MachineIndependent/preprocessor/PpTokens.cpp

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//
// For recording and playing back the stream of tokens in a macro definition.
//

#ifndef _CRT_SECURE_NO_WARNINGS
#define _CRT_SECURE_NO_WARNINGS
#endif

#include <cassert>
#include <cstdlib>
#include <cstring>
#include <cctype>

#include "PpContext.h"
#include "PpTokens.h"

namespace glslang {

// Add a token (including backing string) to the end of a macro
// token stream, for later playback.
void TPpContext::TokenStream::putToken(int atom, TPpToken* ppToken)
{
    TokenStream::Token streamToken(atom, *ppToken);
    stream.push_back(streamToken);
}

// Read the next token from a macro token stream.
int TPpContext::TokenStream::getToken(TParseContextBase& parseContext, TPpToken *ppToken)
{
    if (atEnd())
        return EndOfInput;

    int atom = stream[currentPos++].get(*ppToken);
    ppToken->loc = parseContext.getCurrentLoc();

    // Check for ##, unless the current # is the last character
    if (atom == '#') {
        if (peekToken('#')) {
            parseContext.requireProfile(ppToken->loc, ~EEsProfile, "token pasting (##)");
            parseContext.profileRequires(ppToken->loc, ~EEsProfile, 130, nullptr, "token pasting (##)");
            currentPos++;
            atom = PpAtomPaste;
        }
    }

    return atom;
}

// We are pasting if
//   1. we are preceding a pasting operator within this stream
// or
//   2. the entire macro is preceding a pasting operator (lastTokenPastes)
//      and we are also on the last token
bool TPpContext::TokenStream::peekTokenizedPasting(bool lastTokenPastes)
{
    // 1. preceding ##?

    size_t savePos = currentPos;
    // skip white space
    while (peekToken(' '))
        ++currentPos;
    if (peekToken(PpAtomPaste)) {
        currentPos = savePos;
        return true;
    }

    // 2. last token and we've been told after this there will be a ##

    if (! lastTokenPastes)
        return false;
    // Getting here means the last token will be pasted, after this

    // Are we at the last non-whitespace token?
    savePos = currentPos;
    bool moreTokens = false;
    do {
        if (atEnd())
            break;
        if (!peekToken(' ')) {
            moreTokens = true;
            break;
        }
        ++currentPos;
    } while (true);
    currentPos = savePos;

    return !moreTokens;
}

// See if the next non-white-space tokens are two consecutive #
bool TPpContext::TokenStream::peekUntokenizedPasting()
{
    // don't return early, have to restore this
    size_t savePos = currentPos;

    // skip white-space
    while (peekToken(' '))
        ++currentPos;

    // check for ##
    bool pasting = false;
    if (peekToken('#')) {
        ++currentPos;
        if (peekToken('#'))
            pasting = true;
    }

    currentPos = savePos;

    return pasting;
}

void TPpContext::pushTokenStreamInput(TokenStream& ts, bool prepasting, bool expanded)
{
    pushInput(new tTokenInput(this, &ts, prepasting, expanded));
    ts.reset();
}

int TPpContext::tUngotTokenInput::scan(TPpToken* ppToken)
{
    if (done)
        return EndOfInput;

    int ret = token;
    *ppToken = lval;
    done = true;

    return ret;
}

void TPpContext::UngetToken(int token, TPpToken* ppToken)
{
    pushInput(new tUngotTokenInput(this, token, ppToken));
}

} // end namespace glslang