/*
 * Base64Decoder.h 
 * Copyright (c) 2011 Antillia.com TOSHIYUKI ARAI. ALL RIGHTS RESERVED. 
 */


#pragma once

#include <sol\Object.h>
#include <math.h>
#include <sol/Bytes.h>
#include <sol/StringT.h>

/**
 * Base64Decoder class reprents a base64decoder.
 */
namespace SOL {

class Base64Decoder :public Object {

public:
    /**
     */
    Base64Decoder() {

    }


    /**
     */
    ~Base64Decoder() {

    }

public:
    /**
     * Decode base64encoded string.
     * @param string    [in] NULL terminated string of Base64Encoded data.
     * @param bytes        [out] Reference to ByteArray to return decoded data.
     */
    int decode(__in const StringT<char>& string, __out Bytes& bytes) {
        return decode((const char*)string, bytes);
    }

public:
    /**
     * Decode base64encoded string.
     * @param string    [in] NULL terminated string of Base64Encoded data.
     * @param bytes        [out] Reference to ByteArray to return decoded data.
     */
    int decode(__in const char* string, __out Bytes& bytes) {
        unsigned char* outBytes = NULL;
        unsigned int outLen =0;
        int rc = 0;
        if (string == NULL) {
            return rc;
        }

        rc = decode(string, strlen(string), &outBytes, &outLen);
        if (rc>0) {
            bytes.shallowCopy(outBytes, outLen);
        }
        
        return rc;    
    }

public:

    /**
     * Decode base64encoded data.
     * @param data        [in] NULL terminated string of Base64Encoded data.
     * @param len        [in] Byte length of data.
     * @param outBytes    [out] Pointer to pointer for unsigned char* to return decoded data.
     * @param outLen    [out] Pointer to unsigned int to return the lenghth of decoded dta. 
     */
    int decode(__in const char* data, 
            __in unsigned int len,
            __out unsigned char** outBytes,
            __out unsigned int* outLen) {

        static const char table[] ={
            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
            0x00, 0x00, 0x00, 0x3E, 0x00, 0x00, 0x00, 0x3F,
            0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B,
            0x3C, 0x3D, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
            0x00, 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, 0x00, 0x00, 0x00, 0x00, 0x00,
            0x00, 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, 0x00, 0x00, 0x00, 0x00, 0x00};

        if (data == NULL || len == 0) {
            return 0;
        }
        if (outBytes == NULL || outLen ==NULL) {
            return 0;
        }

        const char PADDING = '=';

        // Compute a length of padding.
        int pad = 0;
        for (int s = len - 1; s >=0; s--) {
            if (data[s] == PADDING) {
                pad++;
            }
        }

        // Allocating a memory for decoded area.
        int length = len * 3 / 4 - pad;

        unsigned char* out = new unsigned char[length];                
        memset(out, 0, length);

        int n = 0;
        //Convert 4 bytes to 3 bytes.
        for (unsigned int i = 0; i <len; i += 4) {
            int block = (table[data[i]] << 18)
                    + (table[data[i + 1]] << 12)
                    + (table[data[i + 2]] << 6)
                    + (table[data[i + 3]]);

            for (unsigned int j = 0; j < 3 && n + j < length; j++) {
                //printf("%d...\n", n+j);
                out[n + j] = ((block >> (8 * (2 - j))) & 0xff);
            }
            n += 3;
        }

        *outBytes = out;
        *outLen   = length;

        return length;
    }
};

}