift();
         fixed_1c8.name_id = sd->status.inventory[index].nameid;
         fixed_1c8.block_id = sd->bl_id;
         fixed_1c8.amount = amount;
@@ -2149,7 +2147,7 @@ void clif_tradestart(dumb_ptr<map_session_data> sd, int type)
  *------------------------------------------
  */
 void clif_tradeadditem(dumb_ptr<map_session_data> sd,
-        dumb_ptr<map_session_data> tsd, int index2, int amount)
+        dumb_ptr<map_session_data> tsd, IOff2 index2, int amount)
 {
     nullpo_retv(sd);
     nullpo_retv(tsd);
@@ -2157,7 +2155,7 @@ void clif_tradeadditem(dumb_ptr<map_session_data> sd,
     Session *s = tsd->sess;
     Packet_Fixed<0x00e9> fixed_e9;
     fixed_e9.amount = amount;
-    if (index2 == 0)
+    if (!index2.ok())
     {
         fixed_e9.name_id = ItemNameId();
         fixed_e9.identify = 0;
@@ -2170,7 +2168,7 @@ void clif_tradeadditem(dumb_ptr<map_session_data> sd,
     }
     else
     {
-        int index0 = index2 - 2;
+        IOff0 index0 = index2.unshift();
         fixed_e9.name_id = sd->status.inventory[index0].nameid;
         fixed_e9.identify = 0;
         fixed_e9.broken_or_attribute = 0;
@@ -2189,7 +2187,7 @@ void clif_tradeadditem(dumb_ptr<map_session_data> sd,
  * アイテム追加成功/失敗
  *------------------------------------------
  */
-int clif_tradeitemok(dumb_ptr<map_session_data> sd, int index2, int amount,
+int clif_tradeitemok(dumb_ptr<map_session_data> sd, IOff2 index2, int amount,
                       int fail)
 {
     nullpo_ret(sd);
@@ -2275,14 +2273,14 @@ int clif_updatestorageamount(dumb_ptr<map_session_data> sd,
  *------------------------------------------
  */
 int clif_storageitemadded(dumb_ptr<map_session_data> sd, Storage *stor,
-                           int index, int amount)
+        SOff0 index, int amount)
 {
     nullpo_ret(sd);
     nullpo_ret(stor);
 
     Session *s = sd->sess;
     Packet_Fixed<0x00f4> fixed_f4;
-    fixed_f4.soff1 = index + 1;
+    fixed_f4.soff1 = index.shift();
     fixed_f4.amount = amount;
     fixed_f4.name_id = stor->storage_[index].nameid;
     fixed_f4.identify = 0;
@@ -2303,14 +2301,14 @@ int clif_storageitemadded(dumb_ptr<map_session_data> sd, Storage *stor,
  * カプラ倉庫からアイテムを取り去る
  *------------------------------------------
  */
-int clif_storageitemremoved(dumb_ptr<map_session_data> sd, int index,
+int clif_storageitemremoved(dumb_ptr<map_session_data> sd, SOff0 index,
                              int amount)
 {
     nullpo_ret(sd);
 
     Session *s = sd->sess;
     Packet_Fixed<0x00f6> fixed_f6;
-    fixed_f6.soff1 = index + 1;
+    fixed_f6.soff1 = index.shift();
     fixed_f6.amount = amount;
     send_fpacket<0x00f6, 8>(s, fixed_f6);
 
@@ -4110,8 +4108,6 @@ RecvResult clif_parse_DropItem(Session *s, dumb_ptr<map_session_data> sd)
     if (rv != RecvResult::Complete)
         return rv;
 
-    int item_index, item_amount;
-
     if (pc_isdead(sd))
     {
         clif_clearchar(sd, BeingRemoveWhy::DEAD);
@@ -4129,8 +4125,10 @@ RecvResult clif_parse_DropItem(Session *s, dumb_ptr<map_session_data> sd)
         return rv;
     }
 
-    item_index = fixed.ioff2 - 2;
-    item_amount = fixed.amount;
+    if (!fixed.ioff2.ok())
+        return RecvResult::Error;
+    IOff0 item_index = fixed.ioff2.unshift();
+    int item_amount = fixed.amount;
 
     pc_dropitem(sd, item_index, item_amount);
 
@@ -4161,7 +4159,9 @@ RecvResult clif_parse_UseItem(Session *s, dumb_ptr<map_session_data> sd)
     if (sd->invincible_timer)
         pc_delinvincibletimer(sd);
 
-    pc_useitem(sd, fixed.ioff2 - 2);
+    if (!fixed.ioff2.ok())
+        return RecvResult::Error;
+    pc_useitem(sd, fixed.ioff2.unshift());
 
     return rv;
 }
@@ -4178,14 +4178,14 @@ RecvResult clif_parse_EquipItem(Session *s, dumb_ptr<map_session_data> sd)
     if (rv != RecvResult::Complete)
         return rv;
 
-    int index;
-
     if (pc_isdead(sd))
     {
         clif_clearchar(sd, BeingRemoveWhy::DEAD);
         return rv;
     }
-    index = fixed.ioff2 - 2;
+    if (!fixed.ioff2.ok())
+        return RecvResult::Error;
+    IOff0 index = fixed.ioff2.unshift();
     if (sd->npc_id)
         return rv;
 
@@ -4214,14 +4214,14 @@ RecvResult clif_parse_UnequipItem(Session *s, dumb_ptr<map_session_data> sd)
     if (rv != RecvResult::Complete)
         return rv;
 
-    int index;
-
     if (pc_isdead(sd))
     {
         clif_clearchar(sd, BeingRemoveWhy::DEAD);
         return rv;
     }
-    index = fixed.ioff2 - 2;
+    if (!fixed.ioff2.ok())
+        return RecvResult::Error;
+    IOff0 index = fixed.ioff2.unshift();
 
     if (sd->npc_id
         || sd->opt1 != Opt1::ZERO)
@@ -4366,6 +4366,8 @@ RecvResult clif_parse_TradeAddItem(Session *s, dumb_ptr<map_session_data> sd)
     if (rv != RecvResult::Complete)
         return rv;
 
+    if (fixed.zeny_or_ioff2.index != 0 && !fixed.zeny_or_ioff2.ok())
+        return RecvResult::Error;
     trade_tradeadditem(sd, fixed.zeny_or_ioff2, fixed.amount);
 
     return rv;
@@ -4577,10 +4579,10 @@ RecvResult clif_parse_MoveToKafra(Session *s, dumb_ptr<map_session_data> sd)
     if (rv != RecvResult::Complete)
         return rv;
 
-    int item_index, item_amount;
-
-    item_index = fixed.ioff2 - 2;
-    item_amount = fixed.amount;
+    if (!fixed.ioff2.ok())
+        return RecvResult::Error;
+    IOff0 item_index = fixed.ioff2.unshift();
+    int item_amount = fixed.amount;
 
     if ((sd->npc_id && !sd->npc_flags.storage) || sd->trade_partner
         || !sd->state.storage_open)
@@ -4604,10 +4606,10 @@ RecvResult clif_parse_MoveFromKafra(Session *s, dumb_ptr<map_session_data> sd)
     if (rv != RecvResult::Complete)
         return rv;
 
-    int item_index, item_amount;
-
-    item_index = fixed.soff1 - 1;
-    item_amount = fixed.amount;
+    if (!fixed.soff1.ok())
+        return RecvResult::Error;
+    SOff0 item_index = fixed.soff1.unshift();
+    int item_amount = fixed.amount;
 
     if ((sd->npc_id && !sd->npc_flags.storage) || sd->trade_partner
         || !sd->state.storage_open)
diff --git a/src/map/clif.hpp b/src/map/clif.hpp
index 3bed955..0087d78 100644
--- a/src/map/clif.hpp
+++ b/src/map/clif.hpp
@@ -80,8 +80,8 @@ void clif_scriptmenu(dumb_ptr<map_session_data>, BlockId, XString);  //self
 void clif_scriptinput(dumb_ptr<map_session_data>, BlockId); //self
 void clif_scriptinputstr(dumb_ptr<map_session_data> sd, BlockId npcid);  // self
 
-int clif_additem(dumb_ptr<map_session_data>, int, int, PickupFail);   //self
-void clif_delitem(dumb_ptr<map_session_data>, int, int);    //self
+int clif_additem(dumb_ptr<map_session_data>, IOff0, int, PickupFail);   //self
+void clif_delitem(dumb_ptr<map_session_data>, IOff0, int);    //self
 int clif_updatestatus(dumb_ptr<map_session_data>, SP);    //self
 int clif_damage(dumb_ptr<block_list>, dumb_ptr<block_list>,
         tick_t, interval_t, interval_t,
@@ -93,14 +93,14 @@ int clif_takeitem(dumb_ptr<block_list> src, dumb_ptr<block_list> dst)
 }
 int clif_changelook(dumb_ptr<block_list>, LOOK, int);   // area
 void clif_changelook_accessories(dumb_ptr<block_list> bl, dumb_ptr<map_session_data> dst); // area or target; list gloves, boots etc.
-int clif_arrowequip(dumb_ptr<map_session_data> sd, int val);    //self
+int clif_arrowequip(dumb_ptr<map_session_data> sd, IOff0 val);    //self
 int clif_arrow_fail(dumb_ptr<map_session_data> sd, int type);   //self
 int clif_statusupack(dumb_ptr<map_session_data>, SP, int, int);   // self
-int clif_equipitemack(dumb_ptr<map_session_data>, int, EPOS, int);  // self
-int clif_unequipitemack(dumb_ptr<map_session_data>, int, EPOS, int);    // self
+int clif_equipitemack(dumb_ptr<map_session_data>, IOff0, EPOS, int);  // self
+int clif_unequipitemack(dumb_ptr<map_session_data>, IOff0, EPOS, int);    // self
 int clif_misceffect(dumb_ptr<block_list>, int);    // area
 int clif_changeoption(dumb_ptr<block_list>);   // area
-int clif_useitemack(dumb_ptr<map_session_data>, int, int, int);    // self
+int clif_useitemack(dumb_ptr<map_session_data>, IOff0, int, int);    // self
 
 void clif_emotion(dumb_ptr<block_list> bl, int type);
 void clif_sitting(Session *, dumb_ptr<map_session_data> sd);
@@ -109,8 +109,8 @@ void clif_sitting(Session *, dumb_ptr<map_session_data> sd);
 void clif_traderequest(dumb_ptr<map_session_data> sd, CharName name);
 void clif_tradestart(dumb_ptr<map_session_data> sd, int type);
 void clif_tradeadditem(dumb_ptr<map_session_data> sd,
-        dumb_ptr<map_session_data> tsd, int index, int amount);
-int clif_tradeitemok(dumb_ptr<map_session_data> sd, int index, int amount,
+        dumb_ptr<map_session_data> tsd, IOff2 index2, int amount);
+int clif_tradeitemok(dumb_ptr<map_session_data> sd, IOff2 index, int amount,
         int fail);
 int clif_tradedeal_lock(dumb_ptr<map_session_data> sd, int fail);
 int clif_tradecancelled(dumb_ptr<map_session_data> sd);
@@ -123,8 +123,8 @@ int clif_storageequiplist(dumb_ptr<map_session_data> sd,
 int clif_updatestorageamount(dumb_ptr<map_session_data> sd,
         Storage *stor);
 int clif_storageitemadded(dumb_ptr<map_session_data> sd, Storage *stor,
-        int index, int amount);
-int clif_storageitemremoved(dumb_ptr<map_session_data> sd, int index,
+        SOff0 index, int amount);
+int clif_storageitemremoved(dumb_ptr<map_session_data> sd, SOff0 index,
         int amount);
 int clif_storageclose(dumb_ptr<map_session_data> sd);
 
diff --git a/src/map/clif.t.hpp b/src/map/clif.t.hpp
index 5b3d32f..ba9a187 100644
--- a/src/map/clif.t.hpp
+++ b/src/map/clif.t.hpp
@@ -27,8 +27,11 @@
 
