libavcodec/avpacket.c

   1 /*
   2  * AVPacket functions for libavcodec
   3  * Copyright (c) 2000, 2001, 2002 Fabrice Bellard
   4  *
   5  * This file is part of FFmpeg.
   6  *
   7  * FFmpeg is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * FFmpeg is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with FFmpeg; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 #include "avcodec.h"
  23
  24
  25 void av_destruct_packet_nofree(AVPacket *pkt)
  26 {
  27     pkt->data = NULL; pkt->size = 0;
  28 }
  29
  30 void av_destruct_packet(AVPacket *pkt)
  31 {
  32     av_free(pkt->data);
  33     pkt->data = NULL; pkt->size = 0;
  34 }
  35
  36 void av_init_packet(AVPacket *pkt)
  37 {
  38     pkt->pts   = AV_NOPTS_VALUE;
  39     pkt->dts   = AV_NOPTS_VALUE;
  40     pkt->pos   = -1;
  41     pkt->duration = 0;
  42     pkt->convergence_duration = 0;
  43     pkt->flags = 0;
  44     pkt->stream_index = 0;
  45     pkt->destruct= NULL;
  46 }
  47
  48 int av_new_packet(AVPacket *pkt, int size)
  49 {
  50     uint8_t *data;
  51     if((unsigned)size > (unsigned)size + FF_INPUT_BUFFER_PADDING_SIZE)
  52         return AVERROR(ENOMEM);
  53     data = av_malloc(size + FF_INPUT_BUFFER_PADDING_SIZE);
  54     if (!data)
  55         return AVERROR(ENOMEM);
  56     memset(data + size, 0, FF_INPUT_BUFFER_PADDING_SIZE);
  57
  58     av_init_packet(pkt);
  59     pkt->data = data;
  60     pkt->size = size;
  61     pkt->destruct = av_destruct_packet;
  62     return 0;
  63 }
  64
  65 void av_shrink_packet(AVPacket *pkt, int size)
  66 {
  67     if (pkt->size <= size) return;
  68     pkt->size = size;
  69     memset(pkt->data + size, 0, FF_INPUT_BUFFER_PADDING_SIZE);
  70 }
  71
  72 int av_dup_packet(AVPacket *pkt)
  73 {
  74     if (((pkt->destruct == av_destruct_packet_nofree) || (pkt->destruct == NULL)) && pkt->data) {
  75         uint8_t *data;
  76         /* We duplicate the packet and don't forget to add the padding again. */
  77         if((unsigned)pkt->size > (unsigned)pkt->size + FF_INPUT_BUFFER_PADDING_SIZE)
  78             return AVERROR(ENOMEM);
  79         data = av_malloc(pkt->size + FF_INPUT_BUFFER_PADDING_SIZE);
  80         if (!data) {
  81             return AVERROR(ENOMEM);
  82         }
  83         memcpy(data, pkt->data, pkt->size);
  84         memset(data + pkt->size, 0, FF_INPUT_BUFFER_PADDING_SIZE);
  85         pkt->data = data;
  86         pkt->destruct = av_destruct_packet;
  87     }
  88     return 0;
  89 }
  90
  91 void av_free_packet(AVPacket *pkt)
  92 {
  93     if (pkt) {
  94         if (pkt->destruct) pkt->destruct(pkt);
  95         pkt->data = NULL; pkt->size = 0;
  96     }
  97 }