495 lines
12 KiB
C++
495 lines
12 KiB
C++
//+--------------------------------------------------------------------------
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//
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// Microsoft Windows
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// Copyright (C) Microsoft Corporation, 1996 - 1999
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//
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// File: base64.cpp
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//
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// Contents: base64 encode/decode implementation
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//
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// History: 25-Jul-96 vich created
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//
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//---------------------------------------------------------------------------
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#include <windows.h>
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#include <assert.h>
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#include <dbgdef.h>
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#include "pkifmt.h"
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//#define BASE64_STRICT // enforce syntax check on input data
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#undef BASE64_STRICT // enforce syntax check on input data
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// The following table translates an ascii subset to 6 bit values as follows
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// (see RFC 1421 and/or RFC 1521):
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//
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// input hex (decimal)
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// 'A' --> 0x00 (0)
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// 'B' --> 0x01 (1)
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// ...
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// 'Z' --> 0x19 (25)
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// 'a' --> 0x1a (26)
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// 'b' --> 0x1b (27)
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// ...
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// 'z' --> 0x33 (51)
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// '0' --> 0x34 (52)
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// ...
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// '9' --> 0x3d (61)
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// '+' --> 0x3e (62)
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// '/' --> 0x3f (63)
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//
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// Encoded lines must be no longer than 76 characters.
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// The final "quantum" is handled as follows: The translation output shall
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// always consist of 4 characters. 'x', below, means a translated character,
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// and '=' means an equal sign. 0, 1 or 2 equal signs padding out a four byte
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// translation quantum means decoding the four bytes would result in 3, 2 or 1
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// unencoded bytes, respectively.
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//
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// unencoded size encoded data
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// -------------- ------------
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// 1 byte "xx=="
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// 2 bytes "xxx="
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// 3 bytes "xxxx"
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#define CB_BASE64LINEMAX 64 // others use 64 -- could be up to 76
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// Any other (invalid) input character value translates to 0x40 (64)
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const BYTE abDecode[256] =
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{
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/* 00: */ 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
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/* 10: */ 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
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/* 20: */ 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 62, 64, 64, 64, 63,
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/* 30: */ 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 64, 64, 64, 64, 64, 64,
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/* 40: */ 64, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
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/* 50: */ 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 64, 64, 64, 64, 64,
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/* 60: */ 64, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
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/* 70: */ 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 64, 64, 64, 64, 64,
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/* 80: */ 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
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/* 90: */ 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
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/* a0: */ 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
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/* b0: */ 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
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/* c0: */ 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
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/* d0: */ 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
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/* e0: */ 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
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/* f0: */ 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
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};
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const UCHAR abEncode[] =
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/* 0 thru 25: */ "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
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/* 26 thru 51: */ "abcdefghijklmnopqrstuvwxyz"
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/* 52 thru 61: */ "0123456789"
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/* 62 and 63: */ "+/";
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#define MOD4(x) ((x) & 3)
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__inline BOOL
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_IsBase64WhiteSpace(
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IN TCHAR const ch)
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{
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return(
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ch == TEXT(' ') ||
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ch == TEXT('\t') ||
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ch == TEXT('\r') ||
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ch == TEXT('\n'));
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}
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DWORD
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Base64DecodeA(
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IN TCHAR const *pchIn,
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IN DWORD cchIn,
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OPTIONAL OUT BYTE *pbOut,
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IN OUT DWORD *pcbOut)
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{
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DWORD dwErr;
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DWORD cchInDecode, cbOutDecode;
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TCHAR const *pchInEnd;
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TCHAR const *pchInT;
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BYTE *pbOutT;
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// Count the translatable characters, skipping whitespace & CR-LF chars.
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cchInDecode = 0;
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pchInEnd = &pchIn[cchIn];
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dwErr = ERROR_INVALID_DATA;
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for (pchInT = pchIn; pchInT < pchInEnd; pchInT++)
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{
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if (sizeof(abDecode) < (unsigned) *pchInT || abDecode[*pchInT] > 63)
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{
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// Found a non-base64 character. Decide what to do.
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DWORD cch;
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if (_IsBase64WhiteSpace(*pchInT))
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{
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continue; // skip all whitespace
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}
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// The length calculation may stop in the middle of the last
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// translation quantum, because the equal sign padding characters
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// are treated as invalid input. If the last translation quantum
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// is not 4 bytes long, there must be 3, 2 or 1 equal sign(s).
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if (0 != cchInDecode)
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{
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cch = MOD4(cchInDecode);
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if (0 != cch)
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{
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cch = 4 - cch;
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while (0 != cch && pchInT < pchInEnd && '=' == *pchInT)
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{
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pchInT++;
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cch--;
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}
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}
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//#ifdef BASE64_STRICT
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if (0 == cch)
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//#endif
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{
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break;
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}
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}
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#if DBG
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DbgPrintf(
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DBG_SS_TRACE,
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"Bad base64 data: \"%.*" szFMTTSTR "...\"\n",
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min(16, SAFE_SUBTRACT_POINTERS(pchInEnd, pchInT)),
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pchInT);
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#endif //DBG
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goto BadBase64Data;
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}
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cchInDecode++; // only count valid base64 chars
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}
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assert(pchInT <= pchInEnd);
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#ifdef BASE64_STRICT
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if (pchInT < pchInEnd)
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{
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TCHAR const *pch;
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DWORD cchEqual = 0;
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for (pch = pchInT; pch < pchInEnd; pch++)
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{
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if (!_IsBase64WhiteSpace(*pch))
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{
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// Allow up to 3 extra trailing equal signs.
