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