// Copyright 2012 Google Inc. All Rights Reserved.

//

// Use of this source code is governed by a BSD-style license

// that can be found in the COPYING file in the root of the source

// tree. An additional intellectual property rights grant can be found

// in the file PATENTS. All contributing project authors may

// be found in the AUTHORS file in the root of the source tree.

// -----------------------------------------------------------------------------

//

// GIF decode.

#include "./gifdec.h"

#include <stdio.h>

#ifdef WEBP_HAVE_GIF

#include <assert.h>

#include <stdlib.h>

#include <string.h>

#include "webp/encode.h"

#include "webp/mux_types.h"

#define GIF_TRANSPARENT_COLOR 0x00000000u

#define GIF_WHITE_COLOR       0xffffffffu

#define GIF_TRANSPARENT_MASK  0x01

#define GIF_DISPOSE_MASK      0x07

#define GIF_DISPOSE_SHIFT     2

// from utils/utils.h

#ifdef __cplusplus

extern "C" {

#endif

extern void WebPCopyPlane(const uint8_t* src, int src_stride,

                          uint8_t* dst, int dst_stride,

                          int width, int height);

extern void WebPCopyPixels(const WebPPicture* const src,

                           WebPPicture* const dst);

#ifdef __cplusplus

}

#endif

void GIFGetBackgroundColor(const ColorMapObject* const color_map,

                           int bgcolor_index, int transparent_index,

                           uint32_t* const bgcolor) {

  if (transparent_index != GIF_INDEX_INVALID &&

      bgcolor_index == transparent_index) {

    *bgcolor = GIF_TRANSPARENT_COLOR;  // Special case.

  } else if (color_map == NULL || color_map->Colors == NULL

             || bgcolor_index >= color_map->ColorCount) {

    *bgcolor = GIF_WHITE_COLOR;

    fprintf(stderr,

            "GIF decode warning: invalid background color index. Assuming "

            "white background.\n");

  } else {

    const GifColorType color = color_map->Colors[bgcolor_index];

    *bgcolor = (0xffu       << 24)

             | (color.Red   << 16)

             | (color.Green <<  8)

             | (color.Blue  <<  0);

  }

}

int GIFReadGraphicsExtension(const GifByteType* const buf, int* const duration,

                             GIFDisposeMethod* const dispose,

                             int* const transparent_index) {

  const int flags = buf[1];

  const int dispose_raw = (flags >> GIF_DISPOSE_SHIFT) & GIF_DISPOSE_MASK;

  const int duration_raw = buf[2] | (buf[3] << 8);  // In 10 ms units.

  if (buf[0] != 4) return 0;

  *duration = duration_raw * 10;  // Duration is in 1 ms units.

  switch (dispose_raw) {

    case 3:

      *dispose = GIF_DISPOSE_RESTORE_PREVIOUS;

      break;

    case 2:

      *dispose = GIF_DISPOSE_BACKGROUND;

      break;

    case 1:

    case 0:

    default:

      *dispose = GIF_DISPOSE_NONE;

      break;

  }

  *transparent_index =

      (flags & GIF_TRANSPARENT_MASK) ? buf[4] : GIF_INDEX_INVALID;

  return 1;

}

static int Remap(const GifFileType* const gif, const uint8_t* const src,

                 int len, int transparent_index, uint32_t* dst) {

  int i;

  const GifColorType* colors;

  const ColorMapObject* const cmap =

      gif->Image.ColorMap ? gif->Image.ColorMap : gif->SColorMap;

  if (cmap == NULL) return 1;

  if (cmap->Colors == NULL || cmap->ColorCount <= 0) return 0;

  colors = cmap->Colors;

  for (i = 0; i < len; ++i) {

    if (src[i] == transparent_index) {

      dst[i] = GIF_TRANSPARENT_COLOR;

    } else if (src[i] < cmap->ColorCount) {

      const GifColorType c = colors[src[i]];

      dst[i] = c.Blue | (c.Green << 8) | (c.Red << 16) | (0xffu << 24);

