c++ base64加密解密源码

/* KeePass Password Safe - The Open-Source Password Manager Copyright (C) 2003-2006 Dominik Reichl <[email protected]> This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */ #include "StdAfx.h" #include "Base64.h" static const char *g_pCodes = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; static const unsigned char g_pMap[256] = { 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 62, 255, 255, 255, 63, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 255, 255, 255, 254, 255, 255, 255, 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, 255, 255, 255, 255, 255, 255, 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, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255 }; CBase64Codec::CBase64Codec() { } CBase64Codec::~CBase64Codec() { } bool CBase64Codec::Encode(const BYTE *pIn, DWORD uInLen, BYTE *pOut, DWORD *uOutLen) const { DWORD i, len2, leven; BYTE *p; //ASSERT((pIn != NULL) && (uInLen != 0) && (pOut != NULL) && (uOutLen != NULL)); len2 = ((uInLen + 2) / 3) << 2; if((*uOutLen) < (len2 + 1)) return false; p = pOut; leven = 3 * (uInLen / 3); for(i = 0; i < leven; i += 3) { *p++ = g_pCodes[pIn[0] >> 2]; *p++ = g_pCodes[((pIn[0] & 3) << 4) + (pIn[1] >> 4)]; *p++ = g_pCodes[((pIn[1] & 0xf) << 2) + (pIn[2] >> 6)]; *p++ = g_pCodes[pIn[2] & 0x3f]; pIn += 3; } if (i < uInLen) { DWORD a = pIn[0]; DWORD b = ((i + 1) < uInLen) ? pIn[1] : 0; DWORD c = 0; *p++ = g_pCodes[a >> 2]; *p++ = g_pCodes[((a & 3) << 4) + (b >> 4)]; *p++ = ((i + 1) < uInLen) ? g_pCodes[((b & 0xf) << 2) + (c >> 6)] : '='; *p++ = '='; } *p = 0; // Append NULL byte *uOutLen = p - pOut; return true; } bool CBase64Codec::Decode(const BYTE *pIn, DWORD uInLen, BYTE *pOut, DWORD *uOutLen) const { DWORD t, x, y, z; BYTE c; DWORD g = 3; //ASSERT((pIn != NULL) && (uInLen != 0) && (pOut != NULL) && (uOutLen != NULL)); for(x = y = z = t = 0; x < uInLen; x++) { c = g_pMap[pIn[x]]; if(c == 255) continue; if(c == 254) { c = 0; g--; } t = (t << 6) | c; if(++y == 4) { if((z + g) > *uOutLen) { return false; } // Buffer overflow pOut[z++] = (BYTE)((t>>16)&255); if(g > 1) pOut[z++] = (BYTE)((t>>8)&255); if(g > 2) pOut[z++] = (BYTE)(t&255); y = t = 0; } } *uOutLen = z; return true; }