X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=libavutil%2Fcrc.c;h=6c9f92809f788c66d16c56831cb0e941f422dbab;hb=28734ac995ef4ea9be2203144362a585b2296637;hp=5ccf03639b0cbae68706cb77fa12071162b325f4;hpb=3abe5fbdc4169047421e9e8794a8f190d794b929;p=ffmpeg

diff --git a/libavutil/crc.c b/libavutil/crc.c
index 5ccf03639b0..6c9f92809f7 100644
--- a/libavutil/crc.c
+++ b/libavutil/crc.c
@@ -1,27 +1,29 @@
 /*
  * copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
  *
- * This file is part of FFmpeg.
+ * This file is part of Libav.
  *
- * FFmpeg is free software; you can redistribute it and/or
+ * 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.
  *
- * FFmpeg is distributed in the hope that it will be useful,
+ * 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 FFmpeg; if not, write to the Free Software
+ * License along with Libav; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
+#include "config.h"
 #include "common.h"
+#include "bswap.h"
 #include "crc.h"
 
-#ifdef CONFIG_HARDCODED_TABLES
+#if CONFIG_HARDCODED_TABLES
 #include "crc_data.h"
 #else
 static struct {
@@ -39,18 +41,19 @@ static AVCRC av_crc_table[AV_CRC_MAX][257];
 #endif
 
 /**
- * Inits a crc table.
- * @param ctx must be an array of sizeof(AVCRC)*257 or sizeof(AVCRC)*1024
- * @param cts_size size of ctx in bytes
- * @param le if 1, lowest bit represents coefficient for highest exponent
- *           of corresponding polynomial (both for poly and actual CRC).
- *           If 0, you must swap the crc parameter and the result of av_crc
+ * Initialize a CRC table.
+ * @param ctx must be an array of size sizeof(AVCRC)*257 or sizeof(AVCRC)*1024
+ * @param le If 1, the lowest bit represents the coefficient for the highest
+ *           exponent of the corresponding polynomial (both for poly and
+ *           actual CRC).
+ *           If 0, you must swap the CRC parameter and the result of av_crc
  *           if you need the standard representation (can be simplified in
  *           most cases to e.g. bswap16):
- *           bswap_32(crc << (32-bits))
+ *           av_bswap32(crc << (32-bits))
  * @param bits number of bits for the CRC
  * @param poly generator polynomial without the x**bits coefficient, in the
  *             representation as specified by le
+ * @param ctx_size size of ctx in bytes
  * @return <0 on failure
  */
 int av_crc_init(AVCRC *ctx, int le, int bits, uint32_t poly, int ctx_size){
@@ -70,11 +73,11 @@ int av_crc_init(AVCRC *ctx, int le, int bits, uint32_t poly, int ctx_size){
         } else {
             for (c = i << 24, j = 0; j < 8; j++)
                 c = (c<<1) ^ ((poly<<(32-bits)) & (((int32_t)c)>>31) );
-            ctx[i] = bswap_32(c);
+            ctx[i] = av_bswap32(c);
         }
     }
     ctx[256]=1;
-#ifndef CONFIG_SMALL
+#if !CONFIG_SMALL
     if(ctx_size >= sizeof(AVCRC)*1024)
         for (i = 0; i < 256; i++)
             for(j=0; j<3; j++)
@@ -90,8 +93,8 @@ int av_crc_init(AVCRC *ctx, int le, int bits, uint32_t poly, int ctx_size){
  * @return a pointer to the CRC table or NULL on failure
  */
 const AVCRC *av_crc_get_table(AVCRCId crc_id){
-#ifndef CONFIG_HARDCODED_TABLES
-    if (!av_crc_table[crc_id][sizeof(av_crc_table[crc_id])-1])
+#if !CONFIG_HARDCODED_TABLES
+    if (!av_crc_table[crc_id][FF_ARRAY_ELEMS(av_crc_table[crc_id])-1])
         if (av_crc_init(av_crc_table[crc_id],
                         av_crc_table_params[crc_id].le,
                         av_crc_table_params[crc_id].bits,
@@ -103,8 +106,8 @@ const AVCRC *av_crc_get_table(AVCRCId crc_id){
 }
 
 /**
- * Calculate the CRC of a block
- * @param crc CRC of previous blocks if any or initial value for CRC.
+ * Calculate the CRC of a block.
+ * @param crc CRC of previous blocks if any or initial value for CRC
  * @return CRC updated with the data from the given block
  *
  * @see av_crc_init() "le" parameter
@@ -112,15 +115,19 @@ const AVCRC *av_crc_get_table(AVCRCId crc_id){
 uint32_t av_crc(const AVCRC *ctx, uint32_t crc, const uint8_t *buffer, size_t length){
     const uint8_t *end= buffer+length;
 
-#ifndef CONFIG_SMALL
-    if(!ctx[256])
+#if !CONFIG_SMALL
+    if(!ctx[256]) {
+        while(((intptr_t) buffer & 3) && buffer < end)
+            crc = ctx[((uint8_t)crc) ^ *buffer++] ^ (crc >> 8);
+
         while(buffer<end-3){
-            crc ^= le2me_32(*(uint32_t*)buffer); buffer+=4;
+            crc ^= av_le2ne32(*(const uint32_t*)buffer); buffer+=4;
             crc =  ctx[3*256 + ( crc     &0xFF)]
                   ^ctx[2*256 + ((crc>>8 )&0xFF)]
                   ^ctx[1*256 + ((crc>>16)&0xFF)]
                   ^ctx[0*256 + ((crc>>24)     )];
         }
+    }
 #endif
     while(buffer<end)
         crc = ctx[((uint8_t)crc) ^ *buffer++] ^ (crc >> 8);
@@ -130,7 +137,7 @@ uint32_t av_crc(const AVCRC *ctx, uint32_t crc, const uint8_t *buffer, size_t le
 
 #ifdef TEST
 #undef printf
-main(void){
+int main(void){
     uint8_t buf[1999];
     int i;
     int p[4][3]={{AV_CRC_32_IEEE_LE, 0xEDB88320, 0x3D5CDD04},
@@ -146,5 +153,6 @@ main(void){
         ctx = av_crc_get_table(p[i][0]);
         printf("crc %08X =%X\n", p[i][1], av_crc(ctx, 0, buf, sizeof(buf)));
     }
+    return 0;
 }
 #endif