    } else {

      return 0;

    }

  }

  return 1;

}

int GIFReadFrame(GifFileType* const gif, int transparent_index,

                 GIFFrameRect* const gif_rect, WebPPicture* const picture) {

  WebPPicture sub_image;

  const GifImageDesc* const image_desc = &gif->Image;

  uint32_t* dst = NULL;

  uint8_t* tmp = NULL;

  const GIFFrameRect rect = {

      image_desc->Left, image_desc->Top, image_desc->Width, image_desc->Height

  };

  const uint64_t memory_needed = 4 * rect.width * (uint64_t)rect.height;

  int ok = 0;

  *gif_rect = rect;

  if (memory_needed != (size_t)memory_needed || memory_needed > (4ULL << 32)) {

    fprintf(stderr, "Image is too large (%d x %d).", rect.width, rect.height);

    return 0;

  }

  // Use a view for the sub-picture:

  if (!WebPPictureView(picture, rect.x_offset, rect.y_offset,

                       rect.width, rect.height, &sub_image)) {

    fprintf(stderr, "Sub-image %dx%d at position %d,%d is invalid!\n",

            rect.width, rect.height, rect.x_offset, rect.y_offset);

    return 0;

  }

  dst = sub_image.argb;

  tmp = (uint8_t*)malloc(rect.width * sizeof(*tmp));

  if (tmp == NULL) goto End;

  if (image_desc->Interlace) {  // Interlaced image.

    // We need 4 passes, with the following offsets and jumps.

    const int interlace_offsets[] = { 0, 4, 2, 1 };

    const int interlace_jumps[]   = { 8, 8, 4, 2 };

    int pass;

    for (pass = 0; pass < 4; ++pass) {

      const size_t stride = (size_t)sub_image.argb_stride;

      int y = interlace_offsets[pass];

      uint32_t* row = dst + y * stride;

      const size_t jump = interlace_jumps[pass] * stride;

      for (; y < rect.height; y += interlace_jumps[pass], row += jump) {

        if (DGifGetLine(gif, tmp, rect.width) == GIF_ERROR) goto End;

        if (!Remap(gif, tmp, rect.width, transparent_index, row)) goto End;

      }

    }

  } else {  // Non-interlaced image.

    int y;

    uint32_t* ptr = dst;

    for (y = 0; y < rect.height; ++y, ptr += sub_image.argb_stride) {

      if (DGifGetLine(gif, tmp, rect.width) == GIF_ERROR) goto End;

      if (!Remap(gif, tmp, rect.width, transparent_index, ptr)) goto End;

    }

  }

  ok = 1;

 End:

  if (!ok) picture->error_code = sub_image.error_code;

  WebPPictureFree(&sub_image);

  free(tmp);

  return ok;

}

int GIFReadLoopCount(GifFileType* const gif, GifByteType** const buf,

                     int* const loop_count) {

  assert(!memcmp(*buf + 1, "NETSCAPE2.0", 11) ||

         !memcmp(*buf + 1, "ANIMEXTS1.0", 11));

  if (DGifGetExtensionNext(gif, buf) == GIF_ERROR) {

    return 0;

  }

  if (*buf == NULL) {

    return 0;  // Loop count sub-block missing.

  }

  if ((*buf)[0] < 3 || (*buf)[1] != 1) {

    return 0;   // wrong size/marker

  }

  *loop_count = (*buf)[2] | ((*buf)[3] << 8);

  return 1;

}

int GIFReadMetadata(GifFileType* const gif, GifByteType** const buf,

                    WebPData* const metadata) {

  const int is_xmp = !memcmp(*buf + 1, "XMP DataXMP", 11);

  const int is_icc = !memcmp(*buf + 1, "ICCRGBG1012", 11);

  assert(is_xmp || is_icc);

  (void)is_icc;  // silence unused warning.

  // Construct metadata from sub-blocks.

