I have a string variable in iOS and I would like to convert that to a character array and then to a hex bytes like 0xD6, 0xD6 etc.
It will be great if there is a library in Objective-C that I can use for this
swift 4
string to byte:
let strChar = "A"
let data1 = [UInt8](self.strChar.utf8)
may be answer is here:
string to chars:
NSString *s = #"Some string";
const char *c = [s UTF8String];
chars to hex:
- (NSData *)dataFromHexString {
const char *chars = [self UTF8String];
int i = 0, len = self.length;
NSMutableData *data = [NSMutableData dataWithCapacity:len / 2];
char byteChars[3] = {'\0','\0','\0'};
unsigned long wholeByte;
while (i < len) {
byteChars[0] = chars[i++];
byteChars[1] = chars[i++];
wholeByte = strtoul(byteChars, NULL, 16);
[data appendBytes:&wholeByte length:1];
}
return data;
}
reference:NSString (hex) to bytes
Related
This question already has answers here:
NSString (hex) to bytes
(7 answers)
Closed 5 years ago.
I want to convert ObjectiveC NSString, that contains for example string "0d" to hex value 0x0d. What's the easiest way to achieve that?
Example:
NSString *str = #"50";
unsigned char mac[1];
mac[0] = 0x50; //<- how to set mac[0] to 0x50 from "str" string?
- (NSData *)dataFromHexString {
const char *chars = [self UTF8String];
int i = 0, len = self.length;
NSMutableData *data = [NSMutableData dataWithCapacity:len/2];
char byteChars[3] = {chars[0],chars[1],'\0'};
unsigned long wholeByte = strtoul(byteChars, NULL, 16);
[data appendBytes:&wholeByte length:1];
return data;
}
I am using these code to get a MD5+Base64 encrypt string, but when I run the code, it sometime can not return a true encryption string, not often.My encryption code like this:
+ (NSString *) md5: (NSData *) data
{
const char* original_str = (const char *)[data bytes];
unsigned char digist[CC_MD5_DIGEST_LENGTH]; //CC_MD5_DIGEST_LENGTH = 16
CC_MD5(original_str, (uint)strlen(original_str), digist);
NSData * md5data = [[NSData alloc] initWithBytes:digist length:sizeof(digist)];
NSString * result = [md5data base64EncodedStringWithOptions:0];
return result;
}
Try
const char *cStr = [#"fd" UTF8String];
unsigned char result[CC_MD5_DIGEST_LENGTH];
CC_MD5(cStr, (int)strlen(cStr), result);
NSMutableString *md5String = [NSMutableString stringWithCapacity:CC_MD5_DIGEST_LENGTH * 2];
for(int i = 0; i < CC_MD5_DIGEST_LENGTH; ++i) {
[md5String appendFormat:#"%02x", result[i]];
}
NSString *encodedString = [NSString stringWithString:md5String];
NSData *nsdata = [encodedString dataUsingEncoding:NSUTF8StringEncoding];
NSString *base64Encoded = [nsdata base64EncodedStringWithOptions:0];
I have got the solution. Just change this code
CC_MD5(original_str, (uint)strlen(original_str), digist);
to
CC_MD5(original_str, (CC_LONG)data.length, digist);
Swift
import CryptoKit
import CommonCrypto
func md5(data: Data) -> String {
let digest = Insecure.MD5.hash(data: data)
return Data(digest).base64EncodedString()
}
I need to write a hex string to NSData but I am getting an extra zero appended to the end and it is causing me some issues. Is there a way to write half bytes to NSData?
For example I am converting 100010002 and I am getting 1000100020 (extra zero).
This is what I am using to convert the hex string to NSData. Thanks.
+ (NSData *)dataFromHexString:(NSString*)stringToConvert {
const char *chars = [stringToConvert UTF8String];
int i = 0;
int len = (int)[stringToConvert length];
NSMutableData *data = [NSMutableData dataWithCapacity:len / 2];
char byteChars[3] = {'\0','\0','\0'};
unsigned long wholeByte;
while (i < len) {
byteChars[0] = chars[i++];
byteChars[1] = chars[i++];
wholeByte = strtoul(byteChars, NULL, 16);
[data appendBytes:&wholeByte length:1];
}
return data;
}
Is there any method in Objective-C that converts a hex string to bytes? For example #"1156FFCD3430AA22" to an unsigned char array {0x11, 0x56, 0xFF, ...}.
