// Copyright 2014 The PDFium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com

#ifndef CORE_FXCODEC_GIF_CFX_GIF_H_
#define CORE_FXCODEC_GIF_CFX_GIF_H_

#include <stddef.h>
#include <stdint.h>

#include <memory>
#include <vector>

#include "core/fxcrt/data_vector.h"

extern const char kGifSignature87[];
extern const char kGifSignature89[];

enum class GifSignature : uint8_t {
  kExtension = 0x21,
  kImage = 0x2C,
  kTrailer = 0x3B,
};

enum class GifExtensionLabel : uint8_t {
  kPlainText = 0x01,
  kGraphicControl = 0xF9,
  kComment = 0xFE,
};

// Sentinel sub-block length that marks the end of a sub-block sequence.
constexpr uint8_t kGifSubBlockTerminator = 0x00;

constexpr uint8_t kGifMaxLzwExp = 12;
constexpr size_t kGifMaxLzwCode = 4096;

enum class GifDecoderStatus : uint8_t {
  kSig = 0x01,
  kTail = 0x02,
  kExt = 0x03,
  kExtCe = 0x05,
  kExtGce = 0x06,
  kExtPte = 0x07,
  kExtUne = 0x08,
  kImgInfo = 0x09,
  kImgData = 0x0A,
};

#pragma pack(1)
struct CFX_GifGlobalFlags {
  uint8_t pal_bits : 3;
  uint8_t sort_flag : 1;
  uint8_t color_resolution : 3;
  uint8_t global_pal : 1;
};

struct CFX_GifLocalFlags {
  uint8_t pal_bits : 3;
  uint8_t reserved : 2;
  uint8_t sort_flag : 1;
  uint8_t interlace : 1;
  uint8_t local_pal : 1;
};

struct CFX_GifHeader {
  char signature[6];
};

struct CFX_GifLocalScreenDescriptor {
  uint16_t width;
  uint16_t height;
  CFX_GifGlobalFlags global_flags;
  uint8_t bc_index;
  uint8_t pixel_aspect;
};

struct CFX_GifImageInfo {
  uint16_t left;
  uint16_t top;
  uint16_t width;
  uint16_t height;
  CFX_GifLocalFlags local_flags;
};

struct CFX_GifControlExtensionFlags {
  uint8_t transparency : 1;
  uint8_t user_input : 1;
  uint8_t disposal_method : 3;
  uint8_t reserved : 3;
};

struct CFX_GifGraphicControlExtension {
  uint8_t block_size;
  CFX_GifControlExtensionFlags gce_flags;
  uint16_t delay_time;
  uint8_t trans_index;
};

struct CFX_GifPlainTextExtension {
  uint8_t block_size;
  uint16_t grid_left;
  uint16_t grid_top;
  uint16_t grid_width;
  uint16_t grid_height;
  uint8_t char_width;
  uint8_t char_height;
  uint8_t fc_index;
  uint8_t bc_index;
};

struct GifApplicationExtension {
  uint8_t block_size;
  uint8_t app_identify[8];
  uint8_t app_authentication[3];
};

struct CFX_GifPalette {
  uint8_t r;
  uint8_t g;
  uint8_t b;
};
#pragma pack()

struct CFX_GifImage {
  CFX_GifImage();
  ~CFX_GifImage();

  std::unique_ptr<CFX_GifGraphicControlExtension> image_GCE;
  std::vector<CFX_GifPalette> local_palettes;
  DataVector<uint8_t> row_buffer;
  CFX_GifImageInfo image_info;
  uint8_t local_palette_exp;
  uint8_t code_exp;
  uint32_t data_pos;
  int32_t row_num;
};

#endif  // CORE_FXCODEC_GIF_CFX_GIF_H_