New mapcache system

* Now each map is in separated file so now it will be easier to know
  which map got updated or delete on updates
* Now there's md5 checksum check for each map
* Now the map cache is platform safe, the old format was not packed
  which may result in undefined behavior
* The map cache tool got converted into hercules plugin

Signed-off-by: hemagx <ibrahem.h.basyone@gmail.com>

3 files changed, 506 insertions, 117 deletions

diff --git a/src/map/map.c b/src/map/map.c
index bb367a08d..780e6f535 100644
--- a/src/map/map.c
+++ b/src/map/map.c
@@ -66,6 +66,7 @@
 #include "common/core.h"
 #include "common/ers.h"
 #include "common/grfio.h"
+#include "common/md5calc.h"
 #include "common/memmgr.h"
 #include "common/nullpo.h"
 #include "common/random.h"
@@ -2899,21 +2900,26 @@ int map_cell2gat(struct mapcell cell) {
 	ShowWarning("map_cell2gat: cell has no matching gat type\n");
 	return 1; // default to 'wall'
 }
-void map_cellfromcache(struct map_data *m) {
-	struct map_cache_map_info *info;
 
+/**
+ * Extracts a map's cell data from its compressed mapcache.
+ *
+ * @param[in, out] m The target map.
+ */
+void map_cellfromcache(struct map_data *m)
+{
 	nullpo_retv(m);
-	info = (struct map_cache_map_info *)m->cellPos;
 
-	if (info) {
+	if (m->cell_buf.data != NULL) {
 		char decode_buffer[MAX_MAP_SIZE];
 		unsigned long size, xy;
 		int i;
 
-		size = (unsigned long)info->xs*(unsigned long)info->ys;
+		size = (unsigned long)m->xs * (unsigned long)m->ys;
 
 		// TO-DO: Maybe handle the scenario, if the decoded buffer isn't the same size as expected? [Shinryo]
-		grfio->decode_zip(decode_buffer, &size, m->cellPos+sizeof(struct map_cache_map_info), info->len);
+		grfio->decode_zip(decode_buffer, &size, m->cell_buf.data, m->cell_buf.len);
+
 		CREATE(m->cell, struct mapcell, size);
 
 		// Set cell properties
@@ -3253,97 +3259,125 @@ int map_eraseipport(unsigned short map_index, uint32 ip, uint16 port) {
 	return 0;
 }
 
-/*==========================================
- * [Shinryo]: Init the mapcache
- *------------------------------------------*/
-char *map_init_mapcache(FILE *fp) {
-	struct map_cache_main_header header;
-	size_t size = 0;
-	char *buffer;
-
-	// No file open? Return..
-	nullpo_ret(fp);
+/**
+ * Reads a map's compressed cell data from its mapcache file.
+ *
+ * @param[in,out] m The target map.
+ * @return The loading success state.
+ * @retval false in case of errors.
+ */
+bool map_readfromcache(struct map_data *m)
+{
+	unsigned int file_size;
+	char file_path[256];
+	FILE *fp = NULL;
+	bool retval = false;
+	int16 version;
 
-	// Get file size
-	fseek(fp, 0, SEEK_END);
-	size = ftell(fp);
-	fseek(fp, 0, SEEK_SET);
+	nullpo_retr(false, m);
 
-	// Allocate enough space
-	CREATE(buffer, char, size);
+	snprintf(file_path, sizeof(file_path), "%s%s%s.%s", "maps/", DBPATH, m->name, "mcache");
+	fp = fopen(file_path, "rb");
 
-	// No memory? Return..
-	nullpo_ret(buffer);
+	if (fp == NULL) {
+		ShowWarning("map_readfromcache: Could not open the mapcache file for map '%s' at path '%s'.\n", m->name, file_path);
+		return false;
+	}
 
-	// Read file into buffer..
-	if(fread(buffer, sizeof(char), size, fp) != size) {
-		ShowError("map_init_mapcache: Could not read entire mapcache file\n");
-		aFree(buffer);
-		return NULL;
+	if (fread(&version, sizeof(version), 1, fp) < 1) {
+		ShowError("map_readfromcache: Could not read file version for map '%s'.\n", m->name);
+		fclose(fp);
+		return false;
 	}
 
-	rewind(fp);
+	fseek(fp, 0, SEEK_END);
+	file_size = (unsigned int)ftell(fp);
+	fseek(fp, 0, SEEK_SET); // Rewind file pointer before passing it to the read function.
 
