objective-c 如何在 iPhone 上进行 Base64 编码

How to Base64 encoding on the iPhone

提问by respectTheCode

How do I do Base64 encoding on the iPhone?

如何在 iPhone 上进行 Base64 编码？

I have found a few examples that looked promising, but could never get any of them to work on the phone.

我发现了一些看起来很有希望的例子，但永远无法让它们在电话上工作。

回答by Ferran Maylinch

You can see an example here.

您可以在此处查看示例。

This is for iOS7+.

这是针对 iOS7+ 的。

I copy the code here, just in case:

我在这里复制代码，以防万一：

// Create NSData object
NSData *nsdata = [@"iOS Developer Tips encoded in Base64"
  dataUsingEncoding:NSUTF8StringEncoding];

// Get NSString from NSData object in Base64
NSString *base64Encoded = [nsdata base64EncodedStringWithOptions:0];

// Print the Base64 encoded string
NSLog(@"Encoded: %@", base64Encoded);

// Let's go the other way...

// NSData from the Base64 encoded str
NSData *nsdataFromBase64String = [[NSData alloc]
  initWithBase64EncodedString:base64Encoded options:0];

// Decoded NSString from the NSData
NSString *base64Decoded = [[NSString alloc] 
  initWithData:nsdataFromBase64String encoding:NSUTF8StringEncoding];
NSLog(@"Decoded: %@", base64Decoded);

回答by kdda

I also had trouble finding working code for the iPhone that I could understand.

我也很难找到我能理解的 iPhone 工作代码。

I finally wrote this.

我终于写了这个。

-(NSString *)Base64Encode:(NSData *)data;

-(NSString *)Base64Encode:(NSData *)data{

    //Point to start of the data and set buffer sizes
    int inLength = [data length];
    int outLength = ((((inLength * 4)/3)/4)*4) + (((inLength * 4)/3)%4 ? 4 : 0);
    const char *inputBuffer = [data bytes];
    char *outputBuffer = malloc(outLength+1);
    outputBuffer[outLength] = 0;

    //64 digit code
    static char Encode[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

    //Start the count
    int cycle = 0;
    int inpos = 0;
    int outpos = 0;
    char temp;

    //Pad the last to bytes, the outbuffer must always be a multiple of 4.
    outputBuffer[outLength-1] = '=';
    outputBuffer[outLength-2] = '=';

    /* http://en.wikipedia.org/wiki/Base64

        Text content     M         a         n
        ASCII            77        97        110
        8 Bit pattern    01001101  01100001  01101110

        6 Bit pattern    010011    010110    000101    101110
        Index            19        22        5         46
        Base64-encoded   T         W         F         u
    */

    while (inpos < inLength){
        switch (cycle) {

            case 0:
                outputBuffer[outpos++] = Encode[(inputBuffer[inpos] & 0xFC) >> 2];
                cycle = 1;
                break;

            case 1:
                temp = (inputBuffer[inpos++] & 0x03) << 4;
                outputBuffer[outpos] = Encode[temp];
                cycle = 2;
                break;

            case 2:
                outputBuffer[outpos++] = Encode[temp|(inputBuffer[inpos]&0xF0) >> 4];
                temp = (inputBuffer[inpos++] & 0x0F) << 2;
                outputBuffer[outpos] = Encode[temp];
                cycle = 3;
                break;

            case 3:
                outputBuffer[outpos++] = Encode[temp|(inputBuffer[inpos]&0xC0) >> 6];
                cycle = 4;
                break;

            case 4:
                outputBuffer[outpos++] = Encode[inputBuffer[inpos++] & 0x3f];
                cycle = 0;
                break;

            default:
                cycle = 0;
                break;
        }
    }
    NSString *pictemp = [NSString stringWithUTF8String:outputBuffer];
    free(outputBuffer);
    return pictemp;
}

回答by Dejell

Use thislibrary to encode Base64.

使用此库对 Base64 进行编码。

It also supports ARC

它还支持 ARC

回答by Suraj K Thomas

Try this out...this worked perfectly for me.create a category Base64.h and Base 64.m,Import to any class you want to use and call it using single line for base 64 encoding to happen.

试试这个……这对我来说非常有效。创建一个类别 Base64.h 和 Base 64.m，导入到您想要使用的任何类，并使用单行调用它以实现 base 64 编码。

//
//  Base64.h
//  CryptTest
//  Created by SURAJ K THOMAS  on 02/05/2013.


