@@ -269,8 +269,7 @@ static int parse_coding_header(DCACoreDecoder *s, enum HeaderType header, int xc

         // Check CRC

         if (s->xxch_crc_present

-            && (s->avctx->err_recognition & (AV_EF_CRCCHECK | AV_EF_CAREFUL))

-            && ff_dca_check_crc(&s->gb, header_pos, header_pos + header_size * 8)) {

+            && ff_dca_check_crc(s->avctx, &s->gb, header_pos, header_pos + header_size * 8)) {

             av_log(s->avctx, AV_LOG_ERROR, "Invalid XXCH channel set header checksum\n");

             return AVERROR_INVALIDDATA;

         }

@@ -977,8 +976,7 @@ static int parse_xxch_frame(DCACoreDecoder *s)

     header_size = get_bits(&s->gb, 6) + 1;

     // Check XXCH frame header CRC

-    if ((s->avctx->err_recognition & (AV_EF_CRCCHECK | AV_EF_CAREFUL))

-        && ff_dca_check_crc(&s->gb, header_pos + 32, header_pos + header_size * 8)) {

+    if (ff_dca_check_crc(s->avctx, &s->gb, header_pos + 32, header_pos + header_size * 8)) {

         av_log(s->avctx, AV_LOG_ERROR, "Invalid XXCH frame header checksum\n");

         return AVERROR_INVALIDDATA;

     }

@@ -1193,8 +1191,7 @@ static int parse_xbr_frame(DCACoreDecoder *s)

     header_size = get_bits(&s->gb, 6) + 1;

     // Check XBR frame header CRC

-    if ((s->avctx->err_recognition & (AV_EF_CRCCHECK | AV_EF_CAREFUL))

-        && ff_dca_check_crc(&s->gb, header_pos + 32, header_pos + header_size * 8)) {

+    if (ff_dca_check_crc(s->avctx, &s->gb, header_pos + 32, header_pos + header_size * 8)) {

         av_log(s->avctx, AV_LOG_ERROR, "Invalid XBR frame header checksum\n");

         return AVERROR_INVALIDDATA;

     }

@@ -1509,8 +1506,7 @@ static int parse_x96_coding_header(DCACoreDecoder *s, int exss, int xch_base)

         // Check CRC

         if (s->x96_crc_present

-            && (s->avctx->err_recognition & (AV_EF_CRCCHECK | AV_EF_CAREFUL))

-            && ff_dca_check_crc(&s->gb, header_pos, header_pos + header_size * 8)) {

+            && ff_dca_check_crc(s->avctx, &s->gb, header_pos, header_pos + header_size * 8)) {

             av_log(s->avctx, AV_LOG_ERROR, "Invalid X96 channel set header checksum\n");

             return AVERROR_INVALIDDATA;

         }

@@ -1665,8 +1661,7 @@ static int parse_x96_frame_exss(DCACoreDecoder *s)

     header_size = get_bits(&s->gb, 6) + 1;

     // Check X96 frame header CRC

-    if ((s->avctx->err_recognition & (AV_EF_CRCCHECK | AV_EF_CAREFUL))

-        && ff_dca_check_crc(&s->gb, header_pos + 32, header_pos + header_size * 8)) {

+    if (ff_dca_check_crc(s->avctx, &s->gb, header_pos + 32, header_pos + header_size * 8)) {

         av_log(s->avctx, AV_LOG_ERROR, "Invalid X96 frame header checksum\n");

         return AVERROR_INVALIDDATA;

     }

@@ -1785,8 +1780,7 @@ static int parse_aux_data(DCACoreDecoder *s)

     skip_bits(&s->gb, 16);

     // Check CRC

-    if ((s->avctx->err_recognition & (AV_EF_CRCCHECK | AV_EF_CAREFUL))

-        && ff_dca_check_crc(&s->gb, aux_pos, get_bits_count(&s->gb))) {

+    if (ff_dca_check_crc(s->avctx, &s->gb, aux_pos, get_bits_count(&s->gb))) {

         av_log(s->avctx, AV_LOG_ERROR, "Invalid auxiliary data checksum\n");

         return AVERROR_INVALIDDATA;

     }

@@ -1884,9 +1878,10 @@ static int parse_optional_info(DCACoreDecoder *s)

                 if (AV_RB32(s->gb.buffer + sync_pos * 4) == DCA_SYNCWORD_XXCH) {

                     s->gb.index = (sync_pos + 1) * 32;

                     size = get_bits(&s->gb, 6) + 1;

-                    if (size >= 11 &&

-                        !ff_dca_check_crc(&s->gb, (sync_pos + 1) * 32,

-                                          sync_pos * 32 + size * 8)) {

+                    dist = s->gb.size_in_bits / 8 - sync_pos * 4;

+                    if (size >= 11 && size <= dist &&

+                        !av_crc(dca->crctab, 0xffff, s->gb.buffer +

+                                (sync_pos + 1) * 4, size - 4)) {

                         s->xxch_pos = sync_pos * 32;

                         break;

                     }

@@ -398,8 +398,7 @@ int ff_dca_exss_parse(DCAExssParser *s, uint8_t *data, int size)

     header_size = get_bits(&s->gb, 8 + 4 * wide_hdr) + 1;

     // Check CRC

-    if ((s->avctx->err_recognition & (AV_EF_CRCCHECK | AV_EF_CAREFUL))

-        && ff_dca_check_crc(&s->gb, 32 + 8, header_size * 8)) {

+    if (ff_dca_check_crc(s->avctx, &s->gb, 32 + 8, header_size * 8)) {

         av_log(s->avctx, AV_LOG_ERROR, "Invalid EXSS header checksum\n");

         return AVERROR_INVALIDDATA;