Fastest NSString category implementation that I could think of (cocktail of some examples):
- (NSData *)dataFromHexString {
const char *chars = [self UTF8String];
int i = 0, len = self.length;
NSMutableData *data = [NSMutableData dataWithCapacity:len / 2];
char byteChars[3] = {'\0','\0','\0'};
unsigned long wholeByte;
while (i < len) {
byteChars[0] = chars[i++];
byteChars[1] = chars[i++];
wholeByte = strtoul(byteChars, NULL, 16);
[data appendBytes:&wholeByte length:1];
}
return data;
}
It is close to 8 times faster than wookay's solution. NSScanner is quite slow.
#interface NSString (NSStringHexToBytes)
-(NSData*) hexToBytes ;
#end
#implementation NSString (NSStringHexToBytes)
-(NSData*) hexToBytes {
NSMutableData* data = [NSMutableData data];
int idx;
for (idx = 0; idx+2 <= self.length; idx+=2) {
NSRange range = NSMakeRange(idx, 2);
NSString* hexStr = [self substringWithRange:range];
NSScanner* scanner = [NSScanner scannerWithString:hexStr];
unsigned int intValue;
[scanner scanHexInt:&intValue];
[data appendBytes:&intValue length:1];
}
return data;
}
#end
/// example
unsigned char bytes[] = { 0x11, 0x56, 0xFF, 0xCD, 0x34, 0x30, 0xAA, 0x22 };
NSData* expectedData = [NSData dataWithBytes:bytes length:sizeof(bytes)];
NSLog(#"data %#", [#"1156FFCD3430AA22" hexToBytes]);
NSLog(#"expectedData isEqual:%d", [expectedData isEqual:[#"1156FFCD3430AA22" hexToBytes]]);
The scanHexInt: and similar methods of NSScanner might be helpful in doing what you want, but you'd probably need to break the string up into smaller chunks first, in which case doing the translation manually might be simpler than using NSScanner.
Not in the way you are doing it. You'll need to write your own method to take every two characters, interpret them as an int, and store them in an array.
Modified approach,
/* Converts a hex string to bytes.
Precondition:
. The hex string can be separated by space or not.
. the string length without space or 0x, must be even. 2 symbols for one byte/char
. sample input: 23 3A F1 OR 233AF1, 0x23 0X231f 2B
*/
+ (NSData *) dataFromHexString:(NSString*)hexString
{
NSString * cleanString = [Util cleanNonHexCharsFromHexString:hexString];
if (cleanString == nil) {
return nil;
}
NSMutableData *result = [[NSMutableData alloc] init];
int i = 0;
for (i = 0; i+2 <= cleanString.length; i+=2) {
NSRange range = NSMakeRange(i, 2);
NSString* hexStr = [cleanString substringWithRange:range];
NSScanner* scanner = [NSScanner scannerWithString:hexStr];
unsigned int intValue;
[scanner scanHexInt:&intValue];
unsigned char uc = (unsigned char) intValue;
[result appendBytes:&uc length:1];
}
NSData * data = [NSData dataWithData:result];
[result release];
return data;
}
/* Clean a hex string by removing spaces and 0x chars.
. The hex string can be separated by space or not.
