mirek/corejson

Core Foundation, libyajl based JSON support.

corejson's Issues

Unable to duplicate claimed performance numbers

Unable to reproduce claimed performance numbers. Timing based on the twitter_public_timeline.json file in Sams json-benchmarks, using (approximately) gcc-4.2 -arch x86_64 -DNS_BLOCK_ASSERTIONS -Os:

JSONKit        | decode: min:      415.000 us, avg:      424.730 us, char/s:  57775527.98, decodes:   1000
json-framework | decode: min:     1675.000 us, avg:     1687.973 us, char/s:  14537554.81, decodes:   1000
CoreJSON       | decode: min:     1230.000 us, avg:     2641.324 us, char/s:   9290416.47, decodes:   1000

It's not clear to me how CoreJSON can significantly improve on the times turned in by YAJL-objc. After parsing overhead is accounted for (which libyajl handles), the next major contributor to overall parsing time is in object instantiation, which is fairly considerable. This primarily how JSONKit is able to turn in better times than the other major libraries- it has a recently instantiated object cache to significantly reduce this overhead.

Leaks like a sieve!

Using

NSError *error = NULL;
NSString *json = [NSString stringWithContentsOfFile:@"example.json" encoding:NSUTF8StringEncoding error:&error];
CoreJSONRef jsonRef = JSONCreateWithString(NULL, (CFStringRef)json);
CFTypeRef jsonObjectRef = JSONGetObject(jsonRef);
[(id)jsonObjectRef autorelease];
JSONRelease(jsonRef);

... leaks memory like a sieve!

shell% leaks -nocontext 20732 | more
 leaks Report Version:  2.0
 Process:         bench [20732]
 Path:            /Users/johne/projects/json/CoreJSON/build/Debug/bench
 Load Address:    0x100000000
 Identifier:      bench
 Version:         ??? (???)
 Code Type:       X86-64 (Native)
 Parent Process:  tcsh [504]
 
 Date/Time:       2011-02-17 12:59:23.723 -0500
 OS Version:      Mac OS X 10.6.6 (10J567)
 Report Version:  6
 
 Process 20732: 2158 nodes malloced for 383 KB
 Process 20732: 114 leaks for 80864 total leaked bytes.
 Leak: 0x100841800  size=1024  zone: DefaultMallocZone_0x100013000       
         Call stack: [thread 0x7fff700c3ca0]: | 0x2 | start | main | JSONCreateWithString | JSONParseWithString | yajl_do_parse | __JSONParserAppen dMapStart | __JSONStackEntryCreate | malloc_zone_malloc 
 Leak: 0x100841c00  size=1024  zone: DefaultMallocZone_0x100013000       
         Call stack: [thread 0x7fff700c3ca0]: | 0x2 | start | main | JSONCreateWithString | JSONParseWithString | yajl_do_parse | __JSONParserAppen dMapStart | __JSONStackEntryCreate | malloc_zone_malloc 
 Leak: 0x100842000  size=1024  zone: DefaultMallocZone_0x100013000       
         Call stack: [thread 0x7fff700c3ca0]: | 0x2 | start | main | JSONCreateWithString | JSONParseWithString | yajl_do_parse | __JSONParserAppen dMapStart | __JSONStackEntryCreate | malloc_zone_malloc 
... [snip] ...