/****************************************************************************
Copyright (c) 2010 cocos2d-x.org

http://www.cocos2d-x.org

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
****************************************************************************/

#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;
}