  // Usual case (including ICC profile): In each sub-block, the

  // first byte specifies its size in bytes (0 to 255) and the

  // rest of the bytes contain the data.

  // Special case for XMP data: In each sub-block, the first byte

  // is also part of the XMP payload. XMP in GIF also has a 257

  // byte padding data. See the XMP specification for details.

  while (1) {

    WebPData subblock;

    const uint8_t* tmp;

    if (DGifGetExtensionNext(gif, buf) == GIF_ERROR) {

      return 0;

    }

    if (*buf == NULL) break;  // Finished.

    subblock.size = is_xmp ? (*buf)[0] + 1 : (*buf)[0];

    assert(subblock.size > 0);

    subblock.bytes = is_xmp ? *buf : *buf + 1;

    // Note: We store returned value in 'tmp' first, to avoid

    // leaking old memory in metadata->bytes on error.

    tmp = (uint8_t*)realloc((void*)metadata->bytes,

                            metadata->size + subblock.size);

    if (tmp == NULL) {

      return 0;

    }

    memcpy((void*)(tmp + metadata->size),

           subblock.bytes, subblock.size);

    metadata->bytes = tmp;

    metadata->size += subblock.size;

  }

  if (is_xmp) {

    // XMP padding data is 0x01, 0xff, 0xfe ... 0x01, 0x00.

    const size_t xmp_pading_size = 257;

    if (metadata->size > xmp_pading_size) {

      metadata->size -= xmp_pading_size;

    }

  }

  return 1;

}

static void ClearRectangle(WebPPicture* const picture,

                           int left, int top, int width, int height) {

  int i, j;

  const size_t stride = picture->argb_stride;

  uint32_t* dst = picture->argb + top * stride + left;

  for (j = 0; j < height; ++j, dst += stride) {

    for (i = 0; i < width; ++i) dst[i] = GIF_TRANSPARENT_COLOR;

  }

}

void GIFClearPic(WebPPicture* const pic, const GIFFrameRect* const rect) {

  if (rect != NULL) {

    ClearRectangle(pic, rect->x_offset, rect->y_offset,

                   rect->width, rect->height);

  } else {

    ClearRectangle(pic, 0, 0, pic->width, pic->height);

  }

}

void GIFCopyPixels(const WebPPicture* const src, WebPPicture* const dst) {

  WebPCopyPixels(src, dst);

}

void GIFDisposeFrame(GIFDisposeMethod dispose, const GIFFrameRect* const rect,

                     const WebPPicture* const prev_canvas,

                     WebPPicture* const curr_canvas) {

  assert(rect != NULL);

  if (dispose == GIF_DISPOSE_BACKGROUND) {

    GIFClearPic(curr_canvas, rect);

  } else if (dispose == GIF_DISPOSE_RESTORE_PREVIOUS) {

    const size_t src_stride = prev_canvas->argb_stride;

    const uint32_t* const src = prev_canvas->argb + rect->x_offset

                              + rect->y_offset * src_stride;

    const size_t dst_stride = curr_canvas->argb_stride;

    uint32_t* const dst = curr_canvas->argb + rect->x_offset

                        + rect->y_offset * dst_stride;

    assert(prev_canvas != NULL);

    WebPCopyPlane((uint8_t*)src, (int)(4 * src_stride),

                  (uint8_t*)dst, (int)(4 * dst_stride),

                  4 * rect->width, rect->height);

  }

}

void GIFBlendFrames(const WebPPicture* const src,

                    const GIFFrameRect* const rect, WebPPicture* const dst) {

  int i, j;

  const size_t src_stride = src->argb_stride;

  const size_t dst_stride = dst->argb_stride;

  assert(src->width == dst->width && src->height == dst->height);

  for (j = rect->y_offset; j < rect->y_offset + rect->height; ++j) {

    for (i = rect->x_offset; i < rect->x_offset + rect->width; ++i) {

      const uint32_t src_pixel = src->argb[j * src_stride + i];

      const int src_alpha = src_pixel >> 24;

      if (src_alpha != 0) {

        dst->argb[j * dst_stride + i] = src_pixel;

      }

    }

  }

}

void GIFDisplayError(const GifFileType* const gif, int gif_error) {

  // libgif 4.2.0 has retired PrintGifError() and added GifErrorString().

