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Diffstat (limited to 'lib/nghttp2_hd_huffman.h')
-rw-r--r-- | lib/nghttp2_hd_huffman.h | 72 |
1 files changed, 72 insertions, 0 deletions
diff --git a/lib/nghttp2_hd_huffman.h b/lib/nghttp2_hd_huffman.h new file mode 100644 index 0000000..2bfd531 --- /dev/null +++ b/lib/nghttp2_hd_huffman.h @@ -0,0 +1,72 @@ +/* + * 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 */ |