     }

@@ -123,8 +123,7 @@ static int chs_parse_header(DCAXllDecoder *s, DCAXllChSet *c, DCAExssAsset *asse

     header_size = get_bits(&s->gb, 10) + 1;

     // Check CRC

-    if ((s->avctx->err_recognition & (AV_EF_CRCCHECK | AV_EF_CAREFUL))

-        && ff_dca_check_crc(&s->gb, header_pos, header_pos + header_size * 8)) {

+    if (ff_dca_check_crc(s->avctx, &s->gb, header_pos, header_pos + header_size * 8)) {

         av_log(s->avctx, AV_LOG_ERROR, "Invalid XLL sub-header checksum\n");

         return AVERROR_INVALIDDATA;

     }

@@ -784,8 +783,7 @@ static int parse_common_header(DCAXllDecoder *s)

     header_size = get_bits(&s->gb, 8) + 1;

     // Check CRC

-    if ((s->avctx->err_recognition & (AV_EF_CRCCHECK | AV_EF_CAREFUL))

-        && ff_dca_check_crc(&s->gb, 32, header_size * 8)) {

+    if (ff_dca_check_crc(s->avctx, &s->gb, 32, header_size * 8)) {

         av_log(s->avctx, AV_LOG_ERROR, "Invalid XLL common header checksum\n");

         return AVERROR_INVALIDDATA;

     }

@@ -993,8 +991,7 @@ static int parse_navi_table(DCAXllDecoder *s)

     skip_bits(&s->gb, 16);

     // Check CRC

-    if ((s->avctx->err_recognition & (AV_EF_CRCCHECK | AV_EF_CAREFUL))

-        && ff_dca_check_crc(&s->gb, navi_pos, get_bits_count(&s->gb))) {

+    if (ff_dca_check_crc(s->avctx, &s->gb, navi_pos, get_bits_count(&s->gb))) {

         av_log(s->avctx, AV_LOG_ERROR, "Invalid NAVI checksum\n");

         return AVERROR_INVALIDDATA;

     }

@@ -76,33 +76,6 @@ int ff_dca_set_channel_layout(AVCodecContext *avctx, int *ch_remap, int dca_mask

     return nchannels;

 }

-static uint16_t crc16(const uint8_t *data, int size)

-{

-    static const uint16_t crctab[16] = {

-        0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5, 0x60c6, 0x70e7,

-        0x8108, 0x9129, 0xa14a, 0xb16b, 0xc18c, 0xd1ad, 0xe1ce, 0xf1ef,

-    };

-

-    uint16_t res = 0xffff;

-    int i;

-

-    for (i = 0; i < size; i++) {

-        res = (res << 4) ^ crctab[(data[i] >> 4) ^ (res >> 12)];

-        res = (res << 4) ^ crctab[(data[i] & 15) ^ (res >> 12)];

-    }

-

-    return res;

-}

-

-int ff_dca_check_crc(GetBitContext *s, int p1, int p2)

-{

-    if (((p1 | p2) & 7) || p1 < 0 || p2 > s->size_in_bits || p2 - p1 < 16)

-        return -1;

-    if (crc16(s->buffer + p1 / 8, (p2 - p1) / 8))

-        return -1;

-    return 0;

-}

-

 void ff_dca_downmix_to_stereo_fixed(DCADSPContext *dcadsp, int32_t **samples,

                                     int *coeff_l, int nsamples, int ch_mask)

 {

@@ -359,6 +332,8 @@ static av_cold int dcadec_init(AVCodecContext *avctx)

     s->core.dcadsp = &s->dcadsp;

     s->xll.dcadsp = &s->dcadsp;

+    s->crctab = av_crc_get_table(AV_CRC_16_CCITT);

+

     switch (avctx->request_channel_layout & ~AV_CH_LAYOUT_NATIVE) {

     case 0:

         s->request_channel_layout = 0;

@@ -22,6 +22,7 @@

 #define AVCODEC_DCADEC_H

 #include "libavutil/common.h"

+#include "libavutil/crc.h"

 #include "libavutil/float_dsp.h"

 #include "avcodec.h"

@@ -49,6 +50,8 @@ typedef struct DCAContext {

     DCADSPContext   dcadsp;

+    const AVCRC     *crctab;

+

     uint8_t         *buffer;    ///< Packet buffer

     unsigned int    buffer_size;

@@ -62,13 +65,25 @@ typedef struct DCAContext {

 int ff_dca_set_channel_layout(AVCodecContext *avctx, int *ch_remap, int dca_mask);

-int ff_dca_check_crc(GetBitContext *s, int p1, int p2);

-

 void ff_dca_downmix_to_stereo_fixed(DCADSPContext *dcadsp, int32_t **samples,

                                     int *coeff_l, int nsamples, int ch_mask);

 void ff_dca_downmix_to_stereo_float(AVFloatDSPContext *fdsp, float **samples,

                                     int *coeff_l, int nsamples, int ch_mask);

+static inline int ff_dca_check_crc(AVCodecContext *avctx, GetBitContext *s,

+                                   int p1, int p2)

+{

+    DCAContext *dca = avctx->priv_data;

+

+    if (!(avctx->err_recognition & (AV_EF_CRCCHECK | AV_EF_CAREFUL)))

+        return 0;

+    if (((p1 | p2) & 7) || p1 < 0 || p2 > s->size_in_bits || p2 - p1 < 16)

+        return -1;

+    if (av_crc(dca->crctab, 0xffff, s->buffer + p1 / 8, (p2 - p1) / 8))

+        return -1;

+    return 0;

+}

+

 static inline int ff_dca_seek_bits(GetBitContext *s, int p)

 {

     if (p < s->index || p > s->size_in_bits)