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-rw-r--r--libavcodec/png_parser.c120
1 files changed, 120 insertions, 0 deletions
diff --git a/libavcodec/png_parser.c b/libavcodec/png_parser.c
new file mode 100644
index 0000000000..6f153d91d6
--- /dev/null
+++ b/libavcodec/png_parser.c
@@ -0,0 +1,120 @@
+/*
+ * PNG parser
+ * Copyright (c) 2009 Peter Holik
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * @file
+ * PNG parser
+ */
+
+#include "parser.h"
+#include "png.h"
+
+typedef struct PNGParseContext
+{
+ ParseContext pc;
+ uint32_t index;
+ uint32_t chunk_length;
+ uint32_t remaining_size;
+} PNGParseContext;
+
+static int png_parse(AVCodecParserContext *s, AVCodecContext *avctx,
+ const uint8_t **poutbuf, int *poutbuf_size,
+ const uint8_t *buf, int buf_size)
+{
+ PNGParseContext *ppc = s->priv_data;
+ int next = END_NOT_FOUND;
+ int i = 0;
+
+ s->pict_type = AV_PICTURE_TYPE_NONE;
+
+ *poutbuf_size = 0;
+ if (buf_size == 0)
+ return 0;
+
+ if (!ppc->pc.frame_start_found) {
+ uint64_t state64 = ppc->pc.state64;
+ for (; i < buf_size; i++) {
+ state64 = (state64 << 8) | buf[i];
+ if (state64 == PNGSIG || state64 == MNGSIG) {
+ i++;
+ ppc->pc.frame_start_found = 1;
+ break;
+ }
+ }
+ ppc->pc.state64 = state64;
+ } else
+ if (ppc->remaining_size) {
+ i = FFMIN(ppc->remaining_size, buf_size);
+ ppc->remaining_size -= i;
+ if (ppc->remaining_size)
+ goto flush;
+ if (ppc->index == -1) {
+ next = i;
+ goto flush;
+ }
+ }
+
+ for (;ppc->pc.frame_start_found && i < buf_size; i++) {
+ ppc->pc.state = (ppc->pc.state<<8) | buf[i];
+ if (ppc->index == 3) {
+ ppc->chunk_length = ppc->pc.state;
+ if (ppc->chunk_length > 0x7fffffff) {
+ ppc->index = ppc->pc.frame_start_found = 0;
+ goto flush;
+ }
+ ppc->chunk_length += 4;
+ } else if (ppc->index == 7) {
+ if (ppc->chunk_length >= buf_size - i)
+ ppc->remaining_size = ppc->chunk_length - buf_size + i + 1;
+ if (ppc->pc.state == MKBETAG('I', 'E', 'N', 'D')) {
+ if (ppc->remaining_size)
+ ppc->index = -1;
+ else
+ next = ppc->chunk_length + i + 1;
+ break;
+ } else {
+ ppc->index = 0;
+ if (ppc->remaining_size)
+ break;
+ else
+ i += ppc->chunk_length;
+ continue;
+ }
+ }
+ ppc->index++;
+ }
+flush:
+ if (ff_combine_frame(&ppc->pc, next, &buf, &buf_size) < 0)
+ return buf_size;
+
+ ppc->index = ppc->pc.frame_start_found = 0;
+
+ *poutbuf = buf;
+ *poutbuf_size = buf_size;
+ return next;
+}
+
+AVCodecParser ff_png_parser = {
+ .codec_ids = { AV_CODEC_ID_PNG },
+ .priv_data_size = sizeof(PNGParseContext),
+ .parser_parse = png_parse,
+ .parser_close = ff_parse_close,
+};