. sample input: 23 3A F1; 233AF1; 0x23 0x3A 0xf1
*/
+ (NSString *) cleanNonHexCharsFromHexString:(NSString *)input
{
if (input == nil) {
return nil;
}
NSString * output = [input stringByReplacingOccurrencesOfString:#"0x" withString:#""
options:NSCaseInsensitiveSearch range:NSMakeRange(0, input.length)];
NSString * hexChars = #"0123456789abcdefABCDEF";
NSCharacterSet *hexc = [NSCharacterSet characterSetWithCharactersInString:hexChars];
NSCharacterSet *invalidHexc = [hexc invertedSet];
NSString * allHex = [[output componentsSeparatedByCharactersInSet:invalidHexc] componentsJoinedByString:#""];
return allHex;
}
First attempt in Swift 2.2:
func hexStringToBytes(hexString: String) -> NSData? {
guard let chars = hexString.cStringUsingEncoding(NSUTF8StringEncoding) else { return nil}
var i = 0
let length = hexString.characters.count
let data = NSMutableData(capacity: length/2)
var byteChars: [CChar] = [0, 0, 0]
var wholeByte: CUnsignedLong = 0
while i < length {
byteChars[0] = chars[i]
i+=1
byteChars[1] = chars[i]
i+=1
wholeByte = strtoul(byteChars, nil, 16)
data?.appendBytes(&wholeByte, length: 1)
}
return data
}
Or, as an extension on String:
extension String {
func dataFromHexString() -> NSData? {
guard let chars = cStringUsingEncoding(NSUTF8StringEncoding) else { return nil}
var i = 0
let length = characters.count
let data = NSMutableData(capacity: length/2)
var byteChars: [CChar] = [0, 0, 0]
var wholeByte: CUnsignedLong = 0
while i < length {
byteChars[0] = chars[i]
i+=1
byteChars[1] = chars[i]
i+=1
wholeByte = strtoul(byteChars, nil, 16)
data?.appendBytes(&wholeByte, length: 1)
}
return data
}
}
This is a continuous work-in-progress, but appears to work well so far.
Further optimizations and a more in-depth discussion can be found on Code Review.
Several solution is returned wrong value if the string like this
"DBA"
The correct data for "DBA" string is "\x0D\xBA" (int value : 3514)
if you got a data is not like this "\x0D\xBA" it mean you got a wrong byte because the value will be different, for example you got data like this "\xDB\x0A" the int value is 56074
Here is rewrite the solution:
+ (NSData *)dataFromHexString:(NSString *) string {
if([string length] % 2 == 1){
string = [#"0"stringByAppendingString:string];
}
const char *chars = [string UTF8String];
int i = 0, len = (int)[string length];
NSMutableData *data = [NSMutableData dataWithCapacity:len / 2];
char byteChars[3] = {'\0','\0','\0'};
unsigned long wholeByte;
while (i < len) {
byteChars[0] = chars[i++];
byteChars[1] = chars[i++];
wholeByte = strtoul(byteChars, NULL, 16);
[data appendBytes:&wholeByte length:1];
}
return data;
}
Is there any method in Objective-C that converts a hex string to bytes? For example #"1156FFCD3430AA22" to an unsigned char array {0x11, 0x56, 0xFF, ...}.
Fastest NSString category implementation that I could think of (cocktail of some examples):
- (NSData *)dataFromHexString {
const char *chars = [self UTF8String];
int i = 0, len = self.length;
NSMutableData *data = [NSMutableData dataWithCapacity:len / 2];
char byteChars[3] = {'\0','\0','\0'};
unsigned long wholeByte;
while (i < len) {
byteChars[0] = chars[i++];
byteChars[1] = chars[i++];
wholeByte = strtoul(byteChars, NULL, 16);
[data appendBytes:&wholeByte length:1];
}
return data;
}
It is close to 8 times faster than wookay's solution. NSScanner is quite slow.
#interface NSString (NSStringHexToBytes)
-(NSData*) hexToBytes ;
#end
#implementation NSString (NSStringHexToBytes)
-(NSData*) hexToBytes {
NSMutableData* data = [NSMutableData data];
int idx;
for (idx = 0; idx+2 <= self.length; idx+=2) {
NSRange range = NSMakeRange(idx, 2);
NSString* hexStr = [self substringWithRange:range];
NSScanner* scanner = [NSScanner scannerWithString:hexStr];
unsigned int intValue;
[scanner scanHexInt:&intValue];
[data appendBytes:&intValue length:1];
}
return data;
}
#end
/// example
unsigned char bytes[] = { 0x11, 0x56, 0xFF, 0xCD, 0x34, 0x30, 0xAA, 0x22 };
NSData* expectedData = [NSData dataWithBytes:bytes length:sizeof(bytes)];
NSLog(#"data %#", [#"1156FFCD3430AA22" hexToBytes]);
NSLog(#"expectedData isEqual:%d", [expectedData isEqual:[#"1156FFCD3430AA22" hexToBytes]]);
The scanHexInt: and similar methods of NSScanner might be helpful in doing what you want, but you'd probably need to break the string up into smaller chunks first, in which case doing the translation manually might be simpler than using NSScanner.