-	// Get main header to verify if data is corrupted
-	if( fread(&header, sizeof(header), 1, fp) != 1 ) {
-		ShowError("map_init_mapcache: Error obtaining main header!\n");
-		aFree(buffer);
-		return NULL;
-	}
-	if( GetULong((unsigned char *)&(header.file_size)) != size ) {
-		ShowError("map_init_mapcache: Map cache is corrupted!\n");
-		aFree(buffer);
-		return NULL;
+	switch(version) {
+	case 1:
+		retval = map->readfromcache_v1(fp, m, file_size);
+		break;
+	default:
+		ShowError("map_readfromcache: Mapcache file has unknown version '%d' for map '%s'.\n", version, m->name);
+		break;
 	}
 
-	return buffer;
+	fclose(fp);
+	return retval;
 }
 
-/*==========================================
- * Map cache reading
- * [Shinryo]: Optimized some behaviour to speed this up
- *==========================================*/
-int map_readfromcache(struct map_data *m, char *buffer) {
-	int i;
-	struct map_cache_main_header *header = (struct map_cache_main_header *)buffer;
-	struct map_cache_map_info *info = NULL;
-	char *p = buffer + sizeof(struct map_cache_main_header);
-
-	nullpo_ret(m);
-	nullpo_ret(buffer);
-
-	for(i = 0; i < header->map_count; i++) {
-		info = (struct map_cache_map_info *)p;
+/**
+ * Reads a map's compressed cell data from its mapcache file (file format
+ * version 1).
+ *
+ * @param[in]     fp        The file pointer to read from (opened and closed by
+ *                          the caller).
+ * @param[in,out] m         The target map.
+ * @param[in]     file_size The size of the file to load from.
+ * @return The loading success state.
+ * @retval false in case of errors.
+ */
+bool map_readfromcache_v1(FILE *fp, struct map_data *m, unsigned int file_size)
+{
+	struct map_cache_header mheader = { 0 };
+	uint8 md5buf[16] = { 0 };
+	int map_size;
+	nullpo_retr(false, fp);
+	nullpo_retr(false, m);
+
+	if (file_size <= sizeof(mheader) || fread(&mheader, sizeof(mheader), 1, fp) < 1) {
+		ShowError("map_readfromcache: Failed to read cache header for map '%s'.\n", m->name);
+		return false;
+	}
 
-		if( strcmp(m->name, info->name) == 0 )
-			break; // Map found
+	if (mheader.len <= 0) {
+		ShowError("map_readfromcache: A file with negative or zero compressed length passed '%d'.\n", mheader.len);
+		return false;
+	}
 
-		// Jump to next entry..
-		p += sizeof(struct map_cache_map_info) + info->len;
+	if (file_size < sizeof(mheader) + mheader.len) {
+		ShowError("map_readfromcache: An incomplete file passed for map '%s'.\n", m->name);
+		return false;
 	}
 
-	if( info && i < header->map_count ) {
-		unsigned long size;
+	if (mheader.ys <= 0 || mheader.xs <= 0) {
+		ShowError("map_readfromcache: A map with invalid size passed '%s' xs: '%d' ys: '%d'.\n", m->name, mheader.xs, mheader.ys);
+		return false;
+	}
 
-		if( info->xs <= 0 || info->ys <= 0 )
-			return 0;// Invalid
+	m->xs = mheader.xs;
+	m->ys = mheader.ys;
+	map_size = (int)mheader.xs * (int)mheader.ys;
 
-		m->xs = info->xs;
-		m->ys = info->ys;
-		size = (unsigned long)info->xs*(unsigned long)info->ys;
+	if (map_size > MAX_MAP_SIZE) {
+		ShowWarning("map_readfromcache: %s exceeded MAX_MAP_SIZE of %d.\n", m->name, MAX_MAP_SIZE);
+		return false;
+	}
 
