/*
 * Base64.cpp
 *
 *  Created on: 2010-11-12
 *      Author: terry
 */

#include "Base64.h"
#include <string.h>
#include <ctype.h>



namespace comn
{

#define FF_ARRAY_ELEMS(a) (sizeof(a) / sizeof((a)[0]))

#ifndef UINT_MAX
#define UINT_MAX      0xffffffffU    /* maximum unsigned int value */
#endif //UINT_MAX


/* ---------------- private code */
static const unsigned char map2[] =
{
    0x3e, 0xff, 0xff, 0xff, 0x3f, 0x34, 0x35, 0x36,
    0x37, 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0xff,
    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00, 0x01,
    0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09,
    0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11,
    0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19,
    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x1a, 0x1b,
    0x1c, 0x1d, 0x1e, 0x1f, 0x20, 0x21, 0x22, 0x23,
    0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b,
    0x2c, 0x2d, 0x2e, 0x2f, 0x30, 0x31, 0x32, 0x33
};

int Base64::decode(unsigned char *out, int out_size, const char *in, int in_size)
{
    int i, v;
    unsigned char *dst = out;

    v = 0;
    //for (i = 0; in[i] && in[i] != '='; i++) {
    for (i = 0; i < in_size && in[i] != '='; i ++) {

        unsigned int index= in[i]-43;
        if (index>=FF_ARRAY_ELEMS(map2) || map2[index] == 0xff)
            return -1;
        v = (v << 6) + map2[index];
        if (i & 3) {
            if (dst - out < out_size) {
                *dst++ = v >> (6 - 2 * (i & 3));
            }
        }
    }

    return dst - out;
}

/*****************************************************************************
* b64_encode: Stolen from VLC's http.c.
* Simplified by Michael.
* Fixed edge cases and made it work from data (vs. strings) by Ryan.
*****************************************************************************/

char * Base64::encode(char *out, int out_size, const unsigned char *in, int in_size)
{
    static const char b64[] =
        "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
    char *ret, *dst;
    unsigned i_bits = 0;
    int i_shift = 0;
    int bytes_remaining = in_size;

    if ((size_t)in_size >= UINT_MAX / 4 ||
        out_size < (in_size+2) / 3 * 4 + 1)
        return NULL;
    ret = dst = out;
    while (bytes_remaining) {
        i_bits = (i_bits << 8) + *in++;
        bytes_remaining--;
        i_shift += 8;

        do {
            *dst++ = b64[(i_bits << 6 >> i_shift) & 0x3f];
            i_shift -= 6;
        } while (i_shift > 6 || (bytes_remaining == 0 && i_shift > 0));
    }
    while ((dst - ret) & 3)
        *dst++ = '=';
    *dst = '\0';

    return ret;
}




}
