SBJsonStreamParserAdapter.h

/*
 Copyright (c) 2010, Stig Brautaset.
 All rights reserved.
 
 Redistribution and use in source and binary forms, with or without
 modification, are permitted provided that the following conditions are
 met:
 
   Redistributions of source code must retain the above copyright
   notice, this list of conditions and the following disclaimer.
  
   Redistributions in binary form must reproduce the above copyright
   notice, this list of conditions and the following disclaimer in the
   documentation and/or other materials provided with the distribution.
 
   Neither the name of the the author nor the names of its contributors
   may be used to endorse or promote products derived from this software
   without specific prior written permission.
 
 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
 PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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 LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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 */

#import <Foundation/Foundation.h>
#import "SBJsonStreamParser.h"

typedef enum {
	SBJsonStreamParserAdapterNone,
	SBJsonStreamParserAdapterArray,
	SBJsonStreamParserAdapterObject,
} SBJsonStreamParserAdapterType;

/**
 Delegate for getting objects & arrays from the stream parser adapter

 */
@protocol SBJsonStreamParserAdapterDelegate

/**
 Called if a JSON array is found
 
 This method is called if a JSON array is found.
 
 */
- (void)parser:(SBJsonStreamParser*)parser foundArray:(NSArray*)array;

/**
 Called when a JSON object is found

 This method is called if a JSON object is found.
 */
- (void)parser:(SBJsonStreamParser*)parser foundObject:(NSDictionary*)dict;

@end

/**
 SBJsonStreamParserDelegate protocol adapter

 Rather than implementing the SBJsonStreamParserDelegate protocol yourself you will
 most likely find it much more convenient to use an instance of this class and
 implement the SBJsonStreamParserAdapterDelegate protocol instead.

 The default behaviour is that the delegate only receives one call from
 either the -parser:foundArray: or -parser:foundObject: method when the
 document is fully parsed. However, if your inputs contains multiple JSON
 documents and you set the parser's -supportMultipleDocuments property to YES
 you will get one call for each full method.

     SBJsonStreamParserAdapter *adapter = [[[SBJsonStreamParserAdapter alloc] init] autorelease];
     adapter.delegate = self;

     SBJsonStreamParser *parser = [[[SBJsonStreamParser alloc] init] autorelease];
     parser.delegate = adapter;
     parser.supportMultipleDocuments = YES;

     // Note that this input contains multiple top-level JSON documents
     NSData *json = [@"[]{}[]{}" dataWithEncoding:NSUTF8StringEncoding];
     [parser parse:data];

 In the above example self will have the following sequence of methods called on it:

 - -parser:foundArray:
 - -parser:foundObject:
 - -parser:foundArray:
 - -parser:foundObject:

 Often you won't have control over the input you're parsing, so can't make use of
 this feature. But, all is not lost: this class will let you get the same effect by
 allowing you to skip one or more of the outer enclosing objects. Thus, the next
 example results in the same sequence of -parser:foundArray: / -parser:foundObject:
 being called on your delegate.

     SBJsonStreamParserAdapter *adapter = [[[SBJsonStreamParserAdapter alloc] init] autorelease];
     adapter.delegate = self;
     adapter.levelsToSkip = 1;

     SBJsonStreamParser *parser = [[[SBJsonStreamParser alloc] init] autorelease];
     parser.delegate = adapter;

     // Note that this input contains A SINGLE top-level document
     NSData *json = [@"[[],{},[],{}]" dataWithEncoding:NSUTF8StringEncoding];
     [parser parse:data];

*/
@interface SBJsonStreamParserAdapter : NSObject <SBJsonStreamParserDelegate> {
@private
	NSUInteger depth;
    NSMutableArray *array;
	NSMutableDictionary *dict;
	NSMutableArray *keyStack;
	NSMutableArray *stack;
	
	SBJsonStreamParserAdapterType currentType;
}

/**
 How many levels to skip
 
 This is useful for parsing huge JSON documents, or documents coming in over a very slow link.
 
 If you set this to N it will skip the outer N levels and call the -parser:foundArray:
 or -parser:foundObject: methods for each of the inner objects, as appropriate.

*/
@property NSUInteger levelsToSkip;

/**
 Your delegate object
 Set this to the object you want to receive the SBJsonStreamParserAdapterDelegate messages.
 */
@property (unsafe_unretained) id<SBJsonStreamParserAdapterDelegate> delegate;

@end