 # include "../ints/little.hpp"
 
+# include "../compat/iter.hpp"
+
 # include "../generic/enum.hpp"
 
+# include "../mmo/consts.hpp"
 # include "../mmo/enums.hpp"
 
 
@@ -583,6 +586,132 @@ bool network_to_native(Position2 *native, NetPosition2 network)
     return true;
 }
 
+struct IOff2;
+struct SOff1;
+
+struct IOff0
+{
+    uint16_t index;
+
+    bool ok() const
+    { return get0() < MAX_INVENTORY; }
+    uint16_t get0() const
+    { return index; }
+    static IOff0 from(uint16_t i)
+    { return IOff0{i}; }
+    static IteratorPair<ValueIterator<IOff0>> iter()
+    { return {IOff0::from(0), IOff0::from(MAX_INVENTORY)}; };
+    friend uint16_t convert_for_printf(IOff0 i0) { return i0.index; }
+
+    IOff0& operator ++() { ++index; return *this; }
+    friend bool operator == (IOff0 l, IOff0 r) { return l.index == r.index; }
+    friend bool operator != (IOff0 l, IOff0 r) { return !(l == r); }
+    IOff2 shift() const;
+
+    IOff0() : index(0) {}
+private:
+    explicit IOff0(uint16_t i) : index(i) {}
+};
+
+struct SOff0
+{
+    uint16_t index;
+
+    bool ok() const
+    { return get0() < MAX_STORAGE; }
+    uint16_t get0() const
+    { return index; }
+    static SOff0 from(uint16_t i)
+    { return SOff0{i}; }
+    static IteratorPair<ValueIterator<SOff0>> iter()
+    { return {SOff0::from(0), SOff0::from(MAX_STORAGE)}; };
+    friend uint16_t convert_for_printf(SOff0 s0) { return s0.index; }
+
+    SOff0& operator ++() { ++index; return *this; }
+    friend bool operator == (SOff0 l, SOff0 r) { return l.index == r.index; }
+    friend bool operator != (SOff0 l, SOff0 r) { return !(l == r); }
+    SOff1 shift() const;
+
+    SOff0() : index(0) {}
+private:
+    explicit SOff0(uint16_t i) : index(i) {}
+};
 
+struct IOff2
+{
+    uint16_t index;
+
+    bool ok() const
+    { return get2() < MAX_INVENTORY; }
+    uint16_t get2() const
+    { return index - 2; }
+    static IOff2 from(uint16_t i)
+    { return IOff2{static_cast<uint16_t>(i + 2)}; }
+    static IteratorPair<ValueIterator<IOff2>> iter()
+    { return {IOff2::from(0), IOff2::from(MAX_INVENTORY)}; };
+
+    IOff2& operator ++() { ++index; return *this; }
+    friend bool operator == (IOff2 l, IOff2 r) { return l.index == r.index; }
+    friend bool operator != (IOff2 l, IOff2 r) { return !(l == r); }
+    IOff0 unshift() const
+    { return IOff0::from(get2()); }
+
+    IOff2() : index(0) {}
+private:
+    explicit IOff2(uint16_t i) : index(i) {}
+};
+
+struct SOff1
+{
+    uint16_t index;
+
+    bool ok() const
+    { return get1() < MAX_STORAGE; }
+    uint16_t get1() const
+    { return index - 1; }
+    static SOff1 from(uint16_t i)
+    { return SOff1{static_cast<uint16_t>(i + 1)}; }
+    static IteratorPair<ValueIterator<SOff1>> iter()
+    { return {SOff1::from(0), SOff1::from(MAX_STORAGE)}; };
+
+    SOff1& operator ++() { ++index; return *this; }
+    friend bool operator == (SOff1 l, SOff1 r) { return l.index == r.index; }
+    friend bool operator != (SOff1 l, SOff1 r) { return !(l == r); }
+    SOff0 unshift() const
+    { return SOff0::from(get1()); }
+
+    SOff1() : index(0) {}
+private:
+    explicit SOff1(uint16_t i) : index(i) {}
+};
+
+inline IOff2 IOff0::shift() const
+{ return IOff2::from(get0()); }
+inline SOff1 SOff0::shift() const
+{ return SOff1::from(get0()); }
+
+inline
+bool native_to_network(Little16 *network, IOff2 native)
+{
+    return native_to_network(network, native.index);
+}
+
+inline
+bool network_to_native(IOff2 *native, Little16 network)
+{
+    return network_to_native(&native->index, network);
+}
+
+inline
+bool native_to_network(Little16 *network, SOff1 native)
+{
+    return native_to_network(network, native.index);
+}
+
+inline
+bool network_to_native(SOff1 *native, Little16 network)
+{
+    return network_to_native(&native->index, network);
+}
 
 #endif // TMWA_MAP_CLIF_T_HPP
diff --git a/src/map/magic-expr.cpp b/src/map/magic-expr.cpp
index b0e68fb..1e5c829 100644
--- a/src/map/magic-expr.cpp
+++ b/src/map/magic-expr.cpp
@@ -858,8 +858,8 @@ int fun_is_equipped(dumb_ptr<env_t>, val_t *result, Slice<val_t> args)
 
     for (EQUIP i : EQUIPs)
     {
-        int idx = chr->equip_index_maybe[i];
-        if (idx >= 0 && chr->status.inventory[idx].nameid == item.nameid)
+        IOff0 idx = chr->equip_index_maybe[i];
+        if (idx.ok() && chr->status.inventory[idx].nameid == item.nameid)
         {
             retval = true;
             break;
diff --git a/src/map/map.hpp b/src/map/map.hpp
index 7e61e56..8fc752b 100644
--- a/src/map/map.hpp
+++ b/src/map/map.hpp
@@ -183,8 +183,8 @@ struct map_session_data : block_list, SessionData
     unsigned char tmw_version;  // tmw client version
     CharKey status_key;
     CharData status;
-    Array<struct item_data *, MAX_INVENTORY> inventory_data;
-    earray<short, EQUIP, EQUIP::COUNT> equip_index_maybe;
+    GenericArray<struct item_data *, InventoryIndexing<IOff0, MAX_INVENTORY>> inventory_data;
+    earray<IOff0, EQUIP, EQUIP::COUNT> equip_index_maybe;
     int weight, max_weight;
     MapName mapname_;
     Session *sess; // use this, you idiots!
@@ -284,7 +284,7 @@ struct map_session_data : block_list, SessionData
     short sc_count;
 
     AccountId trade_partner;
-    Array<int, TRADE_MAX> deal_item_index;
+    Array<IOff2, TRADE_MAX> deal_item_index;
     Array<int, TRADE_MAX> deal_item_amount;
     int deal_zeny;
     short deal_locked;
diff --git a/src/map/mob.cpp b/src/map/mob.cpp
index 336dbe7..01a1029 100644
--- a/src/map/mob.cpp
+++ b/src/map/mob.cpp
@@ -2203,7 +2203,7 @@ void mob_delay_item_drop(TimerData *, tick_t, struct delay_item_drop ditem)
                 pc_additem(ditem.first_sd, &temp_item, ditem.amount))
             != PickupFail::OKAY)
         {
-            clif_additem(ditem.first_sd, 0, 0, flag);
+            clif_additem(ditem.first_sd, IOff0::from(0), 0, flag);
             map_addflooritem(&temp_item, 1,
                     ditem.m, ditem.x, ditem.y,
                     ditem.first_sd, ditem.second_sd, ditem.third_sd);
@@ -2233,7 +2233,7 @@ void mob_delay_item_drop2(TimerData *, tick_t, struct delay_item_drop2 ditem)
                             ditem.item_data.amount))
             != PickupFail::OKAY)
         {
-            clif_additem(ditem.first_sd, 0, 0, flag);
+            clif_additem(ditem.first_sd, IOff0::from(0), 0, flag);
             map_addflooritem(&ditem.item_data, ditem.item_data.amount,
                     ditem.m, ditem.x, ditem.y,
                     ditem.first_sd, ditem.second_sd, ditem.third_sd);
diff --git a/src/map/npc.cpp b/src/map/npc.cpp
index 3232e4d..7d2b8da 100644
--- a/src/map/npc.cpp
+++ b/src/map/npc.cpp
@@ -890,11 +890,11 @@ int npc_selllist(dumb_ptr<map_session_data> sd,
         return 1;
     for (i = 0, z = 0; i < item_list.size(); i++)
     {
-        if (item_list[i].ioff2 - 2 < 0 || item_list[i].ioff2 - 2 >= MAX_INVENTORY)
+        if (!item_list[i].ioff2.ok())
             return 1;
-        ItemNameId nameid = sd->status.inventory[item_list[i].ioff2 - 2].nameid;
+        ItemNameId nameid = sd->status.inventory[item_list[i].ioff2.unshift()].nameid;
         if (!nameid ||
-            sd->status.inventory[item_list[i].ioff2 - 2].amount < item_list[i].count)
+            sd->status.inventory[item_list[i].ioff2.unshift()].amount < item_list[i].count)
             return 1;
         if (sd->trade_partner)
             return 2;           // cant sell while trading
@@ -907,7 +907,7 @@ int npc_selllist(dumb_ptr<map_session_data> sd,
     pc_getzeny(sd, static_cast<int>(z));
     for (i = 0; i < item_list.size(); i++)
     {
-        int item_id = item_list[i].ioff2 - 2;
+        IOff0 item_id = item_list[i].ioff2.unshift();
         pc_delitem(sd, item_id, item_list[i].count, 0);
     }
 
diff --git a/src/map/pc.cpp b/src/map/pc.cpp
index 4d104d1..d37a7ff 100644
--- a/src/map/pc.cpp
+++ b/src/map/pc.cpp
@@ -497,7 +497,7 @@ int pc_setnewpc(dumb_ptr<map_session_data> sd, AccountId account_id, CharId char
     return 0;
 }
 
-EPOS pc_equippoint(dumb_ptr<map_session_data> sd, int n)
+EPOS pc_equippoint(dumb_ptr<map_session_data> sd, IOff0 n)
 {
     nullpo_retr(EPOS::ZERO, sd);
 
@@ -514,7 +514,7 @@ int pc_setinventorydata(dumb_ptr<map_session_data> sd)
 {
     nullpo_ret(sd);
 
-    for (int i = 0; i < MAX_INVENTORY; i++)
+    for (IOff0 i : IOff0::iter())
     {
         ItemNameId id = sd->status.inventory[i].nameid;
         sd->inventory_data[i] = itemdb_search(id);
@@ -571,9 +571,9 @@ int pc_setequipindex(dumb_ptr<map_session_data> sd)
     nullpo_ret(sd);
 
     for (EQUIP i : EQUIPs)
-        sd->equip_index_maybe[i] = -1;
+        sd->equip_index_maybe[i] = IOff0::from(-1);
 
