// 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.

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

//

// Internal header for constants related to WebP file format.

//

// Author: Urvang (urvang@google.com)

#ifndef WEBP_WEBP_FORMAT_CONSTANTS_H_

#define WEBP_WEBP_FORMAT_CONSTANTS_H_

// Create fourcc of the chunk from the chunk tag characters.

#define MKFOURCC(a, b, c, d) ((a) | (b) << 8 | (c) << 16 | (uint32_t)(d) << 24)

// VP8 related constants.

#define VP8_SIGNATURE 0x9d012a // Signature in VP8 data.

#define VP8_MAX_PARTITION0_SIZE (1 << 19) // max size of mode partition

#define VP8_MAX_PARTITION_SIZE (1 << 24) // max size for token partition

#define VP8_FRAME_HEADER_SIZE 10 // Size of the frame header within VP8 data.

// VP8L related constants.

#define VP8L_SIGNATURE_SIZE 1 // VP8L signature size.

#define VP8L_MAGIC_BYTE 0x2f // VP8L signature byte.

#define VP8L_IMAGE_SIZE_BITS 14 // Number of bits used to store

// width and height.

#define VP8L_VERSION_BITS 3 // 3 bits reserved for version.

#define VP8L_VERSION 0 // version 0

#define VP8L_FRAME_HEADER_SIZE 5 // Size of the VP8L frame header.

#define MAX_PALETTE_SIZE 256

#define MAX_CACHE_BITS 11

#define HUFFMAN_CODES_PER_META_CODE 5

#define ARGB_BLACK 0xff000000

#define DEFAULT_CODE_LENGTH 8

#define MAX_ALLOWED_CODE_LENGTH 15

#define NUM_LITERAL_CODES 256

#define NUM_LENGTH_CODES 24

#define NUM_DISTANCE_CODES 40

#define CODE_LENGTH_CODES 19

#define MIN_HUFFMAN_BITS 2 // min number of Huffman bits

#define MAX_HUFFMAN_BITS 9 // max number of Huffman bits

#define TRANSFORM_PRESENT 1 // The bit to be written when next data

// to be read is a transform.

#define NUM_TRANSFORMS 4 // Maximum number of allowed transform

// in a bitstream.

typedef enum {

PREDICTOR_TRANSFORM = 0,

CROSS_COLOR_TRANSFORM = 1,

SUBTRACT_GREEN = 2,

COLOR_INDEXING_TRANSFORM = 3

} VP8LImageTransformType;

// Alpha related constants.

#define ALPHA_HEADER_LEN 1

#define ALPHA_NO_COMPRESSION 0

#define ALPHA_LOSSLESS_COMPRESSION 1

#define ALPHA_PREPROCESSED_LEVELS 1

// Mux related constants.

#define TAG_SIZE 4 // Size of a chunk tag (e.g. "VP8L").

#define CHUNK_SIZE_BYTES 4 // Size needed to store chunk's size.

#define CHUNK_HEADER_SIZE 8 // Size of a chunk header.

#define RIFF_HEADER_SIZE 12 // Size of the RIFF header ("RIFFnnnnWEBP").

#define ANMF_CHUNK_SIZE 16 // Size of an ANMF chunk.

#define ANIM_CHUNK_SIZE 6 // Size of an ANIM chunk.

#define VP8X_CHUNK_SIZE 10 // Size of a VP8X chunk.

#define MAX_CANVAS_SIZE (1 << 24) // 24-bit max for VP8X width/height.

#define MAX_IMAGE_AREA (1ULL << 32) // 32-bit max for width x height.

#define MAX_LOOP_COUNT (1 << 16) // maximum value for loop-count

#define MAX_DURATION (1 << 24) // maximum duration

#define MAX_POSITION_OFFSET (1 << 24) // maximum frame x/y offset

// Maximum chunk payload is such that adding the header and padding won't

// overflow a uint32_t.

#define MAX_CHUNK_PAYLOAD (~0U - CHUNK_HEADER_SIZE - 1)

#endif // WEBP_WEBP_FORMAT_CONSTANTS_H_