lib/roles/http/compression/brotli/brotli.c

   1 /*
   2  * libwebsockets - small server side websockets and web server implementation
   3  *
   4  * Copyright (C) 2010 - 2018 Andy Green <andy@warmcat.com>
   5  *
   6  *  This library is free software; you can redistribute it and/or
   7  *  modify it under the terms of the GNU Lesser General Public
   8  *  License as published by the Free Software Foundation:
   9  *  version 2.1 of the License.
  10  *
  11  *  This library is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  *  Lesser General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU Lesser General Public
  17  *  License along with this library; if not, write to the Free Software
  18  *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
  19  *  MA  02110-1301  USA
  20  */
  21
  22 #include "core/private.h"
  23
  24
  25 static int
  26 lcs_init_compression_brotli(lws_comp_ctx_t *ctx, int decomp)
  27 {
  28         ctx->is_decompression = decomp;
  29
  30         if (!decomp) {
  31                 ctx->u.br_en = BrotliEncoderCreateInstance(NULL, NULL, NULL);
  32                 if (ctx->u.br_en) {
  33                         BrotliEncoderSetParameter(ctx->u.br_en,
  34                                         BROTLI_PARAM_MODE, BROTLI_MODE_TEXT);
  35                         BrotliEncoderSetParameter(ctx->u.br_en,
  36                                 BROTLI_PARAM_QUALITY, BROTLI_MIN_QUALITY);
  37                 }
  38         }
  39         else
  40                 ctx->u.br_de = BrotliDecoderCreateInstance(NULL, NULL, NULL);
  41
  42         return !ctx->u.br_de;
  43 }
  44
  45 static int
  46 lcs_process_brotli(lws_comp_ctx_t *ctx, const void *in, size_t *ilen_iused,
  47                    void *out, size_t *olen_oused)
  48 {
  49         size_t a_in, a_out, t_out;
  50         const uint8_t *n_in;
  51         uint8_t *n_out;
  52         int n;
  53
  54         n_in = (void *)in;
  55         a_in = *ilen_iused;
  56         a_out = *olen_oused;
  57         n_out = out;
  58         t_out = 0;
  59
  60         if (!ctx->is_decompression) {
  61
  62                 if (!a_in && !BrotliEncoderHasMoreOutput(ctx->u.br_en)) {
  63                         *olen_oused = 0;
  64
  65                         goto bail;
  66                 }
  67
  68                 n = BROTLI_OPERATION_PROCESS;
  69                 if (!ctx->buflist_comp && ctx->final_on_input_side)
  70                         n = BROTLI_OPERATION_FINISH;
  71
  72                 if (BrotliEncoderCompressStream(ctx->u.br_en, n, &a_in, &n_in,
  73                                                 &a_out, &n_out, &t_out) ==
  74                     BROTLI_FALSE) {
  75                         lwsl_err("brotli encode failed\n");
  76
  77                         return -1;
  78                 }
  79
  80                 ctx->may_have_more = !a_out;
  81
  82         } else {
  83                 n = BrotliDecoderDecompressStream(ctx->u.br_de, &a_in, &n_in,
  84                                                   &a_out, &n_out, &t_out);
  85
  86                 switch (n) {
  87                 case BROTLI_DECODER_RESULT_ERROR:
  88                         lwsl_err("brotli decoder error\n");
  89                         return -1;
  90                 }
  91         }
  92
  93         *ilen_iused -= a_in;
  94         *olen_oused -= a_out;
  95
  96 bail:
  97         if (!ctx->is_decompression)
  98                 return BrotliEncoderIsFinished(ctx->u.br_en);
  99         else
 100                 return BrotliDecoderIsFinished(ctx->u.br_de);
 101 }
 102
 103 static void
 104 lcs_destroy_brotli(lws_comp_ctx_t *ctx)
 105 {
 106         if (!ctx)
 107                 return;
 108
 109         if (!(*ctx).is_decompression)
 110                 BrotliEncoderDestroyInstance((*ctx).u.br_en);
 111         else
 112                 BrotliDecoderDestroyInstance((*ctx).u.br_de);
 113
 114         (*ctx).u.generic_ctx_ptr = NULL;
 115 }
 116
 117 struct lws_compression_support lcs_brotli = {
 118         /* .encoding_name */            "br",
 119         /* .init_compression */         lcs_init_compression_brotli,
 120         /* .process */                  lcs_process_brotli,
 121         /* .destroy */                  lcs_destroy_brotli,
 122 };