xnu-2422.115.4.tar.gz

[apple/xnu.git] / bsd / hfs / hfscommon / Unicode / UnicodeWrappers.c

diff --git a/bsd/hfs/hfscommon/Unicode/UnicodeWrappers.c b/bsd/hfs/hfscommon/Unicode/UnicodeWrappers.c
index 2eece14e1ad55d8166c5abe7ff189c6d39c39db8..2d1c229007d67be8160b8d9d03e199f28e40ff13 100644 (file)
--- a/bsd/hfs/hfscommon/Unicode/UnicodeWrappers.c
+++ b/bsd/hfs/hfscommon/Unicode/UnicodeWrappers.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2000-2006 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 2000-2013 Apple Computer, Inc. All rights reserved.
  *
  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
  * 
@@ -420,6 +420,68 @@ int32_t FastUnicodeCompare ( register ConstUniCharArrayPtr str1, register ItemCo
                return 1;
 }
 
+/*
+ * UnicodeBinaryCompare
+ * Compare two UTF-16 strings and perform case-sensitive (binary) matching against them.
+ * 
+ * Results are emitted like FastUnicodeCompare:
+ * 
+ * 
+ *         IF                          RESULT
+ *     --------------------------
+ *     str1 < str2             =>      -1
+ *     str1 = str2             =>       0
+ *     str1 > str2             =>      +1
+ *
+ * The case matching source code is greatly simplified due to the lack of case-folding
+ * in this comparison routine. We compare, in order: the lengths, then do character-by-
+ * character comparisons.
+ * 
+ */
+int32_t UnicodeBinaryCompare (register ConstUniCharArrayPtr str1, register ItemCount len1,
+                                                       register ConstUniCharArrayPtr str2, register ItemCount len2) {
+       uint16_t c1;
+       uint16_t c2;
+       int string_length;
+       int32_t result = 0;
+       
+       /* Set default values for the two character pointers */
+       c1 = 0;
+       c2 = 0;
+
+       /* First generate the string length (for comparison purposes) */
+       if (len1 < len2) {
+               string_length = len1;
+               --result;
+       }
+       else if (len1 > len2) {
+               string_length = len2;
+               ++result;
+       }
+       else {
+               string_length = len1;
+       }
+
+       /* now compare the two string pointers */
+       while (string_length--) {
+               c1 = *(str1++);
+               c2 = *(str2++);
+
+               if (c1 > c2) {
+                       result = 1;
+                       break;
+               }
+               
+               if (c1 < c2) {
+                       result = -1;
+                       break;
+               }
+               /* If equal, iterate to the next two respective chars */                
+       }
+
+       return result;
+}
+
 
 OSErr
 ConvertUnicodeToUTF8Mangled(ByteCount srcLen, ConstUniCharArrayPtr srcStr, ByteCount maxDstLen,