axmol/cocos/base/base64.cpp

/****************************************************************************
Copyright (c) 2010-2012 cocos2d-x.org
Copyright (c) 2013-2016 Chukong Technologies Inc.
Copyright (c) 2017-2018 Xiamen Yaji Software Co., Ltd.
 
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The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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****************************************************************************/

#include <stdio.h>
#include <stdlib.h>
#include "base/base64.h"

namespace cocos2d {

unsigned char alphabet[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
    
int _base64Decode(const unsigned char *input, unsigned int input_len, unsigned char *output, unsigned int *output_len )
{
    static char inalphabet[256], decoder[256];
    int c = 0, char_count, errors = 0;
    unsigned int input_idx = 0;
    unsigned int output_idx = 0;

    auto alphabetSize = sizeof(alphabet);
    for (size_t i = 0; i < alphabetSize; i++){
        inalphabet[alphabet[i]] = 1;
        decoder[alphabet[i]] = i;
    }

    char_count = 0;
    int bits = 0;
    for( input_idx=0; input_idx < input_len ; input_idx++ ) {
        c = input[ input_idx ];
        if (c == '=')
            break;
        if (c > 255 || ! inalphabet[c])
            continue;
        bits += decoder[c];
        char_count++;
        if (char_count == 4) {
            output[ output_idx++ ] = (bits >> 16);
            output[ output_idx++ ] = ((bits >> 8) & 0xff);
            output[ output_idx++ ] = ( bits & 0xff);
            bits = 0;
            char_count = 0;
        } else {
            bits <<= 6;
        }
    }
    
    if( c == '=' ) {
        switch (char_count) {
            case 1:
#if (CC_TARGET_PLATFORM != CC_PLATFORM_BADA)
                fprintf(stderr, "base64Decode: encoding incomplete: at least 2 bits missing");
#endif
                errors++;
                break;
            case 2:
                output[ output_idx++ ] = ( bits >> 10 );
                break;
            case 3:
                output[ output_idx++ ] = ( bits >> 16 );
                output[ output_idx++ ] = (( bits >> 8 ) & 0xff);
                break;
            }
    } else if ( input_idx < input_len ) {
        if (char_count) {
#if (CC_TARGET_PLATFORM != CC_PLATFORM_BADA)
            fprintf(stderr, "base64 encoding incomplete: at least %d bits truncated",
                    ((4 - char_count) * 6));
#endif
            errors++;
        }
    }
    
    *output_len = output_idx;
    return errors;
}
    
void _base64Encode( const unsigned char *input, unsigned int input_len, char *output )
{
    unsigned int char_count;
    unsigned int bits;
    unsigned int input_idx = 0;
    unsigned int output_idx = 0;
    
    char_count = 0;
    bits = 0;    
    for( input_idx=0; input_idx < input_len ; input_idx++ ) {
        bits |= input[ input_idx ];
        
        char_count++;
        if (char_count == 3) {
            output[ output_idx++ ] = alphabet[(bits >> 18) & 0x3f];
            output[ output_idx++ ] = alphabet[(bits >> 12) & 0x3f];
            output[ output_idx++ ] = alphabet[(bits >> 6) & 0x3f];
            output[ output_idx++ ] = alphabet[bits & 0x3f];
            bits = 0;
            char_count = 0;
        } else {
            bits <<= 8;
        }
    }
    
    if (char_count) {
        if (char_count == 1) {
            bits <<= 8;
        }

        output[ output_idx++ ] = alphabet[(bits >> 18) & 0x3f];
        output[ output_idx++ ] = alphabet[(bits >> 12) & 0x3f];
        if (char_count > 1) {
            output[ output_idx++ ] = alphabet[(bits >> 6) & 0x3f];
        } else {
            output[ output_idx++ ] = '=';
        }
        output[ output_idx++ ] = '=';
    }
    
    output[ output_idx++ ] = 0;
}
    
int base64Decode(const unsigned char *in, unsigned int inLength, unsigned char **out)
{
    unsigned int outLength = 0;
    
    //should be enough to store 6-bit buffers in 8-bit buffers
    *out = (unsigned char*)malloc(inLength / 4 * 3 + 1);
    if( *out ) {
        int ret = _base64Decode(in, inLength, *out, &outLength);
        
        if (ret > 0 )
        {
#if (CC_TARGET_PLATFORM != CC_PLATFORM_BADA)
            printf("Base64Utils: error decoding");
#endif
            free(*out);
            *out = nullptr;            
            outLength = 0;
        }
    }
    return outLength;
}

int base64Encode(const unsigned char *in, unsigned int inLength, char **out) {
    unsigned int outLength = (inLength + 2) / 3 * 4;
    
    //should be enough to store 8-bit buffers in 6-bit buffers
    *out = (char*)malloc(outLength+1);
    if( *out ) {
        _base64Encode(in, inLength, *out);
    }
    return outLength;
}
    
}//namespace   cocos2d