Source code of Windows XP (NT5)
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//+--------------------------------------------------------------------------
//
// Microsoft Windows
// Copyright (C) Microsoft Corporation, 1996-1996
//
// File: base64.cpp
//
// Contents: base64 encode/decode implementation
//
// History: 25-Jul-96 vich created
//
//---------------------------------------------------------------------------
// 3-Mar-98 tompop took and modified it. Building
// both Ansi and Wchar versions of Encode/Decode
// base 64 for CertWizard, that is in IIS5's UI.
// We merged the examples from NT5's base64.cpp
// and ubase64.cpp files into this single file.
// 5-Aug-98 Sergei Antonov removed above mentioned stuff after tompop
//---------------------------------------------------------------------------
#include "stdafx.h"
#include <malloc.h>
#include <windows.h>
#include "base64.h"
// The following table translates an ascii subset to 6 bit values as follows
// (see rfc 1521):
//
// input hex (decimal)
// 'A' --> 0x00 (0)
// 'B' --> 0x01 (1)
// ...
// 'Z' --> 0x19 (25)
// 'a' --> 0x1a (26)
// 'b' --> 0x1b (27)
// ...
// 'z' --> 0x33 (51)
// '0' --> 0x34 (52)
// ...
// '9' --> 0x3d (61)
// '+' --> 0x3e (62)
// '/' --> 0x3f (63)
//
// Encoded lines must be no longer than 76 characters.
// The final "quantum" is handled as follows: The translation output shall
// always consist of 4 characters. 'x', below, means a translated character,
// and '=' means an equal sign. 0, 1 or 2 equal signs padding out a four byte
// translation quantum means decoding the four bytes would result in 3, 2 or 1
// unencoded bytes, respectively.
//
// unencoded size encoded data
// -------------- ------------
// 1 byte "xx=="
// 2 bytes "xxx="
// 3 bytes "xxxx"
#define CB_BASE64LINEMAX 64 // others use 64 -- could be up to 76
// Any other (invalid) input character value translates to 0x40 (64)
const BYTE abDecode[256] =
{
/* 00: */ 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
/* 10: */ 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
/* 20: */ 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 62, 64, 64, 64, 63,
/* 30: */ 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 64, 64, 64, 64, 64, 64,
/* 40: */ 64, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
/* 50: */ 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 64, 64, 64, 64, 64,
/* 60: */ 64, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
/* 70: */ 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 64, 64, 64, 64, 64,
/* 80: */ 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
/* 90: */ 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
/* a0: */ 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
/* b0: */ 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
/* c0: */ 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
/* d0: */ 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
/* e0: */ 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
/* f0: */ 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
};
const UCHAR abEncode[] =
/* 0 thru 25: */ "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
/* 26 thru 51: */ "abcdefghijklmnopqrstuvwxyz"
/* 52 thru 61: */ "0123456789"
/* 62 and 63: */ "+/";
DWORD
Base64DecodeA(const char * pchIn, DWORD cchIn, BYTE * pbOut, DWORD * pcbOut)
{
DWORD err = ERROR_SUCCESS;
DWORD cchInDecode, cbOutDecode;
CHAR const *pchInEnd;
CHAR const *pchInT;
BYTE *pbOutT;
// Count the translatable characters, skipping whitespace & CR-LF chars.
cchInDecode = 0;
pchInEnd = &pchIn[cchIn];
for (pchInT = pchIn; pchInT < pchInEnd; pchInT++)
{
if (sizeof(abDecode) < (unsigned) *pchInT || abDecode[*pchInT] > 63)
{
// skip all whitespace
if ( *pchInT == ' '
|| *pchInT == '\t'
|| *pchInT == '\r'
|| *pchInT == '\n'
)
{
continue;
}
if (0 != cchInDecode)
{
if ((cchInDecode % 4) == 0)
{
break; // ends on quantum boundary
}
// The length calculation may stop in the middle of the last
// translation quantum, because the equal sign padding
// characters are treated as invalid input. If the last
// translation quantum is not 4 bytes long, it must be 2 or 3
// bytes long.
