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* Buffered I/O for ffmpeg system
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* Copyright (c) 2000,2001 Fabrice Bellard
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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#define IO_BUFFER_SIZE 32768
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int init_put_byte(ByteIOContext *s,
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unsigned char *buffer,
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int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
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int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
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offset_t (*seek)(void *opaque, offset_t offset, int whence))
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s->buffer_size = buffer_size;
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s->write_flag = write_flag;
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s->buf_end = buffer + buffer_size;
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s->write_packet = write_packet;
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s->read_packet = read_packet;
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s->max_packet_size = 0;
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s->update_checksum= NULL;
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static void flush_buffer(ByteIOContext *s)
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if (s->buf_ptr > s->buffer) {
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if (s->write_packet && !s->error){
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int ret= s->write_packet(s->opaque, s->buffer, s->buf_ptr - s->buffer);
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if(s->update_checksum){
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s->checksum= s->update_checksum(s->checksum, s->checksum_ptr, s->buf_ptr - s->checksum_ptr);
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s->checksum_ptr= s->buffer;
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s->pos += s->buf_ptr - s->buffer;
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s->buf_ptr = s->buffer;
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void put_byte(ByteIOContext *s, int b)
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if (s->buf_ptr >= s->buf_end)
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void put_buffer(ByteIOContext *s, const unsigned char *buf, int size)
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len = (s->buf_end - s->buf_ptr);
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memcpy(s->buf_ptr, buf, len);
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if (s->buf_ptr >= s->buf_end)
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void put_flush_packet(ByteIOContext *s)
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offset_t url_fseek(ByteIOContext *s, offset_t offset, int whence)
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if (whence != SEEK_CUR && whence != SEEK_SET)
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if (whence == SEEK_CUR) {
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offset1 = s->pos + (s->buf_ptr - s->buffer);
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offset1 = offset - s->pos;
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if (!s->must_flush &&
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offset1 >= 0 && offset1 < (s->buf_end - s->buffer)) {
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/* can do the seek inside the buffer */
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s->buf_ptr = s->buffer + offset1;
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s->buf_ptr = s->buffer;
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s->seek(s->opaque, offset, SEEK_SET);
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#endif //CONFIG_MUXERS
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if (whence == SEEK_CUR) {
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offset1 = s->pos - (s->buf_end - s->buffer) + (s->buf_ptr - s->buffer);
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offset1 = offset - (s->pos - (s->buf_end - s->buffer));
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if (offset1 >= 0 && offset1 <= (s->buf_end - s->buffer)) {
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/* can do the seek inside the buffer */
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s->buf_ptr = s->buffer + offset1;
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s->buf_ptr = s->buffer;
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s->buf_end = s->buffer;
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if (s->seek(s->opaque, offset, SEEK_SET) == (offset_t)-EPIPE)
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void url_fskip(ByteIOContext *s, offset_t offset)
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url_fseek(s, offset, SEEK_CUR);
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offset_t url_ftell(ByteIOContext *s)
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return url_fseek(s, 0, SEEK_CUR);
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offset_t url_fsize(ByteIOContext *s)
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size = s->seek(s->opaque, -1, SEEK_END) + 1;
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s->seek(s->opaque, s->pos, SEEK_SET);
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int url_feof(ByteIOContext *s)
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return s->eof_reached;
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int url_ferror(ByteIOContext *s)
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#if defined(CONFIG_MUXERS) || defined(CONFIG_PROTOCOLS)
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void put_le32(ByteIOContext *s, unsigned int val)
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put_byte(s, val >> 8);
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put_byte(s, val >> 16);
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put_byte(s, val >> 24);
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void put_be32(ByteIOContext *s, unsigned int val)
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put_byte(s, val >> 24);
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put_byte(s, val >> 16);
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put_byte(s, val >> 8);
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void put_strz(ByteIOContext *s, const char *str)
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put_buffer(s, (const unsigned char *) str, strlen(str) + 1);
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void put_le64(ByteIOContext *s, uint64_t val)
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put_le32(s, (uint32_t)(val & 0xffffffff));
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put_le32(s, (uint32_t)(val >> 32));
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void put_be64(ByteIOContext *s, uint64_t val)
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put_be32(s, (uint32_t)(val >> 32));
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put_be32(s, (uint32_t)(val & 0xffffffff));
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void put_le16(ByteIOContext *s, unsigned int val)
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put_byte(s, val >> 8);
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void put_be16(ByteIOContext *s, unsigned int val)
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put_byte(s, val >> 8);
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void put_le24(ByteIOContext *s, unsigned int val)
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put_le16(s, val & 0xffff);
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put_byte(s, val >> 16);
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void put_be24(ByteIOContext *s, unsigned int val)
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put_be16(s, val >> 8);
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void put_tag(ByteIOContext *s, const char *tag)
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#endif //CONFIG_MUXERS || CONFIG_PROTOCOLS
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static void fill_buffer(ByteIOContext *s)
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/* no need to do anything if EOF already reached */
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if(s->update_checksum){
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if(s->buf_end > s->checksum_ptr)
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s->checksum= s->update_checksum(s->checksum, s->checksum_ptr, s->buf_end - s->checksum_ptr);
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s->checksum_ptr= s->buffer;
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len = s->read_packet(s->opaque, s->buffer, s->buffer_size);
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/* do not modify buffer if EOF reached so that a seek back can
