Avoid some useless memory copying.

[rsync/rsync.git] / checksum.c

diff --git a/checksum.c b/checksum.c
index edc844f..ff9b1fa 100644 (file)
--- a/checksum.c
+++ b/checksum.c
@@ -23,8 +23,8 @@ int csum_length=2; /* initial value */
 
 #define CSUM_CHUNK 64
 
-int checksum_seed = 0;
-extern int remote_version;
+extern int checksum_seed;
+extern int protocol_version;
 
 /*
   a simple 32 bit checksum that can be upadted from either end
@@ -58,7 +58,7 @@ void get_checksum2(char *buf,int len,char *sum)
 
        if (len > len1) {
                if (buf1) free(buf1);
-               buf1 = (char *)malloc(len+4);
+               buf1 = new_array(char, len+4);
                len1 = len;
                if (!buf1) out_of_memory("get_checksum2");
        }
@@ -74,7 +74,13 @@ void get_checksum2(char *buf,int len,char *sum)
        for(i = 0; i + CSUM_CHUNK <= len; i += CSUM_CHUNK) {
                mdfour_update(&m, (uchar *)(buf1+i), CSUM_CHUNK);
        }
-       if (len - i > 0) {
+       /*
+        * Prior to version 27 an incorrect MD4 checksum was computed
+        * by failing to call mdfour_tail() for block sizes that
+        * are multiples of 64.  This is fixed by calling mdfour_update()
+        * even when there are no more bytes.
+        */
+       if (len - i > 0 || protocol_version >= 27) {
                mdfour_update(&m, (uchar *)(buf1+i), (len-i));
        }
        
@@ -88,12 +94,11 @@ void file_checksum(char *fname,char *sum,OFF_T size)
        struct map_struct *buf;
        int fd;
        OFF_T len = size;
-       char tmpchunk[CSUM_CHUNK];
        struct mdfour m;
        
-       memset(sum,0,csum_length);
+       memset(sum,0,MD4_SUM_LENGTH);
        
-       fd = open(fname,O_RDONLY);
+       fd = do_open(fname, O_RDONLY, 0);
        if (fd == -1) return;
        
        buf = map_file(fd,size);
@@ -101,14 +106,16 @@ void file_checksum(char *fname,char *sum,OFF_T size)
        mdfour_begin(&m);
 
        for(i = 0; i + CSUM_CHUNK <= len; i += CSUM_CHUNK) {
-               memcpy(tmpchunk, map_ptr(buf,i,CSUM_CHUNK), CSUM_CHUNK);
-               mdfour_update(&m, (uchar *)tmpchunk, CSUM_CHUNK);
+               mdfour_update(&m, (uchar *)map_ptr(buf, i, CSUM_CHUNK),
+                             CSUM_CHUNK);
        }
 
-       if (len - i > 0) {
-               memcpy(tmpchunk, map_ptr(buf,i,len-i), len-i);
-               mdfour_update(&m, (uchar *)tmpchunk, (len-i));
-       }
+       /* Prior to version 27 an incorrect MD4 checksum was computed
+        * by failing to call mdfour_tail() for block sizes that
+        * are multiples of 64.  This is fixed by calling mdfour_update()
+        * even when there are no more bytes. */
+       if (len - i > 0 || protocol_version >= 27)
+               mdfour_update(&m, (uchar *)map_ptr(buf, i, len-i), len-i);
 
        mdfour_result(&m, (uchar *)sum);
 
@@ -117,30 +124,28 @@ void file_checksum(char *fname,char *sum,OFF_T size)
 }
 
 
-void checksum_init(void)
-{
-  if (remote_version >= 14)
-    csum_length = 2; /* adaptive */
-  else
-    csum_length = SUM_LENGTH;
-}
-
-
-
 static int sumresidue;
 static char sumrbuf[CSUM_CHUNK];
 static struct mdfour md;
 
-void sum_init(void)
+void sum_init(int seed)
 {
        char s[4];
        mdfour_begin(&md);
-       sumresidue=0;
-       SIVAL(s,0,checksum_seed);
-       sum_update(s,4);
+       sumresidue = 0;
+       SIVAL(s, 0, seed);
+       sum_update(s, 4);
 }
 
-void sum_update(char *p,int len)
+/**
+ * Feed data into an MD4 accumulator, md.  The results may be
+ * retrieved using sum_end().  md is used for different purposes at
+ * different points during execution.
+ *
+ * @todo Perhaps get rid of md and just pass in the address each time.
+ * Very slightly clearer and slower.
+ **/
+void sum_update(char *p, int len)
 {
        int i;
        if (len + sumresidue < CSUM_CHUNK) {
@@ -172,7 +177,7 @@ void sum_update(char *p,int len)
 
 void sum_end(char *sum)
 {
-       if (sumresidue) {
+       if (sumresidue || protocol_version >= 27) {
                mdfour_update(&md, (uchar *)sumrbuf, sumresidue);
        }