-		if(size > MAX_MAP_SIZE) {
-			ShowWarning("map_readfromcache: %s exceeded MAX_MAP_SIZE of %d\n", info->name, MAX_MAP_SIZE);
-			return 0; // Say not found to remove it from list.. [Shinryo]
-		}
+	CREATE(m->cell_buf.data, uint8, mheader.len);
+	m->cell_buf.len = mheader.len;
+	if (fread(m->cell_buf.data, mheader.len, 1, fp) < 1) {
+		ShowError("mapreadfromcache: Could not load the compressed cell data for map '%s'.\n", m->name);
+		aFree(m->cell_buf.data);
+		m->cell_buf.data = NULL;
+		m->cell_buf.len = 0;
+		return false;
+	}
 
-		m->cellPos = p;
-		m->cell = (struct mapcell *)0xdeadbeaf;
+	md5->binary(m->cell_buf.data, m->cell_buf.len, md5buf);
 
-		return 1;
+	if (memcmp(md5buf, mheader.md5_checksum, sizeof(md5buf)) != 0) {
+		ShowError("mapreadfromcache: md5 checksum check failed for map '%s'\n", m->name);
+		aFree(m->cell_buf.data);
+		m->cell_buf.data = NULL;
+		m->cell_buf.len = 0;
+		return false;
 	}
 
-	return 0; // Not found
+	m->cell = (struct mapcell *)0xdeadbeaf;
+
+	return true;
 }
 
 /**
@@ -3747,26 +3781,12 @@ void map_removemapdb(struct map_data *m) {
  *--------------------------------------*/
 int map_readallmaps (void) {
 	int i;
-	FILE* fp=NULL;
 	int maps_removed = 0;
 
-	if( map->enable_grf )
+	if (map->enable_grf) {
 		ShowStatus("Loading maps (using GRF files)...\n");
-	else {
-		char mapcachefilepath[256];
-		safesnprintf(mapcachefilepath, 256, "%s/%s%s", map->db_path, DBPATH, "map_cache.dat");
-		ShowStatus("Loading maps (using %s as map cache)...\n", mapcachefilepath);
-		if( (fp = fopen(mapcachefilepath, "rb")) == NULL ) {
-			ShowFatalError("Unable to open map cache file "CL_WHITE"%s"CL_RESET"\n", mapcachefilepath);
-			exit(EXIT_FAILURE); //No use launching server if maps can't be read.
-		}
-
-		// Init mapcache data.. [Shinryo]
-		map->cache_buffer = map->init_mapcache(fp);
-		if(!map->cache_buffer) {
-			ShowFatalError("Failed to initialize mapcache data (%s)..\n", mapcachefilepath);
-			exit(EXIT_FAILURE);
-		}
+	} else {
+		ShowStatus("Loading maps using map cache files...\n");
 	}
 
 	for(i = 0; i < map->count; i++) {
@@ -3780,7 +3800,7 @@ int map_readallmaps (void) {
 		if( !
 			(map->enable_grf?
 			map->readgat(&map->list[i])
-			:map->readfromcache(&map->list[i], map->cache_buffer))
+			:map->readfromcache(&map->list[i]))
 			) {
 				map->delmapid(i);
 				maps_removed++;
@@ -3822,10 +3842,6 @@ int map_readallmaps (void) {
 	// intialization and configuration-dependent adjustments of mapflags
 	map->flags_init();
 
-	if( !map->enable_grf ) {
-		fclose(fp);
-	}
-
 	// finished map loading
 	ShowInfo("Successfully loaded '"CL_WHITE"%d"CL_RESET"' maps."CL_CLL"\n",map->count);
 	instance->start_id = map->count; // Next Map Index will be instances
@@ -6062,6 +6078,11 @@ int do_final(void) {
 	ers_destroy(map->iterator_ers);
 	ers_destroy(map->flooritem_ers);
 
+	for (i = 0; i < map->count; ++i) {
+		if (map->list[i].cell_buf.data != NULL)
+			aFree(map->list[i].cell_buf.data);
+		map->list[i].cell_buf.len = 0;
+	}
 	aFree(map->list);
 
 	if( map->block_free )
@@ -6069,9 +6090,6 @@ int do_final(void) {
 	if( map->bl_list )
 		aFree(map->bl_list);
 