-    for (int i = 0; i < MAX_INVENTORY; i++)
+    for (IOff0 i : IOff0::iter())
     {
         if (!sd->status.inventory[i].nameid)
             continue;
@@ -614,7 +614,7 @@ int pc_setequipindex(dumb_ptr<map_session_data> sd)
 }
 
 static
-int pc_isequip(dumb_ptr<map_session_data> sd, int n)
+int pc_isequip(dumb_ptr<map_session_data> sd, IOff0 n)
 {
     struct item_data *item;
     eptr<struct status_change, StatusChange, StatusChange::MAX_STATUSCHANGE> sc_data;
@@ -970,7 +970,7 @@ int pc_calcstatus(dumb_ptr<map_session_data> sd, int first)
     if (first & 1)
     {
         sd->weight = 0;
-        for (int i = 0; i < MAX_INVENTORY; i++)
+        for (IOff0 i : IOff0::iter())
         {
             if (!sd->status.inventory[i].nameid
                 || sd->inventory_data[i] == NULL)
@@ -1041,8 +1041,8 @@ int pc_calcstatus(dumb_ptr<map_session_data> sd, int first)
 
     for (EQUIP i : EQUIPs_noarrow)
     {
-        int index = sd->equip_index_maybe[i];
-        if (index < 0)
+        IOff0 index = sd->equip_index_maybe[i];
+        if (!index.ok())
             continue;
         if (i == EQUIP::WEAPON && sd->equip_index_maybe[EQUIP::SHIELD] == index)
             continue;
@@ -1077,8 +1077,8 @@ int pc_calcstatus(dumb_ptr<map_session_data> sd, int first)
     // 装備品によるステータス変化はここで実行
     for (EQUIP i : EQUIPs_noarrow)
     {
-        int index = sd->equip_index_maybe[i];
-        if (index < 0)
+        IOff0 index = sd->equip_index_maybe[i];
+        if (!index.ok())
             continue;
         if (i == EQUIP::WEAPON && sd->equip_index_maybe[EQUIP::SHIELD] == index)
             continue;
@@ -1153,10 +1153,10 @@ int pc_calcstatus(dumb_ptr<map_session_data> sd, int first)
         sd->watk_2 += skill_power(sd, SkillID::TMW_BRAWLING) >> 3;  // +25 for 200
     }
 
-    int aidx = sd->equip_index_maybe[EQUIP::ARROW];
-    if (aidx >= 0)
-    {                           // 矢
-        int index = aidx;
+    IOff0 aidx = sd->equip_index_maybe[EQUIP::ARROW];
+    if (aidx.ok())
+    {
+        IOff0 index = aidx;
         if (sd->inventory_data[index])
         {                       //まだ属性が入っていない
             argrec_t arg[2] =
@@ -1824,14 +1824,12 @@ int pc_skill(dumb_ptr<map_session_data> sd, SkillID id, int level, int flag)
  */
 ADDITEM pc_checkadditem(dumb_ptr<map_session_data> sd, ItemNameId nameid, int amount)
 {
-    int i;
-
     nullpo_retr(ADDITEM::ZERO, sd);
 
     if (itemdb_isequip(nameid))
         return ADDITEM::NEW;
 
-    for (i = 0; i < MAX_INVENTORY; i++)
+    for (IOff0 i : IOff0::iter())
     {
         if (sd->status.inventory[i].nameid == nameid)
         {
@@ -1852,11 +1850,11 @@ ADDITEM pc_checkadditem(dumb_ptr<map_session_data> sd, ItemNameId nameid, int am
  */
 int pc_inventoryblank(dumb_ptr<map_session_data> sd)
 {
-    int i, b;
+    int b = 0;
 
     nullpo_ret(sd);
 
-    for (i = 0, b = 0; i < MAX_INVENTORY; i++)
+    for (IOff0 i : IOff0::iter())
     {
         if (!sd->status.inventory[i].nameid)
             b++;
@@ -1906,30 +1904,27 @@ int pc_getzeny(dumb_ptr<map_session_data> sd, int zeny)
  * アイテムを探して、インデックスを返す
  *------------------------------------------
  */
-int pc_search_inventory(dumb_ptr<map_session_data> sd, ItemNameId item_id)
+IOff0 pc_search_inventory(dumb_ptr<map_session_data> sd, ItemNameId item_id)
 {
-    int i;
+    nullpo_retr(IOff0::from(-1), sd);
 
-    nullpo_retr(-1, sd);
-
-    for (i = 0; i < MAX_INVENTORY; i++)
+    for (IOff0 i : IOff0::iter())
     {
         if (sd->status.inventory[i].nameid == item_id &&
             (sd->status.inventory[i].amount > 0 || !item_id))
             return i;
     }
 
-    return -1;
+    return IOff0::from(-1);
 }
 
 int pc_count_all_items(dumb_ptr<map_session_data> player, ItemNameId item_id)
 {
-    int i;
     int count = 0;
 
     nullpo_ret(player);
 
-    for (i = 0; i < MAX_INVENTORY; i++)
+    for (IOff0 i : IOff0::iter())
     {
         if (player->status.inventory[i].nameid == item_id)
             count += player->status.inventory[i].amount;
@@ -1940,12 +1935,12 @@ int pc_count_all_items(dumb_ptr<map_session_data> player, ItemNameId item_id)
 
 int pc_remove_items(dumb_ptr<map_session_data> player, ItemNameId item_id, int count)
 {
-    int i;
-
     nullpo_ret(player);
 
-    for (i = 0; i < MAX_INVENTORY && count; i++)
+    for (IOff0 i : IOff0::iter())
     {
+        if (!count)
+            break;
         if (player->status.inventory[i].nameid == item_id)
         {
             int to_delete = count;
@@ -1973,7 +1968,7 @@ PickupFail pc_additem(dumb_ptr<map_session_data> sd, Item *item_data,
                 int amount)
 {
     struct item_data *data;
-    int i, w;
+    int w;
 
     MAP_LOG_PC(sd, "PICKUP %d %d"_fmt, item_data->nameid, amount);
 
@@ -1986,12 +1981,13 @@ PickupFail pc_additem(dumb_ptr<map_session_data> sd, Item *item_data,
     if ((w = data->weight * amount) + sd->weight > sd->max_weight)
         return PickupFail::TOO_HEAVY;
 
-    i = MAX_INVENTORY;
+    IOff0 i = IOff0::from(MAX_INVENTORY);
 
     if (!itemdb_isequip2(data))
     {
-        // 装 備品ではないので、既所有品なら個数のみ変化させる
-        for (i = 0; i < MAX_INVENTORY; i++)
+        // TODO see if there's any nicer way to preserve the foreach var
+        for (i = IOff0::from(0); i != IOff0::from(MAX_INVENTORY); ++i)
+        {
             if (sd->status.inventory[i].nameid == item_data->nameid)
             {
                 if (sd->status.inventory[i].amount + amount > MAX_AMOUNT)
@@ -2000,12 +1996,12 @@ PickupFail pc_additem(dumb_ptr<map_session_data> sd, Item *item_data,
                 clif_additem(sd, i, amount, PickupFail::OKAY);
                 break;
             }
+        }
     }
-    if (i >= MAX_INVENTORY)
+    if (!i.ok())
     {
-        // 装 備品か未所有品だったので空き欄へ追加
         i = pc_search_inventory(sd, ItemNameId());
-        if (i >= 0)
+        if (i.ok())
         {
             sd->status.inventory[i] = *item_data;
 
@@ -2029,7 +2025,7 @@ PickupFail pc_additem(dumb_ptr<map_session_data> sd, Item *item_data,
  * アイテムを減らす
  *------------------------------------------
  */
-int pc_delitem(dumb_ptr<map_session_data> sd, int n, int amount, int type)
+int pc_delitem(dumb_ptr<map_session_data> sd, IOff0 n, int amount, int type)
 {
     nullpo_retr(1, sd);
 
@@ -2062,14 +2058,14 @@ int pc_delitem(dumb_ptr<map_session_data> sd, int n, int amount, int type)
  * アイテムを落す
  *------------------------------------------
  */
-int pc_dropitem(dumb_ptr<map_session_data> sd, int n, int amount)
+int pc_dropitem(dumb_ptr<map_session_data> sd, IOff0 n, int amount)
 {
     nullpo_retr(1, sd);
 
     if (sd->trade_partner || sd->npc_id || sd->state.storage_open)
         return 0;               // no dropping while trading/npc/storage
 
-    if (n < 0 || n >= MAX_INVENTORY)
+    if (!n.ok())
         return 0;
 
     if (amount <= 0)
@@ -2172,7 +2168,7 @@ int pc_takeitem(dumb_ptr<map_session_data> sd, dumb_ptr<flooritem_data> fitem)
         PickupFail flag = pc_additem(sd, &fitem->item_data, fitem->item_data.amount);
         if (flag != PickupFail::OKAY)
             // 重量overで取得失敗
-            clif_additem(sd, 0, 0, flag);
+            clif_additem(sd, IOff0::from(0), 0, flag);
         else
         {
             // 取得成功
@@ -2185,12 +2181,12 @@ int pc_takeitem(dumb_ptr<map_session_data> sd, dumb_ptr<flooritem_data> fitem)
     }
 
     /* Otherwise, we can't pick up */
-    clif_additem(sd, 0, 0, PickupFail::DROP_STEAL);
+    clif_additem(sd, IOff0::from(0), 0, PickupFail::DROP_STEAL);
     return 0;
 }
 
 static
-int pc_isUseitem(dumb_ptr<map_session_data> sd, int n)
+int pc_isUseitem(dumb_ptr<map_session_data> sd, IOff0 n)
 {
     struct item_data *item;
     ItemNameId nameid;
@@ -2217,13 +2213,13 @@ int pc_isUseitem(dumb_ptr<map_session_data> sd, int n)
  * アイテムを使う
  *------------------------------------------
  */
-int pc_useitem(dumb_ptr<map_session_data> sd, int n)
+int pc_useitem(dumb_ptr<map_session_data> sd, IOff0 n)
 {
     int amount;
 
     nullpo_retr(1, sd);
 
-    if (n >= 0 && n < MAX_INVENTORY && sd->inventory_data[n])
+    if (n.ok() && sd->inventory_data[n])
     {
         amount = sd->status.inventory[n].amount;
         if (!sd->status.inventory[n].nameid
@@ -2716,9 +2712,9 @@ int pc_checkskill(dumb_ptr<map_session_data> sd, SkillID skill_id)
  * 装 備品のチェック
  *------------------------------------------
  */
-int pc_checkequip(dumb_ptr<map_session_data> sd, EPOS pos)
+IOff0 pc_checkequip(dumb_ptr<map_session_data> sd, EPOS pos)
 {
-    nullpo_retr(-1, sd);
+    nullpo_retr(IOff0::from(-1), sd);
 
     for (EQUIP i : EQUIPs)
     {
@@ -2726,7 +2722,7 @@ int pc_checkequip(dumb_ptr<map_session_data> sd, EPOS pos)
             return sd->equip_index_maybe[i];
     }
 
-    return -1;
+    return IOff0::from(-1);
 }
 
 /*==========================================
@@ -3314,13 +3310,13 @@ int pc_resetlvl(dumb_ptr<map_session_data> sd, int type)
     for (EQUIP i : EQUIPs)
     {
         // unequip items that can't be equipped by base 1 [Valaris]
-        short *idx = &sd->equip_index_maybe[i];
-        if (*idx >= 0)
+        IOff0 *idx = &sd->equip_index_maybe[i];
+        if ((*idx).ok())
         {
             if (!pc_isequip(sd, *idx))
             {
                 pc_unequipitem(sd, *idx, CalcStatus::LATER);
-                *idx = -1;
+                *idx = IOff0::from(-1);
             }
         }
     }
@@ -4381,7 +4377,7 @@ int pc_cleareventtimer(dumb_ptr<map_session_data> sd)
  *------------------------------------------
  */
 static
-int pc_signal_advanced_equipment_change(dumb_ptr<map_session_data> sd, int n)
+int pc_signal_advanced_equipment_change(dumb_ptr<map_session_data> sd, IOff0 n)
 {
     if (bool(sd->status.inventory[n].equip & EPOS::SHOES))
         clif_changelook(sd, LOOK::SHOES, 0);
@@ -4396,7 +4392,7 @@ int pc_signal_advanced_equipment_change(dumb_ptr<map_session_data> sd, int n)
     return 0;
 }
 