#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





#import "Base64.h"


@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 
now import the above category to any class and convert the string like below


 NSString *authString = [[NSString stringWithFormat:@"OD0EK819OJFIFT6OJZZXT09Y1YUT1EJ2"]   
stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];


NSData *inputData = [authString dataUsingEncoding:NSUTF8StringEncoding];

NSString *finalAuth =[Base64 encode:inputData];
NSLog(@"Encoded string =%@", finalAuth);
 */
    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

@结尾

Base64.h
Base64.m

回答by MaxEcho

Download following two files from GitHub

从GitHub下载以下两个文件

#import "Base64.h"

Add these files to your project

将这些文件添加到您的项目中

Import header file in desired file

在所需文件中导入头文件

NSString *plainText = @"Your String";

NSString *base64String = [plainText base64EncodedStringWithWrapWidth:0];

And use as to encode

并使用 as 进行编码

NSString *plainText = [base64String base64DecodedString];

Also you can decode it as

您也可以将其解码为

NSString *plainString = @"foo";

回答by kavehmb

reference

参考

NSData *plainData = [plainString dataUsingEncoding:NSUTF8StringEncoding];
NSString *base64String = [plainData base64EncodedStringWithOptions:0];
NSLog(@"%@", base64String); // Zm9v

Encoding

编码

NSData *decodedData = [[NSData alloc] initWithBase64EncodedString:base64String options:0];
NSString *decodedString = [[NSString alloc] initWithData:decodedData encoding:NSUTF8StringEncoding];
NSLog(@"%@", decodedString); // foo 

Decoding

解码

- (NSString*)encodeBase64 {    
    static char* alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";

    unsigned int length = self.length;
    unsigned const char* rawData = self.bytes;

    //empty data = empty output
    if (length == 0) {
        return @"";
    }

    unsigned int outputLength = (((length + 2) / 3) * 4);

    //let's allocate buffer for the output
    char* rawOutput = malloc(outputLength + 1);

    //with each step we get 3 bytes from the input and write 4 bytes to the output
    for (unsigned int i = 0, outputIndex = 0; i < length; i += 3, outputIndex += 4) {
        BOOL triple = NO;
        BOOL quad = NO;

        //get 3 bytes (or only 1 or 2 when we have reached the end of input)
        unsigned int value = rawData[i];
        value <<= 8;

        if (i + 1 < length) {
            value |= rawData[i + 1];
            triple = YES;
        }

        value <<= 8;

        if (i + 2 < length) {
            value |= rawData[i + 2];
            quad = YES;
        }

        //3 * 8 bits written as 4 * 6 bits (indexing the 64 chars of the alphabet)
        //write = if end of input reached
        rawOutput[outputIndex + 3] = (quad) ? alphabet[value & 0x3F] : '=';
        value >>= 6;
        rawOutput[outputIndex + 2] = (triple) ? alphabet[value & 0x3F] : '=';
        value >>= 6;
        rawOutput[outputIndex + 1] = alphabet[value & 0x3F];
        value >>= 6;
        rawOutput[outputIndex] = alphabet[value & 0x3F];
    }

    rawOutput[outputLength] = 0;

    NSString* output = [NSString stringWithCString:rawOutput encoding:NSASCIIStringEncoding];

    free(rawOutput);

    return output;
}

回答by septerr

Seems as of iOS 7 you no longer need any libraries to encode in Base64. Following methods on NSDatacan be used to Base64 encode:

似乎从 iOS 7 开始，您不再需要任何库在 Base64 中进行编码。NSData上的以下方法可用于 Base64 编码：

• base64EncodedDataWithOptions: – base64EncodedStringWithOptions:

• base64EncodedDataWithOptions: – base64EncodedStringWithOptions:

回答by Sulthan

A method in a NSDatacategory

NSData类别中的方法

static char *alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

+ (NSString *)encodeString:(NSString *)data
{
    const char *input = [data cStringUsingEncoding:NSUTF8StringEncoding];
    unsigned long inputLength = [data length];
    unsigned long modulo = inputLength % 3;
    unsigned long outputLength = (inputLength / 3) * 4 + (modulo ? 4 : 0);
    unsigned long j = 0;

    // Do not forget about trailing zero
    unsigned char *output = malloc(outputLength + 1);
    output[outputLength] = 0;

    // Here are no checks inside the loop, so it works much faster than other implementations
    for (unsigned long i = 0; i < inputLength; i += 3) {
        output[j++] = alphabet[ (input[i] & 0xFC) >> 2 ];
        output[j++] = alphabet[ ((input[i] & 0x03) << 4) | ((input[i + 1] & 0xF0) >> 4) ];
        output[j++] = alphabet[ ((input[i + 1] & 0x0F)) << 2 | ((input[i + 2] & 0xC0) >> 6) ];
        output[j++] = alphabet[ (input[i + 2] & 0x3F) ];
    }
    // Padding in the end of encoded string directly depends of modulo
    if (modulo > 0) {
        output[outputLength - 1] = '=';
        if (modulo == 1)
            output[outputLength - 2] = '=';
    }
    NSString *s = [NSString stringWithUTF8String:(const char *)output];
    free(output);
    return s;
}

回答by p_eugene

I did my own implementation, where has been removed all checks inside the loop. So on big amount of data, it works faster. You can take it as a basis for own solution.

我做了自己的实现，其中已删除循环内的所有检查。因此，在大量数据上，它运行得更快。您可以将其作为自己解决方案的基础。

##代码##