/*

 * This code provides a glue layer between PhysicsFS and Simple Directmedia

 *  Layer's (SDL) RWops i/o abstraction.

 *

 * License: this code is public domain. I make no warranty that it is useful,

 *  correct, harmless, or environmentally safe.

 *

 * This particular file may be used however you like, including copying it

 *  verbatim into a closed-source project, exploiting it commercially, and

 *  removing any trace of my name from the source (although I hope you won't

 *  do that). I welcome enhancements and corrections to this file, but I do

 *  not require you to send me patches if you make changes. This code has

 *  NO WARRANTY.

 *

 * Unless otherwise stated, the rest of PhysicsFS falls under the zlib license.

 *  Please see LICENSE.txt in the root of the source tree.

 *

 * SDL 1.2 falls under the LGPL license. SDL 1.3+ is zlib, like PhysicsFS.

 *  You can get SDL at https://www.libsdl.org/

 *

 *  This file was written by Ryan C. Gordon. (icculus@icculus.org).

 */

#include <stdio.h>  /* used for SEEK_SET, SEEK_CUR, SEEK_END ... */

#include "physfsrwops.h"

/* SDL's RWOPS interface changed a little in SDL 2.0... */

#if defined(SDL_VERSION_ATLEAST)

#if SDL_VERSION_ATLEAST(2, 0, 0)

#define TARGET_SDL2 1

#endif

#endif

#if !TARGET_SDL2

#define RW_SEEK_SET SEEK_SET

#define RW_SEEK_CUR SEEK_CUR

#define RW_SEEK_END SEEK_END

#endif

#if TARGET_SDL2

static Sint64 SDLCALL physfsrwops_size(struct SDL_RWops *rw)

{

    PHYSFS_File *handle = (PHYSFS_File *) rw->hidden.unknown.data1;

    return (Sint64) PHYSFS_fileLength(handle);

} /* physfsrwops_size */

#endif

#if TARGET_SDL2

static Sint64 SDLCALL physfsrwops_seek(struct SDL_RWops *rw, Sint64 offset, int whence)

#else

static int physfsrwops_seek(SDL_RWops *rw, int offset, int whence)

#endif

{

    PHYSFS_File *handle = (PHYSFS_File *) rw->hidden.unknown.data1;

    PHYSFS_sint64 pos = 0;

    if (whence == RW_SEEK_SET)

        pos = (PHYSFS_sint64) offset;

    else if (whence == RW_SEEK_CUR)

    {

        const PHYSFS_sint64 current = PHYSFS_tell(handle);

        if (current == -1)

        {

            SDL_SetError("Can't find position in file: %s",

                          PHYSFS_getLastError());

            return -1;

        } /* if */

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

        {

            #if TARGET_SDL2

            return (Sint64) current;

            #else

            return (int) current;

            #endif

        } /* if */

        pos = current + ((PHYSFS_sint64) offset);

    } /* else if */

    else if (whence == RW_SEEK_END)

    {

        const PHYSFS_sint64 len = PHYSFS_fileLength(handle);

        if (len == -1)

        {

            SDL_SetError("Can't find end of file: %s", PHYSFS_getLastError());

            return -1;

        } /* if */

        pos = len + ((PHYSFS_sint64) offset);

    } /* else if */

    else

    {

        SDL_SetError("Invalid 'whence' parameter.");

        return -1;

    } /* else */

    if ( pos < 0 )

    {

        SDL_SetError("Attempt to seek past start of file.");

        return -1;

    } /* if */

    if (!PHYSFS_seek(handle, (PHYSFS_uint64) pos))

    {

        SDL_SetError("PhysicsFS error: %s", PHYSFS_getLastError());

        return -1;

    } /* if */

    #if TARGET_SDL2

    return (Sint64) pos;

    #else

    return (int) pos;

    #endif

} /* physfsrwops_seek */

#if TARGET_SDL2

static size_t SDLCALL physfsrwops_read(struct SDL_RWops *rw, void *ptr,

                                       size_t size, size_t maxnum)