-int pc_equipitem(dumb_ptr<map_session_data> sd, int n, EPOS)
+int pc_equipitem(dumb_ptr<map_session_data> sd, IOff0 n, EPOS)
 {
     ItemNameId nameid;
     struct item_data *id;
@@ -4404,9 +4400,9 @@ int pc_equipitem(dumb_ptr<map_session_data> sd, int n, EPOS)
 
     nullpo_ret(sd);
 
-    if (n < 0 || n >= MAX_INVENTORY)
+    if (!n.ok())
     {
-        clif_equipitemack(sd, 0, EPOS::ZERO, 0);
+        clif_equipitemack(sd, IOff0::from(0), EPOS::ZERO, 0);
         return 0;
     }
 
@@ -4431,11 +4427,11 @@ int pc_equipitem(dumb_ptr<map_session_data> sd, int n, EPOS)
     {
         // アクセサリ用例外処理
         EPOS epor = EPOS::ZERO;
-        int midx = sd->equip_index_maybe[EQUIP::MISC2];
-        int cidx = sd->equip_index_maybe[EQUIP::CAPE];
-        if (midx >= 0)
+        IOff0 midx = sd->equip_index_maybe[EQUIP::MISC2];
+        IOff0 cidx = sd->equip_index_maybe[EQUIP::CAPE];
+        if (midx.ok())
             epor |= sd->status.inventory[midx].equip;
-        if (cidx >= 0)
+        if (cidx.ok())
             epor |= sd->status.inventory[cidx].equip;
         epor &= (EPOS::MISC2 | EPOS::CAPE);
         pos = (epor == EPOS::CAPE ? EPOS::MISC2 : EPOS::CAPE);
@@ -4445,8 +4441,8 @@ int pc_equipitem(dumb_ptr<map_session_data> sd, int n, EPOS)
     {
         if (bool(pos & equip_pos[i]))
         {
-            short *idx = &sd->equip_index_maybe[i];
-            if (*idx >= 0)    //Slot taken, remove item from there.
+            IOff0 *idx = &sd->equip_index_maybe[i];
+            if ((*idx).ok())    //Slot taken, remove item from there.
                 pc_unequipitem(sd, *idx, CalcStatus::LATER);
             *idx = n;
         }
@@ -4542,7 +4538,7 @@ int pc_equipitem(dumb_ptr<map_session_data> sd, int n, EPOS)
  * 装 備した物を外す
  *------------------------------------------
  */
-int pc_unequipitem(dumb_ptr<map_session_data> sd, int n, CalcStatus type)
+int pc_unequipitem(dumb_ptr<map_session_data> sd, IOff0 n, CalcStatus type)
 {
     nullpo_ret(sd);
 
@@ -4557,7 +4553,7 @@ int pc_unequipitem(dumb_ptr<map_session_data> sd, int n, CalcStatus type)
         for (EQUIP i : EQUIPs)
         {
             if (bool(sd->status.inventory[n].equip & equip_pos[i]))
-                sd->equip_index_maybe[i] = -1;
+                sd->equip_index_maybe[i] = IOff0::from(-1);
         }
         if (bool(sd->status.inventory[n].equip & EPOS::WEAPON))
         {
@@ -4605,7 +4601,7 @@ int pc_unequipitem(dumb_ptr<map_session_data> sd, int n, CalcStatus type)
     return 0;
 }
 
-int pc_unequipinvyitem(dumb_ptr<map_session_data> sd, int n, CalcStatus type)
+int pc_unequipinvyitem(dumb_ptr<map_session_data> sd, IOff0 n, CalcStatus type)
 {
     nullpo_retr(1, sd);
 
@@ -4617,7 +4613,7 @@ int pc_unequipinvyitem(dumb_ptr<map_session_data> sd, int n, CalcStatus type)
         {
             //Slot taken, remove item from there.
             pc_unequipitem(sd, sd->equip_index_maybe[i], type);
-            sd->equip_index_maybe[i] = -1;
+            sd->equip_index_maybe[i] = IOff0::from(-1);
         }
     }
 
@@ -4631,28 +4627,29 @@ int pc_unequipinvyitem(dumb_ptr<map_session_data> sd, int n, CalcStatus type)
  */
 int pc_checkitem(dumb_ptr<map_session_data> sd)
 {
-    int i, j, k, calc_flag = 0;
+    int calc_flag = 0;
 
     nullpo_ret(sd);
 
-    // 所持品空き詰め
-    for (i = j = 0; i < MAX_INVENTORY; i++)
+    IOff0 j = IOff0::from(0);
+    for (IOff0 i : IOff0::iter())
     {
         if (!(sd->status.inventory[i].nameid))
             continue;
-        if (i > j)
+        if (i != j)
         {
             sd->status.inventory[j] = sd->status.inventory[i];
             sd->inventory_data[j] = sd->inventory_data[i];
         }
-        j++;
+        ++j;
     }
-    for (k = j; k < MAX_INVENTORY; ++k)
+    for (IOff0 k = j; k != IOff0::from(MAX_INVENTORY); ++k)
+    {
         sd->status.inventory[k] = Item{};
-    for (k = j; k < MAX_INVENTORY; k++)
         sd->inventory_data[k] = NULL;
+    }
 
-    for (i = 0; i < MAX_INVENTORY; i++)
+    for (IOff0 i : IOff0::iter())
     {
         if (!sd->status.inventory[i].nameid)
             continue;
diff --git a/src/map/pc.hpp b/src/map/pc.hpp
index 87ed708..6e07070 100644
--- a/src/map/pc.hpp
+++ b/src/map/pc.hpp
@@ -84,10 +84,10 @@ int pc_setnewpc(dumb_ptr<map_session_data>, AccountId, CharId, int, uint32_t /*t
 int pc_authok(AccountId, int, TimeT, short tmw_version, const CharKey *, const CharData *);
 int pc_authfail(AccountId accid);
 
-EPOS pc_equippoint(dumb_ptr<map_session_data> sd, int n);
+EPOS pc_equippoint(dumb_ptr<map_session_data> sd, IOff0 n);
 
 int pc_checkskill(dumb_ptr<map_session_data> sd, SkillID skill_id);
-int pc_checkequip(dumb_ptr<map_session_data> sd, EPOS pos);
+IOff0 pc_checkequip(dumb_ptr<map_session_data> sd, EPOS pos);
 
 int pc_walktoxy(dumb_ptr<map_session_data>, int, int);
 int pc_stop_walking(dumb_ptr<map_session_data>, int);
@@ -98,18 +98,18 @@ int pc_randomwarp(dumb_ptr<map_session_data> sd, BeingRemoveWhy type);
 
 ADDITEM pc_checkadditem(dumb_ptr<map_session_data>, ItemNameId, int);
 int pc_inventoryblank(dumb_ptr<map_session_data>);
-int pc_search_inventory(dumb_ptr<map_session_data> sd, ItemNameId item_id);
+IOff0 pc_search_inventory(dumb_ptr<map_session_data> sd, ItemNameId item_id);
 int pc_payzeny(dumb_ptr<map_session_data>, int);
 PickupFail pc_additem(dumb_ptr<map_session_data>, Item *, int);
 int pc_getzeny(dumb_ptr<map_session_data>, int);
-int pc_delitem(dumb_ptr<map_session_data>, int, int, int);
+int pc_delitem(dumb_ptr<map_session_data>, IOff0, int, int);
 int pc_checkitem(dumb_ptr<map_session_data>);
 int pc_count_all_items(dumb_ptr<map_session_data> player, ItemNameId item_id);
 int pc_remove_items(dumb_ptr<map_session_data> player,
         ItemNameId item_id, int count);
 
 int pc_takeitem(dumb_ptr<map_session_data>, dumb_ptr<flooritem_data>);
-int pc_dropitem(dumb_ptr<map_session_data>, int, int);
+int pc_dropitem(dumb_ptr<map_session_data>, IOff0, int);
 
 int pc_checkweighticon(dumb_ptr<map_session_data> sd);
 
@@ -134,10 +134,10 @@ int pc_skillup(dumb_ptr<map_session_data>, SkillID);
 int pc_resetlvl(dumb_ptr<map_session_data>, int type);
 int pc_resetstate(dumb_ptr<map_session_data>);
 int pc_resetskill(dumb_ptr<map_session_data>);
-int pc_equipitem(dumb_ptr<map_session_data>, int, EPOS);
-int pc_unequipitem(dumb_ptr<map_session_data>, int, CalcStatus);
-int pc_unequipinvyitem(dumb_ptr<map_session_data>, int, CalcStatus);
-int pc_useitem(dumb_ptr<map_session_data>, int);
+int pc_equipitem(dumb_ptr<map_session_data>, IOff0, EPOS);
+int pc_unequipitem(dumb_ptr<map_session_data>, IOff0, CalcStatus);
+int pc_unequipinvyitem(dumb_ptr<map_session_data>, IOff0, CalcStatus);
+int pc_useitem(dumb_ptr<map_session_data>, IOff0);
 
 int pc_damage(dumb_ptr<block_list>, dumb_ptr<map_session_data>, int);
 int pc_heal(dumb_ptr<map_session_data>, int, int);
diff --git a/src/map/script.cpp b/src/map/script.cpp
index ab9f848..73ddea7 100644
--- a/src/map/script.cpp
+++ b/src/map/script.cpp
@@ -1926,7 +1926,7 @@ static
 void builtin_countitem(ScriptState *st)
 {
     ItemNameId nameid;
-    int count = 0, i;
+    int count = 0;
     dumb_ptr<map_session_data> sd;
 
     struct script_data *data;
@@ -1947,7 +1947,7 @@ void builtin_countitem(ScriptState *st)
 
     if (nameid)
     {
-        for (i = 0; i < MAX_INVENTORY; i++)
+        for (IOff0 i : IOff0::iter())
         {
             if (sd->status.inventory[i].nameid == nameid)
                 count += sd->status.inventory[i].amount;
@@ -2050,7 +2050,7 @@ void builtin_getitem(ScriptState *st)
         PickupFail flag;
         if ((flag = pc_additem(sd, &item_tmp, amount)) != PickupFail::OKAY)
         {
-            clif_additem(sd, 0, 0, flag);
+            clif_additem(sd, IOff0::from(0), 0, flag);
             map_addflooritem(&item_tmp, amount,
                     sd->bl_m, sd->bl_x, sd->bl_y,
                     NULL, NULL, NULL);
@@ -2114,7 +2114,7 @@ static
 void builtin_delitem(ScriptState *st)
 {
     ItemNameId nameid;
-    int amount, i;
+    int amount;
     dumb_ptr<map_session_data> sd;
     struct script_data *data;
 
@@ -2140,7 +2140,7 @@ void builtin_delitem(ScriptState *st)
         return;
     }
 
-    for (i = 0; i < MAX_INVENTORY; i++)
+    for (IOff0 i : IOff0::iter())
     {
         if (sd->status.inventory[i].nameid == nameid)
         {
@@ -2290,7 +2290,7 @@ Array<EPOS, 11> equip //=
 static
 void builtin_getequipid(ScriptState *st)
 {
-    int i, num;
+    int num;
     dumb_ptr<map_session_data> sd;
     struct item_data *item;
 
