/*

    Copyright (C) 2016 Apple Inc. All Rights Reserved.

    See LICENSE.txt for this sample’s licensing information

    Abstract:

    Hex dump utilities.

 */

#import "QHex.h"

@implementation QHex

+ (NSString *)hexStringWithBytes:(const void *)bytes length:(NSUInteger)length {

    NSMutableString *   result;

    NSParameterAssert(bytes != nil);

    result = [[NSMutableString alloc] initWithCapacity:length * 2];

    for (size_t i = 0; i < length; i++) {

        [result appendFormat:@"%02x", ((const uint8_t *) bytes)[i]];

    }

    return result;

}

+ (NSString *)hexStringWithData:(NSData *)data {

    NSParameterAssert(data != nil);

    return [[self class] hexStringWithBytes:data.bytes length:data.length];

}

+ (nullable NSData *)optionalDataWithHexString:(NSString *)hexString {

    NSMutableData *     result;

    NSUInteger          cursor;

    NSUInteger          limit;

    NSParameterAssert(hexString != nil);

    result = nil;

    cursor = 0;

    limit = hexString.length;

    if ((limit % 2) == 0) {

        result = [[NSMutableData alloc] init];

        while (cursor != limit) {

            unsigned int    thisUInt;

            uint8_t         thisByte;

            if ( sscanf([hexString substringWithRange:NSMakeRange(cursor, 2)].UTF8String, "%x", &thisUInt) != 1 ) {

                result = nil;

                break;

            }

            thisByte = (uint8_t) thisUInt;

            [result appendBytes:&thisByte length:sizeof(thisByte)];

            cursor += 2;

        }

    }

    return result;

}

+ (NSData *)dataWithHexString:(NSString *)hexString {

    NSData *    result;

    result = [self optionalDataWithHexString:hexString];

    if (result == nil) {

        abort();

    }

    return result;

}

@end