axmol/cocos2dx/support/base64.cpp

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

unsigned char alphabet[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

INT32 _base64Decode( unsigned char *input, UINT32 input_len, unsigned char *output, UINT32 *output_len )
{
    static char inalphabet[256], decoder[256];
    INT32 i, bits, c, char_count, errors = 0;
	UINT32 input_idx = 0;
	UINT32 output_idx = 0;

    for (i = (sizeof alphabet) - 1; i >= 0 ; i--) {
		inalphabet[alphabet[i]] = 1;
		decoder[alphabet[i]] = i;
    }

    char_count = 0;
    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:
				fprintf(stderr, "base64Decode: encoding incomplete: at least 2 bits missing");
				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) {
			fprintf(stderr, "base64 encoding incomplete: at least %d bits truncated",
					((4 - char_count) * 6));
			errors++;
		}
    }
	
	*output_len = output_idx;
	return errors;
}

INT32 base64Decode(unsigned char *in, UINT32 inLength, unsigned char **out)
{
	UINT32 outLength = 0;
	
	//should be enough to store 6-bit buffers in 8-bit buffers
	*out = (unsigned char *)malloc( (size_t)(inLength * 3.0f / 4.0f + 1));
	if( *out ) {
		INT32 ret = _base64Decode(in, inLength, *out, &outLength);
		
		if (ret > 0 )
		{
			printf("Base64Utils: error decoding");
			free(*out);
			*out = NULL;			
			outLength = 0;
		}
	}
    return outLength;
}