1 files changed, 102 insertions, 0 deletions
diff --git a/Foundation/GTMNSData+Hex.m b/Foundation/GTMNSData+Hex.m
new file mode 100644
index 0000000..c7e740d
--- /dev/null
+++ b/Foundation/GTMNSData+Hex.m
@@ -0,0 +1,102 @@
+//
+//  GTMNSData+Hex.m
+//
+//  Copyright 2009 Google Inc.
+//
+//  Licensed under the Apache License, Version 2.0 (the "License"); you may not
+//  use this file except in compliance with the License.  You may obtain a copy
+//  of the License at
+//
+//  http://www.apache.org/licenses/LICENSE-2.0
+//
+//  Unless required by applicable law or agreed to in writing, software
+//  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+//  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+//  License for the specific language governing permissions and limitations under
+//  the License.
+//
+
+#import "GTMNSData+Hex.h"
+#import "GTMDefines.h"
+
+@implementation NSData (GTMHexAdditions)
+
++ (NSData *)gtm_dataWithHexString:(NSString *)hexString {
+  NSData *hexData = [hexString dataUsingEncoding:NSASCIIStringEncoding];
+  const char *hexBuf = [hexData bytes];
+  NSUInteger hexLen = [hexData length];
+
+  // This indicates an error converting to ASCII.
+  if (hexString && !hexData) {
+    return nil;
+  }
+
+  if ((hexLen % 2) != 0) {
+    return nil;
+  }
+
+  NSMutableData *binaryData = [NSMutableData dataWithLength:(hexLen / 2)];
+  unsigned char *binaryPtr = [binaryData mutableBytes];
+  unsigned char value = 0;
+  for (NSUInteger i = 0; i < hexLen; i++) {
+    char c = hexBuf[i];
+
+    if (!isxdigit(c)) {
+      return nil;
+    }
+
+    if (isdigit(c)) {
+      value += c - '0';
+    } else if (islower(c)) {
+      value += 10 + c - 'a';
+    } else {
+      value += 10 + c - 'A';
+    }
+
+    if (i & 1) {
+      *binaryPtr++ = value;
+      value = 0;
+    } else {
+      value <<= 4;
+    }
+  }
+
+  return [NSData dataWithData:binaryData];
+}
+
+- (NSString *)gtm_hexString {
+  static const char kHexTable[] =
+    "000102030405060708090a0b0c0d0e0f"
+    "101112131415161718191a1b1c1d1e1f"
+    "202122232425262728292a2b2c2d2e2f"
+    "303132333435363738393a3b3c3d3e3f"
+    "404142434445464748494a4b4c4d4e4f"
+    "505152535455565758595a5b5c5d5e5f"
+    "606162636465666768696a6b6c6d6e6f"
+    "707172737475767778797a7b7c7d7e7f"
+    "808182838485868788898a8b8c8d8e8f"
+    "909192939495969798999a9b9c9d9e9f"
+    "a0a1a2a3a4a5a6a7a8a9aaabacadaeaf"
+    "b0b1b2b3b4b5b6b7b8b9babbbcbdbebf"
+    "c0c1c2c3c4c5c6c7c8c9cacbcccdcecf"
+    "d0d1d2d3d4d5d6d7d8d9dadbdcdddedf"
+    "e0e1e2e3e4e5e6e7e8e9eaebecedeeef"
+    "f0f1f2f3f4f5f6f7f8f9fafbfcfdfeff";
+
+  const unsigned char *binaryPtr = [self bytes];
+  NSUInteger binaryLen = [self length];
+
+  NSMutableData *hexData = [NSMutableData dataWithLength:(2 * binaryLen)];
+  char *hexPtr = [hexData mutableBytes];
+
+  for (NSUInteger i = 0; i < binaryLen; i++) {
+    *hexPtr++ = kHexTable[(*binaryPtr)*2];
+    *hexPtr++ = kHexTable[(*binaryPtr)*2 + 1];
+    ++binaryPtr;
+  }
+
+  return [[[NSString alloc] initWithData:hexData
+                                encoding:NSASCIIStringEncoding] autorelease];
+}
+
+@end