Not in the way you are doing it. You'll need to write your own method to take every two characters, interpret them as an int, and store them in an array.
Modified approach,
/* Converts a hex string to bytes.
Precondition:
. The hex string can be separated by space or not.
. the string length without space or 0x, must be even. 2 symbols for one byte/char
. sample input: 23 3A F1 OR 233AF1, 0x23 0X231f 2B
*/
+ (NSData *) dataFromHexString:(NSString*)hexString
{
NSString * cleanString = [Util cleanNonHexCharsFromHexString:hexString];
if (cleanString == nil) {
return nil;
}
NSMutableData *result = [[NSMutableData alloc] init];
int i = 0;
for (i = 0; i+2 <= cleanString.length; i+=2) {
NSRange range = NSMakeRange(i, 2);
NSString* hexStr = [cleanString substringWithRange:range];
NSScanner* scanner = [NSScanner scannerWithString:hexStr];
unsigned int intValue;
[scanner scanHexInt:&intValue];
unsigned char uc = (unsigned char) intValue;
[result appendBytes:&uc length:1];
}
NSData * data = [NSData dataWithData:result];
[result release];
return data;
}
/* Clean a hex string by removing spaces and 0x chars.
. The hex string can be separated by space or not.
. sample input: 23 3A F1; 233AF1; 0x23 0x3A 0xf1
*/
+ (NSString *) cleanNonHexCharsFromHexString:(NSString *)input
{
if (input == nil) {
return nil;
}
NSString * output = [input stringByReplacingOccurrencesOfString:#"0x" withString:#""
options:NSCaseInsensitiveSearch range:NSMakeRange(0, input.length)];
NSString * hexChars = #"0123456789abcdefABCDEF";
NSCharacterSet *hexc = [NSCharacterSet characterSetWithCharactersInString:hexChars];
NSCharacterSet *invalidHexc = [hexc invertedSet];
NSString * allHex = [[output componentsSeparatedByCharactersInSet:invalidHexc] componentsJoinedByString:#""];
return allHex;
}
First attempt in Swift 2.2:
func hexStringToBytes(hexString: String) -> NSData? {
guard let chars = hexString.cStringUsingEncoding(NSUTF8StringEncoding) else { return nil}
var i = 0
let length = hexString.characters.count
let data = NSMutableData(capacity: length/2)
var byteChars: [CChar] = [0, 0, 0]
var wholeByte: CUnsignedLong = 0
while i < length {
byteChars[0] = chars[i]
i+=1
byteChars[1] = chars[i]
i+=1
wholeByte = strtoul(byteChars, nil, 16)
data?.appendBytes(&wholeByte, length: 1)
}
return data
}
Or, as an extension on String:
extension String {
func dataFromHexString() -> NSData? {
guard let chars = cStringUsingEncoding(NSUTF8StringEncoding) else { return nil}
var i = 0
let length = characters.count
let data = NSMutableData(capacity: length/2)
var byteChars: [CChar] = [0, 0, 0]
var wholeByte: CUnsignedLong = 0
while i < length {
byteChars[0] = chars[i]
i+=1
byteChars[1] = chars[i]
i+=1
wholeByte = strtoul(byteChars, nil, 16)
data?.appendBytes(&wholeByte, length: 1)
}
return data
}
}
This is a continuous work-in-progress, but appears to work well so far.
Further optimizations and a more in-depth discussion can be found on Code Review.
Several solution is returned wrong value if the string like this
"DBA"
The correct data for "DBA" string is "\x0D\xBA" (int value : 3514)
if you got a data is not like this "\x0D\xBA" it mean you got a wrong byte because the value will be different, for example you got data like this "\xDB\x0A" the int value is 56074
Here is rewrite the solution:
+ (NSData *)dataFromHexString:(NSString *) string {
if([string length] % 2 == 1){
string = [#"0"stringByAppendingString:string];
}
const char *chars = [string UTF8String];
int i = 0, len = (int)[string length];
NSMutableData *data = [NSMutableData dataWithCapacity:len / 2];
char byteChars[3] = {'\0','\0','\0'};
unsigned long wholeByte;
while (i < len) {
byteChars[0] = chars[i++];
byteChars[1] = chars[i++];
wholeByte = strtoul(byteChars, NULL, 16);
[data appendBytes:&wholeByte length:1];
}
return data;
}