package brotli

/* Copyright 2016 Google Inc. All Rights Reserved.

   Distributed under MIT license.
   See file LICENSE for detail or copy at https://opensource.org/licenses/MIT
*/

/* Specification: 7.3. Encoding of the context map */
const BROTLI_CONTEXT_MAP_MAX_RLE = 16

/* Specification: 2. Compressed representation overview */
const BROTLI_MAX_NUMBER_OF_BLOCK_TYPES = 256

/* Specification: 3.3. Alphabet sizes: insert-and-copy length */
const BROTLI_NUM_LITERAL_SYMBOLS = 256

const BROTLI_NUM_COMMAND_SYMBOLS = 704

const BROTLI_NUM_BLOCK_LEN_SYMBOLS = 26

const BROTLI_MAX_CONTEXT_MAP_SYMBOLS = (BROTLI_MAX_NUMBER_OF_BLOCK_TYPES + BROTLI_CONTEXT_MAP_MAX_RLE)

const BROTLI_MAX_BLOCK_TYPE_SYMBOLS = (BROTLI_MAX_NUMBER_OF_BLOCK_TYPES + 2)

/* Specification: 3.5. Complex prefix codes */
const BROTLI_REPEAT_PREVIOUS_CODE_LENGTH = 16

const BROTLI_REPEAT_ZERO_CODE_LENGTH = 17

const BROTLI_CODE_LENGTH_CODES = (BROTLI_REPEAT_ZERO_CODE_LENGTH + 1)

/* "code length of 8 is repeated" */
const BROTLI_INITIAL_REPEATED_CODE_LENGTH = 8

/* "Large Window Brotli" */
const BROTLI_LARGE_MAX_DISTANCE_BITS = 62

const BROTLI_LARGE_MIN_WBITS = 10

const BROTLI_LARGE_MAX_WBITS = 30

/* Specification: 4. Encoding of distances */
const BROTLI_NUM_DISTANCE_SHORT_CODES = 16

const BROTLI_MAX_NPOSTFIX = 3

const BROTLI_MAX_NDIRECT = 120

const BROTLI_MAX_DISTANCE_BITS = 24

func BROTLI_DISTANCE_ALPHABET_SIZE(NPOSTFIX uint, NDIRECT uint, MAXNBITS uint) uint {
	return BROTLI_NUM_DISTANCE_SHORT_CODES + NDIRECT + uint(MAXNBITS<<(NPOSTFIX+1))
}

/* BROTLI_NUM_DISTANCE_SYMBOLS == 1128 */
const BROTLI_NUM_DISTANCE_SYMBOLS = 1128

const BROTLI_MAX_DISTANCE = 0x3FFFFFC

const BROTLI_MAX_ALLOWED_DISTANCE = 0x7FFFFFFC

/* 7.1. Context modes and context ID lookup for literals */
/* "context IDs for literals are in the range of 0..63" */
const BROTLI_LITERAL_CONTEXT_BITS = 6

/* 7.2. Context ID for distances */
const BROTLI_DISTANCE_CONTEXT_BITS = 2

/* 9.1. Format of the Stream Header */
/* Number of slack bytes for window size. Don't confuse
   with BROTLI_NUM_DISTANCE_SHORT_CODES. */
const BROTLI_WINDOW_GAP = 16

func BROTLI_MAX_BACKWARD_LIMIT(W uint) uint {
	return (uint(1) << W) - BROTLI_WINDOW_GAP
}