#else

static int physfsrwops_read(SDL_RWops *rw, void *ptr, int size, int maxnum)

#endif

{

    PHYSFS_File *handle = (PHYSFS_File *) rw->hidden.unknown.data1;

    const PHYSFS_uint64 readlen = (PHYSFS_uint64) (maxnum * size);

    const PHYSFS_sint64 rc = PHYSFS_readBytes(handle, ptr, readlen);

    if (rc != ((PHYSFS_sint64) readlen))

    {

        if (!PHYSFS_eof(handle)) /* not EOF? Must be an error. */

        {

            SDL_SetError("PhysicsFS error: %s", PHYSFS_getLastError());

            #if TARGET_SDL2

            return 0;

            #else

            return -1;

            #endif

        } /* if */

    } /* if */

    #if TARGET_SDL2

    return (size_t) rc / size;

    #else

    return (int) rc / size;

    #endif

} /* physfsrwops_read */

#if TARGET_SDL2

static size_t SDLCALL physfsrwops_write(struct SDL_RWops *rw, const void *ptr,

                                        size_t size, size_t num)

#else

static int physfsrwops_write(SDL_RWops *rw, const void *ptr, int size, int num)

#endif

{

    PHYSFS_File *handle = (PHYSFS_File *) rw->hidden.unknown.data1;

    const PHYSFS_uint64 writelen = (PHYSFS_uint64) (num * size);

    const PHYSFS_sint64 rc = PHYSFS_writeBytes(handle, ptr, writelen);

    if (rc != ((PHYSFS_sint64) writelen))

        SDL_SetError("PhysicsFS error: %s", PHYSFS_getLastError());

    #if TARGET_SDL2

    return (size_t) rc;

    #else

    return (int) rc;

    #endif

} /* physfsrwops_write */

static int physfsrwops_close(SDL_RWops *rw)

{

    PHYSFS_File *handle = (PHYSFS_File *) rw->hidden.unknown.data1;

    if (!PHYSFS_close(handle))

    {

        SDL_SetError("PhysicsFS error: %s", PHYSFS_getLastError());

        return -1;

    } /* if */

    SDL_FreeRW(rw);

    return 0;

} /* physfsrwops_close */

static SDL_RWops *create_rwops(PHYSFS_File *handle)

{

    SDL_RWops *retval = NULL;

    if (handle == NULL)

        SDL_SetError("PhysicsFS error: %s", PHYSFS_getLastError());

    else

    {

        retval = SDL_AllocRW();

        if (retval != NULL)

        {

            #if TARGET_SDL2

            retval->size  = physfsrwops_size;

            #endif

            retval->seek  = physfsrwops_seek;

            retval->read  = physfsrwops_read;

            retval->write = physfsrwops_write;

            retval->close = physfsrwops_close;

            retval->hidden.unknown.data1 = handle;

        } /* if */

    } /* else */

    return retval;

} /* create_rwops */

SDL_RWops *PHYSFSRWOPS_makeRWops(PHYSFS_File *handle)

{

    SDL_RWops *retval = NULL;

    if (handle == NULL)

        SDL_SetError("NULL pointer passed to PHYSFSRWOPS_makeRWops().");

    else

        retval = create_rwops(handle);

    return retval;

} /* PHYSFSRWOPS_makeRWops */

SDL_RWops *PHYSFSRWOPS_openRead(const char *fname)

{

    return create_rwops(PHYSFS_openRead(fname));

} /* PHYSFSRWOPS_openRead */

SDL_RWops *PHYSFSRWOPS_openWrite(const char *fname)

{

    return create_rwops(PHYSFS_openWrite(fname));

} /* PHYSFSRWOPS_openWrite */

SDL_RWops *PHYSFSRWOPS_openAppend(const char *fname)

{

    return create_rwops(PHYSFS_openAppend(fname));

} /* PHYSFSRWOPS_openAppend */

/* end of physfsrwops.c ... */