Files
OpenSceneGraph/src/osgText/String.cpp

324 lines
9.2 KiB
C++

#include <osgText/String>
#include <osg/Notify>
#include <osg/Math>
#include <iterator>
using namespace osgText;
////////////////////////////////////////////////////////////////////////
//
// helper class to make it safer to query std::string's for encoding.
//
struct look_ahead_iterator
{
look_ahead_iterator(const std::string& string):
_string(string),
_index(0),
_nullCharacter(0) {}
bool valid() const { return _index<_string.length(); }
look_ahead_iterator& operator ++ ()
{
if (_index<_string.length()) ++_index;
return *this;
}
look_ahead_iterator operator ++ (int)
{
look_ahead_iterator tmp(*this);
if (_index<_string.length()) ++_index;
return tmp;
}
look_ahead_iterator& operator += (int offset)
{
if (_index<_string.length()) _index = osg::minimum((unsigned int)(_index+offset),(unsigned int)_string.length());
return *this;
}
unsigned char operator * () const
{
if (_index<_string.length()) return _string[_index];
else return _nullCharacter;
}
unsigned char operator [] (unsigned int offset) const
{
if (_index+offset<_string.length()) return _string[_index+offset];
else return _nullCharacter;
}
const std::string& _string;
unsigned int _index;
unsigned char _nullCharacter;
protected:
look_ahead_iterator& operator = (const look_ahead_iterator&) { return *this; }
};
String::Encoding findEncoding(look_ahead_iterator& charString,String::Encoding overrideEncoding)
{
switch (charString[0])
{
case 0xEF: // 8-bit encoding
{
// 8-bit signature = EF BB BF
if ((charString[1]==0xBB) && (charString[2]==0xBF))
{
charString+=3;
return String::ENCODING_UTF8;
}
break;
}
case 0xFE: // big-endian 16-bit
{
// 16-bit signature = FE FF
if (charString[1]==0xFF)
{
charString+=2;
return String::ENCODING_UTF16_BE;
}
break;
}
case 0xFF: // little-endian
{
// 16-bit signature = FF FE
// 32-bit signature = FF FE 00 00
if (charString[1]==0xFE)
{
// NOTE: There is an a potential problem as a 16-bit empty string
// is identical to a 32-bit start signature
if ((charString[2]==0) && (charString[3]==0) && (overrideEncoding != String::ENCODING_UTF16)) //32-bit
{
charString+=4;
return String::ENCODING_UTF32_LE;
}
else //16-bit
{
charString+=2;
return String::ENCODING_UTF16_LE;
}
}
break;
}
case 0x00: // 32-bit big-endian
{
// 32-bit signature = 00 00 FE FF
if ((charString[1]==0x00) && (charString[2]==0xFE) && (charString[3]==0xFF))
{
charString+=4;
return String::ENCODING_UTF32_BE;
}
break;
}
}
return String::ENCODING_ASCII;
}
unsigned int getNextCharacter(look_ahead_iterator& charString,String::Encoding encoding)
{
// For more info on unicode encodings see:
// http://www-106.ibm.com/developerworks/unicode/library/u-encode.html
switch(encoding)
{
case String::ENCODING_ASCII:
{
return *charString++;
}
case String::ENCODING_UTF8:
{
int char0 = *charString++;
if (char0 < 0x80) // 1-byte character
{
return char0;
}
int char1 = *charString++;
if (char0<0xe0) // 2-byte character
{
return ((char0&0x1f)<<6) | (char1&0x3f);
}
int char2 = *charString++;
if (char0<0xf0) // 3-byte character
{
return ((char0&0xf)<<12) | ((char1&0x3f)<<6) | (char2&0x3f);
}
int char3 = *charString++;
if (char0<0xf8) // 4-byte character
{
return ((char0&0x7)<<18) | ((char1&0x3f)<<12) | ((char2&0x3f)<<6) | (char3&0x3f);
}
break;
}
case String::ENCODING_UTF16_BE:
{
int char0 = *charString++;
int char1 = *charString++;
if ((char0<=0xD7) || (char0>=0xE0)) // simple character
