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libavcodec/avpacket.c

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00001 /*
00002  * AVPacket functions for libavcodec
00003  * Copyright (c) 2000, 2001, 2002 Fabrice Bellard
00004  *
00005  * This file is part of Libav.
00006  *
00007  * Libav is free software; you can redistribute it and/or
00008  * modify it under the terms of the GNU Lesser General Public
00009  * License as published by the Free Software Foundation; either
00010  * version 2.1 of the License, or (at your option) any later version.
00011  *
00012  * Libav is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00015  * Lesser General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU Lesser General Public
00018  * License along with Libav; if not, write to the Free Software
00019  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00020  */
00021 
00022 #include "avcodec.h"
00023 #include "libavutil/avassert.h"
00024 
00025 
00026 void av_destruct_packet_nofree(AVPacket *pkt)
00027 {
00028     pkt->data = NULL; pkt->size = 0;
00029     pkt->side_data       = NULL;
00030     pkt->side_data_elems = 0;
00031 }
00032 
00033 void av_destruct_packet(AVPacket *pkt)
00034 {
00035     int i;
00036 
00037     av_free(pkt->data);
00038     pkt->data = NULL; pkt->size = 0;
00039 
00040     for (i = 0; i < pkt->side_data_elems; i++)
00041         av_free(pkt->side_data[i].data);
00042     av_freep(&pkt->side_data);
00043     pkt->side_data_elems = 0;
00044 }
00045 
00046 void av_init_packet(AVPacket *pkt)
00047 {
00048     pkt->pts   = AV_NOPTS_VALUE;
00049     pkt->dts   = AV_NOPTS_VALUE;
00050     pkt->pos   = -1;
00051     pkt->duration = 0;
00052     pkt->convergence_duration = 0;
00053     pkt->flags = 0;
00054     pkt->stream_index = 0;
00055     pkt->destruct= NULL;
00056     pkt->side_data       = NULL;
00057     pkt->side_data_elems = 0;
00058 }
00059 
00060 int av_new_packet(AVPacket *pkt, int size)
00061 {
00062     uint8_t *data= NULL;
00063     if((unsigned)size < (unsigned)size + FF_INPUT_BUFFER_PADDING_SIZE)
00064         data = av_malloc(size + FF_INPUT_BUFFER_PADDING_SIZE);
00065     if (data){
00066         memset(data + size, 0, FF_INPUT_BUFFER_PADDING_SIZE);
00067     }else
00068         size=0;
00069 
00070     av_init_packet(pkt);
00071     pkt->data = data;
00072     pkt->size = size;
00073     pkt->destruct = av_destruct_packet;
00074     if(!data)
00075         return AVERROR(ENOMEM);
00076     return 0;
00077 }
00078 
00079 void av_shrink_packet(AVPacket *pkt, int size)
00080 {
00081     if (pkt->size <= size) return;
00082     pkt->size = size;
00083     memset(pkt->data + size, 0, FF_INPUT_BUFFER_PADDING_SIZE);
00084 }
00085 
00086 int av_grow_packet(AVPacket *pkt, int grow_by)
00087 {
00088     void *new_ptr;
00089     av_assert0((unsigned)pkt->size <= INT_MAX - FF_INPUT_BUFFER_PADDING_SIZE);
00090     if (!pkt->size)
00091         return av_new_packet(pkt, grow_by);
00092     if ((unsigned)grow_by > INT_MAX - (pkt->size + FF_INPUT_BUFFER_PADDING_SIZE))
00093         return -1;
00094     new_ptr = av_realloc(pkt->data, pkt->size + grow_by + FF_INPUT_BUFFER_PADDING_SIZE);
00095     if (!new_ptr)
00096         return AVERROR(ENOMEM);
00097     pkt->data = new_ptr;
00098     pkt->size += grow_by;
00099     memset(pkt->data + pkt->size, 0, FF_INPUT_BUFFER_PADDING_SIZE);
00100     return 0;
00101 }
00102 
00103 #define DUP_DATA(dst, src, size, padding) \
