[Author: dmaclach]

Added some support for scanning JSON. We don't parse it, but we scan out blobs
that you can then pass to a parser.

DELTA=219 (219 added, 0 deleted, 0 changed)
R=thomasvl

1 files changed, 83 insertions, 0 deletions

diff --git a/Foundation/GTMNSScanner+JSON.m b/Foundation/GTMNSScanner+JSON.m
new file mode 100644
index 0000000..1216698
--- /dev/null
+++ b/Foundation/GTMNSScanner+JSON.m
@@ -0,0 +1,83 @@
+//
+//  GTMNSScanner+JSON.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 "GTMDefines.h"
+#import "GTMNSScanner+JSON.h"
+
+@implementation NSScanner (GTMNSScannerJSONAdditions)
+
+- (BOOL)gtm_scanJSONString:(NSString **)jsonString 
+                 startChar:(unichar)startChar 
+                   endChar:(unichar)endChar {
+  BOOL isGood = NO;
+  NSRange jsonRange = { NSNotFound, 0 };
+  NSString *scanString = [self string];
+  NSUInteger startLocation = [self scanLocation];
+  NSUInteger length = [scanString length];
+  NSUInteger blockOpen = 0;
+  NSCharacterSet *charsToSkip = [self charactersToBeSkipped];
+  BOOL inQuoteMode = NO;
+  NSUInteger i;
+  for (i = startLocation; i < length; ++i) {
+    unichar jsonChar = [scanString characterAtIndex:i];
+    if (jsonChar == startChar && !inQuoteMode) {
+      if (blockOpen == 0) {
+        jsonRange.location = i;
+      }
+      blockOpen += 1;
+    } else if (blockOpen == 0) {
+      // If we haven't opened our block skip over any characters in
+      // charsToSkip.
+      if (![charsToSkip characterIsMember:jsonChar]) {
+        break;
+      }
+    } else if (jsonChar == endChar && !inQuoteMode) {
+      blockOpen -= 1;
+      if (blockOpen == 0) {
+        i += 1; // Move onto next character
+        jsonRange.length = i - jsonRange.location;
+        break;
+      }
+    } else {
+      if (jsonChar == '"') {
+        inQuoteMode = !inQuoteMode;
+      } else if (inQuoteMode && jsonChar == '\\') {
+        // Skip the escaped character if it isn't the last one
+        if (i < length - 1) ++i;
+      }
+    }
+  }
+  [self setScanLocation:i];
+  if (blockOpen == 0 && jsonRange.location != NSNotFound) {
+    isGood = YES;
+    if (jsonString) {
+      *jsonString = [scanString substringWithRange:jsonRange];
+    }
+  }
+  return isGood;
+}
+
+- (BOOL)gtm_scanJSONObjectString:(NSString **)jsonString {
+  return [self gtm_scanJSONString:jsonString startChar:'{' endChar:'}'];  
+}
+
+- (BOOL)gtm_scanJSONArrayString:(NSString**)jsonString {
+  return [self gtm_scanJSONString:jsonString startChar:'[' endChar:']'];  
+}
+
+@end