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if (TEXT('=') == *pch && 3 > cchEqual)
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{
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cchEqual++;
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continue;
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}
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#if DBG
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DbgPrintf(DBG_SS_TRACE,
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"Bad trailing base64 data: \"%.*" szFMTTSTR "...\"\n",
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min(16, SAFE_SUBTRACT_POINTERS(pchInEnd, pch)),
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pch);
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#endif //DBG
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goto BadTrailingBase64Data;
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}
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}
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#if DBG
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if (0 != cchEqual)
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{
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DbgPrintf(DBG_SS_TRACE,
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"Ignored trailing base64 data: \"%.*" szFMTTSTR "\"\n",
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cchEqual,
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TEXT("==="));
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}
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#endif //DBG
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}
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#endif
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pchInEnd = pchInT; // don't process any trailing stuff again
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// We know how many translatable characters are in the input buffer, so now
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// set the output buffer size to three bytes for every four (or fraction of
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// four) input bytes. Compensate for a fractional translation quantum.
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cbOutDecode = ((cchInDecode + 3) >> 2) * 3;
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switch (cchInDecode % 4)
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{
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case 1:
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case 2:
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cbOutDecode -= 2;
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break;
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case 3:
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cbOutDecode--;
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break;
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}
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pbOutT = pbOut;
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if (NULL == pbOut)
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{
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pbOutT += cbOutDecode;
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}
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else
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{
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// Decode one quantum at a time: 4 bytes ==> 3 bytes
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//assert(cbOutDecode <= *pcbOut);
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if (cbOutDecode > *pcbOut)
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{
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*pcbOut = cbOutDecode;
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dwErr = ERROR_MORE_DATA;
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goto MoreDataError;
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}
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pchInT = pchIn;
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while (cchInDecode > 0)
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{
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DWORD i;
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BYTE ab4[4];
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ZeroMemory(ab4, sizeof(ab4));
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for (i = 0; i < min(sizeof(ab4)/sizeof(ab4[0]), cchInDecode); i++)
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{
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while (
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sizeof(abDecode) > (unsigned) *pchInT &&
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63 < abDecode[*pchInT])
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{
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pchInT++;
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}
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assert(pchInT < pchInEnd);
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ab4[i] = (BYTE) *pchInT++;
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}
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// Translate 4 input characters into 6 bits each, and deposit the
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// resulting 24 bits into 3 output bytes by shifting as appropriate.
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// out[0] = in[0]:in[1] 6:2
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// out[1] = in[1]:in[2] 4:4
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// out[2] = in[2]:in[3] 2:6
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*pbOutT++ =
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(BYTE) ((abDecode[ab4[0]] << 2) | (abDecode[ab4[1]] >> 4));
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if (i > 2)
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{
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*pbOutT++ =
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(BYTE) ((abDecode[ab4[1]] << 4) | (abDecode[ab4[2]] >> 2));
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}
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if (i > 3)
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{
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*pbOutT++ = (BYTE) ((abDecode[ab4[2]] << 6) | abDecode[ab4[3]]);
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}
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cchInDecode -= i;
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}
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assert((DWORD) (pbOutT - pbOut) <= cbOutDecode);
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}
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*pcbOut = SAFE_SUBTRACT_POINTERS(pbOutT, pbOut);
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dwErr = ERROR_SUCCESS;
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ErrorReturn:
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return dwErr;
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SET_ERROR(MoreDataError, dwErr)
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SET_ERROR(BadBase64Data, dwErr)
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#ifdef BASE64_STRICT
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SET_ERROR(BadTrailingBase64Data, dwErr)
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#endif
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}
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// Encode a BYTE array into a Base64 text string.
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// Use CR-LF pairs for line breaks, unless CRYPT_STRING_NOCR is set.
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// Do not '\0' terminate the text string -- that's handled by the caller.
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// Do not add -----BEGIN/END headers -- that's also handled by the caller.
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DWORD
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Base64EncodeA(
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IN BYTE const *pbIn,
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IN DWORD cbIn,
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IN DWORD Flags,
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OPTIONAL OUT TCHAR *pchOut,
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IN OUT DWORD *pcchOut)
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{
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DWORD dwErr;
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TCHAR *pchOutT;
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DWORD cchOutEncode;
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BOOL fNoCR = 0 != (CRYPT_STRING_NOCR & Flags);
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// Allocate enough memory for full final translation quantum.
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cchOutEncode = ((cbIn + 2) / 3) * 4;
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// and enough for CR-LF pairs for every CB_BASE64LINEMAX character line.
