RetroZilla/intl/uconv/ucvlatin/nsUCS2BEToUnicode.cpp
2015-10-20 23:03:22 -04:00

321 lines
10 KiB
C++

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is Mozilla Communicator client code.
*
* The Initial Developer of the Original Code is
* Netscape Communications Corporation.
* Portions created by the Initial Developer are Copyright (C) 1998
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
*
* Alternatively, the contents of this file may be used under the terms of
* either of the GNU General Public License Version 2 or later (the "GPL"),
* or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
#include "nsUCConstructors.h"
#include "nsUCS2BEToUnicode.h"
#include "nsUCvLatinDll.h"
#include "nsCharTraits.h"
#include <string.h>
#include "prtypes.h"
#define STATE_NORMAL 0
#define STATE_HALF_CODE_POINT 1
#define STATE_FIRST_CALL 2
#define STATE_FOUND_BOM 3
static nsresult
UTF16ConvertToUnicode(PRUint8& aState, PRUint8& aOddByte,
PRUnichar& aOddHighSurrogate, const char * aSrc,
PRInt32 * aSrcLength, PRUnichar * aDest,
PRInt32 * aDestLength,
PRBool aSwapBytes)
{
const char* src = aSrc;
const char* srcEnd = aSrc + *aSrcLength;
PRUnichar* dest = aDest;
PRUnichar* destEnd = aDest + *aDestLength;
if(STATE_FOUND_BOM == aState) // caller found a BOM
{
if (*aSrcLength < 2)
return NS_ERROR_ILLEGAL_INPUT;
src+=2;
aState = STATE_NORMAL;
} else if(STATE_FIRST_CALL == aState) { // first time called
if (*aSrcLength < 2)
return NS_ERROR_ILLEGAL_INPUT;
// Eliminate BOM (0xFEFF). Note that different endian case is taken care of
// in |Convert| of LE and BE converters. Here, we only have to
// deal with the same endian case. That is, 0xFFFE (byte-swapped BOM) is
// illegal.
if(0xFEFF == *((PRUnichar*)src)) {
src+=2;
} else if(0xFFFE == *((PRUnichar*)src)) {
*aSrcLength=0;
*aDestLength=0;
return NS_ERROR_ILLEGAL_INPUT;
}
aState = STATE_NORMAL;
}
if (src == srcEnd) {
*aDestLength = 0;
return NS_OK;
}
PRUnichar oddHighSurrogate = aOddHighSurrogate;
const char* srcEvenEnd;
PRUnichar u;
if (aState == STATE_HALF_CODE_POINT) {
// the 1st byte of a 16-bit code unit was stored in |aOddByte| in the
// previous run while the 2nd byte has to come from |*src|.
aState = STATE_NORMAL;
#ifdef IS_BIG_ENDIAN
u = (aOddByte << 8) | *src++; // safe, we know we have at least one byte.
#else
u = (*src++ << 8) | aOddByte; // safe, we know we have at least one byte.
#endif
srcEvenEnd = src + ((srcEnd - src) & ~1); // handle even number of bytes in main loop
goto have_codepoint;
} else {
srcEvenEnd = src + ((srcEnd - src) & ~1); // handle even number of bytes in main loop
}
while (src != srcEvenEnd) {
if (dest == destEnd)
goto error;
u = *(const PRUnichar*)src;
src += 2;
have_codepoint:
if (aSwapBytes)
u = u << 8 | u >> 8;
if (!IS_SURROGATE(u)) {
if (oddHighSurrogate) {
*dest++ = UCS2_REPLACEMENT_CHAR;
if (dest == destEnd)
goto error;
oddHighSurrogate = 0;
}
*dest++ = u;
} else if (IS_HIGH_SURROGATE(u)) {
if (oddHighSurrogate) {
*dest++ = UCS2_REPLACEMENT_CHAR;
if (dest == destEnd)
goto error;
}
oddHighSurrogate = u;
}
else /* if (IS_LOW_SURROGATE(u)) */ {
if (oddHighSurrogate) {
if (dest == destEnd - 1) {
*dest++ = UCS2_REPLACEMENT_CHAR;
goto error;
}
*dest++ = oddHighSurrogate;
*dest++ = u;
oddHighSurrogate = 0;
} else {
*dest++ = UCS2_REPLACEMENT_CHAR;
}
}
}
if (src != srcEnd) {
// store the lead byte of a 16-bit unit for the next run.
aOddByte = *src++;
aState = STATE_HALF_CODE_POINT;
}
aOddHighSurrogate = oddHighSurrogate;
*aDestLength = dest - aDest;
*aSrcLength = src - aSrc;
return NS_OK;
error:
*aDestLength = dest - aDest;
*aSrcLength = src - aSrc;
return NS_OK_UDEC_MOREOUTPUT;
}
NS_IMETHODIMP
nsUTF16ToUnicodeBase::Reset()
{
mState = STATE_FIRST_CALL;
mOddByte = 0;
mOddHighSurrogate = 0;
return NS_OK;
}
NS_IMETHODIMP
nsUTF16ToUnicodeBase::GetMaxLength(const char * aSrc, PRInt32 aSrcLength,
PRInt32 * aDestLength)
{
// the left-over data of the previous run have to be taken into account.
