1

我正在尝试将 UIImage 转换为 base64 字符串并上传。

这是我的代码：

NSData *imageData = UIImageJPEGRepresentation(self.image, 0.2);


imageDataBase64 = [NSString stringWithFormat:@"data:image/jpeg;base64,%@", [imageData base64EncodedString]];


 NSURL *url = [NSURL URLWithString:imageDataBase64];


 NSData *imgdata = [NSData dataWithContentsOfURL:url];
 UIImage *ret = [UIImage imageWithData:imgdata];

 [imageView setImage:ret];

当我将 imageDataBase64 设置为 NSString 时，它正在工作。

更新：

base64EncodedString 代码：

。H

void *NewBase64Decode(
    const char *inputBuffer,
    size_t length,
    size_t *outputLength);

char *NewBase64Encode(
    const void *inputBuffer,
    size_t length,
    bool separateLines,
    size_t *outputLength);

@interface NSData (Base64)

+ (NSData *)dataFromBase64String:(NSString *)aString;
- (NSString *)base64EncodedString;

@end

.m

//
// Mapping from 6 bit pattern to ASCII character.
//
static unsigned char base64EncodeLookup[65] =
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

//
// Definition for "masked-out" areas of the base64DecodeLookup mapping
//
#define xx 65

//
// Mapping from ASCII character to 6 bit pattern.
//
static unsigned char base64DecodeLookup[256] =
{
    xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx,
    xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx,
    xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, 62, xx, xx, xx, 63,
    52, 53, 54, 55, 56, 57, 58, 59, 60, 61, xx, xx, xx, xx, xx, xx,
    xx,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
    15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, xx, xx, xx, xx, xx,
    xx, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
    41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, xx, xx, xx, xx, xx,
    xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx,
    xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx,
    xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx,
    xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx,
    xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx,
    xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx,
    xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx,
    xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx, xx,
};

//
// Fundamental sizes of the binary and base64 encode/decode units in bytes
//
#define BINARY_UNIT_SIZE 3
#define BASE64_UNIT_SIZE 4

//
// NewBase64Decode
//
// Decodes the base64 ASCII string in the inputBuffer to a newly malloced
// output buffer.
//
//  inputBuffer - the source ASCII string for the decode
//  length - the length of the string or -1 (to specify strlen should be used)
//  outputLength - if not-NULL, on output will contain the decoded length
//
// returns the decoded buffer. Must be free'd by caller. Length is given by
//  outputLength.
//
void *NewBase64Decode(
                      const char *inputBuffer,
                      size_t length,
                      size_t *outputLength)
{
    if (length == -1)
    {
        length = strlen(inputBuffer);
    }

    size_t outputBufferSize =
    ((length+BASE64_UNIT_SIZE-1) / BASE64_UNIT_SIZE) * BINARY_UNIT_SIZE;
    unsigned char *outputBuffer = (unsigned char *)malloc(outputBufferSize);

    size_t i = 0;
    size_t j = 0;
    while (i < length)
    {
        //
        // Accumulate 4 valid characters (ignore everything else)
        //
        unsigned char accumulated[BASE64_UNIT_SIZE];
        size_t accumulateIndex = 0;
        while (i < length)
        {
            unsigned char decode = base64DecodeLookup[inputBuffer[i++]];
            if (decode != xx)
            {
                accumulated[accumulateIndex] = decode;
                accumulateIndex++;

                if (accumulateIndex == BASE64_UNIT_SIZE)
                {
                    break;
                }
            }
        }

        //
        // Store the 6 bits from each of the 4 characters as 3 bytes
        //
        // (Uses improved bounds checking suggested by Alexandre Colucci)
        //
        if(accumulateIndex >= 2)
            outputBuffer[j] = (accumulated[0] << 2) | (accumulated[1] >> 4);
        if(accumulateIndex >= 3)
            outputBuffer[j + 1] = (accumulated[1] << 4) | (accumulated[2] >> 2);
        if(accumulateIndex >= 4)
            outputBuffer[j + 2] = (accumulated[2] << 6) | accumulated[3];
        j += accumulateIndex - 1;
    }

    if (outputLength)
    {
        *outputLength = j;
    }
    return outputBuffer;
}

//
// NewBase64Encode
//
// Encodes the arbitrary data in the inputBuffer as base64 into a newly malloced
// output buffer.
//
//  inputBuffer - the source data for the encode
//  length - the length of the input in bytes
//  separateLines - if zero, no CR/LF characters will be added. Otherwise
//      a CR/LF pair will be added every 64 encoded chars.
//  outputLength - if not-NULL, on output will contain the encoded length
//      (not including terminating 0 char)
//
// returns the encoded buffer. Must be free'd by caller. Length is given by
//  outputLength.
//
char *NewBase64Encode(
                      const void *buffer,
                      size_t length,
                      bool separateLines,
                      size_t *outputLength)
{
    const unsigned char *inputBuffer = (const unsigned char *)buffer;

#define MAX_NUM_PADDING_CHARS 2
#define OUTPUT_LINE_LENGTH 64
#define INPUT_LINE_LENGTH ((OUTPUT_LINE_LENGTH / BASE64_UNIT_SIZE) * BINARY_UNIT_SIZE)
#define CR_LF_SIZE 2