{
return (char0<<8) | char1;
}
else if ((char0>=0xD8)&&(char0<=0xDB)) //using planes (this should get called very rarely)
{
int char2 = *charString++;
int char3 = *charString++;
int highSurrogate = (char0<<8) | char1;
int lowSurrogate = (char2<<8) | char3;
if ((char2>=0xDC)&&(char2<=0xDF)) //only for the valid range of low surrogate
{
// This covers the range of all 17 unicode planes
return ((highSurrogate-0xD800)*0x400) + (lowSurrogate-0xD800) + 0x10000;
}
}
break;
}
case String::ENCODING_UTF16_LE:
{
int char1 = *charString++;
int char0 = *charString++;
if ((char0<=0xD7) || (char0>=0xE0)) // simple character
{
return (char0<<8) | char1;
}
else if ((char0>=0xD8)&&(char0<=0xDB)) //using planes (this should get called very rarely)
{
int char3 = *charString++;
int char2 = *charString++;
int highSurrogate = (char0<<8) | char1;
int lowSurrogate = (char2<<8) | char3;
if ((char2>=0xDC)&&(char2<=0xDF)) //only for the valid range of low surrogate
{
// This covers the range of all 17 unicode planes
return ((highSurrogate-0xD800)*0x400) + (lowSurrogate-0xD800) + 0x10000;
}
}
break;
}
case String::ENCODING_UTF32_BE:
{
int character = ((((int)charString[0])<<24) | (((int)charString[1])<<16) |
(((int)charString[2])<<8) | charString[3]);
charString+=4;
if (character<0x110000)
{
// Character is constrained to the range set by the unicode standard
return character;
}
break;
}
case String::ENCODING_UTF32_LE:
{
int character = ((((int)charString[3])<<24) | (((int)charString[2])<<16) |
(((int)charString[1])<<8) | charString[0]);
charString+=4;
if (character<0x110000)
{
// Character is constrained to the range set by the unicode standard
return character;
}
break;
}
default:
{
// Should not reach this point unless the encoding is unhandled
// ENCODING_UTF16, ENCODING_UTF32 and ENCODING_SIGNATURE should never enter this method
osg::notify(osg::FATAL)<<"Error: Invalid string encoding"<<std::endl;
break;
}
}
return 0;
}
////////////////////////////////////////////////////////////////////////////
//
// String implemention.
//
String::String(const String& str):
vector_type(str)
{
}
String& String::operator = (const String& str)
{
if (&str==this) return *this;
clear();
std::copy(str.begin(),str.end(),std::back_inserter(*this));
return *this;
}
void String::set(const std::string& text)
{
clear();
for ( std::string::const_iterator it = text.begin(); it != text.end(); ++it )
{
unsigned int charcode = (unsigned char )*it;
push_back( charcode );
}
}
void String::set(const wchar_t* text)
{
clear();
while(*text)
{
push_back(*text++);
}
}
void String::set(const std::string& text,Encoding encoding)
{
clear();
look_ahead_iterator itr(text);
if ((encoding == ENCODING_SIGNATURE) ||
(encoding == ENCODING_UTF16) ||
(encoding == ENCODING_UTF32))
{
encoding = findEncoding(itr,encoding);
}
while(itr.valid())
{
unsigned int c = getNextCharacter(itr,encoding);
if (c) push_back(c);
}
}
std::string String::createUTF8EncodedString() const
{
std::string utf8string;
for(const_iterator itr=begin();
itr!=end();
++itr)
{
unsigned int currentChar = *itr;
if (currentChar < 0x80)
{
utf8string+=(char)currentChar;
}
else if (currentChar < 0x800)
{
utf8string+=(char)(0xc0 | (currentChar>>6));
utf8string+=(char)(0x80 | (currentChar & 0x3f));
}
else
{
utf8string+=(char)(0xe0 | (currentChar>>12));
utf8string+=(char)(0x80 | ((currentChar>>6) & 0x3f));
utf8string+=(char)(0x80 | (currentChar & 0x3f));
}
}
return utf8string;
}