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be done without rereading data */
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s->buf_ptr = s->buffer;
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s->buf_end = s->buffer + len;
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unsigned long get_checksum(ByteIOContext *s){
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s->checksum= s->update_checksum(s->checksum, s->checksum_ptr, s->buf_ptr - s->checksum_ptr);
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s->update_checksum= NULL;
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void init_checksum(ByteIOContext *s, unsigned long (*update_checksum)(unsigned long c, const uint8_t *p, unsigned int len), unsigned long checksum){
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s->update_checksum= update_checksum;
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if(s->update_checksum){
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s->checksum= s->update_checksum(checksum, NULL, 0);
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s->checksum_ptr= s->buf_ptr;
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/* NOTE: return 0 if EOF, so you cannot use it if EOF handling is
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/* XXX: put an inline version */
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int get_byte(ByteIOContext *s)
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if (s->buf_ptr < s->buf_end) {
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return *s->buf_ptr++;
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if (s->buf_ptr < s->buf_end)
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return *s->buf_ptr++;
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/* NOTE: return URL_EOF (-1) if EOF */
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int url_fgetc(ByteIOContext *s)
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if (s->buf_ptr < s->buf_end) {
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return *s->buf_ptr++;
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if (s->buf_ptr < s->buf_end)
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return *s->buf_ptr++;
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int get_buffer(ByteIOContext *s, unsigned char *buf, int size)
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len = s->buf_end - s->buf_ptr;
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if(size > s->buffer_size && !s->update_checksum){
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len = s->read_packet(s->opaque, buf, size);
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/* do not modify buffer if EOF reached so that a seek back can
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be done without rereading data */
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s->buf_ptr = s->buffer;
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s->buf_end = s->buffer/* + len*/;
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len = s->buf_end - s->buf_ptr;
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memcpy(buf, s->buf_ptr, len);
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int get_partial_buffer(ByteIOContext *s, unsigned char *buf, int size)
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len = s->buf_end - s->buf_ptr;
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len = s->buf_end - s->buf_ptr;
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memcpy(buf, s->buf_ptr, len);
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unsigned int get_le16(ByteIOContext *s)
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val |= get_byte(s) << 8;
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unsigned int get_le24(ByteIOContext *s)
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val |= get_byte(s) << 16;
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unsigned int get_le32(ByteIOContext *s)
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val |= get_le16(s) << 16;
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uint64_t get_le64(ByteIOContext *s)
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val = (uint64_t)get_le32(s);
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val |= (uint64_t)get_le32(s) << 32;
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unsigned int get_be16(ByteIOContext *s)
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val = get_byte(s) << 8;
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unsigned int get_be24(ByteIOContext *s)
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val = get_be16(s) << 8;
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unsigned int get_be32(ByteIOContext *s)
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val = get_be16(s) << 16;
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char *get_strz(ByteIOContext *s, char *buf, int maxlen)
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while ((c = get_byte(s))) {
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buf[i] = 0; /* Ensure null terminated, but may be truncated */
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uint64_t get_be64(ByteIOContext *s)
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val = (uint64_t)get_be32(s) << 32;
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val |= (uint64_t)get_be32(s);
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/* link with avio functions */
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static int url_write_packet(void *opaque, uint8_t *buf, int buf_size)
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URLContext *h = opaque;
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return url_write(h, buf, buf_size);
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#define url_write_packet NULL
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#endif //CONFIG_MUXERS
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static int url_read_packet(void *opaque, uint8_t *buf, int buf_size)
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URLContext *h = opaque;
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return url_read(h, buf, buf_size);
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static offset_t url_seek_packet(void *opaque, offset_t offset, int whence)
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URLContext *h = opaque;
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return url_seek(h, offset, whence);
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int url_fdopen(ByteIOContext *s, URLContext *h)
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int buffer_size, max_packet_size;
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max_packet_size = url_get_max_packet_size(h);
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if (max_packet_size) {
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buffer_size = max_packet_size; /* no need to bufferize more than one packet */
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buffer_size = IO_BUFFER_SIZE;
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buffer = av_malloc(buffer_size);
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if (init_put_byte(s, buffer, buffer_size,
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(h->flags & URL_WRONLY || h->flags & URL_RDWR), h,
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url_read_packet, url_write_packet, url_seek_packet) < 0) {
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s->is_streamed = h->is_streamed;
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s->max_packet_size = max_packet_size;
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/* XXX: must be called before any I/O */
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int url_setbufsize(ByteIOContext *s, int buf_size)
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buffer = av_malloc(buf_size);
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s->buffer_size = buf_size;
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s->buf_end = buffer + buf_size;
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/* NOTE: when opened as read/write, the buffers are only used for
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int url_fopen(ByteIOContext *s, const char *filename, int flags)
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err = url_open(&h, filename, flags);
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err = url_fdopen(s, h);
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int url_fclose(ByteIOContext *s)
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URLContext *h = s->opaque;
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memset(s, 0, sizeof(ByteIOContext));
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URLContext *url_fileno(ByteIOContext *s)
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/* XXX: currently size is limited */
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int url_fprintf(ByteIOContext *s, const char *fmt, ...)
