/*
  SDL_image:  An example image loading library for use with SDL
  Copyright (C) 1997-2016 Sam Lantinga <slouken@libsdl.org>

  This software is provided 'as-is', without any express or implied
  warranty.  In no event will the authors be held liable for any damages
  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely, subject to the following restrictions:

  1. The origin of this software must not be misrepresented; you must not
     claim that you wrote the original software. If you use this software
     in a product, an acknowledgment in the product documentation would be
     appreciated but is not required.
  2. Altered source versions must be plainly marked as such, and must not be
     misrepresented as being the original software.
  3. This notice may not be removed or altered from any source distribution.
*/

#if !defined(__APPLE__) || defined(SDL_IMAGE_USE_COMMON_BACKEND)

/* This is a TIFF image file loading framework */

#include <stdio.h>

#include "SDL_image.h"

#ifdef LOAD_TIF

#include <tiffio.h>

static struct {
    int loaded;
    void *handle;
    TIFF* (*TIFFClientOpen)(const char*, const char*, thandle_t, TIFFReadWriteProc, TIFFReadWriteProc, TIFFSeekProc, TIFFCloseProc, TIFFSizeProc, TIFFMapFileProc, TIFFUnmapFileProc);
    void (*TIFFClose)(TIFF*);
    int (*TIFFGetField)(TIFF*, ttag_t, ...);
    int (*TIFFReadRGBAImage)(TIFF*, uint32, uint32, uint32*, int);
    TIFFErrorHandler (*TIFFSetErrorHandler)(TIFFErrorHandler);
} lib;

#ifdef LOAD_TIF_DYNAMIC
int IMG_InitTIF()
{
    if ( lib.loaded == 0 ) {
        lib.handle = SDL_LoadObject(LOAD_TIF_DYNAMIC);
        if ( lib.handle == NULL ) {
            return -1;
        }
        lib.TIFFClientOpen =
            (TIFF* (*)(const char*, const char*, thandle_t, TIFFReadWriteProc, TIFFReadWriteProc, TIFFSeekProc, TIFFCloseProc, TIFFSizeProc, TIFFMapFileProc, TIFFUnmapFileProc))
            SDL_LoadFunction(lib.handle, "TIFFClientOpen");
        if ( lib.TIFFClientOpen == NULL ) {
            SDL_UnloadObject(lib.handle);
            return -1;
        }
        lib.TIFFClose =
            (void (*)(TIFF*))
            SDL_LoadFunction(lib.handle, "TIFFClose");
        if ( lib.TIFFClose == NULL ) {
            SDL_UnloadObject(lib.handle);
            return -1;
        }
        lib.TIFFGetField =
            (int (*)(TIFF*, ttag_t, ...))
            SDL_LoadFunction(lib.handle, "TIFFGetField");
        if ( lib.TIFFGetField == NULL ) {
            SDL_UnloadObject(lib.handle);
            return -1;
        }
        lib.TIFFReadRGBAImage =
            (int (*)(TIFF*, uint32, uint32, uint32*, int))
            SDL_LoadFunction(lib.handle, "TIFFReadRGBAImage");
        if ( lib.TIFFReadRGBAImage == NULL ) {
            SDL_UnloadObject(lib.handle);
            return -1;
        }
        lib.TIFFSetErrorHandler =
            (TIFFErrorHandler (*)(TIFFErrorHandler))
            SDL_LoadFunction(lib.handle, "TIFFSetErrorHandler");
        if ( lib.TIFFSetErrorHandler == NULL ) {
            SDL_UnloadObject(lib.handle);
            return -1;
        }
    }
    ++lib.loaded;

    return 0;
}
void IMG_QuitTIF()
{
    if ( lib.loaded == 0 ) {
        return;
    }
    if ( lib.loaded == 1 ) {
        SDL_UnloadObject(lib.handle);
    }
    --lib.loaded;
}
#else
int IMG_InitTIF()
{
    if ( lib.loaded == 0 ) {
        lib.TIFFClientOpen = TIFFClientOpen;
        lib.TIFFClose = TIFFClose;
        lib.TIFFGetField = TIFFGetField;
        lib.TIFFReadRGBAImage = TIFFReadRGBAImage;
        lib.TIFFSetErrorHandler = TIFFSetErrorHandler;
    }
    ++lib.loaded;

    return 0;
}
void IMG_QuitTIF()
{
    if ( lib.loaded == 0 ) {
        return;
    }
    if ( lib.loaded == 1 ) {
    }
    --lib.loaded;
}
#endif /* LOAD_TIF_DYNAMIC */

