Created
September 3, 2012 18:38
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Base64 Encode
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#import <Foundation/Foundation.h> | |
@interface NSString (base64encode) | |
- (NSString *)base64encode; | |
@end | |
@interface NSData (base64encode) | |
- (NSString *)base64encode; | |
@end | |
@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 |
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#import "Base64.h" | |
@implementation NSString (base64encode) | |
- (NSString *)base64encode { | |
[Base64 initialize]; | |
return [Base64 encode:[self dataUsingEncoding:NSUTF8StringEncoding]]; | |
} | |
@end | |
@implementation NSData (base64encode) | |
- (NSString *)base64encode { | |
[Base64 initialize]; | |
return [Base64 encode:self]; | |
} | |
@end | |
@implementation Base64 | |
#define ArrayLength(x) (sizeof(x)/sizeof(*(x))) | |
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] ; | |
} | |
+ (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 |
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