如何将NSData编码为base64？(iPhone/ipad公司)

Question

我正在尝试将UIImage添加到HTML电子邮件中,但是我遇到了问题.我已经浏览了很多其他帖子,他们都声明我需要将我转换NSData为base64,但是他们所建议的方法似乎不再存在(除非我遗漏了什么？!).

这是我到目前为止的代码:

UIImage *mapImage = [mapViewController convertMapToImage];
NSData *imageData = [NSData dataWithData:UIImagePNGRepresentation(mapImage)];
NSString *base64String = // [imageData base64EncodedString];   --- this method isn't recognised

请有人帮帮我吗？

Answer 1

+ (NSString*)base64forData:(NSData*)theData {
const uint8_t* input = (const uint8_t*)[theData bytes];
NSInteger length = [theData length];

static char table[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";

NSMutableData* data = [NSMutableData dataWithLength:((length + 2) / 3) * 4];
uint8_t* output = (uint8_t*)data.mutableBytes;

NSInteger i;
for (i=0; i < length; i += 3) {
    NSInteger value = 0;
    NSInteger j;
    for (j = i; j < (i + 3); j++) {
        value <<= 8;

        if (j < length) {
            value |= (0xFF & input[j]);
        }
    }

    NSInteger theIndex = (i / 3) * 4;
    output[theIndex + 0] =                    table[(value >> 18) & 0x3F];
    output[theIndex + 1] =                    table[(value >> 12) & 0x3F];
    output[theIndex + 2] = (i + 1) < length ? table[(value >> 6)  & 0x3F] : '=';
    output[theIndex + 3] = (i + 2) < length ? table[(value >> 0)  & 0x3F] : '=';
}

return [[[NSString alloc] initWithData:data encoding:NSASCIIStringEncoding] autorelease];
}