crc: add ANSI CRC16 LE

This adds the reversed byte-order version of the ANSI CRC16.
Signed-off-by: Anton Khirnov <anton@khirnov.net>

doc/APIchanges

@@ -13,6 +13,9 @@ libavutil:     2013-12-xx
 
 API changes, most recent first:
 
+2014-04-xx - xxxxxxx - lavu 53.12.0 - crc.h
+  Add AV_CRC_16_ANSI_LE crc variant.
+
 2014-04-xx - xxxxxxx - lavu 53.11.0 - pixfmt.h
   Add AV_PIX_FMT_YVYU422 pixel format.
 

libavutil/crc.c

@@ -209,6 +209,41 @@ static const AVCRC av_crc_table[AV_CRC_MAX][257] = {
         0x54DE5729, 0x23D967BF, 0xB3667A2E, 0xC4614AB8, 0x5D681B02, 0x2A6F2B94,
         0xB40BBE37, 0xC30C8EA1, 0x5A05DF1B, 0x2D02EF8D, 0x00000001
     },
+    [AV_CRC_16_ANSI_LE] = {
+        0x0000, 0xC0C1, 0xC181, 0x0140, 0xC301, 0x03C0, 0x0280, 0xC241,
+        0xC601, 0x06C0, 0x0780, 0xC741, 0x0500, 0xC5C1, 0xC481, 0x0440,
+        0xCC01, 0x0CC0, 0x0D80, 0xCD41, 0x0F00, 0xCFC1, 0xCE81, 0x0E40,
+        0x0A00, 0xCAC1, 0xCB81, 0x0B40, 0xC901, 0x09C0, 0x0880, 0xC841,
+        0xD801, 0x18C0, 0x1980, 0xD941, 0x1B00, 0xDBC1, 0xDA81, 0x1A40,
+        0x1E00, 0xDEC1, 0xDF81, 0x1F40, 0xDD01, 0x1DC0, 0x1C80, 0xDC41,
+        0x1400, 0xD4C1, 0xD581, 0x1540, 0xD701, 0x17C0, 0x1680, 0xD641,
+        0xD201, 0x12C0, 0x1380, 0xD341, 0x1100, 0xD1C1, 0xD081, 0x1040,
+        0xF001, 0x30C0, 0x3180, 0xF141, 0x3300, 0xF3C1, 0xF281, 0x3240,
+        0x3600, 0xF6C1, 0xF781, 0x3740, 0xF501, 0x35C0, 0x3480, 0xF441,
+        0x3C00, 0xFCC1, 0xFD81, 0x3D40, 0xFF01, 0x3FC0, 0x3E80, 0xFE41,
+        0xFA01, 0x3AC0, 0x3B80, 0xFB41, 0x3900, 0xF9C1, 0xF881, 0x3840,
+        0x2800, 0xE8C1, 0xE981, 0x2940, 0xEB01, 0x2BC0, 0x2A80, 0xEA41,
+        0xEE01, 0x2EC0, 0x2F80, 0xEF41, 0x2D00, 0xEDC1, 0xEC81, 0x2C40,
+        0xE401, 0x24C0, 0x2580, 0xE541, 0x2700, 0xE7C1, 0xE681, 0x2640,
+        0x2200, 0xE2C1, 0xE381, 0x2340, 0xE101, 0x21C0, 0x2080, 0xE041,
+        0xA001, 0x60C0, 0x6180, 0xA141, 0x6300, 0xA3C1, 0xA281, 0x6240,
+        0x6600, 0xA6C1, 0xA781, 0x6740, 0xA501, 0x65C0, 0x6480, 0xA441,
+        0x6C00, 0xACC1, 0xAD81, 0x6D40, 0xAF01, 0x6FC0, 0x6E80, 0xAE41,
+        0xAA01, 0x6AC0, 0x6B80, 0xAB41, 0x6900, 0xA9C1, 0xA881, 0x6840,
+        0x7800, 0xB8C1, 0xB981, 0x7940, 0xBB01, 0x7BC0, 0x7A80, 0xBA41,
+        0xBE01, 0x7EC0, 0x7F80, 0xBF41, 0x7D00, 0xBDC1, 0xBC81, 0x7C40,
+        0xB401, 0x74C0, 0x7580, 0xB541, 0x7700, 0xB7C1, 0xB681, 0x7640,
+        0x7200, 0xB2C1, 0xB381, 0x7340, 0xB101, 0x71C0, 0x7080, 0xB041,
+        0x5000, 0x90C1, 0x9181, 0x5140, 0x9301, 0x53C0, 0x5280, 0x9241,
+        0x9601, 0x56C0, 0x5780, 0x9741, 0x5500, 0x95C1, 0x9481, 0x5440,
+        0x9C01, 0x5CC0, 0x5D80, 0x9D41, 0x5F00, 0x9FC1, 0x9E81, 0x5E40,
+        0x5A00, 0x9AC1, 0x9B81, 0x5B40, 0x9901, 0x59C0, 0x5880, 0x9841,
+        0x8801, 0x48C0, 0x4980, 0x8941, 0x4B00, 0x8BC1, 0x8A81, 0x4A40,
+        0x4E00, 0x8EC1, 0x8F81, 0x4F40, 0x8D01, 0x4DC0, 0x4C80, 0x8C41,
+        0x4400, 0x84C1, 0x8581, 0x4540, 0x8701, 0x47C0, 0x4680, 0x8641,
+        0x8201, 0x42C0, 0x4380, 0x8341, 0x4100, 0x81C1, 0x8081, 0x4040,
+        0x0001
+    },
 };
 #else
 static struct {
@@ -221,6 +256,7 @@ static struct {
     [AV_CRC_16_CCITT]   = { 0, 16,     0x1021 },
     [AV_CRC_32_IEEE]    = { 0, 32, 0x04C11DB7 },
     [AV_CRC_32_IEEE_LE] = { 1, 32, 0xEDB88320 },
+    [AV_CRC_16_ANSI_LE] = { 1, 16,     0xA001 },
 };
 static AVCRC av_crc_table[AV_CRC_MAX][257];
 #endif
@@ -302,8 +338,9 @@ int main(void)
 {
     uint8_t buf[1999];
     int i;
-    int p[4][3] = { { AV_CRC_32_IEEE_LE, 0xEDB88320, 0x3D5CDD04 },
+    int p[5][3] = { { AV_CRC_32_IEEE_LE, 0xEDB88320, 0x3D5CDD04 },
                     { AV_CRC_32_IEEE   , 0x04C11DB7, 0xC0F5BAE0 },
+                    { AV_CRC_16_ANSI_LE, 0xA001    , 0xBFD8     },
                     { AV_CRC_16_ANSI   , 0x8005    , 0x1FBB     },
                     { AV_CRC_8_ATM     , 0x07      , 0xE3       }
     };
@@ -312,7 +349,7 @@ int main(void)
     for (i = 0; i < sizeof(buf); i++)
         buf[i] = i + i * i;
 
