@synchronized(self) {
	OSMemoryBarrier();

	// ...

	OSMemoryBarrier();
}

hackbunny fucked around with this message at 19:41 on Apr 29, 2016

1. Mapping the characterss to their respective glyphs
   
2. ...doing everything else
   
3. Fetching the kern table
   
4. Parsing the kern table, which is a pain since there are multiple versions, and various subtables for handling all kinds of esoteric stuff like vertical kerning that must be dealt with/ignored
   
5. Trying to reverse the mapping of characters to glyphs, since the kern table only contains glyphs

Doc Block fucked around with this message at 22:31 on Apr 29, 2016

lord funk fucked around with this message at 22:51 on May 1, 2016

hackbunny fucked around with this message at 23:22 on May 1, 2016

#import <Foundation/Foundation.h>
#include <libkern/OSAtomic.h>

@interface TurdFileManager : NSObject

- (void) append:(NSString*)logEntry;

@end

#define FILE_PATH @"turd"

@implementation TurdFileManager {
    NSFileHandle *fhWrite;
    unsigned long long fileSize;
    NSFileManager *fileManager;
    NSData *encodingKey;
    const char *encodingKeyBytes;
    NSUInteger encodingKeySize;
    NSUInteger encodingKeyOffset;
}

- (id) init
{
    self = [super init];
    if (self != nil) {
        static char key[] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 };
        encodingKey = [[NSData dataWithBytesNoCopy:key length:sizeof(key) freeWhenDone:NO] retain];
        encodingKeyBytes = [encodingKey bytes];
        encodingKeySize = [encodingKey length];
        encodingKeyOffset = 0;

        fileManager = [[NSFileManager alloc] init];

        [self createTurdFile];
        [self handlers];
    }
    return self;
}

- (void) dealloc
{
    [fhWrite release];
    [fileManager release];
    [encodingKey release];
    [super dealloc];
}

- (void) createTurdFile
{
    NSString* aStr = @"";
    NSData* aData = [aStr dataUsingEncoding: NSUTF8StringEncoding];
    [fileManager createFileAtPath:FILE_PATH contents:aData attributes:nil];
}

- (void) handlers
{
    fhWrite = [[NSFileHandle fileHandleForWritingAtPath:FILE_PATH] retain];
    fileSize = [fhWrite seekToEndOfFile];
    encodingKeyOffset = fileSize % encodingKeySize;
}

- (void) append:(NSString*)toAppend
{
    NSUInteger size = [toAppend maximumLengthOfBytesUsingEncoding:NSUTF8StringEncoding];
    char *bytes = malloc(size);

    [toAppend getBytes:bytes
             maxLength:size
            usedLength:&size
              encoding:NSUTF8StringEncoding
               options:0
                 range:NSMakeRange(0, [toAppend length])
        remainingRange:NULL];
    
    @synchronized(self) {
        OSMemoryBarrier();

        for (NSUInteger i = 0; i < size; ++ i, encodingKeyOffset = (encodingKeyOffset + 1) % encodingKeySize) {
            bytes[i] ^= encodingKeyBytes[encodingKeyOffset];
        }

        [fhWrite writeData:[NSData dataWithBytesNoCopy:bytes length:size freeWhenDone:NO]];
        fileSize += size;

        OSMemoryBarrier();
    }

    free(bytes);
}

@end

hackbunny fucked around with this message at 10:54 on May 2, 2016

• the first call writes 157 bytes. Except, 158 bytes are actually written: an extra byte is written at offset 16
  
• second call writes 92 bytes at file offset 158, but 93 bytes are written. Extra byte at block offset 50 (file offset 209)
  
• third call writes 84 bytes at file offset 251
  
• fourth call writes 255 bytes at file offset 335 but a whopping 3 extra bytes are written: offsets 51, 161, 226 (file offsets 386, 496, 561)
  

hackbunny fucked around with this message at 14:39 on May 2, 2016

- (void) turdDidSucceed {
    @synchronized(self) {
        if (turds.count > 1 && currentTurd > 0) {
            // Rotate the list of turds so that the successful turd is in front
            NSMutableArray *newTurds = [turds mutableCopy];

            for (NSUInteger i = currentTurd; i < turds.count; ++ i) {
                [newTurds addObject:turds[i]];
            }

            for (NSUInteger i = 0; i < currentTurd; ++ i) {
                [newTurds addObject:turds[i]];
            }

            currentTurd = 0;
            turds = [newTurds copy];
        }
    }
}

hackbunny fucked around with this message at 17:08 on May 2, 2016

hackbunny fucked around with this message at 18:37 on May 2, 2016