bmp: add a standalone parser

Signed-off-by: Vittorio Giovara <vittorio.giovara@gmail.com>

1 files changed, 91 insertions, 0 deletions

diff --git a/libavcodec/bmp_parser.c b/libavcodec/bmp_parser.c
new file mode 100644
index 0000000000..b85dd8bcb5
--- /dev/null
+++ b/libavcodec/bmp_parser.c
@@ -0,0 +1,91 @@
+/*
+ * BMP parser
+ * Copyright (c) 2012 Paul B Mahol
+ *
+ * This file is part of Libav.
+ *
+ * Libav 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.
+ *
+ * Libav 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 Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * @file
+ * BMP parser
+ */
+
+#include "libavutil/bswap.h"
+#include "libavutil/common.h"
+
+#include "parser.h"
+
+typedef struct BMPParseContext {
+    ParseContext pc;
+    uint32_t fsize;
+    uint32_t remaining_size;
+} BMPParseContext;
+
+static int bmp_parse(AVCodecParserContext *s, AVCodecContext *avctx,
+                     const uint8_t **poutbuf, int *poutbuf_size,
+                     const uint8_t *buf, int buf_size)
+{
+    BMPParseContext *bpc = s->priv_data;
+    uint64_t state = bpc->pc.state64;
+    int next = END_NOT_FOUND;
+    int i = 0;
+
+    *poutbuf_size = 0;
+    if (buf_size == 0)
+        return 0;
+
+    if (!bpc->pc.frame_start_found) {
+        for (; i < buf_size; i++) {
+            state = (state << 8) | buf[i];
+            if ((state >> 48) == (('B' << 8) | 'M')) {
+                bpc->fsize = av_bswap32(state >> 16);
+                bpc->pc.frame_start_found = 1;
+                if (bpc->fsize > buf_size - i + 7)
+                    bpc->remaining_size = bpc->fsize - buf_size + i - 7;
+                else
+                    next = bpc->fsize + i - 7;
+                break;
+            }
+        }
+        bpc->pc.state64 = state;
+    } else {
+        if (bpc->remaining_size) {
+            i = FFMIN(bpc->remaining_size, buf_size);
+            bpc->remaining_size -= i;
+            if (bpc->remaining_size)
+                goto flush;
+            next = i;
+        }
+    }
+
+flush:
+    if (ff_combine_frame(&bpc->pc, next, &buf, &buf_size) < 0)
+        return buf_size;
+
+    bpc->pc.frame_start_found = 0;
+
+    *poutbuf      = buf;
+    *poutbuf_size = buf_size;
+    return next;
+}
+
+AVCodecParser ff_bmp_parser = {
+    .codec_ids      = { AV_CODEC_ID_BMP },
+    .priv_data_size = sizeof(BMPParseContext),
+    .parser_parse   = bmp_parse,
+    .parser_close   = ff_parse_close,
+};