*aDestLength = (aSrcLength +
((STATE_HALF_CODE_POINT == mState) ? 1 : 0)) / 2 +
((mOddHighSurrogate != 0) ? 1 : 0);
return NS_OK;
}
NS_IMETHODIMP
nsUTF16BEToUnicode::Convert(const char * aSrc, PRInt32 * aSrcLength,
PRUnichar * aDest, PRInt32 * aDestLength)
{
#ifdef IS_LITTLE_ENDIAN
// Remove the BOM if we're little-endian. The 'same endian' case with the
// leading BOM will be taken care of by |UTF16ConvertToUnicode|.
if(STATE_FIRST_CALL == mState) // Called for the first time.
{
mState = STATE_NORMAL;
if (*aSrcLength < 2)
return NS_ERROR_ILLEGAL_INPUT;
if(0xFFFE == *((PRUnichar*)aSrc)) {
// eliminate BOM (on LE machines, BE BOM is 0xFFFE)
mState = STATE_FOUND_BOM;
} else if(0xFEFF == *((PRUnichar*)aSrc)) {
*aSrcLength=0;
*aDestLength=0;
return NS_ERROR_ILLEGAL_INPUT;
}
}
#endif
nsresult rv = UTF16ConvertToUnicode(mState, mOddByte, mOddHighSurrogate,
aSrc, aSrcLength, aDest, aDestLength,
#ifdef IS_LITTLE_ENDIAN
PR_TRUE
#else
PR_FALSE
#endif
);
return rv;
}
NS_IMETHODIMP
nsUTF16LEToUnicode::Convert(const char * aSrc, PRInt32 * aSrcLength,
PRUnichar * aDest, PRInt32 * aDestLength)
{
#ifdef IS_BIG_ENDIAN
// Remove the BOM if we're big-endian. The 'same endian' case with the
// leading BOM will be taken care of by |UTF16ConvertToUnicode|.
if(STATE_FIRST_CALL == mState) // first time called
{
mState = STATE_NORMAL;
if (*aSrcLength < 2)
return NS_ERROR_ILLEGAL_INPUT;
if(0xFFFE == *((PRUnichar*)aSrc)) {
// eliminate BOM (on BE machines, LE BOM is 0xFFFE)
mState = STATE_FOUND_BOM;
} else if(0xFEFF == *((PRUnichar*)aSrc)) {
*aSrcLength=0;
*aDestLength=0;
return NS_ERROR_ILLEGAL_INPUT;
}
}
#endif
nsresult rv = UTF16ConvertToUnicode(mState, mOddByte, mOddHighSurrogate,
aSrc, aSrcLength, aDest, aDestLength,
#ifdef IS_BIG_ENDIAN
PR_TRUE
#else
PR_FALSE
#endif
);
return rv;
}
NS_IMETHODIMP
nsUTF16ToUnicode::Reset()
{
mEndian = kUnknown;
mFoundBOM = PR_FALSE;
return nsUTF16ToUnicodeBase::Reset();
}
NS_IMETHODIMP
nsUTF16ToUnicode::Convert(const char * aSrc, PRInt32 * aSrcLength,
PRUnichar * aDest, PRInt32 * aDestLength)
{
if(STATE_FIRST_CALL == mState) // first time called
{
mState = STATE_NORMAL;
if (*aSrcLength < 2)
return NS_ERROR_ILLEGAL_INPUT;
// check if BOM (0xFEFF) is at the beginning, remove it if found, and
// set mEndian accordingly.
if(0xFF == PRUint8(aSrc[0]) && 0xFE == PRUint8(aSrc[1])) {
mState = STATE_FOUND_BOM;
mEndian = kLittleEndian;
mFoundBOM = PR_TRUE;
}
else if(0xFE == PRUint8(aSrc[0]) && 0xFF == PRUint8(aSrc[1])) {
mState = STATE_FOUND_BOM;
mEndian = kBigEndian;
mFoundBOM = PR_TRUE;
}
// BOM is not found, but we can use a simple heuristic to determine
// the endianness. Assume the first character is [U+0001, U+00FF].
// Not always valid, but it's very likely to hold for html/xml/css.
else if(!aSrc[0] && aSrc[1]) { // 0x00 0xhh (hh != 00)
mEndian = kBigEndian;
}
else if(aSrc[0] && !aSrc[1]) { // 0xhh 0x00 (hh != 00)
mEndian = kLittleEndian;
}
else { // Neither BOM nor 'plausible' byte patterns at the beginning.
// Just assume it's BE (following Unicode standard)
// and let the garbage show up in the browser. (security concern?)
// (bug 246194)
mEndian = kBigEndian;
}
}
nsresult rv = UTF16ConvertToUnicode(mState, mOddByte, mOddHighSurrogate,
aSrc, aSrcLength, aDest, aDestLength,
#ifdef IS_BIG_ENDIAN
(mEndian == kLittleEndian)
#elif defined(IS_LITTLE_ENDIAN)
(mEndian == kBigEndian)
#else
#error "Unknown endianness"
#endif
);
// If BOM is not found and we're to return NS_OK, signal that BOM
// is not found. Otherwise, return |rv| from |UTF16ConvertToUnicode|
return (rv == NS_OK && !mFoundBOM) ? NS_OK_UDEC_NOBOMFOUND : rv;
}