if (*pchInT == '=' && (cchInDecode % 4) != 1)
{
break; // normal termination
}
}
err = ERROR_INVALID_DATA;
goto error;
}
cchInDecode++;
}
ASSERT(pchInT <= pchInEnd);
pchInEnd = pchInT; // don't process any trailing stuff again
// We know how many translatable characters are in the input buffer, so now
// set the output buffer size to three bytes for every four (or fraction of
// four) input bytes.
cbOutDecode = ((cchInDecode + 3) / 4) * 3;
pbOutT = pbOut;
if (NULL == pbOut)
{
pbOutT += cbOutDecode;
}
else
{
// Decode one quantum at a time: 4 bytes ==> 3 bytes
ASSERT(cbOutDecode <= *pcbOut);
pchInT = pchIn;
while (cchInDecode > 0)
{
DWORD i;
BYTE ab4[4];
memset(ab4, 0, sizeof(ab4));
for (i = 0; i < min(sizeof(ab4)/sizeof(ab4[0]), cchInDecode); i++)
{
while (
sizeof(abDecode) > (unsigned) *pchInT &&
63 < abDecode[*pchInT])
{
pchInT++;
}
ASSERT(pchInT < pchInEnd);
ab4[i] = (BYTE) *pchInT++;
}
// Translate 4 input characters into 6 bits each, and deposit the
// resulting 24 bits into 3 output bytes by shifting as appropriate.
// out[0] = in[0]:in[1] 6:2
// out[1] = in[1]:in[2] 4:4
// out[2] = in[2]:in[3] 2:6
*pbOutT++ =
(BYTE) ((abDecode[ab4[0]] << 2) | (abDecode[ab4[1]] >> 4));
if (i > 2)
{
*pbOutT++ =
(BYTE) ((abDecode[ab4[1]] << 4) | (abDecode[ab4[2]] >> 2));
}
if (i > 3)
{
*pbOutT++ = (BYTE) ((abDecode[ab4[2]] << 6) | abDecode[ab4[3]]);
}
cchInDecode -= i;
}
ASSERT((DWORD) (pbOutT - pbOut) <= cbOutDecode);
}
*pcbOut = (DWORD)(pbOutT - pbOut);
error:
return(err);
}
// Base64EncodeA
//
// RETURNS 0 (i.e. ERROR_SUCCESS) on success
//
DWORD
Base64EncodeA(
IN BYTE const *pbIn,
IN DWORD cbIn,
OUT CHAR *pchOut,
OUT DWORD *pcchOut)
{
CHAR *pchOutT;
DWORD cchOutEncode;
// Allocate enough memory for full final translation quantum.
cchOutEncode = ((cbIn + 2) / 3) * 4;
// and enough for CR-LF pairs for every CB_BASE64LINEMAX character line.
cchOutEncode +=
2 * ((cchOutEncode + CB_BASE64LINEMAX - 1) / CB_BASE64LINEMAX);
pchOutT = pchOut;
if (NULL == pchOut)
{
pchOutT += cchOutEncode;
}
else
{
DWORD cCol;
ASSERT(cchOutEncode <= *pcchOut);
cCol = 0;
while ((long) cbIn > 0) // signed comparison -- cbIn can wrap
{
BYTE ab3[3];
if (cCol == CB_BASE64LINEMAX/4)
{
cCol = 0;
*pchOutT++ = '\r';
*pchOutT++ = '\n';
}
cCol++;
memset(ab3, 0, sizeof(ab3));
ab3[0] = *pbIn++;
if (cbIn > 1)
{
ab3[1] = *pbIn++;
if (cbIn > 2)
{
ab3[2] = *pbIn++;
}
}
*pchOutT++ = abEncode[ab3[0] >> 2];
*pchOutT++ = abEncode[((ab3[0] << 4) | (ab3[1] >> 4)) & 0x3f];
*pchOutT++ = (cbIn > 1)?