@@ -2301,8 +2301,8 @@ void builtin_getequipid(ScriptState *st)
         return;
     }
     num = conv_num(st, &AARGO2(2));
-    i = pc_checkequip(sd, equip[num - 1]);
-    if (i >= 0)
+    IOff0 i = pc_checkequip(sd, equip[num - 1]);
+    if (i.ok())
     {
         item = sd->inventory_data[i];
         if (item)
@@ -2323,7 +2323,7 @@ void builtin_getequipid(ScriptState *st)
 static
 void builtin_getequipname(ScriptState *st)
 {
-    int i, num;
+    int num;
     dumb_ptr<map_session_data> sd;
     struct item_data *item;
 
@@ -2331,8 +2331,8 @@ void builtin_getequipname(ScriptState *st)
 
     sd = script_rid2sd(st);
     num = conv_num(st, &AARGO2(2));
-    i = pc_checkequip(sd, equip[num - 1]);
-    if (i >= 0)
+    IOff0 i = pc_checkequip(sd, equip[num - 1]);
+    if (i.ok())
     {
         item = sd->inventory_data[i];
         if (item)
@@ -3522,10 +3522,10 @@ static
 void builtin_getinventorylist(ScriptState *st)
 {
     dumb_ptr<map_session_data> sd = script_rid2sd(st);
-    int i, j = 0;
+    int j = 0;
     if (!sd)
         return;
-    for (i = 0; i < MAX_INVENTORY; i++)
+    for (IOff0 i : IOff0::iter())
     {
         if (sd->status.inventory[i].nameid
             && sd->status.inventory[i].amount > 0)
@@ -3730,8 +3730,8 @@ void builtin_nude(ScriptState *st)
 
     for (EQUIP i : EQUIPs)
     {
-        int idx = sd->equip_index_maybe[i];
-        if (idx >= 0)
+        IOff0 idx = sd->equip_index_maybe[i];
+        if (idx.ok())
             pc_unequipitem(sd, idx, CalcStatus::LATER);
     }
     pc_calcstatus(sd, 0);
@@ -3754,8 +3754,8 @@ void builtin_unequipbyid(ScriptState *st)
 
     if (slot_id >= EQUIP() && slot_id < EQUIP::COUNT)
     {
-        int idx = sd->equip_index_maybe[slot_id];
-        if (idx >= 0)
+        IOff0 idx = sd->equip_index_maybe[slot_id];
+        if (idx.ok())
             pc_unequipitem(sd, idx, CalcStatus::LATER);
     }
 
diff --git a/src/map/storage.cpp b/src/map/storage.cpp
index e9c2cd6..88db8c4 100644
--- a/src/map/storage.cpp
+++ b/src/map/storage.cpp
@@ -105,7 +105,6 @@ int storage_additem(dumb_ptr<map_session_data> sd, Storage *stor,
                             Item *item_data, int amount)
 {
     struct item_data *data;
-    int i;
 
     if (!item_data->nameid || amount <= 0)
         return 1;
@@ -114,7 +113,7 @@ int storage_additem(dumb_ptr<map_session_data> sd, Storage *stor,
 
     if (!itemdb_isequip2(data))
     {                           //Stackable
-        for (i = 0; i < MAX_STORAGE; i++)
+        for (SOff0 i : SOff0::iter())
         {
             if (compare_item(&stor->storage_[i], item_data))
             {
@@ -128,9 +127,12 @@ int storage_additem(dumb_ptr<map_session_data> sd, Storage *stor,
         }
     }
     //Add item
-    for (i = 0; i < MAX_STORAGE && stor->storage_[i].nameid; i++);
-
-    if (i >= MAX_STORAGE)
+    SOff0 i = *std::find_if(SOff0::iter().begin(), SOff0::iter().end(),
+            [&stor](SOff0 i_)
+            {
+                return !stor->storage_[i_].nameid;
+            });
+    if (!i.ok())
         return 1;
 
     stor->storage_[i] = *item_data;
@@ -148,7 +150,7 @@ int storage_additem(dumb_ptr<map_session_data> sd, Storage *stor,
  */
 static
 int storage_delitem(dumb_ptr<map_session_data> sd, Storage *stor,
-                            int n, int amount)
+        SOff0 n, int amount)
 {
 
     if (!stor->storage_[n].nameid || stor->storage_[n].amount < amount)
@@ -171,7 +173,7 @@ int storage_delitem(dumb_ptr<map_session_data> sd, Storage *stor,
  * Add an item to the storage from the inventory.
  *------------------------------------------
  */
-int storage_storageadd(dumb_ptr<map_session_data> sd, int index, int amount)
+int storage_storageadd(dumb_ptr<map_session_data> sd, IOff0 index, int amount)
 {
     Storage *stor;
 
@@ -182,7 +184,7 @@ int storage_storageadd(dumb_ptr<map_session_data> sd, int index, int amount)
     if ((stor->storage_amount > MAX_STORAGE) || !stor->storage_status)
         return 0;               // storage full / storage closed
 
-    if (index < 0 || index >= MAX_INVENTORY)
+    if (!index.ok())
         return 0;
 
     if (!sd->status.inventory[index].nameid)
@@ -206,7 +208,7 @@ int storage_storageadd(dumb_ptr<map_session_data> sd, int index, int amount)
  * Retrieve an item from the storage.
  *------------------------------------------
  */
-int storage_storageget(dumb_ptr<map_session_data> sd, int index, int amount)
+int storage_storageget(dumb_ptr<map_session_data> sd, SOff0 index, int amount)
 {
     Storage *stor;
     PickupFail flag;
@@ -215,7 +217,7 @@ int storage_storageget(dumb_ptr<map_session_data> sd, int index, int amount)
     stor = account2storage2(sd->status_key.account_id);
     nullpo_ret(stor);
 
-    if (index < 0 || index >= MAX_STORAGE)
+    if (!index.ok())
         return 0;
 
     if (!stor->storage_[index].nameid)
@@ -227,7 +229,7 @@ int storage_storageget(dumb_ptr<map_session_data> sd, int index, int amount)
     if ((flag = pc_additem(sd, &stor->storage_[index], amount)) == PickupFail::OKAY)
         storage_delitem(sd, stor, index, amount);
     else
-        clif_additem(sd, 0, 0, flag);
+        clif_additem(sd, IOff0::from(0), 0, flag);
 //  log_fromstorage(sd, index, 0);
     return 1;
 }
diff --git a/src/map/storage.hpp b/src/map/storage.hpp
index 3eab087..fe29664 100644
--- a/src/map/storage.hpp
+++ b/src/map/storage.hpp
@@ -27,9 +27,11 @@
 
 # include "../mmo/fwd.hpp"
 
+# include "clif.t.hpp"
+
 int storage_storageopen(dumb_ptr<map_session_data> sd);
-int storage_storageadd(dumb_ptr<map_session_data> sd, int index, int amount);
-int storage_storageget(dumb_ptr<map_session_data> sd, int index, int amount);
+int storage_storageadd(dumb_ptr<map_session_data> sd, IOff0 index, int amount);
+int storage_storageget(dumb_ptr<map_session_data> sd, SOff0 index, int amount);
 int storage_storageclose(dumb_ptr<map_session_data> sd);
 void do_final_storage(void);
 Storage *account2storage(AccountId account_id);
diff --git a/src/map/trade.cpp b/src/map/trade.cpp
index af5d1aa..7a4913a 100644
--- a/src/map/trade.cpp
+++ b/src/map/trade.cpp
@@ -123,7 +123,7 @@ void trade_tradeack(dumb_ptr<map_session_data> sd, int type)
  * アイテム追加
  *------------------------------------------
  */
-void trade_tradeadditem(dumb_ptr<map_session_data> sd, int index, int amount)
+void trade_tradeadditem(dumb_ptr<map_session_data> sd, IOff2 index, int amount)
 {
     dumb_ptr<map_session_data> target_sd;
     struct item_data *id;
@@ -131,27 +131,26 @@ void trade_tradeadditem(dumb_ptr<map_session_data> sd, int index, int amount)
     int trade_weight = 0;
     int free_ = 0;
     int c;
-    int i;
 
     nullpo_retv(sd);
 
     if (((target_sd = map_id2sd(account_to_block(sd->trade_partner))) != NULL)
         && (sd->deal_locked < 1))
     {
-        if (index < 2 || index >= MAX_INVENTORY + 2)
+        if (!index.ok())
         {
-            if (index == 0 && amount > 0 && amount <= sd->status.zeny)
+            if (index.index == 0 && amount > 0 && amount <= sd->status.zeny)
             {
                 sd->deal_zeny = amount;
-                clif_tradeadditem(sd, target_sd, 0, amount);
+                clif_tradeadditem(sd, target_sd, index, amount);
             }
         }
         // note: amount is overridden below!
-        else if (amount <= sd->status.inventory[index - 2].amount
+        else if (amount <= sd->status.inventory[index.unshift()].amount
                  && amount > 0)
         {
             // determine free slots of receiver
-            for (i = 0; i < MAX_INVENTORY; i++)
+            for (IOff0 i : IOff0::iter())
             {
                 if (!target_sd->status.inventory[i].nameid
                     && target_sd->inventory_data[i] == NULL)
@@ -163,13 +162,13 @@ void trade_tradeadditem(dumb_ptr<map_session_data> sd, int index, int amount)
                 {
                     // calculate trade weight
                     trade_weight +=
-                        sd->inventory_data[index - 2]->weight * amount;
+                        sd->inventory_data[index.unshift()]->weight * amount;
 
                     // determine if item is a stackable already in receivers inventory, and up free count
-                    for (i = 0; i < MAX_INVENTORY; i++)
+                    for (IOff0 i : IOff0::iter())
                     {
                         if (target_sd->status.inventory[i].nameid ==
-                            sd->status.inventory[index - 2].nameid
+                            sd->status.inventory[index.unshift()].nameid
                             && target_sd->inventory_data[i] != NULL)
                         {
                             id = target_sd->inventory_data[i];
@@ -205,7 +204,7 @@ void trade_tradeadditem(dumb_ptr<map_session_data> sd, int index, int amount)
                                 return;
                             }
                         }
-                        pc_unequipinvyitem(sd, index - 2, CalcStatus::NOW);
+                        pc_unequipinvyitem(sd, index.unshift(), CalcStatus::NOW);
                         sd->deal_item_index[trade_i] = index;
                         sd->deal_item_amount[trade_i] += amount;
                         clif_tradeitemok(sd, index, amount, 0);    //success to add item
@@ -217,15 +216,15 @@ void trade_tradeadditem(dumb_ptr<map_session_data> sd, int index, int amount)
                 {
                     // calculate weight for stored deal
                     trade_weight +=
-                        sd->inventory_data[sd->deal_item_index[trade_i] -
-                                           2]->weight *
+                        sd->inventory_data[sd->deal_item_index[trade_i].unshift()
+                                           ]->weight *
                         sd->deal_item_amount[trade_i];
                     // count free stackables in stored deal
-                    for (i = 0; i < MAX_INVENTORY; i++)
+                    for (IOff0 i : IOff0::iter())
                     {
                         if (target_sd->status.inventory[i].nameid ==
                             sd->status.
-                            inventory[sd->deal_item_index[trade_i] - 2].nameid
+                            inventory[sd->deal_item_index[trade_i].unshift()].nameid
                             && target_sd->inventory_data[i] != NULL)
                         {
                             id = target_sd->inventory_data[i];
@@ -260,11 +259,11 @@ void trade_tradeok(dumb_ptr<map_session_data> sd)
 
