WebSVN – HelenOS – Diff – /branches/dd/kernel/generic/src/lib/memstr.c

 /*
  * Copyright (c) 2001-2004 Jakub Jermar
+ * Copyright (c) 2008 Jiri Svoboda
  * All rights reserved.
+ *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
 /**
  * @file
  * @brief   Memory string operations.
+ *
- * This file provides architecture independent functions
+ * This file provides architecture independent functions to manipulate blocks of
- * to manipulate blocks of memory. These functions
- * are optimized as much as generic functions of
+ * memory. These functions are optimized as much as generic functions of this
- * this type can be. However, architectures are
+ * type can be. However, architectures are free to provide even more optimized
- * free to provide even more optimized versions of these
- * functions.
+ * versions of these functions.
  */
 #include <memstr.h>
 #include <arch/types.h>
 #include <align.h>
-/** Copy block of memory
+/** Copy block of memory.
+ *
- * Copy cnt bytes from src address to dst address.
+ * Copy cnt bytes from src address to dst address.  The copying is done
- * The copying is done word-by-word and then byte-by-byte.
+ * word-by-word and then byte-by-byte.  The source and destination memory areas
- * The source and destination memory areas cannot overlap.
+ * cannot overlap.
+ *
- * @param src Origin address to copy from.
+ * @param src       Source address to copy from.
- * @param dst Origin address to copy to.
+ * @param dst       Destination address to copy to.
- * @param cnt Number of bytes to copy.
+ * @param cnt       Number of bytes to copy.
+ *
+ * @return      Destination address.
  */
-void *_memcpy(void * dst, const void *src, size_t cnt)
+void *_memcpy(void *dst, const void *src, size_t cnt)
+{
     unsigned int i, j;
     if (ALIGN_UP((uintptr_t) src, sizeof(unative_t)) != (uintptr_t) src ||
         ALIGN_UP((uintptr_t) dst, sizeof(unative_t)) != (uintptr_t) dst) {
         for (i = 0; i < cnt; i++)
             ((uint8_t *) dst)[i] = ((uint8_t *) src)[i];
     } else {
-        for (i = 0; i < cnt/sizeof(unative_t); i++)
+        for (i = 0; i < cnt / sizeof(unative_t); i++)
             ((unative_t *) dst)[i] = ((unative_t *) src)[i];
-        for (j = 0; j < cnt%sizeof(unative_t); j++)
+        for (j = 0; j < cnt % sizeof(unative_t); j++)
+            ((uint8_t *)(((unative_t *) dst) + i))[j] =
-            ((uint8_t *)(((unative_t *) dst) + i))[j] = ((uint8_t *)(((unative_t *) src) + i))[j];
+                ((uint8_t *)(((unative_t *) src) + i))[j];
+    }
-    return (char *) src;
+    return (char *) dst;
+}
-/** Fill block of memory
+/** Move memory block with possible overlapping.
+ *
- * Fill cnt bytes at dst address with the value x.
+ * Copy cnt bytes from src address to dst address. The source and destination
- * The filling is done byte-by-byte.
+ * memory areas may overlap.
+ *
- * @param dst Origin address to fill.
+ * @param src       Source address to copy from.
- * @param cnt Number of bytes to fill.
+ * @param dst       Destination address to copy to.
- * @param x   Value to fill.
+ * @param cnt       Number of bytes to copy.
+ *
+ * @return      Destination address.
  */
-void _memsetb(uintptr_t dst, size_t cnt, uint8_t x)
+void *memmove(void *dst, const void *src, size_t n)
+{
+    const uint8_t *sp;
-    unsigned int i;
+    uint8_t *dp;
+    /* Nothing to do? */
+    if (src == dst)
+        return dst;
+    /* Non-overlapping? */
+    if (dst >= src + n || src >= dst + n) {
-    uint8_t *p = (uint8_t *) dst;
+        return memcpy(dst, src, n);
+    }
-    for (i = 0; i < cnt; i++)
+    /* Which direction? */
+    if (src > dst) {
+        /* Forwards. */
+        sp = src;
-        p[i] = x;
+        dp = dst;
+        while (n-- != 0)
+            *dp++ = *sp++;
+    } else {
+        /* Backwards. */
+        sp = src + (n - 1);
+        dp = dst + (n - 1);
+        while (n-- != 0)
+            *dp-- = *sp--;
+    }
+    return dst;
+}
 /** Fill block of memory
+ *
- * Fill cnt words at dst address with the value x.
+ * Fill cnt bytes at dst address with the value x.  The filling is done
- * The filling is done word-by-word.
+ * byte-by-byte.
+ *
- * @param dst Origin address to fill.
+ * @param dst       Destination address to fill.
- * @param cnt Number of words to fill.
+ * @param cnt       Number of bytes to fill.
- * @param x   Value to fill.
+ * @param x     Value to fill.
+ *
  */
-void _memsetw(uintptr_t dst, size_t cnt, uint16_t x)
+void _memsetb(void *dst, size_t cnt, uint8_t x)
+{
     unsigned int i;
-    uint16_t *p = (uint16_t *) dst;
+    uint8_t *p = (uint8_t *) dst;
     for (i = 0; i < cnt; i++)
         p[i] = x;
+}
-/** Copy string
+/** Fill block of memory.
+ *
- * Copy string from src address to dst address.
+ * Fill cnt words at dst address with the value x.  The filling is done
- * The copying is done char-by-char until the null
- * character. The source and destination memory areas
- * cannot overlap.
+ * word-by-word.
+ *
- * @param src Origin string to copy from.
+ * @param dst       Destination address to fill.
- * @param dst Origin string to copy to.
+ * @param cnt       Number of words to fill.
+ * @param x     Value to fill.
+ *
  */
-char *strcpy(char *dest, const char *src)
+void _memsetw(void *dst, size_t cnt, uint16_t x)
+{
-    char *orig = dest;
+    unsigned int i;
+    uint16_t *p = (uint16_t *) dst;
-    while ((*(dest++) = *(src++)))
+    for (i = 0; i < cnt; i++)
-        ;
-    return orig;
+        p[i] = x;
+}
 /** @}
  */

Subversion Repositories HelenOS

(root)/branches/dd/kernel/generic/src/lib/memstr.c – Rev 3022 → 4055