qt-creator/src/libs/glsl/glslparser.cpp

/**************************************************************************
**
** This file is part of Qt Creator
**
** Copyright (c) 2010 Nokia Corporation and/or its subsidiary(-ies).
**
** Contact: Nokia Corporation (qt-info@nokia.com)
**
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**
** Licensees holding valid Qt Commercial licenses may use this file in
** accordance with the Qt Commercial License Agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Nokia.
**
** GNU Lesser General Public License Usage
**
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** If you are unsure which license is appropriate for your use, please
** contact the sales department at http://qt.nokia.com/contact.
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**************************************************************************/

#include "glslparser.h"
#include <iostream>

using namespace GLSL;

namespace GLSL {
void dumpAST(AST *);
void deleteAST(AST *ast);
}

Parser::Parser(const char *source, unsigned size, int variant)
    : _tos(-1), _index(0)
{
    _tokens.reserve(1024);

    _stateStack.resize(128);
    _locationStack.resize(128);
    _astStack.resize(128);

    _tokens.push_back(Token()); // invalid token

    std::stack<int> parenStack;
    std::stack<int> bracketStack;
    std::stack<int> braceStack;

    Lexer lexer(source, size);
    lexer.setVariant(variant);
    Token tk;
    do {
        lexer.yylex(&tk);

        switch (tk.kind) {
        case T_LEFT_PAREN:
            parenStack.push(_tokens.size());
            break;
        case T_LEFT_BRACKET:
            bracketStack.push(_tokens.size());
            break;
        case T_LEFT_BRACE:
            braceStack.push(_tokens.size());
            break;

        case T_RIGHT_PAREN:
            if (! parenStack.empty()) {
                _tokens[parenStack.top()].matchingBrace = _tokens.size();
                parenStack.pop();
            }
            break;
        case T_RIGHT_BRACKET:
            if (! bracketStack.empty()) {
                _tokens[bracketStack.top()].matchingBrace = _tokens.size();
                bracketStack.pop();
            }
            break;
        case T_RIGHT_BRACE:
            if (! braceStack.empty()) {
                _tokens[braceStack.top()].matchingBrace = _tokens.size();
                braceStack.pop();
            }
            break;
        default:
            break;
        }

        _tokens.push_back(tk);
    } while (tk.isNot(EOF_SYMBOL));

    _index = 1;
}

Parser::~Parser()
{
}

void Parser::dump(AST *ast)
{
    dumpAST(ast);
}

bool Parser::parse()
{
    int action = 0;
    int yytoken = -1;
    int yyloc = -1;
    Operand *opd = 0;

    _tos = -1;

    do {
        if (yytoken == -1 && -TERMINAL_COUNT != action_index[action]) {
            yyloc = consumeToken();
            yytoken = tokenKind(yyloc);
            if (yytoken == T_IDENTIFIER && t_action(action, T_TYPE_NAME) != 0) {
                const Token &la = tokenAt(_index);

                if (la.is(T_IDENTIFIER)) {
                    yytoken = T_TYPE_NAME;
                } else if (la.is(T_LEFT_BRACKET) && la.matchingBrace != 0 &&
                           tokenAt(la.matchingBrace + 1).is(T_IDENTIFIER)) {
                    yytoken = T_TYPE_NAME;
                }
            }
            opd = new Operand(yyloc);
        }

        if (unsigned(++_tos) == _stateStack.size()) {
            _stateStack.resize(_tos * 2);
            _locationStack.resize(_tos * 2);
            _astStack.resize(_tos * 2);
        }

        _stateStack[_tos] = action;
        action = t_action(action, yytoken);
        if (action > 0) {
            if (action == ACCEPT_STATE) {
                --_tos;
                dump(_astStack[0]);
                deleteAST(_astStack[0]);
                return true;
            }
            _astStack[_tos] = opd;
            _locationStack[_tos] = yyloc;
            yytoken = -1;
        } else if (action < 0) {
            const int ruleno = -action - 1;
            const int N = rhs[ruleno];
            _tos -= N;
            if (N == 0)
                _astStack[_tos] = 0;
            else
                _astStack[_tos] = new Operator(ruleno, &_astStack[_tos], &_astStack[_tos + N]);
            action = nt_action(_stateStack[_tos], lhs[ruleno] - TERMINAL_COUNT);
        }
    } while (action);

    fprintf(stderr, "unexpected token `%s' at line %d\n", yytoken != -1 ? spell[yytoken] : "",
        _tokens[yyloc].line + 1);

    return false;
}