| /* |
| * 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 |
| |
| #ifdef HAVE_CONFIG_H |
| # include <config.h> |
| #endif /* HAVE_CONFIG_H */ |
| |
| #include <nghttp2/nghttp2.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 */ |