| /* |
| * 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. |
| */ |
| #include "nghttp2_hd_huffman.h" |
| |
| #include <string.h> |
| #include <assert.h> |
| #include <stdio.h> |
| |
| #include "nghttp2_hd.h" |
| #include "nghttp2_net.h" |
| |
| size_t nghttp2_hd_huff_encode_count(const uint8_t *src, size_t len) { |
| size_t i; |
| size_t nbits = 0; |
| |
| for (i = 0; i < len; ++i) { |
| nbits += huff_sym_table[src[i]].nbits; |
| } |
| /* pad the prefix of EOS (256) */ |
| return (nbits + 7) / 8; |
| } |
| |
| int nghttp2_hd_huff_encode(nghttp2_bufs *bufs, const uint8_t *src, |
| size_t srclen) { |
| const nghttp2_huff_sym *sym; |
| const uint8_t *end = src + srclen; |
| uint64_t code = 0; |
| uint32_t x; |
| size_t nbits = 0; |
| size_t avail; |
| int rv; |
| |
| avail = nghttp2_bufs_cur_avail(bufs); |
| |
| for (; src != end;) { |
| sym = &huff_sym_table[*src++]; |
| code |= (uint64_t)sym->code << (32 - nbits); |
| nbits += sym->nbits; |
| if (nbits < 32) { |
| continue; |
| } |
| if (avail >= 4) { |
| x = htonl((uint32_t)(code >> 32)); |
| memcpy(bufs->cur->buf.last, &x, 4); |
| bufs->cur->buf.last += 4; |
| avail -= 4; |
| code <<= 32; |
| nbits -= 32; |
| continue; |
| } |
| |
| for (; nbits >= 8;) { |
| rv = nghttp2_bufs_addb(bufs, (uint8_t)(code >> 56)); |
| if (rv != 0) { |
| return rv; |
| } |
| code <<= 8; |
| nbits -= 8; |
| } |
| |
| avail = nghttp2_bufs_cur_avail(bufs); |
| } |
| |
| for (; nbits >= 8;) { |
| rv = nghttp2_bufs_addb(bufs, (uint8_t)(code >> 56)); |
| if (rv != 0) { |
| return rv; |
| } |
| code <<= 8; |
| nbits -= 8; |
| } |
| |
| if (nbits) { |
| rv = nghttp2_bufs_addb( |
| bufs, (uint8_t)((uint8_t)(code >> 56) | ((1 << (8 - nbits)) - 1))); |
| if (rv != 0) { |
| return rv; |
| } |
| } |
| |
| return 0; |
| } |
| |
| void nghttp2_hd_huff_decode_context_init(nghttp2_hd_huff_decode_context *ctx) { |
| ctx->fstate = NGHTTP2_HUFF_ACCEPTED; |
| } |
| |
| ssize_t nghttp2_hd_huff_decode(nghttp2_hd_huff_decode_context *ctx, |
| nghttp2_buf *buf, const uint8_t *src, |
| size_t srclen, int final) { |
| const uint8_t *end = src + srclen; |
| nghttp2_huff_decode node = {ctx->fstate, 0}; |
| const nghttp2_huff_decode *t = &node; |
| uint8_t c; |
| |
| /* We use the decoding algorithm described in |
| http://graphics.ics.uci.edu/pub/Prefix.pdf */ |
| for (; src != end;) { |
| c = *src++; |
| t = &huff_decode_table[t->fstate & 0x1ff][c >> 4]; |
| if (t->fstate & NGHTTP2_HUFF_SYM) { |
| *buf->last++ = t->sym; |
| } |
| |
| t = &huff_decode_table[t->fstate & 0x1ff][c & 0xf]; |
| if (t->fstate & NGHTTP2_HUFF_SYM) { |
| *buf->last++ = t->sym; |
| } |
| } |
| |
| ctx->fstate = t->fstate; |
| |
| if (final && !(ctx->fstate & NGHTTP2_HUFF_ACCEPTED)) { |
| return NGHTTP2_ERR_HEADER_COMP; |
| } |
| |
| return (ssize_t)srclen; |
| } |
| |
| int nghttp2_hd_huff_decode_failure_state(nghttp2_hd_huff_decode_context *ctx) { |
| return ctx->fstate == 0x100; |
| } |