-	if( !map->enable_grf )
-		aFree(map->cache_buffer);
-
 	aFree(map->MAP_CONF_NAME);
 	aFree(map->BATTLE_CONF_FILENAME);
 	aFree(map->ATCOMMAND_CONF_FILENAME);
@@ -6687,7 +6705,6 @@ void map_defaults(void) {
 	map->list = NULL;
 
 	map->iterator_ers = NULL;
-	map->cache_buffer = NULL;
 
 	map->flooritem_ers = NULL;
 	/* */
@@ -6834,8 +6851,8 @@ void map_defaults(void) {
 	map->iwall_nextxy = map_iwall_nextxy;
 	map->create_map_data_other_server = create_map_data_other_server;
 	map->eraseallipport_sub = map_eraseallipport_sub;
-	map->init_mapcache = map_init_mapcache;
 	map->readfromcache = map_readfromcache;
+	map->readfromcache_v1 = map_readfromcache_v1;
 	map->addmap = map_addmap;
 	map->delmapid = map_delmapid;
 	map->zone_db_clear = map_zone_db_clear;
diff --git a/src/map/map.h b/src/map/map.h
index facf1d921..5c4c6d59d 100644
--- a/src/map/map.h
+++ b/src/map/map.h
@@ -909,7 +909,10 @@ struct map_data {
 	/* */
 	int (*getcellp)(struct map_data* m, const struct block_list *bl, int16 x, int16 y, cell_chk cellchk);
 	void (*setcell) (int16 m, int16 x, int16 y, cell_t cell, bool flag);
-	char *cellPos;
+	struct {
+		uint8 *data;
+		int len;
+	} cell_buf;
 
 	/* ShowEvent Data Cache */
 	struct questinfo *qi_data;
@@ -1064,20 +1067,20 @@ struct charid2nick {
 	struct charid_request* requests;// requests of notification on this nick
 };
 
-// This is the main header found at the very beginning of the map cache
-struct map_cache_main_header {
-	uint32 file_size;
-	uint16 map_count;
-};
-
-// This is the header appended before every compressed map cells info in the map cache
-struct map_cache_map_info {
-	char name[MAP_NAME_LENGTH];
+// New mcache file format header
+#if !defined(sun) && (!defined(__NETBSD__) || __NetBSD_Version__ >= 600000000) // NetBSD 5 and Solaris don't like pragma pack but accept the packed attribute
+#pragma pack(push, 1)
+#endif // not NetBSD < 6 / Solaris
+struct map_cache_header {
+	int16 version;
+	uint8 md5_checksum[16];
 	int16 xs;
 	int16 ys;
 	int32 len;
-};
-
+} __attribute__((packed));
+#if !defined(sun) && (!defined(__NETBSD__) || __NetBSD_Version__ >= 600000000) // NetBSD 5 and Solaris don't like pragma pack but accept the packed attribute
+#pragma pack(pop)
+#endif // not NetBSD < 6 / Solaris
 
