path: root/src/fs/virtfs/fsziprwops.cpp

/*
 *  The ManaPlus Client
 *  Copyright (C) 2013-2019  The ManaPlus Developers
 *
 *  This file is part of The ManaPlus Client.
 *
 *  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 2 of the License, or
 *  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 "fs/virtfs/fsziprwops.h"

#include "logger.h"

#include "fs/virtfs/file.h"
#include "fs/virtfs/fsfuncs.h"

#include "utils/cast.h"

PRAGMA48(GCC diagnostic push)
PRAGMA48(GCC diagnostic ignored "-Wshadow")
#include <SDL_rwops.h>
PRAGMA48(GCC diagnostic pop)

#include "debug.h"

namespace VirtFs
{

namespace FsZip
{
    RWOPSINT rwops_seek(SDL_RWops *const rw,
                        const RWOPSINT offset,
                        const int whence)
    {
        if (rw == nullptr)
            return -1;
        File *const handle = static_cast<File *>(
            rw->hidden.unknown.data1);
        size_t mPos = handle->mPos;
        size_t mSize = handle->mSize;

        RWOPSINT pos = 0;

        if (whence == SEEK_SET)
        {
            pos = offset;
        }
        else if (whence == SEEK_CUR)
        {
            const int64_t current = mPos;
            if (current == -1)
            {
                logger->assertLog(
                    "VirtFs::rwops_seek: Can't find position in file.");
                return -1;
            }

            pos = CAST_S32(current);
            if (static_cast<int64_t>(pos) != current)
            {
                logger->assertLog("VirtFs::rwops_seek: "
                    "Can't fit current file position in an int!");
                return -1;
            }

            if (offset == 0)  /* this is a "tell" call. We're done. */
                return pos;

            pos += offset;
        }
        else if (whence == SEEK_END)
        {
            pos = static_cast<RWOPSINT>(mSize + offset);
        }
        else
        {
            logger->assertLog(
                "VirtFs::rwops_seek: Invalid 'whence' parameter.");
            return -1;
        }

        if (pos < 0)
        {
            logger->assertLog("VirtFs::rwops_seek: "
                "Attempt to seek past start of file.");
            return -1;
        }

        handle->mPos = pos;

        if (pos > static_cast<RWOPSINT>(mSize))
        {
            logger->assertLog("VirtFs::rwops_seek: seek error.");
            return -1;
        }

        return pos;
    }

    RWOPSSIZE rwops_read(SDL_RWops *const rw,
                         void *const ptr,
                         const RWOPSSIZE size,
                         const RWOPSSIZE maxnum)
    {
        if (rw == nullptr)
            return 0;
        File *const handle = static_cast<File *>(
            rw->hidden.unknown.data1);

        const int64_t rc = handle->funcs->read(handle,
            ptr,
            CAST_U32(size),
            CAST_U32(maxnum));
        return CAST_S32(rc);
    }

    RWOPSSIZE rwops_write(SDL_RWops *const rw A_UNUSED,
                          const void *const ptr A_UNUSED,
                          const RWOPSSIZE size A_UNUSED,
                          const RWOPSSIZE num A_UNUSED)
    {
        return 0;
    }

    int rwops_close(SDL_RWops *const rw)
    {
        if (rw == nullptr)
            return 0;
        File *const handle = static_cast<File*>(
            rw->hidden.unknown.data1);
        delete handle;
        SDL_FreeRW(rw);
        return 0;
    }

#ifdef USE_SDL2
    RWOPSINT rwops_size(SDL_RWops *const rw)
    {
        if (!rw)
            return 0;
        File *const handle = static_cast<File *>(
            rw->hidden.unknown.data1);
        return handle->mSize;
    }
#endif  // USE_SDL2

}  // namespace FsZip

}  // namespace VirtFs