00104     do { \
00105         void *data; \
00106         if (padding) { \
00107             if ((unsigned)(size) > (unsigned)(size) + FF_INPUT_BUFFER_PADDING_SIZE) \
00108                 goto failed_alloc; \
00109             data = av_malloc(size + FF_INPUT_BUFFER_PADDING_SIZE); \
00110         } else { \
00111             data = av_malloc(size); \
00112         } \
00113         if (!data) \
00114             goto failed_alloc; \
00115         memcpy(data, src, size); \
00116         if (padding) \
00117             memset((uint8_t*)data + size, 0, FF_INPUT_BUFFER_PADDING_SIZE); \
00118         dst = data; \
00119     } while(0)
00120 
00121 int av_dup_packet(AVPacket *pkt)
00122 {
00123     AVPacket tmp_pkt;
00124 
00125     if (((pkt->destruct == av_destruct_packet_nofree) || (pkt->destruct == NULL)) && pkt->data) {
00126         tmp_pkt = *pkt;
00127 
00128         pkt->data      = NULL;
00129         pkt->side_data = NULL;
00130         DUP_DATA(pkt->data, tmp_pkt.data, pkt->size, 1);
00131         pkt->destruct = av_destruct_packet;
00132 
00133         if (pkt->side_data_elems) {
00134             int i;
00135 
00136             DUP_DATA(pkt->side_data, tmp_pkt.side_data,
00137                      pkt->side_data_elems * sizeof(*pkt->side_data), 0);
00138             memset(pkt->side_data, 0, pkt->side_data_elems * sizeof(*pkt->side_data));
00139             for (i = 0; i < pkt->side_data_elems; i++) {
00140                 DUP_DATA(pkt->side_data[i].data, tmp_pkt.side_data[i].data,
00141                          pkt->side_data[i].size, 1);
00142             }
00143         }
00144     }
00145     return 0;
00146 failed_alloc:
00147     av_destruct_packet(pkt);
00148     return AVERROR(ENOMEM);
00149 }
00150 
00151 void av_free_packet(AVPacket *pkt)
00152 {
00153     if (pkt) {
00154         if (pkt->destruct) pkt->destruct(pkt);
00155         pkt->data = NULL; pkt->size = 0;
00156         pkt->side_data       = NULL;
00157         pkt->side_data_elems = 0;
00158     }
00159 }
00160 
00161 uint8_t* av_packet_new_side_data(AVPacket *pkt, enum AVPacketSideDataType type,
00162                                  int size)
00163 {
00164     int elems = pkt->side_data_elems;
00165 
00166     if ((unsigned)elems + 1 > INT_MAX / sizeof(*pkt->side_data))
00167         return NULL;
00168     if ((unsigned)size > INT_MAX - FF_INPUT_BUFFER_PADDING_SIZE)
00169         return NULL;
00170 
00171     pkt->side_data = av_realloc(pkt->side_data, (elems + 1) * sizeof(*pkt->side_data));
00172     if (!pkt->side_data)
00173         return NULL;
00174 
00175     pkt->side_data[elems].data = av_malloc(size + FF_INPUT_BUFFER_PADDING_SIZE);
00176     if (!pkt->side_data[elems].data)
00177         return NULL;
00178     pkt->side_data[elems].size = size;
00179     pkt->side_data[elems].type = type;
00180     pkt->side_data_elems++;
00181 
00182     return pkt->side_data[elems].data;
00183 }
00184 
00185 uint8_t* av_packet_get_side_data(AVPacket *pkt, enum AVPacketSideDataType type,
00186                                  int *size)
00187 {
00188     int i;
00189 
00190     for (i = 0; i < pkt->side_data_elems; i++) {
00191         if (pkt->side_data[i].type == type) {
00192             if (size)
00193                 *size = pkt->side_data[i].size;
00194             return pkt->side_data[i].data;
00195         }
00196     }
00197     return NULL;
00198 }
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