sogo/SoObjects/SOGo/NSDictionary+BSJSONAdditions.m

//
//  BSJSONAdditions
//
//  Created by Blake Seely on 2/1/06.
//  Copyright 2006 Blake Seely - http://www.blakeseely.com  All rights reserved.
//  Permission to use this code:
//
//  Feel free to use this code in your software, either as-is or 
//  in a modified form. Either way, please include a credit in 
//  your software's "About" box or similar, mentioning at least 
//  my name (Blake Seely).
//
//  Permission to redistribute this code:
//
//  You can redistribute this code, as long as you keep these 
//  comments. You can also redistribute modified versions of the 
//  code, as long as you add comments to say that you've made 
//  modifications (keeping these original comments too).
//
//  If you do use or redistribute this code, an email would be 
//  appreciated, just to let me know that people are finding my 
//  code useful. You can reach me at blakeseely@mac.com

#import <Foundation/NSArray.h>
#import <Foundation/NSDecimalNumber.h>
#import <Foundation/NSEnumerator.h>
#import <Foundation/NSNull.h>
#import <Foundation/NSValue.h>

#import "NSDictionary+BSJSONAdditions.h"
#import "NSScanner+BSJSONAdditions.h"

NSString *jsonIndentString = @"\t"; // Modify this string to change how the output formats.
const int jsonDoNotIndent = -1;

@implementation NSDictionary (BSJSONAdditions)

+ (NSDictionary *)dictionaryWithJSONString:(NSString *)jsonString
{
  NSScanner *scanner = [[NSScanner alloc] initWithString:jsonString];
  NSDictionary *dictionary = nil;
  [scanner scanJSONObject:&dictionary];
  [scanner release];
  return dictionary;
}

- (NSString *)jsonStringValue
{
  return [self jsonStringValueWithIndentLevel:0];
}

@end

@implementation NSDictionary (PrivateBSJSONAdditions)

- (NSString *)jsonStringValueWithIndentLevel:(int)level
{
  NSMutableString *jsonString = [[NSMutableString alloc] init];
  [jsonString appendString:jsonObjectStartString];
	
  NSEnumerator *keyEnum = [self keyEnumerator];
  NSString *keyString = [keyEnum nextObject];
  NSString *valueString;
  if (keyString != nil) {
    valueString = [self jsonStringForValue:[self objectForKey:keyString] withIndentLevel:level];
    if (level != jsonDoNotIndent) { // indent before each key
      [jsonString appendString:[self jsonIndentStringForLevel:level]];
    }            
    [jsonString appendFormat:@" %@ %@ %@", [self jsonStringForString:keyString], jsonKeyValueSeparatorString, valueString];
  }
	
  while ((keyString = [keyEnum nextObject])) {
    valueString = [self jsonStringForValue:[self objectForKey:keyString] withIndentLevel:level]; // TODO bail if valueString is nil? How to bail successfully from here?
    [jsonString appendString:jsonValueSeparatorString];
    if (level != jsonDoNotIndent) { // indent before each key
      [jsonString appendFormat:@"%@", [self jsonIndentStringForLevel:level]];
    }
    [jsonString appendFormat:@" %@ %@ %@", [self jsonStringForString:keyString], jsonKeyValueSeparatorString, valueString];
  }
	
  //[jsonString appendString:@"\n"];
  [jsonString appendString:jsonObjectEndString];
	
  return [jsonString autorelease];
}

- (NSString *)jsonStringForValue:(id)value withIndentLevel:(int)level
{	
  NSString *jsonString;
  if ([value respondsToSelector:@selector(characterAtIndex:)]) // String
    jsonString = [self jsonStringForString:(NSString *)value];
  else if ([value respondsToSelector:@selector(keyEnumerator)]) // Dictionary
    jsonString = [(NSDictionary *)value jsonStringValueWithIndentLevel:(level + 1)];
  else if ([value respondsToSelector:@selector(objectAtIndex:)]) // Array
    jsonString = [self jsonStringForArray:(NSArray *)value withIndentLevel:level];
  else if (value == [NSNull null]) // null
    jsonString = jsonNullString;
  else if ([value respondsToSelector:@selector(objCType)]) { // NSNumber - representing true, false, and any form of numeric
    NSNumber *number = (NSNumber *)value;
    if (((*[number objCType]) == 'c') && ([number boolValue] == YES)) // true
      jsonString = jsonTrueString;
    else if (((*[number objCType]) == 'c') && ([number boolValue] == NO)) // false
      jsonString = jsonFalseString;
    else // attempt to handle as a decimal number - int, fractional, exponential
      // TODO: values converted from exponential json to dict and back to json do not format as exponential again
      jsonString = [[NSDecimalNumber decimalNumberWithDecimal:[number decimalValue]] stringValue];
  } else {
    // TODO: error condition - it's not any of the types that I know about.
    return nil;
  }
	
  return jsonString;
}

- (NSString *)jsonStringForArray:(NSArray *)array withIndentLevel:(int)level
{
  NSMutableString *jsonString = [[NSMutableString alloc] init];
  [jsonString appendString:jsonArrayStartString];
	
  if ([array count] > 0) {
    [jsonString appendString:[self jsonStringForValue:[array objectAtIndex:0] withIndentLevel:level]];
  }
	
  int i;
  for (i = 1; i < [array count]; i++) {
    [jsonString appendFormat:@"%@ %@", jsonValueSeparatorString, [self jsonStringForValue:[array objectAtIndex:i] withIndentLevel:level]];
  }
	
  [jsonString appendString:jsonArrayEndString];
  return [jsonString autorelease];
}

- (NSString *)jsonStringForString:(NSString *)string
{
  NSMutableString *jsonString = [[NSMutableString alloc] init];
  [jsonString appendString:jsonStringDelimiterString];

  // Build the result one character at a time, inserting escaped characters as necessary
  int i;
  unichar nextChar;
  for (i = 0; i < [string length]; i++) {
    nextChar = [string characterAtIndex:i];
    switch (nextChar) {
    case '\"':
      [jsonString appendString:@"\\\""];
      break;
    case '\\':
      [jsonString appendString:@"\\n"];
      break;
      /* TODO: email out to json group on this - spec says to handlt his, examples and example code don't handle this.
	 case '\/':
	 [jsonString appendString:@"\\/"];
	 break;
      */ 
    case '\b':
      [jsonString appendString:@"\\b"];
      break;
    case '\f':
      [jsonString appendString:@"\\f"];
      break;
    case '\n':
      [jsonString appendString:@"\\n"];
      break;
    case '\r':
      [jsonString appendString:@"\\r"];
      break;
    case '\t':
      [jsonString appendString:@"\\t"];
      break;
      /* TODO: Find and encode unicode characters here?
	 case '\u':
	 [jsonString appendString:@"\\n"];
	 break;
      */
    default:
      [jsonString appendString:[NSString stringWithCharacters:&nextChar length:1]];
      break;
    }
  }
  [jsonString appendString:jsonStringDelimiterString];
  return [jsonString autorelease];
}

- (NSString *)jsonIndentStringForLevel:(int)level
{
  NSMutableString *indentString = [[NSMutableString alloc] init];
  if (level != jsonDoNotIndent) {
    [indentString appendString:@"\n"];
    int i;
    for (i = 0; i < level; i++) {
      [indentString appendString:jsonIndentString];
    }
  }
    
  return [indentString autorelease];
}

@end