I wrote a JSON-parser by myself. You can use it if you want to by copying the code into your class source.
You use it in this way:
NSObject *obj = [self jsonToObj:yourJsonString];
It returns a NSDictionary, NSString or NSArray depending on the input. The difference between my parser and others is, that it also accepts numerical keys, which are not allowed in the JSON-standard. I can't guarantee that there are no bugs in it or that it works with all JSON-strings. Please give me some feedback, if it works for you!
-(NSObject*)jsonToObj:(NSString *)json {
int nextOffset;
return [self jsonToObj:json offset:0 nextOffset:&nextOffset];
}
static int indexOfChar(NSString *str, unichar c, int offset) {
int length = [str length];
for (int i = offset; i < length; i++) {
if ([str characterAtIndex:i] == c) {
return i;
}
}
return -1;
}
static int indexOfNonWhitespace(NSString *str, int offset) {
int len = [str length];
NSCharacterSet *cSet = [NSCharacterSet whitespaceAndNewlineCharacterSet];
for (int i = offset; i < len; i++) {
if (![cSet characterIsMember:[str characterAtIndex:i]]) {
return i;
}
}
return -1;
}
static int indexOfNonNumber(NSString *str, int offset) {
int len = [str length];
for (int i = offset; i < len; i++) {
unichar c = [str characterAtIndex:i];
if (c != '-' && c != '.' && (c < '0' || c > '9')) return i;
}
return -1;
}
static int parseHex(NSString *hexStr) {
unsigned int result = 0;
int len = [hexStr length];
for (int i = 0; i < len; i++) {
result <<= 4;
unsigned int v = 0;
unichar c = [hexStr characterAtIndex:i];
if (c >= '0' && c <= '9') {
v = c-'0';
} else if (c >= 'a' && c <= 'f') {
v = c-'a'+10;
} else if (c >= 'A' && c <= 'F') {
v = c-'A'+10;
}
result += v;
}
return result;
}
-(NSObject*)jsonToObj:(NSString *)json offset:(int)offset nextOffset:(int*)nextOffset {
offset = indexOfNonWhitespace(json, offset);
static NSString *jsonExceptionName = @"InvalidJSONException";
if (offset == -1) {
@throw [NSException exceptionWithName:jsonExceptionName reason:@"no non-whitespace 1" userInfo:nil];
}
unichar startChar = [json characterAtIndex:offset];
if (startChar == '{') {
NSMutableDictionary *result = [NSMutableDictionary dictionary];
int curPos = offset+1;
while (YES) {
curPos = indexOfNonWhitespace(json, curPos);
if (curPos == -1) {
@throw [NSException exceptionWithName:jsonExceptionName reason:@"no non-whitespace 2" userInfo:nil];
}
unichar curChar = [json characterAtIndex:curPos];
if (curChar == ',') {
curPos++;
continue;
} else if (curChar == '}') {
*nextOffset = curPos+1;
return result;
}
unichar quotChar = curChar;
if ((quotChar != '\'' && quotChar != '"') || [json characterAtIndex:curPos-1]=='\\') {
quotChar = 0;
}
NSString *key = nil;
int semiIndex = 0;
if (quotChar != 0) {
int quotStart = curPos+1;
int quotEnd = quotStart;
while (YES) {
quotEnd = indexOfChar(json, quotChar, quotEnd);
if (quotEnd == -1) {
@throw [NSException exceptionWithName:jsonExceptionName reason:@"quotation-end not found 1" userInfo:nil];
}
if ([json characterAtIndex:quotEnd-1] != '\\') break;
else quotEnd++;
}
key = [json substringWithRange:NSMakeRange(quotStart, quotEnd-quotStart)];
semiIndex = indexOfChar(json, ':', quotEnd);
if (semiIndex == -1) {
@throw [NSException exceptionWithName:jsonExceptionName reason:@"semicolon not found 1" userInfo:nil];
}
} else {
semiIndex = indexOfChar(json, ':', curPos);
if (semiIndex == -1) {
@throw [NSException exceptionWithName:jsonExceptionName reason:@"semicolon not found 2" userInfo:nil];
}
key = [[json substringWithRange:NSMakeRange(curPos, semiIndex-curPos)] stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
}
[result setObject:[self jsonToObj:json offset:semiIndex+1 nextOffset:&curPos] forKey:key];
}
} else if (startChar == '[') {
NSMutableArray *result = [NSMutableArray array];
int curPos = offset+1;
while (YES) {
curPos = indexOfNonWhitespace(json, curPos);
if (curPos == -1) {
@throw [NSException exceptionWithName:jsonExceptionName reason:@"no non-whitespace 3" userInfo:nil];
}
unichar curChar = [json characterAtIndex:curPos];
if (curChar == ',') {
curPos++;
continue;
} else if (curChar == ']') {
*nextOffset = curPos+1;
return result;
}
[result addObject:[self jsonToObj:json offset:curPos nextOffset:&curPos]];
}
} else {
unichar quotChar = startChar;
if ((quotChar != '\'' && quotChar != '"') || [json characterAtIndex:offset-1]=='\\') {
quotChar = 0;
}
if (quotChar != 0) {
int quotStart = offset+1;
int quotEnd = quotStart;
while (YES) {
quotEnd = indexOfChar(json, quotChar, quotEnd);
if (quotEnd == -1) {
@throw [NSException exceptionWithName:jsonExceptionName reason:@"quotation-end not found 2" userInfo:nil];
}
if ([json characterAtIndex:quotEnd-1] != '\\') break;
else quotEnd++;
}
*nextOffset = quotEnd+1;
NSString *str = [json substringWithRange:NSMakeRange(quotStart, quotEnd-quotStart)];
str = [str stringByReplacingOccurrencesOfString:@"\\\"" withString:@"\""];
NSMutableString *result = [NSMutableString stringWithCapacity:[str length]];
int len = [str length];
for (int i = 0; i < len; i++) {
unichar c = [str characterAtIndex:i];
if (c != '\\') {
[result appendString:[NSString stringWithCharacters:&c length:1]];
} else if (i+1 < len) {
unichar c2 = [str characterAtIndex:i+1];
if (c2 == '\\') {
[result appendString:[NSString stringWithCharacters:&c2 length:1]];
i++;
} else if (c2 == 'u') {
unichar cUni = parseHex([str substringWithRange:NSMakeRange(i+2, 4)]);
[result appendString:[NSString stringWithCharacters:&cUni length:1]];
i += 5;
}
}
}
return result;
} else {
int numberEnd = indexOfNonNumber(json, offset);
if (numberEnd == -1) {
@throw [NSException exceptionWithName:jsonExceptionName reason:@"number-end not found" userInfo:nil];
}
//BOOL isFloat = indexOfChar(json, '.', offset)!=-1;
NSString *numberStr = [json substringWithRange:NSMakeRange(offset, numberEnd-offset)];
*nextOffset = numberEnd;
return numberStr;
}
}
}