 /*=====================================
 * Interface : map.h
@@ -1167,7 +1170,6 @@ END_ZEROED_BLOCK;
 	struct map_data *list;
 	/* [Ind/Hercules] */
 	struct eri *iterator_ers;
-	char *cache_buffer; // Has the uncompressed gat data of all maps, so just one allocation has to be made
 	/* */
 	struct eri *flooritem_ers;
 	/* */
@@ -1317,8 +1319,8 @@ END_ZEROED_BLOCK;
 	void (*iwall_nextxy) (int16 x, int16 y, int8 dir, int pos, int16 *x1, int16 *y1);
 	struct DBData (*create_map_data_other_server) (union DBKey key, va_list args);
 	int (*eraseallipport_sub) (union DBKey key, struct DBData *data, va_list va);
-	char* (*init_mapcache) (FILE *fp);
-	int (*readfromcache) (struct map_data *m, char *buffer);
+	bool (*readfromcache) (struct map_data *m);
+	bool (*readfromcache_v1) (FILE *fp, struct map_data *m, unsigned int file_size);
 	int (*addmap) (const char *mapname);
 	void (*delmapid) (int id);
 	void (*zone_db_clear) (void);
diff --git a/src/plugins/mapcache.c b/src/plugins/mapcache.c
new file mode 100644
index 000000000..95e6ead04
--- /dev/null
+++ b/src/plugins/mapcache.c
@@ -0,0 +1,370 @@
+/**
+* This file is part of Hercules.
+* http://herc.ws - http://github.com/HerculesWS/Hercules
+*
+* Copyright (C) 2013-2015  Hercules Dev Team
+*
+* Hercules 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/>.
+*/
+
+/**
+ * Mapcache Plugin
+ * This Plugin is made to handle the creation and update the new format of mapcache
+ * it also handles the convertion from the old to the new mapcache format
+ **/
+
+#include "common/hercules.h" /* Should always be the first Hercules file included! (if you don't make it first, you won't be able to use interfaces) */
+
+#include "common/memmgr.h"
+#include "common/md5calc.h"
+#include "common/nullpo.h"
+#include "common/grfio.h"
+#include "common/utils.h"
+#include "map/map.h"
+
+#include "common/HPMDataCheck.h" /* should always be the last Hercules file included! (if you don't make it last, it'll intentionally break compile time) */
+
+#include <stdio.h>
+#include <string.h>
+
+HPExport struct hplugin_info pinfo = {
+	"Mapcache",      ///< Plugin name
+	SERVER_TYPE_MAP, ///< Which server types this plugin works with?
+	"1.0.0",         ///< Plugin version
+	HPM_VERSION,     ///< HPM Version (don't change, macro is automatically updated)
+};
+
+/**
+ * Yes.. old mapcache was never packed, and we loaded and wrote a compiler paded structs
+ * DON'T BLAME IF SOMETHING EXPLODED [hemagx]
+ **/
+// This is the main header found at the very beginning of the map cache
+struct old_mapcache_main_header {
+	uint32 file_size;
+	uint16 map_count;
+};
+
+// This is the header appended before every compressed map cells info in the map cache
+struct old_mapcache_map_info {
+	char name[MAP_NAME_LENGTH];
+	int16 xs;
+	int16 ys;
+	int32 len;
+};
+
+/**
+ *
+ */
+
+#define NO_WATER 1000000
+
+VECTOR_DECL(char *) maplist;
+
+
+/**
+ * code from utlis.c until it's interfaced
+ **/
+
+#ifdef WIN32
+#	ifndef F_OK
+#		define F_OK   0x0
+#	endif  /* F_OK */
+#else
+#	include <unistd.h>
+#endif
+
+
+// Reads an uint32 in little-endian from the buffer
+uint32 GetULong(const unsigned char* buf)
+{
+	return (((uint32)(buf[0])))
+		| (((uint32)(buf[1])) << 0x08)
+		| (((uint32)(buf[2])) << 0x10)
+		| (((uint32)(buf[3])) << 0x18);
+}
+
+// Reads a float (32 bits) from the buffer
+float GetFloat(const unsigned char* buf)
+{
+	uint32 val = GetULong(buf);
+	return *((float*)(void*)&val);
