//
// Copyright (C) 2002-2005  3Dlabs Inc. Ltd.
// Copyright (C) 2013 LunarG, Inc.
// Copyright (C) 2015-2018 Google, Inc.
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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
#if (defined(_MSC_VER) && _MSC_VER < 1900 /*vs2015*/)
#define snprintf sprintf_s
#endif

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

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

namespace glslang {


namespace {

    // When recording (and playing back) should the backing name string
    // be saved (restored)?
    bool SaveName(int atom)
    {
        switch (atom) {
        case PpAtomIdentifier:
        case PpAtomConstString:
        case PpAtomConstInt:
        case PpAtomConstUint:
        case PpAtomConstInt64:
        case PpAtomConstUint64:
    #ifdef AMD_EXTENSIONS
        case PpAtomConstInt16:
        case PpAtomConstUint16:
    #endif
        case PpAtomConstFloat:
        case PpAtomConstDouble:
        case PpAtomConstFloat16:
            return true;
        default:
            return false;
        }
    }

    // When recording (and playing back) should the numeric value
    // be saved (restored)?
    bool SaveValue(int atom)
    {
        switch (atom) {
        case PpAtomConstInt:
        case PpAtomConstUint:
        case PpAtomConstInt64:
        case PpAtomConstUint64:
    #ifdef AMD_EXTENSIONS
        case PpAtomConstInt16:
        case PpAtomConstUint16:
    #endif
        case PpAtomConstFloat:
        case PpAtomConstDouble:
        case PpAtomConstFloat16:
            return true;
        default:
            return false;
        }
    }
}

// push onto back of stream
void TPpContext::TokenStream::putSubtoken(char subtoken)
{
    data.push_back(static_cast<unsigned char>(subtoken));
}

// get the next token in stream
int TPpContext::TokenStream::getSubtoken()
{
    if (current < data.size())
        return data[current++];
    else
        return EndOfInput;
}

// back up one position in the stream
void TPpContext::TokenStream::ungetSubtoken()
{
    if (current > 0)
        --current;
}

// Add a complete token (including backing string) to the end of a list
// for later playback.
void TPpContext::TokenStream::putToken(int atom, TPpToken* ppToken)
{
    // save the atom
    assert((atom & ~0xff) == 0);
    putSubtoken(static_cast<char>(atom));

    // save the backing name string
    if (SaveName(atom)) {
        const char* s = ppToken->name;
        while (*s)
            putSubtoken(*s++);
        putSubtoken(0);
    }

    // save the numeric value
    if (SaveValue(atom)) {
        const char* n = reinterpret_cast<const char*>(&ppToken->i64val);
        for (size_t i = 0; i < sizeof(ppToken->i64val); ++i)
            putSubtoken(*n++);
    }
}

// Read the next token from a token stream.
// (Not the source stream, but a stream used to hold a tokenized macro).
int TPpContext::TokenStream::getToken(TParseContextBase& parseContext, TPpToken *ppToken)
{
    // get the atom
    int atom = getSubtoken();
    if (atom == EndOfInput)
        return atom;

    // init the token
    ppToken->clear();
    ppToken->loc = parseContext.getCurrentLoc();

    // get the backing name string
    if (SaveName(atom)) {
        int ch = getSubtoken();
        int len = 0;
        while (ch != 0 && ch != EndOfInput) {
            if (len < MaxTokenLength) {
                ppToken->name[len] = (char)ch;
                len++;
                ch = getSubtoken();
            } else {
                parseContext.error(ppToken->loc, "token too long", "", "");
                break;
            }
        }
        ppToken->name[len] = 0;
    }

    // Check for ##, unless the current # is the last character
    if (atom == '#') {
        if (current < data.size()) {
            if (getSubtoken() == '#') {
                parseContext.requireProfile(ppToken->loc, ~EEsProfile, "token pasting (##)");
                parseContext.profileRequires(ppToken->loc, ~EEsProfile, 130, 0, "token pasting (##)");
                atom = PpAtomPaste;
            } else
                ungetSubtoken();
        }
    }

    // get the numeric value
    if (SaveValue(atom)) {
        char* n = reinterpret_cast<char*>(&ppToken->i64val);
        for (size_t i = 0; i < sizeof(ppToken->i64val); ++i)
            *n++ = (char)getSubtoken();
    }

    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 = current;
    int subtoken;
    // skip white space
    do {
        subtoken = getSubtoken();
    } while (subtoken == ' ');
    current = savePos;
    if (subtoken == PpAtomPaste)
        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 = current;
    bool moreTokens = false;
    do {
        subtoken = getSubtoken();
        if (subtoken == EndOfInput)
            break;
        if (subtoken != ' ') {
            moreTokens = true;
            break;
        }
    } while (true);
    current = 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 = current;

    // skip white-space
    int subtoken;
    do {
        subtoken = getSubtoken();
    } while (subtoken == ' ');

    // check for ##
    bool pasting = false;
    if (subtoken == '#') {
        subtoken = getSubtoken();
        if (subtoken == '#')
            pasting = true;
    }

    current = savePos;

    return pasting;
}

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