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ret = vsnprintf(buf, sizeof(buf), fmt, ap);
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put_buffer(s, buf, strlen(buf));
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#endif //CONFIG_MUXERS
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/* note: unlike fgets, the EOL character is not returned and a whole
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line is parsed. return NULL if first char read was EOF */
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char *url_fgets(ByteIOContext *s, char *buf, int buf_size)
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if (c == EOF || c == '\n')
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if ((q - buf) < buf_size - 1)
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* Return the maximum packet size associated to packetized buffered file
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* handle. If the file is not packetized (stream like http or file on
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* disk), then 0 is returned.
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* @param h buffered file handle
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* @return maximum packet size in bytes
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int url_fget_max_packet_size(ByteIOContext *s)
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return s->max_packet_size;
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/* buffer handling */
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int url_open_buf(ByteIOContext *s, uint8_t *buf, int buf_size, int flags)
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return init_put_byte(s, buf, buf_size,
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(flags & URL_WRONLY || flags & URL_RDWR),
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NULL, NULL, NULL, NULL);
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/* return the written or read size */
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int url_close_buf(ByteIOContext *s)
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return s->buf_ptr - s->buffer;
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/* output in a dynamic buffer */
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typedef struct DynBuffer {
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int pos, size, allocated_size;
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uint8_t io_buffer[1];
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static int dyn_buf_write(void *opaque, uint8_t *buf, int buf_size)
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DynBuffer *d = opaque;
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int new_size, new_allocated_size;
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/* reallocate buffer if needed */
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new_size = d->pos + buf_size;
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new_allocated_size = d->allocated_size;
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if(new_size < d->pos || new_size > INT_MAX/2)
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while (new_size > new_allocated_size) {
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if (!new_allocated_size)
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new_allocated_size = new_size;
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new_allocated_size += new_allocated_size / 2 + 1;
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if (new_allocated_size > d->allocated_size) {
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d->buffer = av_realloc(d->buffer, new_allocated_size);
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if(d->buffer == NULL)
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d->allocated_size = new_allocated_size;
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memcpy(d->buffer + d->pos, buf, buf_size);
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if (d->pos > d->size)
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static int dyn_packet_buf_write(void *opaque, uint8_t *buf, int buf_size)
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unsigned char buf1[4];
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/* packetized write: output the header */
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buf1[0] = (buf_size >> 24);
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buf1[1] = (buf_size >> 16);
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buf1[2] = (buf_size >> 8);
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buf1[3] = (buf_size);
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ret= dyn_buf_write(opaque, buf1, 4);
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return dyn_buf_write(opaque, buf, buf_size);
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static offset_t dyn_buf_seek(void *opaque, offset_t offset, int whence)
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DynBuffer *d = opaque;
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if (whence == SEEK_CUR)
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else if (whence == SEEK_END)
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if (offset < 0 || offset > 0x7fffffffLL)
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static int url_open_dyn_buf_internal(ByteIOContext *s, int max_packet_size)
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int io_buffer_size, ret;
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io_buffer_size = max_packet_size;
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io_buffer_size = 1024;
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if(sizeof(DynBuffer) + io_buffer_size < io_buffer_size)
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d = av_malloc(sizeof(DynBuffer) + io_buffer_size);
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d->io_buffer_size = io_buffer_size;
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d->allocated_size = 0;
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ret = init_put_byte(s, d->io_buffer, io_buffer_size,
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max_packet_size ? dyn_packet_buf_write : dyn_buf_write,
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max_packet_size ? NULL : dyn_buf_seek);
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s->max_packet_size = max_packet_size;
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* Open a write only memory stream.
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* @param s new IO context
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* @return zero if no error.
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int url_open_dyn_buf(ByteIOContext *s)
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return url_open_dyn_buf_internal(s, 0);
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* Open a write only packetized memory stream with a maximum packet
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* size of 'max_packet_size'. The stream is stored in a memory buffer
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* with a big endian 4 byte header giving the packet size in bytes.
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* @param s new IO context
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* @param max_packet_size maximum packet size (must be > 0)
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* @return zero if no error.
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int url_open_dyn_packet_buf(ByteIOContext *s, int max_packet_size)
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if (max_packet_size <= 0)
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return url_open_dyn_buf_internal(s, max_packet_size);
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* Return the written size and a pointer to the buffer. The buffer
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* must be freed with av_free().
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* @param s IO context
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* @param pointer to a byte buffer
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* @return the length of the byte buffer
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int url_close_dyn_buf(ByteIOContext *s, uint8_t **pbuffer)
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DynBuffer *d = s->opaque;
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*pbuffer = d->buffer;
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#endif //CONFIG_MUXERS