     for (trade_i = 0; trade_i < TRADE_MAX; trade_i++)
     {
-        int index = sd->deal_item_index[trade_i];
-        if (index < 2 || index >= MAX_INVENTORY + 2)
+        IOff2 index = sd->deal_item_index[trade_i];
+        if (!index.ok())
             continue;
         if (sd->deal_item_amount[trade_i] >
-            sd->status.inventory[index - 2].amount
+            sd->status.inventory[index.unshift()].amount
             || sd->deal_item_amount[trade_i] < 0)
         {
             trade_tradecancel(sd);
@@ -276,7 +275,7 @@ void trade_tradeok(dumb_ptr<map_session_data> sd)
     if ((target_sd = map_id2sd(account_to_block(sd->trade_partner))) != NULL)
     {
         sd->deal_locked = 1;
-        clif_tradeitemok(sd, 0, 0, 0);
+        clif_tradeitemok(sd, IOff2::from(0), 0, 0);
         clif_tradedeal_lock(sd, 0);
         clif_tradedeal_lock(target_sd, 1);
     }
@@ -299,20 +298,22 @@ void trade_tradecancel(dumb_ptr<map_session_data> sd)
         {                       //give items back (only virtual)
             if (sd->deal_item_amount[trade_i] != 0)
             {
+                assert (sd->deal_item_index[trade_i].ok());
                 clif_additem(sd,
-                        sd->deal_item_index[trade_i] - 2,
+                        sd->deal_item_index[trade_i].unshift(),
                         sd->deal_item_amount[trade_i],
                         PickupFail::OKAY);
-                sd->deal_item_index[trade_i] = 0;
+                sd->deal_item_index[trade_i] = IOff2::from(0);
                 sd->deal_item_amount[trade_i] = 0;
             }
             if (target_sd->deal_item_amount[trade_i] != 0)
             {
+                assert (target_sd->deal_item_index[trade_i].ok());
                 clif_additem(target_sd,
-                        target_sd->deal_item_index[trade_i] - 2,
+                        target_sd->deal_item_index[trade_i].unshift(),
                         target_sd->deal_item_amount[trade_i],
                         PickupFail::OKAY);
-                target_sd->deal_item_index[trade_i] = 0;
+                target_sd->deal_item_index[trade_i] = IOff2::from(0);
                 target_sd->deal_item_amount[trade_i] = 0;
             }
         }
@@ -379,7 +380,8 @@ void trade_tradecommit(dumb_ptr<map_session_data> sd)
                 {
                     if (sd->deal_item_amount[trade_i] != 0)
                     {
-                        int n = sd->deal_item_index[trade_i] - 2;
+                        assert (sd->deal_item_index[trade_i].ok());
+                        IOff0 n = sd->deal_item_index[trade_i].unshift();
                         PickupFail flag = pc_additem(target_sd,
                                 &sd->status.inventory[n],
                                 sd->deal_item_amount[trade_i]);
@@ -390,12 +392,13 @@ void trade_tradecommit(dumb_ptr<map_session_data> sd)
                             clif_additem(sd, n,
                                     sd->deal_item_amount[trade_i],
                                     PickupFail::OKAY);
-                        sd->deal_item_index[trade_i] = 0;
+                        sd->deal_item_index[trade_i] = IOff2::from(0);
                         sd->deal_item_amount[trade_i] = 0;
                     }
                     if (target_sd->deal_item_amount[trade_i] != 0)
                     {
-                        int n = target_sd->deal_item_index[trade_i] - 2;
+                        assert (target_sd->deal_item_index[trade_i].ok());
+                        IOff0 n = target_sd->deal_item_index[trade_i].unshift();
                         PickupFail flag = pc_additem(sd,
                                 &target_sd->status.inventory[n],
                                 target_sd->deal_item_amount[trade_i]);
@@ -405,10 +408,9 @@ void trade_tradecommit(dumb_ptr<map_session_data> sd)
                                         1);
                         else
                             clif_additem(target_sd, n,
-
                                     target_sd->deal_item_amount[trade_i],
                                     PickupFail::OKAY);
-                        target_sd->deal_item_index[trade_i] = 0;
+                        target_sd->deal_item_index[trade_i] = IOff2::from(0);
                         target_sd->deal_item_amount[trade_i] = 0;
                     }
                 }
@@ -454,7 +456,7 @@ void trade_verifyzeny(dumb_ptr<map_session_data> sd)
         if (sd->deal_zeny > sd->status.zeny)
         {
             if (sd->deal_locked < 1)
-                trade_tradeadditem(sd, 0, sd->status.zeny);    // Fix money ammount
+                trade_tradeadditem(sd, IOff2::from(0), sd->status.zeny);    // Fix money ammount
             else
                 trade_tradecancel(sd); // Or cancel the trade if we can't fix it
         }
diff --git a/src/map/trade.hpp b/src/map/trade.hpp
index 9d542a4..370fcdf 100644
--- a/src/map/trade.hpp
+++ b/src/map/trade.hpp
@@ -25,9 +25,11 @@
 
 # include "../generic/fwd.hpp"
 
+# include "clif.t.hpp"
+
 void trade_traderequest(dumb_ptr<map_session_data> sd, BlockId target_id);
 void trade_tradeack(dumb_ptr<map_session_data> sd, int type);
-void trade_tradeadditem(dumb_ptr<map_session_data> sd, int index, int amount);
+void trade_tradeadditem(dumb_ptr<map_session_data> sd, IOff2 index, int amount);
 void trade_tradeok(dumb_ptr<map_session_data> sd);
 void trade_tradecancel(dumb_ptr<map_session_data> sd);
 void trade_tradecommit(dumb_ptr<map_session_data> sd);
diff --git a/src/mmo/version.hpp b/src/mmo/version.hpp
index 5d28b5d..f2c146b 100644
--- a/src/mmo/version.hpp
+++ b/src/mmo/version.hpp
@@ -47,6 +47,35 @@ struct Version
     uint8_t which;
     uint16_t vend;
     // can't add vendor name yet
+
+    constexpr friend
+    bool operator < (Version l, Version r)
+    {
+        return (l.major < r.major
+                || (l.major == r.major
+                    && (l.minor < r.minor
+                        || (l.minor == r.minor
+                            && (l.patch < r.patch
+                                || (l.patch == r.patch
+                                    && (l.devel < r.devel
+                                        || (l.devel == r.devel
+                                            && l.vend < r.vend))))))));
+    }
+    constexpr friend
+    bool operator > (Version l, Version r)
+    {
+        return r < l;
+    }
+    constexpr friend
+    bool operator <= (Version l, Version r)
+    {
+        return !(r < l);
+    }
+    constexpr friend
+    bool operator >= (Version l, Version r)
+    {
+        return !(l < r);
+    }
 };
 static_assert(sizeof(Version) == 8, "this is sent over the network, can't change");
 
@@ -60,33 +89,4 @@ extern LString CURRENT_VERSION_STRING;
 
 bool extract(XString str, Version *vers);
 
-constexpr
-bool operator < (Version l, Version r)
-{
-    return (l.major < r.major
-            || (l.major == r.major
-                && (l.minor < r.minor
-                    || (l.minor == r.minor
-                        && (l.patch < r.patch
-                            || (l.patch == r.patch
-                                && (l.devel < r.devel
-                                    || (l.devel == r.devel
-                                        && l.vend < r.vend))))))));
-}
-constexpr
-bool operator > (Version l, Version r)
-{
-    return r < l;
-}
-constexpr
-bool operator <= (Version l, Version r)
-{
-    return !(r < l);
-}
-constexpr
-bool operator >= (Version l, Version r)
-{
-    return !(l < r);
-}
-
 #endif // TMWA_MMO_VERSION_HPP
diff --git a/src/proto2/include_clif_t_test.cpp b/src/proto2/include_clif_t_test.cpp
index 93c7f90..75d36a0 100644
--- a/src/proto2/include_clif_t_test.cpp
+++ b/src/proto2/include_clif_t_test.cpp
@@ -34,3 +34,5 @@ using Test_PickupFail = PickupFail;
 using Test_DamageType = DamageType;
 using Test_SP = SP;
 using Test_LOOK = LOOK;
+using Test_IOff2 = IOff2;
+using Test_SOff1 = SOff1;
diff --git a/src/proto2/map-user.hpp b/src/proto2/map-user.hpp
index b4ea4d8..598ef3b 100644
--- a/src/proto2/map-user.hpp
+++ b/src/proto2/map-user.hpp
@@ -510,7 +510,7 @@ struct Packet_Fixed<0x00a0>
 
     // TODO remove this
     uint16_t magic_packet_id = PACKET_ID;
-    uint16_t ioff2 = {};
+    IOff2 ioff2 = {};
     uint16_t amount = {};
     ItemNameId name_id = {};
     uint8_t identify = {};
@@ -542,7 +542,7 @@ struct Packet_Fixed<0x00a2>
 
     // TODO remove this
     uint16_t magic_packet_id = PACKET_ID;
-    uint16_t ioff2 = {};
+    IOff2 ioff2 = {};
     uint16_t amount = {};
 };
 
@@ -561,7 +561,7 @@ struct Packet_Repeat<0x00a4>
 {
     static const uint16_t PACKET_ID = 0x00a4;
 
-    uint16_t ioff2 = {};
+    IOff2 ioff2 = {};
     ItemNameId name_id = {};
     ItemType item_type = {};
     uint8_t identify = {};
@@ -590,7 +590,7 @@ struct Packet_Repeat<0x00a6>
 {
     static const uint16_t PACKET_ID = 0x00a6;
 
-    uint16_t soff1 = {};
+    SOff1 soff1 = {};
     ItemNameId name_id = {};
     ItemType item_type = {};
     uint8_t identify = {};
@@ -611,7 +611,7 @@ struct Packet_Fixed<0x00a7>
 
     // TODO remove this
     uint16_t magic_packet_id = PACKET_ID;
-    uint16_t ioff2 = {};
+    IOff2 ioff2 = {};
     uint32_t unused_id = {};
 };
 
@@ -622,7 +622,7 @@ struct Packet_Fixed<0x00a8>
 
     // TODO remove this
     uint16_t magic_packet_id = PACKET_ID;
-    uint16_t ioff2 = {};
+    IOff2 ioff2 = {};
     uint16_t amount = {};
     uint8_t ok = {};
 };
@@ -634,7 +634,7 @@ struct Packet_Fixed<0x00a9>
 
     // TODO remove this
     uint16_t magic_packet_id = PACKET_ID;
-    uint16_t ioff2 = {};
+    IOff2 ioff2 = {};
     EPOS epos_ignored = {};
 };
 
@@ -645,7 +645,7 @@ struct Packet_Fixed<0x00aa>
 
     // TODO remove this
     uint16_t magic_packet_id = PACKET_ID;
-    uint16_t ioff2 = {};
+    IOff2 ioff2 = {};
     EPOS epos = {};
     uint8_t ok = {};
 };
@@ -657,7 +657,7 @@ struct Packet_Fixed<0x00ab>
 
     // TODO remove this
     uint16_t magic_packet_id = PACKET_ID;
-    uint16_t ioff2 = {};
+    IOff2 ioff2 = {};
 };
 
 template<>
@@ -667,7 +667,7 @@ struct Packet_Fixed<0x00ac>
 
     // TODO remove this
     uint16_t magic_packet_id = PACKET_ID;
-    uint16_t ioff2 = {};
+    IOff2 ioff2 = {};
     EPOS epos = {};
     uint8_t ok = {};
 };
@@ -679,7 +679,7 @@ struct Packet_Fixed<0x00af>
 
     // TODO remove this
     uint16_t magic_packet_id = PACKET_ID;
-    uint16_t ioff2 = {};
+    IOff2 ioff2 = {};
     uint16_t amount = {};
 };
 
@@ -971,7 +971,7 @@ struct Packet_Repeat<0x00c7>
 {
     static const uint16_t PACKET_ID = 0x00c7;
 
