I convert NSString to byte Array. It ok, then I convert NSData to base64 is wrong. if "010203040506" is right but with high number (exam: #"333435363738") is wrong. This is my code. Please help me.
In Android: ISIjJCUm and iOS: MzQ1Njc4.
NSString *command = #"333435363738";
NSMutableData *commandToSend= [[NSMutableData alloc] init];
unsigned long whole_byte;
char byte_chars[3] = {'\0','\0','\0'};
int i;
for (i=0; i < [command length] /2; i++) {
NSLog(#"%d",[command characterAtIndex:i*2]);
NSLog(#"%d",[command characterAtIndex:i*2 + 1]);
byte_chars[0] = [command characterAtIndex:i*2];
byte_chars[1] = [command characterAtIndex:i*2 + 1];
whole_byte = strtol(byte_chars, NULL, 16);
[commandToSend appendBytes:&whole_byte length:1];
}
NSString *base64String;
if ([commandToSend respondsToSelector:#selector(base64EncodedStringWithOptions:)]) {
base64String = [commandToSend base64EncodedStringWithOptions:kNilOptions]; // iOS 7+
} else {
base64String = [commandToSend base64Encoding]; // pre iOS7
}
Your code produces the string MzQ1Njc4 which is the bas64 encoding of the bytes 0x33, 0x34, 0x35, 0x36, 0x37, 0x38. This appears to be what the code is meant to do.
The string ISIjJCUm is the base64 encoding of 0x21, 0x22, 0x23, 0x24, 0x25, 0x26.
Note that 0x21 is 33 decimal. So it looks like you were either meant to interpret the string as decimal on iOS or as hex on Android.
Related
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
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;
}
I need to represent a NSInteger and NSString into array of bytes. below are the sample of what I am looking for.
For how, this harcodings are working fine. I want to do this through code. Any clue.
First, NSInteger into bytes of Hex:
NSInteger test = 1;
unsigned char byte[] = { 0x00, 0x01 };
NSInteger test = 16;
unsigned char byte[] = { 0x00, 0x10 };
NSData *data = [NSData dataWithBytes:byte length:sizeof(byte)];
Second, NSString into bytes of Hex:
NSString *test = #"31C5B562-BD07-4616-BCBD-130BA6822790";
unsigned char byte[] = {0x31, 0xC5, 0xB5, 0x62, 0xBD, 0x07, 0x46, 0x16, 0xBC, 0xBD, 0x13, 0x0B, 0xA6, 0x82, 0x27, 0x90};
NSData *data = [NSData dataWithBytes:byte length:sizeof(byte)];
I tried with below code and it works well for my UUID but for NSInteger to to be working I need to send "0010" instead of 16 and "0001" instead of 1. So any clue on how to do this conversion.
- (NSData *)hexData {
NSMutableData *hexData = [NSMutableData data];
int idx = 0;
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];
[hexData appendBytes:&intValue length:1];
}
return hexData;
}
EDIT:
int8_t test = -59;
int8_t bytes = CFSwapInt16HostToBig(test);
NSData *data1 = [NSData dataWithBytes:&bytes length:sizeof(bytes)];
Reaching as 0xFF instead of 0xC4
Since your string is a UUID string you can do something like this:
NSString *test = #"";
uuid_t uuid;
uuid_parse([test UTF8String], uuid)
NSData *data = [NSData dataWithBytes:uuid length:16];
For the number you can do:
NSInteger test = 1;
NSData *data = [NSData dataWithBytes:&test length:sizeof(test)];
Keep in mind that NSInteger is probably more than two bytes and you may also need to worry about byte order.
Update: Since it seems you need the integer value to be two bytes, you should do:
uint16_t test = 1;
NSData *data = [NSData dataWithBytes:&test length:sizeof(test)];
This will ensure 2 bytes. You also need to worry about byte ordering so you really need:
uint16_t test = 1;
uint16_t bytes = CFSwapInt16HostToBig(test);
NSData *data = [NSData dataWithBytes:&bytes length:sizeof(bytes)];
Change CFSwapInt16HostToBig to CFSwapInt16HostToLitte if appropriate.