name : nghttp2_hd_huffman.h /* * 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 */