-    for (i = 0; i < 4; i++) {
+    for (i = 0; i < 5; i++) {
         ctx = av_crc_get_table(p[i][0]);
         printf("crc %08X = %X\n", p[i][1], av_crc(ctx, 0, buf, sizeof(buf)));
     }

libavutil/crc.h

@@ -33,6 +33,7 @@ typedef enum {
     AV_CRC_16_CCITT,
     AV_CRC_32_IEEE,
     AV_CRC_32_IEEE_LE,  /*< reversed bitorder version of AV_CRC_32_IEEE */
+    AV_CRC_16_ANSI_LE,  /*< reversed bitorder version of AV_CRC_16_ANSI */
     AV_CRC_MAX,         /*< Not part of public API! Do not use outside libavutil. */
 }AVCRCId;
 

libavutil/version.h

@@ -54,7 +54,7 @@
  */
 
 #define LIBAVUTIL_VERSION_MAJOR 53
-#define LIBAVUTIL_VERSION_MINOR 11
+#define LIBAVUTIL_VERSION_MINOR 12
 #define LIBAVUTIL_VERSION_MICRO  0
 
 #define LIBAVUTIL_VERSION_INT   AV_VERSION_INT(LIBAVUTIL_VERSION_MAJOR, \

tests/ref/fate/crc

 crc EDB88320 = 3D5CDD04
 crc 04C11DB7 = E0BAF5C0
+crc 0000A001 = BFD8
 crc 00008005 = BB1F
 crc 00000007 = E3