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// validateunicode.cpp
//
// This file is a part of Unicode NSIS.
//
// Copyright (C) 2009-2020 Jim Park
//
// Licensed under the zlib/libpng license (the "License");
// you may not use this file except in compliance with the License.
//
// This software is provided 'as-is', without any expressed or implied
// warranty.
//
// This class can be used to check a buffer to see if it has the expected
// Unicode encoding and look for byte order marks.
#ifdef _UNICODE
#include "validateunicode.h"
#include <vector>
int CValidateUnicode::ValidateUTF8(unsigned char* buf, size_t characters)
{
bool hasNonAscii = false;
int bytesToFollow = 0;
for ( ; characters != 0 ; --characters)
{
unsigned char ch = *buf++;
if (bytesToFollow != 0) // in the middle of a multi-byte sequence?
{
if ((ch & 0xC0) != 0x80)
return 0; // we expected a continuation byte
hasNonAscii = true;
--bytesToFollow;
}
else if (ch & 0x80)
{
if ((ch & 0xC0) == 0x80)
return 0; // continuation byte outside multi-byte sequence
else if ((ch & 0xE0) == 0xC0)
bytesToFollow = 1;
else if ((ch & 0xF0) == 0xE0)
bytesToFollow = 2;
else if ((ch & 0xF8) == 0xF0)
bytesToFollow = 3;
else
return 0; // byte is invalid UTF-8 (outside RFC 3629)
}
else if (ch == 0 && characters != 1)
return 0; // NUL character in the middle of the buffer
}
if (bytesToFollow != 0)
return 0; // end of buffer in the middle of a multi-byte sequence
return hasNonAscii ? 2 : 1;
}
bool CValidateUnicode::ValidateUTF16LE(unsigned char* buf, size_t bytes)
{
// We need to make sure the endianness matches the processor.
// Intel x86 is little endian.
return ValidateUTF16((unsigned short*)(buf), bytes/2);
}
bool CValidateUnicode::ValidateUTF16BE(unsigned char* buf, size_t bytes)
{
std::vector<unsigned short> correctedBuf(bytes/2);
for (size_t i = 0; i < bytes; i += 2)
{
correctedBuf[i/2] = buf[i] << 8 | buf[i+1];
}
return ValidateUTF16(&correctedBuf[0], correctedBuf.size());
}
bool CValidateUnicode::ValidateUTF16(unsigned short* buf, size_t characters)
{
unsigned short ch;
bool valid = true;
while (valid && characters > 0)
{
// Last character may be 0.
if ((ch = *buf) == 0 && characters != 1)
{
valid = false;
}
else if (ch >= 0xd800 && ch <= 0xdbff)
{
unsigned short trailing = *(++buf);
--characters;
// Unpaired leading surrogate found?
if (trailing < 0xdc00 || trailing > 0xdfff)
{
valid = false;
}
// Invalid surrogate pairs found?
else if ((ch == 0xd83f ||
ch == 0xd87f ||
ch == 0xd8bf ||
ch == 0xd8ff ||
ch == 0xd93f ||
ch == 0xd97f ||
ch == 0xd9bf ||
ch == 0xd9ff ||
ch == 0xda3f ||
ch == 0xdA7f ||
ch == 0xdabf ||
ch == 0xdaff ||
ch == 0xdb3f ||
ch == 0xdb7f ||
ch == 0xdbbf ||
ch == 0xdbff)
&&
(trailing == 0xdffe || trailing == 0xdfff))
{
valid = false;
}
}
// Unpaired trailing surrogate!
else if (ch >= 0xdc00 && ch <= 0xdfff)
{
valid = false;
}
// Invalid values
else if (ch == 0xfffe || ch == 0xffff ||
(ch >= 0xfdd0 && ch <= 0xfdef))
{
valid = false;
}
++buf;
--characters;
}
return valid;
}
CValidateUnicode::FILE_TYPE CValidateUnicode::CheckBOM(
unsigned char* buf,
size_t bytes)
{
FILE_TYPE result = UNKNOWN;
if (bytes >= 2)
{
if (buf[0] == 0xff && buf[1] == 0xfe)
{
result = UTF_16LE;
}
else if (buf[0] == 0xfe && buf[1] == 0xff)
{
result = UTF_16BE;
}
else if (bytes >= 3 &&
buf[0] == 0xef &&
buf[1] == 0xbb &&
buf[2] == 0xbf)
{
result = UTF_8;
}
else if (bytes >= 4)
{
if (buf[0] == 0 &&
buf[1] == 0 &&
buf[2] == 0xfe &&
buf[3] == 0xff)
{
result = UTF_32BE;
}
else if (buf[0] == 0xff &&
buf[1] == 0xfe &&
buf[2] == 0 &&
buf[3] == 0)
{
result = UTF_32LE;
}
}
}
return result;
}
const TCHAR* CValidateUnicode::TypeToName(CValidateUnicode::FILE_TYPE ftype)
{
static const TCHAR* names[] =
{
_T("UTF-8"),
_T("UTF-16LE"),
_T("UTF-16BE"),
_T("UTF-32LE"),
_T("UTF-32BE"),
_T("UNKNOWN")
};
return names[ftype];
}
#endif
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