data is nil when using base64 decoding in iPhone - iphone

Question

Im parsing(JSON parsing) an image and tried to display in an image view.
I used the base64 decode method for decoding.
I used the below code for this:
NSString *base64String = responseObj.content;
NSData* data = [Base64 decode:base64String];
image.frame = CGRectMake(0, 0, 100, 100);
image.backgroundColor = [UIColor blueColor];
image.image = [UIImage imageWithData:data];
The Base64 class is
.h
#import <Foundation/Foundation.h>
#interface Base64 : NSObject {
}
+ (void) initialize;
+ (NSString*) encode:(const uint8_t*) input length:(NSInteger) length;
+ (NSString*) encode:(NSData*) rawBytes;
+ (NSData*) decode:(const char*) string length:(NSInteger) inputLength;
+ (NSData*) decode:(NSString*) string;
#end
.m
static char encodingTable[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
static char decodingTable[128];
+ (void) initialize {
if (self == [Base64 class]) {
memset(decodingTable, 0, ArrayLength(decodingTable));
for (NSInteger i = 0; i < ArrayLength(encodingTable); i++) {
decodingTable[encodingTable[i]] = i;
}
}
}
+ (NSString*) encode:(const uint8_t*) input length:(NSInteger) length {
NSMutableData* data = [NSMutableData dataWithLength:((length + 2) / 3) * 4];
uint8_t* output = (uint8_t*)data.mutableBytes;
for (NSInteger i = 0; i < length; i += 3) {
NSInteger value = 0;
for (NSInteger j = i; j < (i + 3); j++) {
value <<= 8;
if (j < length) {
value |= (0xFF & input[j]);
}
}
NSInteger index = (i / 3) * 4;
output[index + 0] = encodingTable[(value >> 18) & 0x3F];
output[index + 1] = encodingTable[(value >> 12) & 0x3F];
output[index + 2] = (i + 1) < length ? encodingTable[(value >> 6) & 0x3F] : '=';
output[index + 3] = (i + 2) < length ? encodingTable[(value >> 0) & 0x3F] : '=';
}
return [[[NSString alloc] initWithData:data
encoding:NSASCIIStringEncoding] autorelease];
}
+ (NSString*) encode:(NSData*) rawBytes {
return [self encode:(const uint8_t*) rawBytes.bytes length:rawBytes.length];
}
+ (NSData*) decode:(const char*) string length:(NSInteger) inputLength {
if ((string == NULL) || (inputLength % 4 != 0)) {
return nil;
}
while (inputLength > 0 && string[inputLength - 1] == '=') {
inputLength--;
}
NSInteger outputLength = inputLength * 3 / 4;
NSMutableData* data = [NSMutableData dataWithLength:outputLength];
uint8_t* output = data.mutableBytes;
NSInteger inputPoint = 0;
NSInteger outputPoint = 0;
while (inputPoint < inputLength) {
char i0 = string[inputPoint++];
char i1 = string[inputPoint++];
char i2 = inputPoint < inputLength ? string[inputPoint++] : 'A'; /* 'A' will decode to \0 */
char i3 = inputPoint < inputLength ? string[inputPoint++] : 'A';
output[outputPoint++] = (decodingTable[i0] << 2) | (decodingTable[i1] >> 4);
if (outputPoint < outputLength) {
output[outputPoint++] = ((decodingTable[i1] & 0xf) << 4) | (decodingTable[i2] >> 2);
}
if (outputPoint < outputLength) {
output[outputPoint++] = ((decodingTable[i2] & 0x3) << 6) | decodingTable[i3];
}
}
return data;
}
+ (NSData*) decode:(NSString*) string {
return [self decode:[string cStringUsingEncoding:NSASCIIStringEncoding] length:string.length];
}
#end
When i tried to see the contents of NSString it is showing the contents correctly.
But when i tried to see the contents of data it is showing
(NSData *) $2 = 0x00000000 .
Can anyone please tell me where I'm going wrong and why the data is nil.

Answer 1

i had a similar problem with some googled copy&paste base64 encoding method, so i would recommend to use QSUtilities:
This library provides general purposes libraries (string cleanup, net access, etc.) within Objective-C classes.
Take a look at the QSString Class

Answer 2

Try this:
NSString *base64String = responseObj.content;// U have base64 String
[Base64 initialize]; //U forgot this
NSData* data = [Base64 decode:base64String];
image.frame = CGRectMake(0, 0, 100, 100);
image.backgroundColor = [UIColor blueColor];
image.image = [UIImage imageWithData:data];