-    uint16_t ioff2 = {};
+    IOff2 ioff2 = {};
     uint32_t base_price = {};
     uint32_t actual_price = {};
 };
@@ -1010,7 +1010,7 @@ struct Packet_Repeat<0x00c9>
 {
     static const uint16_t PACKET_ID = 0x00c9;
 
-    uint16_t ioff2 = {};
+    IOff2 ioff2 = {};
     uint16_t count = {};
 };
 
@@ -1091,7 +1091,7 @@ struct Packet_Fixed<0x00e8>
 
     // TODO remove this
     uint16_t magic_packet_id = PACKET_ID;
-    uint16_t zeny_or_ioff2 = {};
+    IOff2 zeny_or_ioff2 = {};
     uint32_t amount = {};
 };
 
@@ -1187,7 +1187,7 @@ struct Packet_Fixed<0x00f3>
 
     // TODO remove this
     uint16_t magic_packet_id = PACKET_ID;
-    uint16_t ioff2 = {};
+    IOff2 ioff2 = {};
     uint32_t amount = {};
 };
 
@@ -1198,7 +1198,7 @@ struct Packet_Fixed<0x00f4>
 
     // TODO remove this
     uint16_t magic_packet_id = PACKET_ID;
-    uint16_t soff1 = {};
+    SOff1 soff1 = {};
     uint32_t amount = {};
     ItemNameId name_id = {};
     uint8_t identify = {};
@@ -1217,7 +1217,7 @@ struct Packet_Fixed<0x00f5>
 
     // TODO remove this
     uint16_t magic_packet_id = PACKET_ID;
-    uint16_t soff1 = {};
+    SOff1 soff1 = {};
     uint32_t amount = {};
 };
 
@@ -1228,7 +1228,7 @@ struct Packet_Fixed<0x00f6>
 
     // TODO remove this
     uint16_t magic_packet_id = PACKET_ID;
-    uint16_t soff1 = {};
+    SOff1 soff1 = {};
     uint32_t amount = {};
 };
 
@@ -1582,7 +1582,7 @@ struct Packet_Fixed<0x013c>
 
     // TODO remove this
     uint16_t magic_packet_id = PACKET_ID;
-    uint16_t ioff2 = {};
+    IOff2 ioff2 = {};
 };
 
 template<>
@@ -1723,7 +1723,7 @@ struct Packet_Fixed<0x01b1>
 
     // TODO remove this
     uint16_t magic_packet_id = PACKET_ID;
-    uint16_t ioff2 = {};
+    IOff2 ioff2 = {};
     uint16_t amount = {};
     uint8_t fail = {};
 };
@@ -1735,7 +1735,7 @@ struct Packet_Fixed<0x01c8>
 
     // TODO remove this
     uint16_t magic_packet_id = PACKET_ID;
-    uint16_t ioff2 = {};
+    IOff2 ioff2 = {};
     ItemNameId name_id = {};
     BlockId block_id = {};
     uint16_t amount = {};
@@ -1923,7 +1923,7 @@ struct Packet_Repeat<0x01ee>
 {
     static const uint16_t PACKET_ID = 0x01ee;
 
-    uint16_t ioff2 = {};
+    IOff2 ioff2 = {};
     ItemNameId name_id = {};
     ItemType item_type = {};
     uint8_t identify = {};
@@ -1950,7 +1950,7 @@ struct Packet_Repeat<0x01f0>
 {
     static const uint16_t PACKET_ID = 0x01f0;
 
-    uint16_t soff1 = {};
+    SOff1 soff1 = {};
     ItemNameId name_id = {};
     ItemType item_type = {};
     uint8_t identify = {};
diff --git a/src/proto2/types.hpp b/src/proto2/types.hpp
index f46acf3..e6730c1 100644
--- a/src/proto2/types.hpp
+++ b/src/proto2/types.hpp
@@ -58,42 +58,22 @@ struct NetArray
 {
     T data[N];
 };
-template<class T, class U, size_t N>
-bool native_to_network(NetArray<T, N> *network, Array<U, N> native)
+template<class T, class U, class I>
+bool native_to_network(NetArray<T, I::alloc_size> *network, GenericArray<U, I> native)
 {
-    for (size_t i = 0; i < N; ++i)
+    for (size_t i = 0; i < I::alloc_size; ++i)
     {
-        if (!native_to_network(&(*network).data[i], native[i]))
+        if (!native_to_network(&(*network).data[i], native[I::offset_to_index(i)]))
             return false;
     }
     return true;
 }
-template<class T, class U, size_t N>
-bool network_to_native(Array<U, N> *native, NetArray<T, N> network)
+template<class T, class U, class I>
+bool network_to_native(GenericArray<U, I> *native, NetArray<T, I::alloc_size> network)
 {
-    for (size_t i = 0; i < N; ++i)
+    for (size_t i = 0; i < I::alloc_size; ++i)
     {
-        if (!network_to_native(&(*native)[i], network.data[i]))
-            return false;
-    }
-    return true;
-}
-template<class T, class U, size_t N, class I>
-bool native_to_network(NetArray<T, N> *network, earray<U, I, static_cast<I>(N)> native)
-{
-    for (size_t i = 0; i < N; ++i)
-    {
-        if (!native_to_network(&(*network).data[i], native[static_cast<I>(i)]))
-            return false;
-    }
-    return true;
-}
-template<class T, class U, size_t N, class I>
-bool network_to_native(earray<U, I, static_cast<I>(N)> *native, NetArray<T, N> network)
-{
-    for (size_t i = 0; i < N; ++i)
-    {
-        if (!network_to_native(&(*native)[static_cast<I>(i)], network.data[i]))
+        if (!network_to_native(&(*native)[I::offset_to_index(i)], network.data[i]))
             return false;
     }
     return true;
@@ -1184,7 +1164,7 @@ struct CharData
     uint16_t mapport = {};
     Point last_point = {};
     Point save_point = {};
-    Array<Item, MAX_INVENTORY> inventory = {};
+    GenericArray<Item, InventoryIndexing<IOff0, MAX_INVENTORY>> inventory = {};
     earray<SkillValue, SkillID, MAX_SKILL> skill = {};
     uint32_t global_reg_num = {};
     Array<GlobalReg, GLOBAL_REG_NUM> global_reg = {};
@@ -1403,7 +1383,7 @@ struct Storage
     AccountId account_id = {};
     uint16_t storage_status = {};
     uint16_t storage_amount = {};
-    Array<Item, MAX_STORAGE> storage_ = {};
+    GenericArray<Item, InventoryIndexing<SOff0, MAX_STORAGE>> storage_ = {};
 };
 struct NetStorage
 {
diff --git a/tools/protocol.py b/tools/protocol.py
index 4090b2b..a6214fc 100755
--- a/tools/protocol.py
+++ b/tools/protocol.py
@@ -23,6 +23,7 @@
 import glob
 import itertools
 import os
+from pipes import quote
 from posixpath import relpath
 
 # The following code should be relatively easy to understand, but please
@@ -53,6 +54,31 @@ copyright = '''//    {filename} - {description}
 //    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 '''
 
+class OpenWrite(object):
+    def __init__(self, filename):
+        self.filename = filename
+
+    def __enter__(self):
+        self.handle = open(self.filename + '.tmp', 'w')
+        return self.handle
+
+    def __exit__(self, ty, v, tb):
+        self.handle.close()
+        if ty is not None:
+            return
+        frag = '''
+        if cmp {0}.tmp {0}.old
+        then
+            echo Unchanged: {0}
+            rm {0}.tmp
+            mv {0}.old {0}
+        else
+            echo Changed: {0}
+            rm {0}.old
+            mv {0}.tmp {0}
+        fi
+        '''.format(quote(self.filename))
+        os.system(frag)
 
 class LowType(object):
     __slots__ = ()
@@ -366,6 +392,20 @@ class EArrayType(Type):
     def network_tag(self):
         return 'NetArray<%s, static_cast<size_t>(%s)>' % (self.element.network_tag(), self.count)
 
+class InvArrayType(Type):
+    __slots__ = ('element', 'index', 'count')
+
+    def __init__(self, element, index, count):
+        self.element = element
+        self.index = index
+        self.count = count
+
+    def native_tag(self):
+        return 'GenericArray<%s, InventoryIndexing<%s, %s>>' % (self.element.native_tag(), self.index, self.count)
+
+    def network_tag(self):
+        return 'NetArray<%s, %s>' % (self.element.network_tag(), self.count)
+
 
 class Include(object):
     __slots__ = ('path', '_types')
@@ -380,7 +420,7 @@ class Include(object):
         filename = 'include_%s_test.cpp' % root.replace('.', '_')
         desc = 'testsuite for protocol includes'
         poison = relpath('src/poison.hpp', outdir)
-        with open(os.path.join(outdir, filename), 'w') as f:
+        with OpenWrite(os.path.join(outdir, filename)) as f:
             f.write(self.pp(0))
             f.write(copyright.format(filename=filename, description=desc))
             f.write('\n')
@@ -511,7 +551,7 @@ class Channel(object):
         header = '%s-%s.hpp' % (server, client)
         test = '%s-%s_test.cpp' % (server, client)
         desc = 'TMWA network protocol: %s/%s' % (server, client)
-        with open(os.path.join(outdir, header), 'w') as f:
+        with OpenWrite(os.path.join(outdir, header)) as f:
             proto2 = relpath(outdir, 'src')
             define = ('TMWA_%s_%s_%s_HPP' % (proto2, server, client)).upper()
             f.write('#ifndef %s\n' % define)
@@ -542,7 +582,7 @@ class Channel(object):
             f.write('\n')
             f.write('#endif // %s\n' % define)
 
-        with open(os.path.join(outdir, test), 'w') as f:
+        with OpenWrite(os.path.join(outdir, test)) as f:
             poison = relpath('src/poison.hpp', outdir)
             f.write('#include "%s"\n' % header)
             f.write(copyright.format(filename=test, description=desc))
@@ -594,9 +634,9 @@ class Context(object):
     def dump(self):
         outdir = self.outdir
         for g in glob.glob(os.path.join(outdir, '*.[ch]pp')):
-            os.remove(g)
+            os.rename(g, g + '.old')
         proto2 = relpath(outdir, 'src')
-        with open(os.path.join(outdir, 'fwd.hpp'), 'w') as f:
+        with OpenWrite(os.path.join(outdir, 'fwd.hpp')) as f:
             header = '%s/fwd.hpp' % proto2
             desc = 'Forward declarations of network packets'
             sanity = relpath('src/sanity.hpp', outdir)
@@ -619,7 +659,7 @@ class Context(object):
             f.write('\n')
             f.write('#endif // %s\n' % define)
 
