Changeset beb9336 in mainline for uspace/lib/c/generic/str.c

Timestamp:

2012-08-24T14:07:52Z (13 years ago)

Author:

Frantisek Princ <frantisek.princ@…>

Branches:

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

Children:

041ab64

Parents:

bd29f9c9 (diff), db81577 (diff)
Note: this is a merge changeset, the changes displayed below correspond to the merge itself.
Use the (diff) links above to see all the changes relative to each parent.

Message:

Merge with mainline

File:

• uspace/lib/c/generic/str.c (modified) (5 diffs)

uspace/lib/c/generic/str.c

@@ -136 +136 @@
 }
 
+/** Decode a single character from a string to the left.
+ *
+ * Decode a single character from a string of size @a size. Decoding starts
+ * at @a offset and this offset is moved to the beginning of the previous
+ * character. In case of decoding error, offset generally decreases at least
+ * by one. However, offset is never moved before 0.
+ *
+ * @param str    String (not necessarily NULL-terminated).
+ * @param offset Byte offset in string where to start decoding.
+ * @param size   Size of the string (in bytes).
+ *
+ * @return Value of decoded character, U_SPECIAL on decoding error or
+ *         NULL if attempt to decode beyond @a start of str.
+ *
+ */
+wchar_t str_decode_reverse(const char *str, size_t *offset, size_t size)
+{
+        if (*offset == 0)
+                return 0;
+        
+        size_t processed = 0;
+        /* Continue while continuation bytes found */
+        while (*offset > 0 && processed < 4) {
+                uint8_t b = (uint8_t) str[--(*offset)];
+                
+                if (processed == 0 && (b & 0x80) == 0) {
+                        /* 0xxxxxxx (Plain ASCII) */
+                        return b & 0x7f;
+                }
+                else if ((b & 0xe0) == 0xc0 || (b & 0xf0) == 0xe0 ||
+                    (b & 0xf8) == 0xf0) {
+                        /* Start byte */
+                        size_t start_offset = *offset;
+                        return str_decode(str, &start_offset, size);
+                }
+                else if ((b & 0xc0) != 0x80) {
+                        /* Not a continuation byte */
+                        return U_SPECIAL;
+                }
+                processed++;
+        }
+        /* Too many continuation bytes */
+        return U_SPECIAL;
+}
+
 /** Encode a single character to string representation.
  *
@@ -399 +444 @@
 }
 
+/** Get character display width on a character cell display.
+ *
+ * @param ch    Character
+ * @return      Width of character in cells.
+ */
+size_t chr_width(wchar_t ch)
+{
+        return 1;
+}
+
+/** Get string display width on a character cell display.
+ *
+ * @param str   String
+ * @return      Width of string in cells.
+ */
+size_t str_width(const char *str)
+{
+        size_t width = 0;
+        size_t offset = 0;
+        wchar_t ch;
+        
+        while ((ch = str_decode(str, &offset, STR_NO_LIMIT)) != 0)
+                width += chr_width(ch);
+        
+        return width;
+}
+
 /** Check whether character is plain ASCII.
  *
@@ -431 +503 @@
  * and both strings consist of the same sequence of characters.
  *
- * A string is smaller than another string iff it is shorter or
- * has a character with lower value at the first position where
- * the strings differ.
+ * A string S1 is less than another string S2 if it has a character with
+ * lower value at the first character position where the strings differ.
+ * If the strings differ in length, the shorter one is treated as if
+ * padded by characters with a value of zero.
  *
  * @param s1 First string to compare.
  * @param s2 Second string to compare.
  *
- * @return 0 if the strings are equal, -1 if first is smaller,
- *         1 if second smaller.
+ * @return 0 if the strings are equal, -1 if the first is less than the second,
+ *         1 if the second is less than the first.
  *
  */
@@ -475 +548 @@
  * up to max_len characters.
  *
- * A string is smaller than another string iff it is shorter or
- * has a character with lower value at the first position where
- * the strings differ, considering only first max_len characters.
+ * A string S1 is less than another string S2 if it has a character with
+ * lower value at the first character position where the strings differ.
+ * If the strings differ in length, the shorter one is treated as if
+ * padded by characters with a value of zero. Only the first max_len
+ * characters are considered.
  *
  * @param s1      First string to compare.
@@ -483 +558 @@
  * @param max_len Maximum number of characters to consider.
  *
- * @return 0 if the strings are equal, -1 if first is smaller,
- *         1 if second smaller.
+ * @return 0 if the strings are equal, -1 if the first is less than the second,
+ *         1 if the second is less than the first.
  *
  */