axmol/core/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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all copies or substantial portions of the Software.

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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