-        with open(os.path.join(outdir, 'types.hpp'), 'w') as f:
+        with OpenWrite(os.path.join(outdir, 'types.hpp')) as f:
             header = '%s/types.hpp' % proto2
             desc = 'Forward declarations of packet component types'
             define = ('TMWA_%s_TYPES_HPP' % proto2).upper()
@@ -653,38 +693,20 @@ class Context(object):
             f.write('struct NetArray\n{\n')
             f.write('    T data[N];\n')
             f.write('};\n')
-            f.write('template<class T, class U, size_t N>\n')
-            f.write('bool native_to_network(NetArray<T, N> *network, Array<U, N> native)\n{\n')
-            f.write('    for (size_t i = 0; i < N; ++i)\n')
+            f.write('template<class T, class U, class I>\n')
+            f.write('bool native_to_network(NetArray<T, I::alloc_size> *network, GenericArray<U, I> native)\n{\n')
+            f.write('    for (size_t i = 0; i < I::alloc_size; ++i)\n')
             f.write('    {\n')
-            f.write('        if (!native_to_network(&(*network).data[i], native[i]))\n')
+            f.write('        if (!native_to_network(&(*network).data[i], native[I::offset_to_index(i)]))\n')
             f.write('            return false;\n')
             f.write('    }\n')
             f.write('    return true;\n')
             f.write('}\n')
-            f.write('template<class T, class U, size_t N>\n')
-            f.write('bool network_to_native(Array<U, N> *native, NetArray<T, N> network)\n{\n')
-            f.write('    for (size_t i = 0; i < N; ++i)\n')
+            f.write('template<class T, class U, class I>\n')
+            f.write('bool network_to_native(GenericArray<U, I> *native, NetArray<T, I::alloc_size> network)\n{\n')
+            f.write('    for (size_t i = 0; i < I::alloc_size; ++i)\n')
             f.write('    {\n')
-            f.write('        if (!network_to_native(&(*native)[i], network.data[i]))\n')
-            f.write('            return false;\n')
-            f.write('    }\n')
-            f.write('    return true;\n')
-            f.write('}\n')
-            f.write('template<class T, class U, size_t N, class I>\n')
-            f.write('bool native_to_network(NetArray<T, N> *network, earray<U, I, static_cast<I>(N)> native)\n{\n')
-            f.write('    for (size_t i = 0; i < N; ++i)\n')
-            f.write('    {\n')
-            f.write('        if (!native_to_network(&(*network).data[i], native[static_cast<I>(i)]))\n')
-            f.write('            return false;\n')
-            f.write('    }\n')
-            f.write('    return true;\n')
-            f.write('}\n')
-            f.write('template<class T, class U, size_t N, class I>\n')
-            f.write('bool network_to_native(earray<U, I, static_cast<I>(N)> *native, NetArray<T, N> network)\n{\n')
-            f.write('    for (size_t i = 0; i < N; ++i)\n')
-            f.write('    {\n')
-            f.write('        if (!network_to_native(&(*native)[static_cast<I>(i)], network.data[i]))\n')
+            f.write('        if (!network_to_native(&(*native)[I::offset_to_index(i)], network.data[i]))\n')
             f.write('            return false;\n')
             f.write('    }\n')
             f.write('    return true;\n')
@@ -764,6 +786,9 @@ class Context(object):
                 ty.dump(f)
             f.write('#endif // %s\n' % define)
 
+        for g in glob.glob(os.path.join(outdir, '*.old')):
+            print('Obsolete: %s' % g)
+            os.remove(g)
 
     # types
 
@@ -806,6 +831,10 @@ class Context(object):
         rv = EArrayType(element, index, count)
         return rv
 
+    def invarray(self, element, index, count):
+        rv = InvArrayType(element, index, count)
+        return rv
+
 
 def main():
 
@@ -920,6 +949,8 @@ def main():
     DamageType = clif_th.native('DamageType')
     SP = clif_th.native('SP')
     LOOK = clif_th.native('LOOK')
+    IOff2 = clif_th.native('IOff2')
+    SOff1 = clif_th.native('SOff1')
 
     SkillID = skill_th.native('SkillID')
     StatusChange = skill_th.native('StatusChange')
@@ -949,6 +980,8 @@ def main():
     damage_type = ctx.enum(DamageType, u8)
     sp = ctx.enum(SP, u16)
     look = ctx.enum(LOOK, u8)
+    ioff2 = ctx.provided(IOff2, Little16)
+    soff1 = ctx.provided(SOff1, Little16)
 
     skill_id = ctx.enum(SkillID, u16)
     status_change = ctx.enum(StatusChange, u16)
@@ -1178,7 +1211,7 @@ def main():
                 at(None, u16, 'mapport'),
                 at(None, point, 'last point'),
                 at(None, point, 'save point'),
-                at(None, ctx.array(item, 'MAX_INVENTORY'), 'inventory'),
+                at(None, ctx.invarray(item, 'IOff0', 'MAX_INVENTORY'), 'inventory'),
                 at(None, ctx.earray(skill_value, 'SkillID', 'MAX_SKILL'), 'skill'),
                 at(None, u32, 'global reg num'),
                 at(None, ctx.array(global_reg, 'GLOBAL_REG_NUM'), 'global reg'),
@@ -1220,7 +1253,7 @@ def main():
                 at(None, account_id, 'account id'),
                 at(None, u16, 'storage status'),
                 at(None, u16, 'storage amount'),
-                at(None, ctx.array(item, 'MAX_STORAGE'), 'storage_'),
+                at(None, ctx.invarray(item, 'SOff0', 'MAX_STORAGE'), 'storage_'),
             ],
             size=None,
     )
@@ -1779,7 +1812,7 @@ def main():
     map_user.s(0x00a0,
         fixed=[
             at(0, u16, 'packet id'),
-            at(2, u16, 'ioff2'),
+            at(2, ioff2, 'ioff2'),
             at(4, u16, 'amount'),
             at(6, item_name_id, 'name id'),
             at(8, u8, 'identify'),
@@ -1805,7 +1838,7 @@ def main():
     map_user.r(0x00a2,
         fixed=[
             at(0, u16, 'packet id'),
-            at(2, u16, 'ioff2'),
+            at(2, ioff2, 'ioff2'),
             at(4, u16, 'amount'),
         ],
         fixed_size=6,
@@ -1817,7 +1850,7 @@ def main():
         ],
         head_size=4,
         repeat=[
-            at(0, u16, 'ioff2'),
+            at(0, ioff2, 'ioff2'),
             at(2, item_name_id, 'name id'),
             at(4, item_type, 'item type'),
             at(5, u8, 'identify'),
@@ -1839,7 +1872,7 @@ def main():
         ],
         head_size=4,
         repeat=[
-            at(0, u16, 'soff1'),
+            at(0, soff1, 'soff1'),
             at(2, item_name_id, 'name id'),
             at(4, item_type, 'item type'),
             at(5, u8, 'identify'),
@@ -1857,7 +1890,7 @@ def main():
     map_user.r(0x00a7,
         fixed=[
             at(0, u16, 'packet id'),
-            at(2, u16, 'ioff2'),
+            at(2, ioff2, 'ioff2'),
             at(4, u32, 'unused id'),
         ],
         fixed_size=8,
@@ -1865,7 +1898,7 @@ def main():
     map_user.s(0x00a8,
         fixed=[
             at(0, u16, 'packet id'),
-            at(2, u16, 'ioff2'),
+            at(2, ioff2, 'ioff2'),
             at(4, u16, 'amount'),
             at(6, u8, 'ok'),
         ],
@@ -1874,7 +1907,7 @@ def main():
     map_user.r(0x00a9,
         fixed=[
             at(0, u16, 'packet id'),
-            at(2, u16, 'ioff2'),
+            at(2, ioff2, 'ioff2'),
             at(4, epos, 'epos ignored'),
         ],
         fixed_size=6,
@@ -1882,7 +1915,7 @@ def main():
     map_user.s(0x00aa,
         fixed=[
             at(0, u16, 'packet id'),
-            at(2, u16, 'ioff2'),
+            at(2, ioff2, 'ioff2'),
             at(4, epos, 'epos'),
             at(6, u8, 'ok'),
         ],
@@ -1891,14 +1924,14 @@ def main():
     map_user.r(0x00ab,
         fixed=[
             at(0, u16, 'packet id'),
-            at(2, u16, 'ioff2'),
+            at(2, ioff2, 'ioff2'),
         ],
         fixed_size=4,
     )
     map_user.s(0x00ac,
         fixed=[
             at(0, u16, 'packet id'),
-            at(2, u16, 'ioff2'),
+            at(2, ioff2, 'ioff2'),
             at(4, epos, 'epos'),
             at(6, u8, 'ok'),
         ],
@@ -1907,7 +1940,7 @@ def main():
     map_user.s(0x00af,
         fixed=[
             at(0, u16, 'packet id'),
-            at(2, u16, 'ioff2'),
+            at(2, ioff2, 'ioff2'),
             at(4, u16, 'amount'),
         ],
         fixed_size=6,
@@ -2117,7 +2150,7 @@ def main():
         ],
         head_size=4,
         repeat=[
-            at(0, u16, 'ioff2'),
+            at(0, ioff2, 'ioff2'),
             at(2, u32, 'base price'),
             at(6, u32, 'actual price'),
         ],
@@ -2142,7 +2175,7 @@ def main():
         ],
         head_size=4,
         repeat=[
-            at(0, u16, 'ioff2'),
+            at(0, ioff2, 'ioff2'),
             at(2, u16, 'count'),
         ],
         repeat_size=4,
@@ -2199,7 +2232,7 @@ def main():
     map_user.r(0x00e8,
         fixed=[
             at(0, u16, 'packet id'),
-            at(2, u16, 'zeny or ioff2'),
+            at(2, ioff2, 'zeny or ioff2'),
             at(4, u32, 'amount'),
         ],
         fixed_size=8,
@@ -2268,7 +2301,7 @@ def main():
     map_user.r(0x00f3,
         fixed=[
             at(0, u16, 'packet id'),
-            at(2, u16, 'ioff2'),
+            at(2, ioff2, 'ioff2'),
             at(4, u32, 'amount'),
         ],
         fixed_size=8,
@@ -2276,7 +2309,7 @@ def main():
     map_user.s(0x00f4,
         fixed=[
             at(0, u16, 'packet id'),
-            at(2, u16, 'soff1'),
+            at(2, soff1, 'soff1'),
             at(4, u32, 'amount'),
             at(8, item_name_id, 'name id'),
             at(10, u8, 'identify'),
@@ -2292,7 +2325,7 @@ def main():
     map_user.r(0x00f5,
         fixed=[
             at(0, u16, 'packet id'),
-            at(2, u16, 'soff1'),
+            at(2, soff1, 'soff1'),
             at(4, u32, 'amount'),
         ],
         fixed_size=8,
@@ -2300,7 +2333,7 @@ def main():
     map_user.s(0x00f6,
         fixed=[
             at(0, u16, 'packet id'),
-            at(2, u16, 'soff1'),
+            at(2, soff1, 'soff1'),
             at(4, u32, 'amount'),
         ],
         fixed_size=8,
@@ -2551,7 +2584,7 @@ def main():
     map_user.s(0x013c,
         fixed=[
             at(0, u16, 'packet id'),
-            at(2, u16, 'ioff2'),
+            at(2, ioff2, 'ioff2'),
         ],
         fixed_size=4,
     )
@@ -2653,7 +2686,7 @@ def main():
     map_user.s(0x01b1,
         fixed=[
             at(0, u16, 'packet id'),
-            at(2, u16, 'ioff2'),
+            at(2, ioff2, 'ioff2'),
             at(4, u16, 'amount'),
             at(6, u8, 'fail'),
         ],
@@ -2662,7 +2695,7 @@ def main():
     map_user.s(0x01c8,
         fixed=[
             at(0, u16, 'packet id'),
-            at(2, u16, 'ioff2'),
+            at(2, ioff2, 'ioff2'),
             at(4, item_name_id, 'name id'),
             at(6, block_id, 'block id'),
             at(10, u16, 'amount'),
@@ -2821,7 +2854,7 @@ def main():
         ],
         head_size=4,
         repeat=[
-            at(0, u16, 'ioff2'),
+            at(0, ioff2, 'ioff2'),
             at(2, item_name_id, 'name id'),
             at(4, item_type, 'item type'),
             at(5, u8, 'identify'),
@@ -2841,7 +2874,7 @@ def main():
         ],
         head_size=4,
         repeat=[
-            at(0, u16, 'soff1'),
+            at(0, soff1, 'soff1'),
             at(2, item_name_id, 'name id'),
             at(4, item_type, 'item type'),
             at(5, u8, 'identify'),