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CMake/Source/cmGeneratorExpressionLexer.cxx

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cmGeneratorExpression: Re-write for multi-stage evaluation The expressions may be parsed and then cached and evaluated multiple times. They are evaluated lazily so that literals such as ',' can be treated as universal parameter separators, and can be processed from results without appearing literally, and without interfering with the parsing/evaluation of the entire expression.
2012-09-11 21:53:38 +04:00
/*============================================================================
CMake - Cross Platform Makefile Generator
Copyright 2012 Stephen Kelly <steveire@gmail.com>
Distributed under the OSI-approved BSD License (the "License");
see accompanying file Copyright.txt for details.
This software is distributed WITHOUT ANY WARRANTY; without even the
implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
See the License for more information.
============================================================================*/
#include "cmGeneratorExpressionLexer.h"
//----------------------------------------------------------------------------
cmGeneratorExpressionLexer::cmGeneratorExpressionLexer()
: SawBeginExpression(false), SawGeneratorExpression(false)
{
}
//----------------------------------------------------------------------------
static void InsertText(const char *upto, const char *c,
std::vector<cmGeneratorExpressionToken> &result)
{
if (upto != c)
{
result.push_back(cmGeneratorExpressionToken(
cmGeneratorExpressionToken::Text, upto, c - upto));
}
}
//----------------------------------------------------------------------------
std::vector<cmGeneratorExpressionToken>
cmGeneratorExpressionLexer::Tokenize(const char *input)
{
std::vector<cmGeneratorExpressionToken> result;
if (!input)
return result;
const char *c = input;
const char *upto = c;
for ( ; *c; ++c)
{
cmGeneratorExpressionLexer: Use a switch statement to parse Optimize cmGeneratorExpressionLexer::Tokenize to use a switch statement. The many dereferences of the input pointer were expensive. Also remove excess pointer arithmetic.
2014-02-08 21:01:30 +04:00
switch(*c)
{
case '$':
if(c[1] == '<')
{
InsertText(upto, c, result);
result.push_back(cmGeneratorExpressionToken(
cmGeneratorExpressionToken::BeginExpression, c, 2));
upto = c + 2;
++c;
SawBeginExpression = true;
}
break;
case '>':
InsertText(upto, c, result);
result.push_back(cmGeneratorExpressionToken(
cmGeneratorExpressionToken::EndExpression, c, 1));
upto = c + 1;
SawGeneratorExpression = SawBeginExpression;
break;
case ':':
InsertText(upto, c, result);
result.push_back(cmGeneratorExpressionToken(
cmGeneratorExpressionToken::ColonSeparator, c, 1));
upto = c + 1;
break;
case ',':
InsertText(upto, c, result);
result.push_back(cmGeneratorExpressionToken(
cmGeneratorExpressionToken::CommaSeparator, c, 1));
upto = c + 1;
break;
default:
break;
}
cmGeneratorExpression: Re-write for multi-stage evaluation The expressions may be parsed and then cached and evaluated multiple times. They are evaluated lazily so that literals such as ',' can be treated as universal parameter separators, and can be processed from results without appearing literally, and without interfering with the parsing/evaluation of the entire expression.
2012-09-11 21:53:38 +04:00
}
InsertText(upto, c, result);
return result;
}