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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "nsUTF7ToUnicode.h"
#define ENC_DIRECT 0
#define ENC_BASE64 1
//----------------------------------------------------------------------
// Class nsBasicUTF7Decoder [implementation]
nsBasicUTF7Decoder::nsBasicUTF7Decoder(char aLastChar, char aEscChar)
: nsBufferDecoderSupport(1)
{
mLastChar = aLastChar;
mEscChar = aEscChar;
Reset();
}
nsresult nsBasicUTF7Decoder::DecodeDirect(
const char * aSrc,
int32_t * aSrcLength,
char16_t * aDest,
int32_t * aDestLength)
{
const char * srcEnd = aSrc + *aSrcLength;
const char * src = aSrc;
char16_t * destEnd = aDest + *aDestLength;
char16_t * dest = aDest;
nsresult res = NS_OK;
char ch;
while (src < srcEnd) {
ch = *src;
// stop when we meet other chars or end of direct encoded seq.
// if (!(DirectEncodable(ch)) || (ch == mEscChar)) {
// but we are decoding; so we should be lax; pass everything until escchar
if (ch == mEscChar) {
res = NS_ERROR_UDEC_ILLEGALINPUT;
break;
}
if (dest >= destEnd) {
res = NS_OK_UDEC_MOREOUTPUT;
break;
} else {
*dest++ = ch;
src++;
}
}
*aSrcLength = src - aSrc;
*aDestLength = dest - aDest;
return res;
}
nsresult nsBasicUTF7Decoder::DecodeBase64(
const char * aSrc,
int32_t * aSrcLength,
char16_t * aDest,
int32_t * aDestLength)
{
const char * srcEnd = aSrc + *aSrcLength;
const char * src = aSrc;
char16_t * destEnd = aDest + *aDestLength;
char16_t * dest = aDest;
nsresult res = NS_OK;
char ch;
uint32_t value;
while (src < srcEnd) {
ch = *src;
// stop when we meet other chars or end of direct encoded seq.
value = CharToValue(ch);
if (value > 0xff) {
res = NS_ERROR_UDEC_ILLEGALINPUT;
break;
}
switch (mEncStep) {
case 0:
mEncBits = value << 10;
break;
case 1:
mEncBits += value << 4;
break;
case 2:
if (dest >= destEnd) {
res = NS_OK_UDEC_MOREOUTPUT;
break;
}
mEncBits += value >> 2;
*(dest++) = (char16_t) mEncBits;
mEncBits = (value & 0x03) << 14;
break;
case 3:
mEncBits += value << 8;
break;
case 4:
mEncBits += value << 2;
break;
case 5:
if (dest >= destEnd) {
res = NS_OK_UDEC_MOREOUTPUT;
break;
}
mEncBits += value >> 4;
*(dest++) = (char16_t) mEncBits;
mEncBits = (value & 0x0f) << 12;
break;
case 6:
mEncBits += value << 6;
break;
case 7:
if (dest >= destEnd) {
res = NS_OK_UDEC_MOREOUTPUT;
break;
}
mEncBits += value;
*(dest++) = (char16_t) mEncBits;
mEncBits = 0;
break;
}
if (res != NS_OK) break;
src++;
(++mEncStep)%=8;
}
*aSrcLength = src - aSrc;
*aDestLength = dest - aDest;
return res;
}
uint32_t nsBasicUTF7Decoder::CharToValue(char aChar) {
if ((aChar>='A')&&(aChar<='Z'))
return (uint8_t)(aChar-'A');
else if ((aChar>='a')&&(aChar<='z'))
return (uint8_t)(26+aChar-'a');
else if ((aChar>='0')&&(aChar<='9'))
return (uint8_t)(26+26+aChar-'0');
else if (aChar=='+')
return (uint8_t)(26+26+10);
else if (aChar==mLastChar)
return (uint8_t)(26+26+10+1);
else
return 0xffff;
}
//----------------------------------------------------------------------
// Subclassing of nsBufferDecoderSupport class [implementation]
NS_IMETHODIMP nsBasicUTF7Decoder::ConvertNoBuff(const char * aSrc,
int32_t * aSrcLength,
char16_t * aDest,
int32_t * aDestLength)
{
const char * srcEnd = aSrc + *aSrcLength;
const char * src = aSrc;
char16_t * destEnd = aDest + *aDestLength;
char16_t * dest = aDest;
int32_t bcr,bcw;
nsresult res = NS_OK;
while (src < srcEnd) {
// fist, attept to decode in the current mode
bcr = srcEnd - src;
bcw = destEnd - dest;
if (mEncoding == ENC_DIRECT)
res = DecodeDirect(src, &bcr, dest, &bcw);
else if ((mFreshBase64) && (*src == '-')) {
*dest = mEscChar;
bcr = 0;
bcw = 1;
res = NS_ERROR_UDEC_ILLEGALINPUT;
} else {
mFreshBase64 = false;
res = DecodeBase64(src, &bcr, dest, &bcw);
}
src += bcr;
dest += bcw;
// if an illegal char was encountered, test if it is an escape seq.
if (res == NS_ERROR_UDEC_ILLEGALINPUT) {
if (mEncoding == ENC_DIRECT) {
if (*src == mEscChar) {
mEncoding = ENC_BASE64;
mFreshBase64 = true;
mEncBits = 0;
mEncStep = 0;
src++;
res = NS_OK;
} else break;
} else {
mEncoding = ENC_DIRECT;
res = NS_OK;
// absorbe end of escape sequence
if (*src == '-') src++;
}
} else if (res != NS_OK) break;
}
*aSrcLength = src - aSrc;
*aDestLength = dest - aDest;
return res;
}
NS_IMETHODIMP nsBasicUTF7Decoder::Reset()
{
mEncoding = ENC_DIRECT;
mEncBits = 0;
mEncStep = 0;
return nsBufferDecoderSupport::Reset();
}
//----------------------------------------------------------------------
// Class nsUTF7ToUnicode [implementation]
nsUTF7ToUnicode::nsUTF7ToUnicode()
: nsBasicUTF7Decoder('/', '+')
{
}
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