//
//Copyright (C) 2002-2005  3Dlabs Inc. Ltd.
//Copyright (C) 2013 LunarG, Inc.
//All rights reserved.
//
//Redistribution and use in source and binary forms, with or without
//modification, are permitted provided that the following conditions
//are met:
//
//    Redistributions of source code must retain the above copyright
//    notice, this list of conditions and the following disclaimer.
//
//    Redistributions in binary form must reproduce the above
//    copyright notice, this list of conditions and the following
//    disclaimer in the documentation and/or other materials provided
//    with the distribution.
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/****************************************************************************\
Copyright (c) 2002, NVIDIA Corporation.

NVIDIA Corporation("NVIDIA") supplies this software to you in
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\****************************************************************************/
//
// scanner.c
//

#define _CRT_SECURE_NO_WARNINGS

#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "PpContext.h"
#include "PpTokens.h"
#include "../Scan.h"

namespace glslang {

int TPpContext::InitScanner()
{
    // Add various atoms needed by the CPP line scanner:
    if (!InitCPP())
        return 0;

    previous_token = '\n';

    return 1;
}

///////////////////////////////////////////////////////////////////////////////////////////////
/////////////////////////////////// Floating point constants: /////////////////////////////////
///////////////////////////////////////////////////////////////////////////////////////////////

/*
* lFloatConst() - Scan a single- or double-precision floating point constant.  Assumes that the scanner
*         has seen at least one digit, followed by either a decimal '.' or the
*         letter 'e', or a precision ending (e.g., F or LF).
*/

int TPpContext::lFloatConst(int len, int ch, TPpToken* ppToken)
{
    bool HasDecimalOrExponent = false;
    int declen;
    int str_len;
    int isDouble = 0;

    declen = 0;

    str_len=len;
    char* str = ppToken->name;
    if (ch == '.') {
        HasDecimalOrExponent = true;
        str[len++] = (char)ch;
        ch = getChar();
        while (ch >= '0' && ch <= '9') {
            if (len < MaxTokenLength) {
                declen++;
                if (len > 0 || ch != '0') {
                    str[len] = (char)ch;
                    len++;
                    str_len++;
                }
                ch = getChar();
            } else {
                parseContext.ppError(ppToken->loc, "float literal too long", "", "");
                len = 1;
                str_len = 1;
            }
        }
    }

    // Exponent:

    if (ch == 'e' || ch == 'E') {
        HasDecimalOrExponent = true;
        if (len >= MaxTokenLength) {
            parseContext.ppError(ppToken->loc, "float literal too long", "", "");
            len = 1;
            str_len = 1;
        } else {
            str[len++] = (char)ch;
            ch = getChar();
            if (ch == '+') {
                str[len++] = (char)ch;
                ch = getChar();
            } else if (ch == '-') {
                str[len++] = (char)ch;
                ch = getChar();
            }
            if (ch >= '0' && ch <= '9') {
                while (ch >= '0' && ch <= '9') {
                    if (len < MaxTokenLength) {
                        str[len++] = (char)ch;
                        ch = getChar();
                    } else {
                        parseContext.ppError(ppToken->loc, "float literal too long", "", "");
                        len = 1;
                        str_len = 1;
                    }
                }
            } else {
                parseContext.ppError(ppToken->loc, "bad character in float exponent", "", "");
            }
        }
    }

    if (len == 0) {
        ppToken->dval = 0.0;
        strcpy(str, "0.0");
    } else {
        if (ch == 'l' || ch == 'L') {
            parseContext.doubleCheck(ppToken->loc, "double floating-point suffix");
            if (! HasDecimalOrExponent)
                parseContext.ppError(ppToken->loc, "float literal needs a decimal point or exponent", "", "");
            int ch2 = getChar();
            if (ch2 != 'f' && ch2 != 'F') {
                ungetChar();
                ungetChar();
            } else {
                if (len < MaxTokenLength) {
                    str[len++] = (char)ch;
                    str[len++] = (char)ch2;
                    isDouble = 1;
                } else {
                    parseContext.ppError(ppToken->loc, "float literal too long", "", "");
                    len = 1,str_len=1;
                }
            }
        } else if (ch == 'f' || ch == 'F') {
            parseContext.profileRequires(ppToken->loc,  EEsProfile, 300, nullptr, "floating-point suffix");
            if (! parseContext.relaxedErrors())
                parseContext.profileRequires(ppToken->loc, ~EEsProfile, 120, nullptr, "floating-point suffix");
            if (! HasDecimalOrExponent)
                parseContext.ppError(ppToken->loc, "float literal needs a decimal point or exponent", "", "");
            if (len < MaxTokenLength)
                str[len++] = (char)ch;
            else {
                parseContext.ppError(ppToken->loc, "float literal too long", "", "");
                len = 1,str_len=1;
            }
        } else 
            ungetChar();

        str[len]='\0';

        ppToken->dval = strtod(str, nullptr);
    }

    if (isDouble)
        return PpAtomConstDouble;
    else
        return PpAtomConstFloat;
}

