Line data    Source code

       1             : /*
       2             :  * nghttp2 - HTTP/2 C Library
       3             :  *
       4             :  * Copyright (c) 2013 Tatsuhiro Tsujikawa
       5             :  *
       6             :  * Permission is hereby granted, free of charge, to any person obtaining
       7             :  * a copy of this software and associated documentation files (the
       8             :  * "Software"), to deal in the Software without restriction, including
       9             :  * without limitation the rights to use, copy, modify, merge, publish,
      10             :  * distribute, sublicense, and/or sell copies of the Software, and to
      11             :  * permit persons to whom the Software is furnished to do so, subject to
      12             :  * the following conditions:
      13             :  *
      14             :  * The above copyright notice and this permission notice shall be
      15             :  * included in all copies or substantial portions of the Software.
      16             :  *
      17             :  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
      18             :  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
      19             :  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
      20             :  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
      21             :  * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
      22             :  * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
      23             :  * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
      24             :  */
      25             : #include "nghttp2_hd_huffman.h"
      26             : 
      27             : #include <string.h>
      28             : #include <assert.h>
      29             : #include <stdio.h>
      30             : 
      31             : //#include "nghttp2_hd.h"
      32             : //#include "nghttp2_net.h"
      33             : 
      34          24 : void nghttp2_hd_huff_decode_context_init(nghttp2_hd_huff_decode_context *ctx) {
      35          24 :   ctx->fstate = NGHTTP2_HUFF_ACCEPTED;
      36          24 : }
      37             : 
      38             : nghttp2_ssize nghttp2_hd_huff_decode(nghttp2_hd_huff_decode_context *ctx,
      39             :                                      nghttp2_buf *buf, const uint8_t *src,
      40          24 :                                      size_t srclen, int final) {
      41          24 :   const uint8_t *end = src + srclen;
      42          24 :   nghttp2_huff_decode node = {ctx->fstate, 0};
      43          24 :   const nghttp2_huff_decode *t = &node;
      44          24 :   uint8_t c;
      45             : 
      46             :   /* We use the decoding algorithm described in
      47             :       - http://graphics.ics.uci.edu/pub/Prefix.pdf [!!! NO LONGER VALID !!!]
      48             :       - https://ics.uci.edu/~dan/pubs/Prefix.pdf
      49             :       - https://github.com/nghttp2/nghttp2/files/15141264/Prefix.pdf */
      50         267 :   for (; src != end;) {
      51         243 :     c = *src++;
      52         243 :     t = &huff_decode_table[t->fstate & 0x1ff][c >> 4];
      53         243 :     if (t->fstate & NGHTTP2_HUFF_SYM) {
      54         150 :       *buf->last++ = t->sym;
      55         150 :     }
      56             : 
      57         243 :     t = &huff_decode_table[t->fstate & 0x1ff][c & 0xf];
      58         243 :     if (t->fstate & NGHTTP2_HUFF_SYM) {
      59         171 :       *buf->last++ = t->sym;
      60         171 :     }
      61         243 :   }
      62             : 
      63          24 :   ctx->fstate = t->fstate;
      64             : 
      65          24 :   if (final && !(ctx->fstate & NGHTTP2_HUFF_ACCEPTED)) {
      66           0 :     return NGHTTP2_ERR_HEADER_COMP;
      67           0 :   }
      68             : 
      69          24 :   return (nghttp2_ssize)srclen;
      70          24 : }