/*
* nghttp2 - HTTP/2 C Library
*
* Copyright (c) 2013 Tatsuhiro Tsujikawa
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
#ifndef NGHTTP2_HD_HUFFMAN_H
#define NGHTTP2_HD_HUFFMAN_H
#include <stdint.h>
#include <arpa/inet.h>
typedef enum {
/* FSA accepts this state as the end of huffman encoding
sequence. */
NGHTTP2_HUFF_ACCEPTED = 1 << 14,
/* This state emits symbol */
NGHTTP2_HUFF_SYM = 1 << 15,
} nghttp2_huff_decode_flag;
typedef struct {
/* fstate is the current huffman decoding state, which is actually
the node ID of internal huffman tree with
nghttp2_huff_decode_flag OR-ed. We have 257 leaf nodes, but they
are identical to root node other than emitting a symbol, so we
have 256 internal nodes [1..255], inclusive. The node ID 256 is
a special node and it is a terminal state that means decoding
failed. */
uint16_t fstate;
/* symbol if NGHTTP2_HUFF_SYM flag set */
uint8_t sym;
} nghttp2_huff_decode;
typedef nghttp2_huff_decode huff_decode_table_type[16];
typedef struct {
/* fstate is the current huffman decoding state. */
uint16_t fstate;
} nghttp2_hd_huff_decode_context;
typedef struct {
/* The number of bits in this code */
uint32_t nbits;
/* Huffman code aligned to LSB */
uint32_t code;
} nghttp2_huff_sym;
extern const nghttp2_huff_sym huff_sym_table[];
extern const nghttp2_huff_decode huff_decode_table[][16];
#endif /* NGHTTP2_HD_HUFFMAN_H */
|