[FFmpeg-devel] [PATCH] avcodec/dca: remove GetBitContext usage from avpriv_dca_parse_core_frame_header()

[James Almer]

This prevents potential ABI issues with GetBitContext.

Signed-off-by: James Almer <jamrial at gmail.com>
---
 libavcodec/dca.c        | 12 +++++++++++-
 libavcodec/dca.h        |  7 +++++--
 libavcodec/dca_core.c   |  2 +-
 libavcodec/dca_parser.c |  4 +---
 libavformat/dtsdec.c    |  4 +---
 5 files changed, 19 insertions(+), 10 deletions(-)

diff --git a/libavcodec/dca.c b/libavcodec/dca.c
index 39f8f3d81c..307b21471e 100644
--- a/libavcodec/dca.c
+++ b/libavcodec/dca.c
@@ -88,7 +88,7 @@ int avpriv_dca_convert_bitstream(const uint8_t *src, int src_size, uint8_t *dst,
     }
 }
 
-int avpriv_dca_parse_core_frame_header(GetBitContext *gb, DCACoreFrameHeader *h)
+int ff_dca_parse_core_frame_header(DCACoreFrameHeader *h, GetBitContext *gb)
 {
     if (get_bits_long(gb, 32) != DCA_SYNCWORD_CORE_BE)
         return DCA_PARSE_ERROR_SYNC_WORD;
@@ -145,3 +145,13 @@ int avpriv_dca_parse_core_frame_header(GetBitContext *gb, DCACoreFrameHeader *h)
     h->dn_code = get_bits(gb, 4);
     return 0;
 }
+
+int avpriv_dca_parse_core_frame_header(DCACoreFrameHeader *h, uint8_t *buf, int size)
+{
+    GetBitContext gb;
+
+    if (init_get_bits8(&gb, buf, size) < 0)
+        return DCA_PARSE_ERROR_INVALIDDATA;
+
+    return ff_dca_parse_core_frame_header(h, &gb);
+}
diff --git a/libavcodec/dca.h b/libavcodec/dca.h
index cf6204e554..172c965b3b 100644
--- a/libavcodec/dca.h
+++ b/libavcodec/dca.h
@@ -45,7 +45,8 @@ enum DCAParseError {
     DCA_PARSE_ERROR_SAMPLE_RATE     = -6,
     DCA_PARSE_ERROR_RESERVED_BIT    = -7,
     DCA_PARSE_ERROR_LFE_FLAG        = -8,
-    DCA_PARSE_ERROR_PCM_RES         = -9
+    DCA_PARSE_ERROR_PCM_RES         = -9,
+    DCA_PARSE_ERROR_INVALIDDATA     = -10,
 };
 
 typedef struct DCACoreFrameHeader {
@@ -212,6 +213,8 @@ int avpriv_dca_convert_bitstream(const uint8_t *src, int src_size, uint8_t *dst,
  * Parse and validate core frame header
  * @return 0 on success, negative DCA_PARSE_ERROR_ code on failure
  */
-int avpriv_dca_parse_core_frame_header(GetBitContext *gb, DCACoreFrameHeader *h);
+int avpriv_dca_parse_core_frame_header(DCACoreFrameHeader *h, uint8_t *buf, int size);
+
+int ff_dca_parse_core_frame_header(DCACoreFrameHeader *h, GetBitContext *gb);
 
 #endif /* AVCODEC_DCA_H */
diff --git a/libavcodec/dca_core.c b/libavcodec/dca_core.c
index 3add9f812b..6cb1f30a3c 100644
--- a/libavcodec/dca_core.c
+++ b/libavcodec/dca_core.c
@@ -82,7 +82,7 @@ static void get_array(GetBitContext *s, int32_t *array, int size, int n)
 static int parse_frame_header(DCACoreDecoder *s)
 {
     DCACoreFrameHeader h = { 0 };
-    int err = avpriv_dca_parse_core_frame_header(&s->gb, &h);
+    int err = ff_dca_parse_core_frame_header(&h, &s->gb);
 
     if (err < 0) {
         switch (err) {
diff --git a/libavcodec/dca_parser.c b/libavcodec/dca_parser.c
index 7e99b16bf0..11ddb8f188 100644
--- a/libavcodec/dca_parser.c
+++ b/libavcodec/dca_parser.c
@@ -263,9 +263,7 @@ static int dca_parse_params(DCAParseContext *pc1, const uint8_t *buf,
     if ((ret = avpriv_dca_convert_bitstream(buf, DCA_CORE_FRAME_HEADER_SIZE,
                                             hdr, DCA_CORE_FRAME_HEADER_SIZE)) < 0)
         return ret;
-    if ((ret = init_get_bits8(&gb, hdr, ret)) < 0)
-        return ret;
-    if (avpriv_dca_parse_core_frame_header(&gb, &h) < 0)
+    if (avpriv_dca_parse_core_frame_header(&h, hdr, ret) < 0)
         return AVERROR_INVALIDDATA;
 
     *duration = h.npcmblocks * DCA_PCMBLOCK_SAMPLES;
diff --git a/libavformat/dtsdec.c b/libavformat/dtsdec.c
index 6e0048f9bc..a3e52cd596 100644
--- a/libavformat/dtsdec.c
+++ b/libavformat/dtsdec.c
@@ -101,9 +101,7 @@ static int dts_probe(AVProbeData *p)
         if ((ret = avpriv_dca_convert_bitstream(buf - 2, DCA_CORE_FRAME_HEADER_SIZE,
                                                 hdr,     DCA_CORE_FRAME_HEADER_SIZE)) < 0)
             continue;
-        if (init_get_bits8(&gb, hdr, ret) < 0)
-            continue;
-        if (avpriv_dca_parse_core_frame_header(&gb, &h) < 0)
+        if (avpriv_dca_parse_core_frame_header(&h, hdr, ret) < 0)
             continue;
 
         marker += 4 * h.sr_code;
-- 
2.13.3