Changeset abf09311 in mainline for uspace/lib/c/generic/str.c

Timestamp:

2010-04-17T01:12:35Z (14 years ago)

Author:

Martin Decky <martin@…>

Branches:

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

Children:

46416ab

Parents:

d7f8796c

Message:

much safer implementation of str_dup() and str_ndup()
port str_dup() and str_ndup() into the kernel

File:

• uspace/lib/c/generic/str.c (modified) (4 diffs)

uspace/lib/c/generic/str.c

@@ -471 +471 @@
  * null-terminated and containing only complete characters.
  *
- * @param dest   Destination buffer.
+ * @param dest  Destination buffer.
  * @param count Size of the destination buffer (must be > 0).
  * @param src   Source string.
@@ -477 +477 @@
 void str_cpy(char *dest, size_t size, const char *src)
 {
-        wchar_t ch;
-        size_t src_off;
-        size_t dest_off;
-
         /* There must be space for a null terminator in the buffer. */
         assert(size > 0);
         
-        src_off = 0;
-        dest_off = 0;
-
+        size_t src_off = 0;
+        size_t dest_off = 0;
+        
+        wchar_t ch;
         while ((ch = str_decode(src, &src_off, STR_NO_LIMIT)) != 0) {
                 if (chr_encode(ch, dest, &dest_off, size - 1) != EOK)
                         break;
         }
-
+        
         dest[dest_off] = '\0';
 }
@@ -505 +502 @@
  * have to be null-terminated.
  *
- * @param dest   Destination buffer.
+ * @param dest  Destination buffer.
  * @param count Size of the destination buffer (must be > 0).
  * @param src   Source string.
- * @param n     Maximum number of bytes to read from @a src.
+ * @param n     Maximum number of bytes to read from @a src.
  */
 void str_ncpy(char *dest, size_t size, const char *src, size_t n)
 {
-        wchar_t ch;
-        size_t src_off;
-        size_t dest_off;
-
         /* There must be space for a null terminator in the buffer. */
         assert(size > 0);
         
-        src_off = 0;
-        dest_off = 0;
-
+        size_t src_off = 0;
+        size_t dest_off = 0;
+        
+        wchar_t ch;
         while ((ch = str_decode(src, &src_off, n)) != 0) {
                 if (chr_encode(ch, dest, &dest_off, size - 1) != EOK)
                         break;
         }
-
+        
         dest[dest_off] = '\0';
 }
@@ -896 +890 @@
 }
 
+/** Duplicate string.
+ *
+ * Allocate a new string and copy characters from the source
+ * string into it. The duplicate string is allocated via sleeping
+ * malloc(), thus this function can sleep in no memory conditions.
+ *
+ * The allocation cannot fail and the return value is always
+ * a valid pointer. The duplicate string is always a well-formed
+ * null-terminated UTF-8 string, but it can differ from the source
+ * string on the byte level.
+ *
+ * @param src Source string.
+ *
+ * @return Duplicate string.
+ *
+ */
 char *str_dup(const char *src)
 {
-        size_t size = str_size(src);
-        void *dest = malloc(size + 1);
-        
+        size_t size = str_size(src) + 1;
+        char *dest = (char *) malloc(size);
         if (dest == NULL)
                 return (char *) NULL;
         
-        return (char *) memcpy(dest, src, size + 1);
-}
-
-char *str_ndup(const char *src, size_t max_size)
+        str_cpy(dest, size, src);
+        return dest;
+}
+
+/** Duplicate string with size limit.
+ *
+ * Allocate a new string and copy up to @max_size bytes from the source
+ * string into it. The duplicate string is allocated via sleeping
+ * malloc(), thus this function can sleep in no memory conditions.
+ * No more than @max_size + 1 bytes is allocated, but if the size
+ * occupied by the source string is smaller than @max_size + 1,
+ * less is allocated.
+ *
+ * The allocation cannot fail and the return value is always
+ * a valid pointer. The duplicate string is always a well-formed
+ * null-terminated UTF-8 string, but it can differ from the source
+ * string on the byte level.
+ *
+ * @param src Source string.
+ * @param n   Maximum number of bytes to duplicate.
+ *
+ * @return Duplicate string.
+ *
+ */
+char *str_ndup(const char *src, size_t n)
 {
         size_t size = str_size(src);
-        if (size > max_size)
-                size = max_size;
+        if (size > n)
+                size = n;
         
         char *dest = (char *) malloc(size + 1);
-        
         if (dest == NULL)
                 return (char *) NULL;
         
-        memcpy(dest, src, size);
-        dest[size] = 0;
+        str_ncpy(dest, size + 1, src, size);
         return dest;
 }