//
// Scanner used to tokenize source stream.
//
int TPpContext::tStringInput::scan(TPpToken* ppToken)
{
    char* tokenText = ppToken->name;
    int AlreadyComplained = 0;
    int len = 0;
    int ch = 0;
    int ii = 0;
    unsigned ival = 0;

    ppToken->ival = 0;
    ppToken->space = false;
    ch = getch();
    for (;;) {
        while (ch == ' ' || ch == '\t') {
            ppToken->space = true;
            ch = getch();
        }

        ppToken->loc = pp->parseContext.getCurrentLoc();
        len = 0;
        switch (ch) {
        default:
            // Single character token, including EndOfInput, '#' and '\' (escaped newlines are handled at a lower level, so this is just a '\' token)
            return ch;

        case 'A': case 'B': case 'C': case 'D': case 'E':
        case 'F': case 'G': case 'H': case 'I': case 'J':
        case 'K': case 'L': case 'M': case 'N': case 'O':
        case 'P': case 'Q': case 'R': case 'S': case 'T':
        case 'U': case 'V': case 'W': case 'X': case 'Y':
        case 'Z': case '_':
        case 'a': case 'b': case 'c': case 'd': case 'e':
        case 'f': case 'g': case 'h': case 'i': case 'j':
        case 'k': case 'l': case 'm': case 'n': case 'o':
        case 'p': case 'q': case 'r': case 's': case 't':
        case 'u': case 'v': case 'w': case 'x': case 'y':
        case 'z':
            do {
                if (len < MaxTokenLength) {
                    tokenText[len++] = (char)ch;
                    ch = getch();
                } else {
                    if (! AlreadyComplained) {
                        pp->parseContext.ppError(ppToken->loc, "name too long", "", "");
                        AlreadyComplained = 1;
                    }
                    ch = getch();
                }
            } while ((ch >= 'a' && ch <= 'z') ||
                     (ch >= 'A' && ch <= 'Z') ||
                     (ch >= '0' && ch <= '9') ||
                     ch == '_');

            // line continuation with no token before or after makes len == 0, and need to start over skipping white space, etc.
            if (len == 0)
                continue;

            tokenText[len] = '\0';
            ungetch();
            ppToken->atom = pp->LookUpAddString(tokenText);
            return PpAtomIdentifier;
        case '0':
            ppToken->name[len++] = (char)ch;
            ch = getch();
            if (ch == 'x' || ch == 'X') {
                // must be hexidecimal

                bool isUnsigned = false;
                ppToken->name[len++] = (char)ch;
                ch = getch();
                if ((ch >= '0' && ch <= '9') ||
                    (ch >= 'A' && ch <= 'F') ||
                    (ch >= 'a' && ch <= 'f')) {

                    ival = 0;
                    do {
                        if (ival <= 0x0fffffff) {
                            ppToken->name[len++] = (char)ch;
                            if (ch >= '0' && ch <= '9') {
                                ii = ch - '0';
                            } else if (ch >= 'A' && ch <= 'F') {
                                ii = ch - 'A' + 10;
                            } else if (ch >= 'a' && ch <= 'f') {
                                ii = ch - 'a' + 10;
                            } else
                                pp->parseContext.ppError(ppToken->loc, "bad digit in hexidecimal literal", "", "");
                            ival = (ival << 4) | ii;
                        } else {
                            if (! AlreadyComplained) {
                                pp->parseContext.ppError(ppToken->loc, "hexidecimal literal too big", "", "");
                                AlreadyComplained = 1;
                            }
                            ival = 0xffffffff;
                        }
                        ch = getch();
                    } while ((ch >= '0' && ch <= '9') ||
                             (ch >= 'A' && ch <= 'F') ||
                             (ch >= 'a' && ch <= 'f'));
                } else {
                    pp->parseContext.ppError(ppToken->loc, "bad digit in hexidecimal literal", "", "");
                }
                if (ch == 'u' || ch == 'U') {
                    if (len < MaxTokenLength)
                        ppToken->name[len++] = (char)ch;
                    isUnsigned = true;
                } else
                    ungetch();
                ppToken->name[len] = '\0';
                ppToken->ival = (int)ival;

                if (isUnsigned)
                    return PpAtomConstUint;
                else
                    return PpAtomConstInt;
            } else {
                // could be octal integer or floating point, speculative pursue octal until it must be floating point

                bool isUnsigned = false;
                bool octalOverflow = false;
                bool nonOctal = false;
                ival = 0;

