Swift example - Debug Output

BridgeHeader.h

#import <Foundation/Foundation.h>

@interface NSData (DebugOutput)

- (NSString *)debugOutputObjc;

- (NSString *)debugOutputSwift;

@end

NSData+DebugOutput.m

#import "BridgeHeader.h"

@implementation NSData (DebugOutput)

- (NSString *)debugOutputObjc
{
    int rowlength = 16;
    const uint8_t *data = [self bytes];
    NSMutableString *str = [NSMutableString new];
    for (NSInteger i = 0; i < (NSInteger) [self length]; ) {
        [str appendFormat:@"\n%08x: ", i];
        for (NSInteger j = 0; j < rowlength; j++, i++) {
            if (i >= (NSInteger) [self length] || i < 0) {
                [str appendString:@"   "];
            } else {
                [str appendFormat:@"%02x ", data[i]];
            }
        }
        i -= rowlength;
        [str appendString:@" "];
        for (NSInteger j = 0; j < rowlength; j++, i++) {
            if (i >= (NSInteger) [self length] || i < 0) {
                [str appendString:@" "];
            } else if (data[i] < 33 || data[i] > '~') {
                [str appendString:@"."];
            } else {
                [str appendFormat:@"%c", data[i]];
            }
        }
    }
    return str;
}

@end

NSDataDebugOutput.swift

import Foundation

extension NSData {

    func debugOutputSwift() -> NSString {
        let rowLength = 16
        let str = NSMutableString()
        let data = UnsafeArray(start: UnsafePointer<UInt8>(self.bytes), length: self.length)

        for var rowOffset = 0; rowOffset < self.length; rowOffset += rowLength {
            str.appendFormat("\n%08x: ", rowOffset)
            for index in rowOffset .. rowOffset + rowLength {
                if index >= self.length || index < 0 {
                    str.appendString("   ")
                } else {
                    let byte = data[index]
                    str.appendFormat("%02x ", byte)
                }
            }
            str.appendString(" ")
            for index in rowOffset .. rowOffset + rowLength {
                if index >= self.length || index < 0 {
                    str.appendString(" ")
                } else {
                    let byte = data[index]
                    if byte < 33 || byte > 126 {
                        str.appendString(".")
                    } else {
                        str.appendFormat("%c", byte)
                    }
                }
            }
        }
        return str
    }
    
}