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cchOutEncode +=
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(fNoCR? 1 : 2) *
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((cchOutEncode + CB_BASE64LINEMAX - 1) / CB_BASE64LINEMAX);
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pchOutT = pchOut;
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if (NULL == pchOut)
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{
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pchOutT += cchOutEncode;
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//printf("cchOut: =%x Computed=%x\n", (DWORD) (pchOutT - pchOut), cchOutEncode);
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}
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else
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{
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DWORD cCol;
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if (cchOutEncode > *pcchOut)
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{
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*pcchOut = cchOutEncode;
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dwErr = ERROR_MORE_DATA;
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goto MoreDataError;
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}
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cCol = 0;
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while ((long) cbIn > 0) // signed comparison -- cbIn can wrap
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{
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BYTE ab3[3];
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if (cCol == CB_BASE64LINEMAX/4)
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{
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cCol = 0;
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if (!fNoCR)
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{
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*pchOutT++ = '\r';
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}
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*pchOutT++ = '\n';
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}
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cCol++;
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ZeroMemory(ab3, sizeof(ab3));
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ab3[0] = *pbIn++;
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if (cbIn > 1)
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{
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ab3[1] = *pbIn++;
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if (cbIn > 2)
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{
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ab3[2] = *pbIn++;
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}
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}
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*pchOutT++ = abEncode[ab3[0] >> 2];
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*pchOutT++ = abEncode[((ab3[0] << 4) | (ab3[1] >> 4)) & 0x3f];
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*pchOutT++ = (cbIn > 1)?
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abEncode[((ab3[1] << 2) | (ab3[2] >> 6)) & 0x3f] : '=';
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*pchOutT++ = (cbIn > 2)? abEncode[ab3[2] & 0x3f] : '=';
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cbIn -= 3;
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}
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// Append CR-LF only if there was input data
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if (pchOutT != pchOut)
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{
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if (!fNoCR)
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{
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*pchOutT++ = '\r';
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}
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*pchOutT++ = '\n';
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}
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//printf("cchOut: Actual=%x Computed=%x Buffer=%x\n", (DWORD) (pchOutT - pchOut), cchOutEncode, *pcchOut);
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assert((DWORD) (pchOutT - pchOut) == cchOutEncode);
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}
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*pcchOut = SAFE_SUBTRACT_POINTERS(pchOutT, pchOut);
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dwErr = ERROR_SUCCESS;
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ErrorReturn:
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return dwErr;
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SET_ERROR(MoreDataError, dwErr)
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}
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DWORD
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Base64EncodeW(
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IN BYTE const *pbIn,
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IN DWORD cbIn,
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IN DWORD Flags,
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OUT WCHAR *wszOut,
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OUT DWORD *pcchOut)
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{
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DWORD cchOut;
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CHAR *pch = NULL;
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DWORD cch;
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DWORD err;
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assert(pcchOut != NULL);
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// only want to know how much to allocate
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// we know all base64 char map 1-1 with unicode
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if (wszOut == NULL)
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{
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// get the number of characters
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*pcchOut = 0;
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err = Base64EncodeA(pbIn, cbIn, Flags, NULL, pcchOut);
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}
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// otherwise we have an output buffer
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else {
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// char count is the same be it ascii or unicode,
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cchOut = *pcchOut;
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cch = 0;
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err = ERROR_OUTOFMEMORY;
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pch = (CHAR *) malloc(cchOut);
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if (NULL != pch)
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{
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err = Base64EncodeA(pbIn, cbIn, Flags, pch, &cchOut);
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if (ERROR_SUCCESS == err)
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{
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// should not fail!
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cch = MultiByteToWideChar(0, 0, pch, cchOut, wszOut, *pcchOut);
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// check to make sure we did not fail
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assert(*pcchOut == 0 || cch != 0);
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}
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}
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}
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if(pch != NULL)
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free(pch);
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return(err);
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}
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DWORD
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Base64DecodeW(
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IN const WCHAR * wszIn,
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IN DWORD cch,
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OUT BYTE *pbOut,
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OUT DWORD *pcbOut)
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{
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CHAR *pch;
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DWORD err = ERROR_SUCCESS;
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// in all cases we need to convert to an ascii string
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// we know the ascii string is less
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if ((pch = (CHAR *) malloc(cch)) == NULL)
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{
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err = ERROR_OUTOFMEMORY;
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}
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// we know no base64 wide char map to more than 1 ascii char
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else if (WideCharToMultiByte(0, 0, wszIn, cch, pch, cch, NULL, NULL) == 0)
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{
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err = ERROR_NO_DATA;
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}
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// get the length of the buffer
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else if (pbOut == NULL)
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{
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*pcbOut = 0;
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err = Base64Decode(pch, cch, NULL, pcbOut);
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}
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// otherwise fill in the buffer
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else {
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err = Base64Decode(pch, cch, pbOut, pcbOut);
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}
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if(pch != NULL)
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free(pch);
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return(err);
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}
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