abEncode[((ab3[1] << 2) | (ab3[2] >> 6)) & 0x3f] : '=';
*pchOutT++ = (cbIn > 2)? abEncode[ab3[2] & 0x3f] : '=';
cbIn -= 3;
}
*pchOutT++ = '\r';
*pchOutT++ = '\n';
ASSERT((DWORD) (pchOutT - pchOut) <= cchOutEncode);
}
*pcchOut = (DWORD)(pchOutT - pchOut);
return(ERROR_SUCCESS);
}
// Base64EncodeW
//
// RETURNS 0 (i.e. ERROR_SUCCESS) on success
//
DWORD Base64EncodeW(
BYTE const *pbIn,
DWORD cbIn,
WCHAR *wszOut,
DWORD *pcchOut)
{
DWORD cchOut;
char *pch = NULL;
DWORD cch;
DWORD err;
ASSERT(pcchOut != NULL);
// only want to know how much to allocate
// we know all base64 char map 1-1 with unicode
if( wszOut == NULL ) {
// get the number of characters
*pcchOut = 0;
err = Base64EncodeA(
pbIn,
cbIn,
NULL,
pcchOut);
}
// otherwise we have an output buffer
else {
// char count is the same be it ascii or unicode,
cchOut = *pcchOut;
cch = 0;
err = ERROR_OUTOFMEMORY;
if( (pch = (char *) malloc(cchOut)) != NULL &&
(err = Base64EncodeA(
pbIn,
cbIn,
pch,
&cchOut)) == ERROR_SUCCESS ) {
// should not fail!
cch = MultiByteToWideChar(0,
0,
pch,
cchOut,
wszOut,
*pcchOut);
// check to make sure we did not fail
ASSERT(*pcchOut == 0 || cch != 0);
}
}
if(pch != NULL)
free(pch);
return(err);
}
// Base64DecodeW
//
// RETURNS 0 (i.e. ERROR_SUCCESS) on success
//
DWORD Base64DecodeW(
const WCHAR * wszIn,
DWORD cch,
BYTE *pbOut,
DWORD *pcbOut)
{
char *pch;
DWORD err = ERROR_SUCCESS;
if( (pch = (char *) malloc(cch)) == NULL )
{
err = ERROR_OUTOFMEMORY;
}
else if( WideCharToMultiByte(0, 0, wszIn, cch, pch, cch,
NULL, NULL) == 0 )
{
err = ERROR_NO_DATA;
}
else if( pbOut == NULL )
{
*pcbOut = 0;
err = Base64DecodeA(pch, cch, NULL, pcbOut);
}
else
{
err = Base64DecodeA(pch, cch, pbOut, pcbOut);
}
if(pch != NULL)
free(pch);
return(err);
}
#if 0
// sanity tests... Lets make sure that the encode and decode
// works...
BOOL test_Base64EncodeW()
{
BYTE pbIn[120]; // for the test we just use the random stack data
DWORD cbIn = sizeof( pbIn );
WCHAR *wszB64Out;
DWORD pcchB64Out;
DWORD err;
// BASE64 encode pkcs 10
if( (err = Base64EncodeW(
pbIn,
cbIn,
NULL,
&pcchB64Out)) != ERROR_SUCCESS ||
(wszB64Out = (WCHAR *) _alloca(pcchB64Out * sizeof(WCHAR))) == NULL ||
(err = Base64EncodeW(
pbIn,
cbIn,
wszB64Out,
&pcchB64Out)) != ERROR_SUCCESS )
{
SetLastError(err);
return FALSE; //goto ErrorBase64Encode;
}
// well the encode worked lets test the decode
//
// pcchB64Out holds the B64 data length
// wszB64Out holds the actual data
DWORD blob_cbData; // we store in these variables what
BYTE* blob_pbData; // we read in..
// They should match the stuff stored in:
// BYTE pbIn[120];
// DWORD cbIn = sizeof( pbIn );
// This we be tested after the decode.
// base64 decode
if( (err = Base64DecodeW(
wszB64Out,
pcchB64Out,
NULL,
&blob_cbData)) != ERROR_SUCCESS ||
(blob_pbData = (BYTE *) _alloca(blob_cbData)) == NULL ||
(err = Base64DecodeW(
wszB64Out,
pcchB64Out,
blob_pbData,
&blob_cbData)) != ERROR_SUCCESS )
{
SetLastError(err);
return(FALSE); //goto ErrorBase64Decode;
}
//do compare
return( (blob_cbData==cbIn)
&& (memcmp(blob_pbData, pbIn,cbIn)==0) );
}
#endif