93 lines
2.5 KiB
C++
93 lines
2.5 KiB
C++
//========= Copyright c 1996-2014, Valve Corporation, All rights reserved. ============//
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//
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// Purpose:
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//
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//=============================================================================//
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static inline void CopyStringTruncatingMalformedUTF8Tail( char *pchBuffer, char const *szSrc, int numBufferBytes )
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{
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//
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// There's a bug in Steam client where the clan tag may be truncated
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// in the middle of UTF-8 sequence. Also we have a more restrictive
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// clan tags length in the game to not bloat the name string.
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//
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if ( numBufferBytes <= 0 )
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{
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Assert( numBufferBytes > 0 );
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return;
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}
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if ( numBufferBytes == 1 )
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{
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pchBuffer[0] = 0;
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return;
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}
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int nStrLen = V_strlen( szSrc );
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if ( nStrLen <= 0 )
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{
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pchBuffer[ 0 ] = 0;
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return;
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}
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// Now we know that input is non-empty string, and buffer can hold at least one character
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// let's figure out how many characters can fit?
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if ( nStrLen > numBufferBytes - 1 )
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nStrLen = numBufferBytes - 1;
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//
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// Check what the last character in the source string is?
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//
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// The last character is a UTF-8 sequence begin character or sequence continuation character
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// See how many characters must have been in the end of the string?
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for ( int numCheck = 0; numCheck < nStrLen; ++ numCheck )
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{
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int idxCheck = nStrLen - 1 - numCheck;
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if ( ( szSrc[ idxCheck ] & ( 0x80 | 0x40 ) ) == ( 0x80 | 0x40 ) )
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{
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// This is the start of UTF8 sequence
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int numCharactersSequenceLengthSeen = numCheck + 1;
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int numCharactersSequenceMarker = 2; // at least two bytes
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for ( uint8 uiMarker = uint8( uint8( szSrc[ idxCheck ] ) << 2 );
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( ( uiMarker & 0x80 ) != 0 );
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uiMarker <<= 1 )
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++ numCharactersSequenceMarker;
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// If the marker shows more characters than seen, discard the tail
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if ( numCharactersSequenceMarker != numCharactersSequenceLengthSeen )
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nStrLen -= numCharactersSequenceLengthSeen;
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break;
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}
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else if ( ( szSrc[ idxCheck ] & ( 0x80 | 0x40 ) ) == ( 0x80 ) )
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{
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// This is a continuation of UTF8 sequence
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if ( idxCheck )
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continue; // Keep looking backwards
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else
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{ // Scanned all the way back to start of string and found no UTF8 sequence start character
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nStrLen = 0;
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break;
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}
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}
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else
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{
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// Looking at regular lower ASCII 0x00-0x7F character, valid for string termination
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nStrLen -= numCheck;
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break;
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}
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}
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if ( !nStrLen )
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{
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// This was an entirely invalid string, copy a questionmark
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pchBuffer[0] = '?';
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pchBuffer[1] = 0;
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return;
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}
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// Copy whatever we determined
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V_strncpy( pchBuffer, szSrc, nStrLen + 1 );
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}
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