#if LOCAL_GIF_PREREQ(4,2)

#if LOCAL_GIF_PREREQ(5,0)

  // Static string actually, hence the const char* cast.

  const char* error_str = (const char*)GifErrorString(

      (gif == NULL) ? gif_error : gif->Error);

#else

  const char* error_str = (const char*)GifErrorString();

  (void)gif;

#endif

  if (error_str == NULL) error_str = "Unknown error";

  fprintf(stderr, "GIFLib Error %d: %s\n", gif_error, error_str);

#else

  (void)gif;

  fprintf(stderr, "GIFLib Error %d: ", gif_error);

  PrintGifError();

  fprintf(stderr, "\n");

#endif

}

#else  // !WEBP_HAVE_GIF

static void ErrorGIFNotAvailable() {

  fprintf(stderr, "GIF support not compiled. Please install the libgif-dev "

          "package before building.\n");

}

void GIFGetBackgroundColor(const struct ColorMapObject* const color_map,

                           int bgcolor_index, int transparent_index,

                           uint32_t* const bgcolor) {

  (void)color_map;

  (void)bgcolor_index;

  (void)transparent_index;

  (void)bgcolor;

  ErrorGIFNotAvailable();

}

int GIFReadGraphicsExtension(const GifByteType* const data, int* const duration,

                             GIFDisposeMethod* const dispose,

                             int* const transparent_index) {

  (void)data;

  (void)duration;

  (void)dispose;

  (void)transparent_index;

  ErrorGIFNotAvailable();

  return 0;

}

int GIFReadFrame(struct GifFileType* const gif, int transparent_index,

                 GIFFrameRect* const gif_rect,

                 struct WebPPicture* const picture) {

  (void)gif;

  (void)transparent_index;

  (void)gif_rect;

  (void)picture;

  ErrorGIFNotAvailable();

  return 0;

}

int GIFReadLoopCount(struct GifFileType* const gif, GifByteType** const buf,

                     int* const loop_count) {

  (void)gif;

  (void)buf;

  (void)loop_count;

  ErrorGIFNotAvailable();

  return 0;

}

int GIFReadMetadata(struct GifFileType* const gif, GifByteType** const buf,

                    struct WebPData* const metadata) {

  (void)gif;

  (void)buf;

  (void)metadata;

  ErrorGIFNotAvailable();

  return 0;

}

void GIFDisposeFrame(GIFDisposeMethod dispose, const GIFFrameRect* const rect,

                     const struct WebPPicture* const prev_canvas,

                     struct WebPPicture* const curr_canvas) {

  (void)dispose;

  (void)rect;

  (void)prev_canvas;

  (void)curr_canvas;

  ErrorGIFNotAvailable();

}

void GIFBlendFrames(const struct WebPPicture* const src,

                    const GIFFrameRect* const rect,

                    struct WebPPicture* const dst) {

  (void)src;

  (void)rect;

  (void)dst;

  ErrorGIFNotAvailable();

}

void GIFDisplayError(const struct GifFileType* const gif, int gif_error) {

  (void)gif;

  (void)gif_error;

  ErrorGIFNotAvailable();

}

void GIFClearPic(struct WebPPicture* const pic,

                 const GIFFrameRect* const rect) {

  (void)pic;

  (void)rect;

  ErrorGIFNotAvailable();

}

void GIFCopyPixels(const struct WebPPicture* const src,

                   struct WebPPicture* const dst) {

  (void)src;

  (void)dst;

  ErrorGIFNotAvailable();

}

#endif  // WEBP_HAVE_GIF

// -----------------------------------------------------------------------------