                // see how much octal-like stuff we can read
                while (ch >= '0' && ch <= '7') {
                    if (len < MaxTokenLength)
                        ppToken->name[len++] = (char)ch;
                    else if (! AlreadyComplained) {
                        pp->parseContext.ppError(ppToken->loc, "numeric literal too long", "", "");
                        AlreadyComplained = 1;
                    }
                    if (ival <= 0x1fffffff) {
                        ii = ch - '0';
                        ival = (ival << 3) | ii;
                    } else
                        octalOverflow = true;
                    ch = getch();
                }

                // could be part of a float...
                if (ch == '8' || ch == '9') {
                    nonOctal = true;
                    do {
                        if (len < MaxTokenLength)
                            ppToken->name[len++] = (char)ch;
                        else if (! AlreadyComplained) {
                            pp->parseContext.ppError(ppToken->loc, "numeric literal too long", "", "");
                            AlreadyComplained = 1;
                        }
                        ch = getch();
                    } while (ch >= '0' && ch <= '9');
                }
                if (ch == '.' || ch == 'e' || ch == 'f' || ch == 'E' || ch == 'F' || ch == 'l' || ch == 'L') 
                    return pp->lFloatConst(len, ch, ppToken);
                
                // wasn't a float, so must be octal...
                if (nonOctal)
                    pp->parseContext.ppError(ppToken->loc, "octal literal digit too large", "", "");

                if (ch == 'u' || ch == 'U') {
                    if (len < MaxTokenLength)
                        ppToken->name[len++] = (char)ch;
                    isUnsigned = true;
                } else
                    ungetch();
                ppToken->name[len] = '\0';

                if (octalOverflow)
                    pp->parseContext.ppError(ppToken->loc, "octal literal too big", "", "");

                ppToken->ival = (int)ival;

                if (isUnsigned)
                    return PpAtomConstUint;
                else
                    return PpAtomConstInt;
            }
            break;
        case '1': case '2': case '3': case '4':
        case '5': case '6': case '7': case '8': case '9':
            // can't be hexidecimal or octal, is either decimal or floating point

            do {
                if (len < MaxTokenLength)
                    ppToken->name[len++] = (char)ch;
                else if (! AlreadyComplained) {
                    pp->parseContext.ppError(ppToken->loc, "numeric literal too long", "", "");
                    AlreadyComplained = 1;
                }
                ch = getch();
            } while (ch >= '0' && ch <= '9');
            if (ch == '.' || ch == 'e' || ch == 'f' || ch == 'E' || ch == 'F' || ch == 'l' || ch == 'L') {
                return pp->lFloatConst(len, ch, ppToken);
            } else {
                // Finish handling signed and unsigned integers
                int numericLen = len;
                bool uint = false;
                if (ch == 'u' || ch == 'U') {
                    if (len < MaxTokenLength)
                        ppToken->name[len++] = (char)ch;
                    uint = true;
                } else
                    ungetch();

                ppToken->name[len] = '\0';
                ival = 0;
                const unsigned oneTenthMaxInt  = 0xFFFFFFFFu / 10;
                const unsigned remainderMaxInt = 0xFFFFFFFFu - 10 * oneTenthMaxInt;
                for (int i = 0; i < numericLen; i++) {
                    ch = ppToken->name[i] - '0';
                    if ((ival > oneTenthMaxInt) || (ival == oneTenthMaxInt && (unsigned)ch > remainderMaxInt)) {
                        pp->parseContext.ppError(ppToken->loc, "numeric literal too big", "", "");
                        ival = 0xFFFFFFFFu;
                        break;
                    } else
                        ival = ival * 10 + ch;
                }
                ppToken->ival = (int)ival;

                if (uint)
                    return PpAtomConstUint;
                else
                    return PpAtomConstInt;
            }
            break;
        case '-':
            ch = getch();
            if (ch == '-') {
                return PpAtomDecrement;
            } else if (ch == '=') {
                return PpAtomSub;
            } else {
                ungetch();
                return '-';
            }
        case '+':
            ch = getch();
            if (ch == '+') {
                return PpAtomIncrement;
            } else if (ch == '=') {
                return PpAtomAdd;
            } else {
                ungetch();
                return '+';
            }
        case '*':
            ch = getch();
            if (ch == '=') {
                return PpAtomMul;
            } else {
                ungetch();
                return '*';
            }
        case '%':
            ch = getch();
            if (ch == '=') {
                return PpAtomMod;
            } else {
                ungetch();
                return '%';
            }
        case '^':
            ch = getch();
            if (ch == '^') {
                return PpAtomXor;
            } else {
                if (ch == '=')
                    return PpAtomXorAssign;
                else{
                    ungetch();
                    return '^';
                }
            }

