diff options
-rw-r--r-- | libavformat/avio_internal.h | 4 | ||||
-rw-r--r-- | libavformat/aviobuf.c | 27 |
2 files changed, 20 insertions, 11 deletions
diff --git a/libavformat/avio_internal.h b/libavformat/avio_internal.h index c575df8035..fe87f2a288 100644 --- a/libavformat/avio_internal.h +++ b/libavformat/avio_internal.h @@ -100,7 +100,9 @@ int ffio_realloc_buf(AVIOContext *s, int buf_size); * * Will ensure that when reading sequentially up to buf_size, seeking * within the current pos and pos+buf_size is possible. - * Once the stream position moves outside this window this guarantee is lost. + * Once the stream position moves outside this window or another + * ffio_ensure_seekback call requests a buffer outside this window this + * guarantee is lost. */ int ffio_ensure_seekback(AVIOContext *s, int64_t buf_size); diff --git a/libavformat/aviobuf.c b/libavformat/aviobuf.c index aa1d6c0830..75ddf52efc 100644 --- a/libavformat/aviobuf.c +++ b/libavformat/aviobuf.c @@ -991,35 +991,42 @@ URLContext* ffio_geturlcontext(AVIOContext *s) return NULL; } +static void update_checksum(AVIOContext *s) +{ + if (s->update_checksum && s->buf_ptr > s->checksum_ptr) { + s->checksum = s->update_checksum(s->checksum, s->checksum_ptr, + s->buf_ptr - s->checksum_ptr); + } +} + int ffio_ensure_seekback(AVIOContext *s, int64_t buf_size) { uint8_t *buffer; int max_buffer_size = s->max_packet_size ? s->max_packet_size : IO_BUFFER_SIZE; - int filled = s->buf_end - s->buffer; - ptrdiff_t checksum_ptr_offset = s->checksum_ptr ? s->checksum_ptr - s->buffer : -1; + ptrdiff_t filled = s->buf_end - s->buf_ptr; if (buf_size <= s->buf_end - s->buf_ptr) return 0; - buf_size += s->buf_ptr - s->buffer + max_buffer_size - 1; + buf_size += max_buffer_size - 1; - if (buf_size <= s->buffer_size || s->seekable || !s->read_packet) + if (buf_size + s->buf_ptr - s->buffer <= s->buffer_size || s->seekable || !s->read_packet) return 0; av_assert0(!s->write_flag); + buf_size = FFMAX(buf_size, s->buffer_size); buffer = av_malloc(buf_size); if (!buffer) return AVERROR(ENOMEM); - - memcpy(buffer, s->buffer, filled); + update_checksum(s); + memcpy(buffer, s->buf_ptr, filled); av_free(s->buffer); - s->buf_ptr = buffer + (s->buf_ptr - s->buffer); - s->buf_end = buffer + (s->buf_end - s->buffer); s->buffer = buffer; s->buffer_size = buf_size; - if (checksum_ptr_offset >= 0) - s->checksum_ptr = s->buffer + checksum_ptr_offset; + s->buf_ptr = s->buffer; + s->buf_end = s->buffer + filled; + s->checksum_ptr = s->buffer; return 0; } |