Changeset 7a817d00 in mainline

Timestamp:

2008-12-23T16:48:53Z (16 years ago)

Author:

Jiri Svoboda <jirik.svoboda@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

576845ec

Parents:

6b080e54

Message:

Re-implement memmove(), which was totally broken.

File:

• uspace/lib/libc/generic/string.c (modified) (1 diff)

uspace/lib/libc/generic/string.c

@@ -190 +190 @@
 }
 
+/** Move memory block with possible overlapping. */
 void *memmove(void *dst, const void *src, size_t n)
 {
-        int i, j;
-        
-        if (src > dst)
+        uint8_t *dp, *sp;
+
+        /* Nothing to do? */
+        if (src == dst)
+                return dst;
+
+        /* Non-overlapping? */
+        if (dst >= src + n || src >= dst + n) { 
                 return memcpy(dst, src, n);
-
-        for (j = (n % sizeof(unsigned long)) - 1; j >= 0; j--)
-                ((unsigned char *) ((unsigned long *) dst))[j] =
-                    ((unsigned char *) ((unsigned long *) src))[j];
-
-        for (i = n / sizeof(unsigned long) - 1; i >=0 ; i--)
-                ((unsigned long *) dst)[i] = ((unsigned long *) src)[i];
-                
-        return (char *) dst;
+        }
+
+        /* Which direction? */
+        if (src > dst) {
+                /* Forwards. */
+                sp = src;
+                dp = dst;
+
+                while (n-- != 0)
+                        *dp++ = *sp++;
+        } else {
+                /* Backwards. */
+                sp = src + (n - 1);
+                dp = dst + (n - 1);
+
+                while (n-- != 0)
+                        *dp-- = *sp--;
+        }
+
+        return dst;
 }