#include "stdafx.h"
#include "Base64.h"
#include <string.h>
namespace zl{
	namespace util{

		static size_t base64EncodeImpl(const char *src, size_t len, std::string& dst);
		static size_t base64DecodeImpl(const char *src, size_t len, std::string& dst);

		size_t base64Encode(const char *src, size_t len, char *dst)
		{
			std::string dest;
			int size = base64EncodeImpl(src, len, dest);
			//strncpy(dst, dest.data(), size);
			::memcpy(dst, dest.data(), size);
			return size;
		}

		size_t base64Encode(const char *src, size_t len, std::string& dst)
		{
			return base64EncodeImpl(src, len, dst);
		}

		size_t base64Encode(const std::string& src, std::string& dst)
		{
			return base64EncodeImpl(src.data(), src.size(), dst);
		}

		std::string    base64Encode(const char *src, size_t len)
		{
			std::string dst;
			base64EncodeImpl(src, len, dst);
			return dst;
		}

		std::string    base64Encode(const std::string& src)
		{
			std::string dst;
			base64EncodeImpl(src.data(), src.size(), dst);
			return dst;
		}


		size_t base64Decode(const char *src, size_t len, char *dst)
		{
			std::string dest;
			int size = base64DecodeImpl(src, len, dest);
			::memcpy(dst, dest.c_str(), size);
			return size;
		}

		size_t base64Decode(const char *src, size_t len, std::string& dst)
		{
			return base64DecodeImpl(src, len, dst);
		}

		size_t base64Decode(const std::string& src, std::string& dst)
		{
			return base64DecodeImpl(src.data(), src.size(), dst);
		}

		std::string    base64Decode(const char *src, size_t len)
		{
			std::string dst;
			base64DecodeImpl(src, len, dst);
			return dst;
		}

		std::string    base64Decode(const std::string& src)
		{
			std::string dst;
			base64DecodeImpl(src.data(), src.size(), dst);
			return dst;
		}


		static size_t base64EncodeImpl(const char *src, size_t len, std::string& dst)
		{
			//������
			static const char EncodeTable[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

			unsigned char Tmp[4] = { 0 };
			int LineLength = 0;
			for (int i = 0; i<(int)(len / 3); i++)
			{
				Tmp[1] = *src++;
				Tmp[2] = *src++;
				Tmp[3] = *src++;
				dst += EncodeTable[Tmp[1] >> 2];
				dst += EncodeTable[((Tmp[1] << 4) | (Tmp[2] >> 4)) & 0x3F];
				dst += EncodeTable[((Tmp[2] << 2) | (Tmp[3] >> 6)) & 0x3F];
				dst += EncodeTable[Tmp[3] & 0x3F];
				if (LineLength += 4, LineLength == 76) { dst += "\r\n"; LineLength = 0; }
			}
			//��ʣ�����ݽ��б���
			int Mod = len % 3;
			if (Mod == 1)
			{
				Tmp[1] = *src++;
				dst += EncodeTable[(Tmp[1] & 0xFC) >> 2];
				dst += EncodeTable[((Tmp[1] & 0x03) << 4)];
				dst += "==";
			}
			else if (Mod == 2)
			{
				Tmp[1] = *src++;
				Tmp[2] = *src++;
				dst += EncodeTable[(Tmp[1] & 0xFC) >> 2];
				dst += EncodeTable[((Tmp[1] & 0x03) << 4) | ((Tmp[2] & 0xF0) >> 4)];
				dst += EncodeTable[((Tmp[2] & 0x0F) << 2)];
				dst += "=";
			}

			return dst.size();
		}

		static size_t base64DecodeImpl(const char *src, size_t len, std::string& dst)
		{
			//������
			static const char DecodeTable[] =
			{
				0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
				0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
				0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 62, 0, 0, 0, 63,
				52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 0, 0, 0, 0, 0, 0,
				0, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
				15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 0, 0, 0, 0, 0,
				0, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
				41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 0, 0, 0, 0, 0
			};

			int nValue = 0;
			size_t i = 0;
			while (i < len)
			{
				if (*src != '\r' && *src != '\n')
				{
					nValue = DecodeTable[(int)*src++] << 18;
					nValue += DecodeTable[(int)*src++] << 12;
					dst += (nValue & 0x00FF0000) >> 16;
					if (*src != '=')
					{
						nValue += DecodeTable[(int)*src++] << 6;
						dst += (nValue & 0x0000FF00) >> 8;
						if (*src != '=')
						{
							nValue += DecodeTable[(int)*src++];
							dst += nValue & 0x000000FF;
						}
					}
					i += 4;
				}
				else   // �س�����,����
				{
					src++;
					i++;
				}
			}

			return dst.size();
		}

	}
}