adx_parser: rewrite.

The previous code ended in multiple different infinite
loops. See stl_ten_1_big.sfd as example with and without zzuf
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Signed-off-by: Justin Ruggles <justin.ruggles@gmail.com>

libavcodec/adx_parser.c

@@ -22,7 +22,7 @@
  * @file
  * ADX audio parser
  *
- * Reads header to extradata and splits packets into individual blocks.
+ * Splits packets into individual blocks.
  */
 
 #include "libavutil/intreadwrite.h"
@@ -33,11 +33,9 @@ typedef struct ADXParseContext {
     ParseContext pc;
     int header_size;
     int block_size;
-    int buf_pos;
+    int remaining;
 } ADXParseContext;
 
-#define MIN_HEADER_SIZE 24
-
 static int adx_parse(AVCodecParserContext *s1,
                            AVCodecContext *avctx,
                            const uint8_t **poutbuf, int *poutbuf_size,
@@ -46,45 +44,36 @@ static int adx_parse(AVCodecParserContext *s1,
     ADXParseContext *s = s1->priv_data;
     ParseContext *pc = &s->pc;
     int next = END_NOT_FOUND;
+    int i;
+    uint64_t state = pc->state64;
 
-    if (!avctx->extradata_size) {
-        int ret;
-
-        ff_combine_frame(pc, END_NOT_FOUND, &buf, &buf_size);
-
-        if (!s->header_size && pc->index >= MIN_HEADER_SIZE) {
-            if (ret = avpriv_adx_decode_header(avctx, pc->buffer, pc->index,
-                                               &s->header_size, NULL))
-                return AVERROR_INVALIDDATA;
-            s->block_size = BLOCK_SIZE * avctx->channels;
-        }
-        if (s->header_size && s->header_size <= pc->index) {
-            avctx->extradata = av_mallocz(s->header_size + FF_INPUT_BUFFER_PADDING_SIZE);
-            if (!avctx->extradata)
-                return AVERROR(ENOMEM);
-            avctx->extradata_size = s->header_size;
-            memcpy(avctx->extradata, pc->buffer, s->header_size);
-            memmove(pc->buffer, pc->buffer + s->header_size, s->header_size);
-            pc->index -= s->header_size;
+    if (!s->header_size) {
+        for (i = 0; i < buf_size; i++) {
+            state = (state << 8) | buf[i];
+            /* check for fixed fields in ADX header for possible match */
+            if ((state & 0xFFFF0000FFFFFF00) == 0x8000000003120400ULL) {
+                int channels    = state & 0xFF;
+                int header_size = ((state >> 32) & 0xFFFF) + 4;
+                if (channels > 0 && header_size >= 8) {
+                    s->header_size = header_size;
+                    s->block_size  = BLOCK_SIZE * channels;
+                    s->remaining   = i - 7 + s->header_size + s->block_size;
+                    break;
+                }
+            }
         }
-        *poutbuf      = NULL;
-        *poutbuf_size = 0;
-        return buf_size;
+        pc->state64 = state;
     }
 
-    if (pc->index - s->buf_pos >= s->block_size) {
-        *poutbuf      = &pc->buffer[s->buf_pos];
-        *poutbuf_size = s->block_size;
-        s->buf_pos   += s->block_size;
-        return 0;
-    }
-    if (pc->index && s->buf_pos) {
-        memmove(pc->buffer, &pc->buffer[s->buf_pos], pc->index - s->buf_pos);
-        pc->index -= s->buf_pos;
-        s->buf_pos = 0;
+    if (s->header_size) {
+        if (!s->remaining)
+            s->remaining = s->block_size;
+        if (s->remaining <= buf_size) {
+            next = s->remaining;
+            s->remaining = 0;
+        } else
+            s->remaining -= buf_size;
     }
-    if (buf_size + pc->index >= s->block_size)
-        next = s->block_size - pc->index;
 
     if (ff_combine_frame(pc, next, &buf, &buf_size) < 0 || !buf_size) {
         *poutbuf      = NULL;