+}
+
+bool write_mapcache(const uint8 *buf, int32 buf_len, bool is_compressed, const char *mapname, int16 xs, int16 ys)
+{
+	struct map_cache_header header = { 0 };
+	char file_path[255];
+	int mapname_len;
+	unsigned long compressed_buf_len;
+	uint8 *compressed_buf = NULL;
+	FILE *new_mapcache_fp;
+
+	nullpo_retr(false, buf);
+	nullpo_retr(false, mapname);
+
+	mapname_len = (int)strlen(mapname);
+
+	if (mapname_len > MAP_NAME_LENGTH || mapname_len < 1) {
+		ShowError("write_mapcache: A map with invalid name length has beed passed '%s' size (%d)\n", mapname, mapname_len);
+		return false;
+	}
+
+	if ((xs < 0 || ys < 0)) {
+		ShowError("write_mapcache: '%s' given with invalid coords xs = %d, ys = %d\n", mapname, xs, ys);
+		return false;
+	}
+
+	if (((int)xs * ys) > MAX_MAP_SIZE) {
+		ShowError("write_mapcache: map '%s' exceeded MAX_MAP_SIZE of %d\n", mapname, MAX_MAP_SIZE);
+		return false;
+	}
+
+
+
+	snprintf(file_path, sizeof(file_path), "%s%s%s.%s", "maps/", DBPATH, mapname, "mcache");
+	new_mapcache_fp = fopen(file_path, "w+b");
+
+	if (new_mapcache_fp == NULL) {
+		ShowWarning("Could not open file '%s', map cache creating failed.\n", file_path);
+		return false;
+	}
+
+	header.version = 0x1;
+	header.xs = xs;
+	header.ys = ys;
+
+	if (is_compressed == false) {
+		compressed_buf_len = buf_len * 2; //Creating big enough buffer to ensure ability to hold compressed data
+		CREATE(compressed_buf, uint8, compressed_buf_len);
+		grfio->encode_zip(compressed_buf, &compressed_buf_len, buf, buf_len);
+
+		header.len = (int)compressed_buf_len;
+		md5->binary(compressed_buf, (int)compressed_buf_len, header.md5_checksum);
+	} else {
+		header.len = buf_len;
+		md5->binary(buf, buf_len, header.md5_checksum);
+	}
+
+
+	fwrite(&header, sizeof(header), 1, new_mapcache_fp);
+	if (is_compressed == false)
+		fwrite(compressed_buf, compressed_buf_len, 1, new_mapcache_fp);
+	else
+		fwrite(buf, buf_len, 1, new_mapcache_fp);
+
+	fclose(new_mapcache_fp);
+	if (compressed_buf != NULL)
+		aFree(compressed_buf);
+
+	return true;
+}
+
+bool convert_old_mapcache(void)
+{
+	const char *path = "db/"DBPATH"map_cache.dat";
+	FILE *mapcache_fp = fopen(path, "rb");
+	struct old_mapcache_main_header header = { 0 };
+	uint8 *p, *cursor;
+	uint32 file_size;
+	int i;
+
+	if (mapcache_fp == NULL) {
+		ShowError("Could not open mapcache file in the following path '%s' \n", path);
+		return false;
+	}
+
+	if (fread(&header, sizeof(header), 1, mapcache_fp) != 1) {
+		ShowError("Failed to read mapcache header \n");
+		fclose(mapcache_fp);
+		return false;
+	}
+
+	fseek(mapcache_fp, 0, SEEK_END);
+	file_size = (int)ftell(mapcache_fp);
+	fseek(mapcache_fp, 0, SEEK_SET);
+
+	if (file_size != header.file_size) {
+		ShowError("File size in mapcache header doesn't match actual mapcache file size \n");
+		fclose(mapcache_fp);
+		return false;
+	}
+
+	CREATE(p, uint8, header.file_size);
+	cursor = p + sizeof(header);
+
+	if (fread(p, header.file_size, 1, mapcache_fp) != 1) {
+		ShowError("Could not load mapcache file into memory, fread failed.\n");
+		aFree(p);
+		fclose(mapcache_fp);
+		return false;
+	}
+
+	for (i = 0; i < header.map_count; ++i) {
+		struct old_mapcache_map_info *info = (struct old_mapcache_map_info *)cursor;
+
+		ShowStatus("Creating mapcache: %s"CL_CLL"\n", info->name);
+
+		if (write_mapcache((uint8 *)info + sizeof(*info), info->len, true, info->name, info->xs, info->ys) == false) {