    //
    // Byte accurate calculation of final buffer size
    //
    size_t outputBufferSize =
    ((length / BINARY_UNIT_SIZE)
     + ((length % BINARY_UNIT_SIZE) ? 1 : 0))
    * BASE64_UNIT_SIZE;
    if (separateLines)
    {
        outputBufferSize +=
        (outputBufferSize / OUTPUT_LINE_LENGTH) * CR_LF_SIZE;
    }

    //
    // Include space for a terminating zero
    //
    outputBufferSize += 1;

    //
    // Allocate the output buffer
    //
    char *outputBuffer = (char *)malloc(outputBufferSize);
    if (!outputBuffer)
    {
        return NULL;
    }

    size_t i = 0;
    size_t j = 0;
    const size_t lineLength = separateLines ? INPUT_LINE_LENGTH : length;
    size_t lineEnd = lineLength;

    while (true)
    {
        if (lineEnd > length)
        {
            lineEnd = length;
        }

        for (; i + BINARY_UNIT_SIZE - 1 < lineEnd; i += BINARY_UNIT_SIZE)
        {
            //
            // Inner loop: turn 48 bytes into 64 base64 characters
            //
            outputBuffer[j++] = base64EncodeLookup[(inputBuffer[i] & 0xFC) >> 2];
            outputBuffer[j++] = base64EncodeLookup[((inputBuffer[i] & 0x03) << 4)
                                                   | ((inputBuffer[i + 1] & 0xF0) >> 4)];
            outputBuffer[j++] = base64EncodeLookup[((inputBuffer[i + 1] & 0x0F) << 2)
                                                   | ((inputBuffer[i + 2] & 0xC0) >> 6)];
            outputBuffer[j++] = base64EncodeLookup[inputBuffer[i + 2] & 0x3F];
        }

        if (lineEnd == length)
        {
            break;
        }

        //
        // Add the newline
        //
        outputBuffer[j++] = '\r';
        outputBuffer[j++] = '\n';
        lineEnd += lineLength;
    }

    if (i + 1 < length)
    {
        //
        // Handle the single '=' case
        //
        outputBuffer[j++] = base64EncodeLookup[(inputBuffer[i] & 0xFC) >> 2];
        outputBuffer[j++] = base64EncodeLookup[((inputBuffer[i] & 0x03) << 4)
                                               | ((inputBuffer[i + 1] & 0xF0) >> 4)];
        outputBuffer[j++] = base64EncodeLookup[(inputBuffer[i + 1] & 0x0F) << 2];
        outputBuffer[j++] = '=';
    }
    else if (i < length)
    {
        //
        // Handle the double '=' case
        //
        outputBuffer[j++] = base64EncodeLookup[(inputBuffer[i] & 0xFC) >> 2];
        outputBuffer[j++] = base64EncodeLookup[(inputBuffer[i] & 0x03) << 4];
        outputBuffer[j++] = '=';
        outputBuffer[j++] = '=';
    }
    outputBuffer[j] = 0;

    //
    // Set the output length and return the buffer
    //
    if (outputLength)
    {
        *outputLength = j;
    }
    return outputBuffer;
}

@implementation NSData (Base64)

//
// dataFromBase64String:
//
// Creates an NSData object containing the base64 decoded representation of
// the base64 string 'aString'
//
// Parameters:
//    aString - the base64 string to decode
//
// returns the autoreleased NSData representation of the base64 string
//
+ (NSData *)dataFromBase64String:(NSString *)aString
{
    NSData *data = [aString dataUsingEncoding:NSASCIIStringEncoding];
    size_t outputLength;
    void *outputBuffer = NewBase64Decode([data bytes], [data length], &outputLength);
    NSData *result = [NSData dataWithBytes:outputBuffer length:outputLength];
    free(outputBuffer);
    return result;
}

//
// base64EncodedString
//
// Creates an NSString object that contains the base 64 encoding of the
// receiver's data. Lines are broken at 64 characters long.
//
// returns an autoreleased NSString being the base 64 representation of the
//  receiver.
//
- (NSString *)base64EncodedString
{
    size_t outputLength;
    char *outputBuffer =
    NewBase64Encode([self bytes], [self length], true, &outputLength);

    NSString *result = [[[NSString alloc] initWithBytes:outputBuffer
                                                 length:outputLength
                                               encoding:NSASCIIStringEncoding] autorelease];
    free(outputBuffer);
    return result;
}

@end
4

2 回答 2

2

重复的问题！试试这个链接：在 UIImage 和 Base64 字符串之间转换

总之，您需要使用 base64 类别将 NSData 编码为字符串，例如 https://github.com/l4u/NSData-Base64/

该类别为 NSData 类提供了以下方法，您可以使用这些方法将 NSData 来回转换为 NSString（base 64 编码）。

+ (NSData *)dataFromBase64String:(NSString *)aString;
- (NSString *)base64EncodedString;

尝试更改此行：

imageDataBase64 = [NSString stringWithFormat:@"data:image/jpeg;base64,%@", [imageData base64EncodedString]]

至

NSString *imageDataBase64encodedString = [imageData base64EncodedString];

要对其进行解码，您可以使用相反的方法：

NSData *theImageData = [NSData dataFromBase64String:imageDataBase64encodedString];
UIImage *ret = [UIImage theImageData];
于 2013-05-03T08:51:24.077 回答
0

在使用它初始化 UIImage 之前，您必须解码图像数据。UIImage 不透明地处理 base64

于 2013-05-03T08:51:08.087 回答