/*
 * These are the thunking routine to use the SDL_RWops* routines from
 * libtiff's internals.
*/

static tsize_t tiff_read(thandle_t fd, tdata_t buf, tsize_t size)
{
    return SDL_RWread((SDL_RWops*)fd, buf, 1, size);
}

static toff_t tiff_seek(thandle_t fd, toff_t offset, int origin)
{
    return SDL_RWseek((SDL_RWops*)fd, offset, origin);
}

static tsize_t tiff_write(thandle_t fd, tdata_t buf, tsize_t size)
{
    return SDL_RWwrite((SDL_RWops*)fd, buf, 1, size);
}

static int tiff_close(thandle_t fd)
{
    /*
     * We don't want libtiff closing our SDL_RWops*, but if it's not given
         * a routine to try, and if the image isn't a TIFF, it'll segfault.
     */
    return 0;
}

static int tiff_map(thandle_t fd, tdata_t* pbase, toff_t* psize)
{
    return (0);
}

static void tiff_unmap(thandle_t fd, tdata_t base, toff_t size)
{
    return;
}

static toff_t tiff_size(thandle_t fd)
{
    Sint64 save_pos;
    toff_t size;

    save_pos = SDL_RWtell((SDL_RWops*)fd);
    SDL_RWseek((SDL_RWops*)fd, 0, RW_SEEK_END);
    size = SDL_RWtell((SDL_RWops*)fd);
    SDL_RWseek((SDL_RWops*)fd, save_pos, RW_SEEK_SET);
    return size;
}

int IMG_isTIF(SDL_RWops* src)
{
    Sint64 start;
    int is_TIF;
    Uint8 magic[4];

    if ( !src )
        return 0;
    start = SDL_RWtell(src);
    is_TIF = 0;
    if ( SDL_RWread(src, magic, 1, sizeof(magic)) == sizeof(magic) ) {
        if ( (magic[0] == 'I' &&
                      magic[1] == 'I' &&
              magic[2] == 0x2a &&
                      magic[3] == 0x00) ||
             (magic[0] == 'M' &&
                      magic[1] == 'M' &&
              magic[2] == 0x00 &&
                      magic[3] == 0x2a) ) {
            is_TIF = 1;
        }
    }
    SDL_RWseek(src, start, RW_SEEK_SET);
    return(is_TIF);
}

SDL_Surface* IMG_LoadTIF_RW(SDL_RWops* src)
{
    Sint64 start;
    TIFF* tiff;
    SDL_Surface* surface = NULL;
    Uint32 img_width, img_height;
    Uint32 Rmask, Gmask, Bmask, Amask;
    Uint32 x, y;
    Uint32 half;

    if ( !src ) {
        /* The error message has been set in SDL_RWFromFile */
        return NULL;
    }
    start = SDL_RWtell(src);

    if ( !IMG_Init(IMG_INIT_TIF) ) {
        return NULL;
    }

    /* turn off memory mapped access with the m flag */
    tiff = lib.TIFFClientOpen("SDL_image", "rm", (thandle_t)src,
        tiff_read, tiff_write, tiff_seek, tiff_close, tiff_size, tiff_map, tiff_unmap);
    if(!tiff)
        goto error;

    /* Retrieve the dimensions of the image from the TIFF tags */
    lib.TIFFGetField(tiff, TIFFTAG_IMAGEWIDTH, &img_width);
    lib.TIFFGetField(tiff, TIFFTAG_IMAGELENGTH, &img_height);

    Rmask = 0x000000FF;
    Gmask = 0x0000FF00;
    Bmask = 0x00FF0000;
    Amask = 0xFF000000;
    surface = SDL_CreateRGBSurface(SDL_SWSURFACE, img_width, img_height, 32,
        Rmask, Gmask, Bmask, Amask);
    if(!surface)
        goto error;

    if(!lib.TIFFReadRGBAImage(tiff, img_width, img_height, (uint32 *)surface->pixels, 0))
        goto error;

    /* libtiff loads the image upside-down, flip it back */
    half = img_height / 2;
    for(y = 0; y < half; y++)
    {
            Uint32 *top = (Uint32 *)surface->pixels + y * surface->pitch/4;
            Uint32 *bot = (Uint32 *)surface->pixels
                      + (img_height - y - 1) * surface->pitch/4;
        for(x = 0; x < img_width; x++)
        {
                Uint32 tmp = top[x];
            top[x] = bot[x];
            bot[x] = tmp;
        }
    }
    lib.TIFFClose(tiff);

    return surface;

error:
    SDL_RWseek(src, start, RW_SEEK_SET);
    if ( surface ) {
        SDL_FreeSurface(surface);
    }
    return NULL;
}

#else

int IMG_InitTIF()
{
    IMG_SetError("TIFF images are not supported");
    return(-1);
}

void IMG_QuitTIF()
{
}

/* See if an image is contained in a data source */
int IMG_isTIF(SDL_RWops *src)
{
    return(0);
}

/* Load a TIFF type image from an SDL datasource */
SDL_Surface *IMG_LoadTIF_RW(SDL_RWops *src)
{
    return(NULL);
}

#endif /* LOAD_TIF */

#endif /* !defined(__APPLE__) || defined(SDL_IMAGE_USE_COMMON_BACKEND) */