+			ShowError("failed To convert map '%s'\n", info->name);
+		}
+
+		cursor += sizeof(*info) + info->len;
+	}
+
+	aFree(p);
+	fclose(mapcache_fp);
+	return true;
+}
+
+bool mapcache_read_maplist(const char *filepath)
+{
+	char line[4096] = { 0 };
+	FILE *fp;
+
+	nullpo_retr(false, filepath);
+
+	fp = fopen(filepath, "r");
+
+	if (fp == NULL)
+		return false;
+
+	while (fgets(line, sizeof(line), fp)) {
+		char map_name[MAP_NAME_LENGTH];
+		if (line[0] == '/' && line[1] == '/')
+			continue;
+
+		if (sscanf(line, "%11s", map_name) == 1) {
+			VECTOR_ENSURE(maplist, 1, 1);
+			VECTOR_PUSH(maplist, aStrdup(map_name));
+		}
+	}
+
+	ShowStatus("%d map loaded from map_index.txt\n", VECTOR_LENGTH(maplist));
+	fclose(fp);
+	return true;
+}
+
+bool mapcache_cache_map(const char *mapname)
+{
+	char filepath[255] = { 0 };
+	uint8 *gat, *rsw, *gat_cursor;
+	uint8 *cells;
+	int water_height, map_size, xy;
+	int16 xs, ys;
+
+	nullpo_retr(false, mapname);
+
+	snprintf(filepath, sizeof(filepath), "data\\%s.gat", mapname);
+	gat = grfio_read(filepath);
+
+	if (gat == NULL) {
+		ShowError("mapcache_cache_map: Could not read %s, aborting caching map %s\n", filepath, mapname);
+		return false;
+	}
+
+	snprintf(filepath, sizeof(filepath), "data\\%s.rsw", mapname);
+
+	rsw = grfio_read(filepath);
+
+	if (rsw == NULL) {
+		water_height = NO_WATER;
+	} else {
+		water_height = (int)GetFloat(rsw + 166);
+		aFree(rsw);
+	}
+
+	xs = (int16)GetULong(gat + 6);
+	ys = (int16)GetULong(gat + 10);
+
+	if (xs <= 0 || ys <= 0) {
+		ShowError("mapcache_cache_map: map '%s' doesn't have valid size xs = %d, ys = %d\n", mapname, xs, ys);
+		aFree(gat);
+		return false;
+	}
+
+	map_size = xs * ys;
+	CREATE(cells, uint8, map_size);
+
+	gat_cursor = gat;
+	for (xy = 0; xy < map_size; ++xy) {
+		float height = GetFloat(gat_cursor + 14);
+		uint32 type = GetULong(gat_cursor + 30);
+		gat_cursor += 20;
+
+		if (type == 0 && water_height != NO_WATER && height > water_height)
+			type = 3;
+
+		cells[xy] = (uint8)type;
+	}
+
+	write_mapcache(cells, map_size, false, mapname, xs, ys);
+
+	aFree(gat);
+	aFree(cells);
+	return true;
+}
+
+bool mapcache_rebuild(void)
+{
+	int i;
+	char file_path[255];
+
+	if (mapcache_read_maplist("db/map_index.txt") == false) {
+		ShowError("mapcache_rebuild: Could not read maplist, aborting\n");
+		return false;
+	}
+
+	for (i = 0; i < VECTOR_LENGTH(maplist); ++i) {
+		snprintf(file_path, sizeof(file_path), "%s%s%s.%s", "maps/", DBPATH, VECTOR_INDEX(maplist, i), "mcache");
+		if (access(file_path, F_OK) == 0 && remove(file_path) != 0) {
+			ShowWarning("mapcache_rebuild: Could not remove file '%s' \n", file_path);
+		}
+	}
+
+	grfio->init("conf/grf-files.txt");
+
+	for (i = 0; i < VECTOR_LENGTH(maplist); ++i) {
+		ShowStatus("Creating mapcache: %s"CL_CLL"\r", VECTOR_INDEX(maplist, i));
+		mapcache_cache_map(VECTOR_INDEX(maplist, i));
+	}
+
+	return true;
+}
+
+CMDLINEARG(convertmapcache)
+{
+	map->minimal = true;
+	return convert_old_mapcache();
+}
+
+CMDLINEARG(rebuild)
+{
+	map->minimal = true;
+	return mapcache_rebuild();
+}
+
+HPExport void server_preinit(void)
+{
+	addArg("--convert-old-mapcache", false, convertmapcache,
+			"Converts an old db/"DBPATH"map_cache.dat file to the new format.");
+	addArg("--rebuild-mapcache", false, rebuild,
+			"Rebuilds the entire mapcache folder (maps/"DBPATH"), using db/map_index.txt as index.");
+
+	VECTOR_INIT(maplist);
+}
+
+HPExport void plugin_final(void)
+{
+	VECTOR_CLEAR(maplist);
+}