        case '=':
            ch = getch();
            if (ch == '=') {
                return PpAtomEQ;
            } else {
                ungetch();
                return '=';
            }
        case '!':
            ch = getch();
            if (ch == '=') {
                return PpAtomNE;
            } else {
                ungetch();
                return '!';
            }
        case '|':
            ch = getch();
            if (ch == '|') {
                return PpAtomOr;
            } else if (ch == '=') {
                return PpAtomOrAssign;
            } else {
                ungetch();
                return '|';
            }
        case '&':
            ch = getch();
            if (ch == '&') {
                return PpAtomAnd;
            } else if (ch == '=') {
                return PpAtomAndAssign;
            } else {
                ungetch();
                return '&';
            }
        case '<':
            ch = getch();
            if (ch == '<') {
                ch = getch();
                if (ch == '=')
                    return PpAtomLeftAssign;
                else {
                    ungetch();
                    return PpAtomLeft;
                }
            } else if (ch == '=') {
                return PpAtomLE;
            } else {
                ungetch();
                return '<';
            }
        case '>':
            ch = getch();
            if (ch == '>') {
                ch = getch();
                if (ch == '=')
                    return PpAtomRightAssign;
                else {
                    ungetch();
                    return PpAtomRight;
                }
            } else if (ch == '=') {
                return PpAtomGE;
            } else {
                ungetch();
                return '>';
            }
        case '.':
            ch = getch();
            if (ch >= '0' && ch <= '9') {
                ungetch();
                return pp->lFloatConst(0, '.', ppToken);
            } else {
                ungetch();
                return '.';
            }
        case '/':
            ch = getch();
            if (ch == '/') {
                pp->inComment = true;
                do {
                    ch = getch();
                } while (ch != '\n' && ch != EndOfInput);
                ppToken->space = true;
                pp->inComment = false;

                return ch;
            } else if (ch == '*') {
                ch = getch();
                do {
                    while (ch != '*') {
                        if (ch == EndOfInput) {
                            pp->parseContext.ppError(ppToken->loc, "End of input in comment", "comment", "");
                            return ch;
                        }
                        ch = getch();
                    }
                    ch = getch();
                    if (ch == EndOfInput) {
                        pp->parseContext.ppError(ppToken->loc, "End of input in comment", "comment", "");
                        return ch;
                    }
                } while (ch != '/');
                ppToken->space = true;
                // loop again to get the next token...
                break;
            } else if (ch == '=') {
                return PpAtomDiv;
            } else {
                ungetch();
                return '/';
            }
            break;
        case '"':
            ch = getch();
            while (ch != '"' && ch != '\n' && ch != EndOfInput) {
                if (len < MaxTokenLength) {
                    tokenText[len] = (char)ch;
                    len++;
                    ch = getch();
                } else
                    break;
            };
            tokenText[len] = '\0';
            if (ch != '"') {
                ungetch();
                pp->parseContext.ppError(ppToken->loc, "End of line in string", "string", "");
            }
            return PpAtomConstString;
        }

        ch = getch();
    }
}

//
// The main functional entry-point into the preprocessor, which will
// scan the source strings to figure out and return the next processing token.
//
// Return string pointer to next token.
// Return 0 when no more tokens.
//
const char* TPpContext::tokenize(TPpToken* ppToken)
{    
    int token = '\n';

    for(;;) {
        token = scanToken(ppToken);
        ppToken->token = token;
        if (token == EndOfInput) {
            missingEndifCheck();
            return nullptr;
        }
        if (token == '#') {
            if (previous_token == '\n') {
                token = readCPPline(ppToken);
                if (token == EndOfInput) {
                    missingEndifCheck();
                    return nullptr;
                }
                continue;
            } else {
                parseContext.ppError(ppToken->loc, "preprocessor directive cannot be preceded by another token", "#", "");
                return nullptr;
            }
        }
        previous_token = token;

        if (token == '\n')
            continue;

        // expand macros
        if (token == PpAtomIdentifier && MacroExpand(ppToken->atom, ppToken, false, true) != 0)
            continue;

        const char* tokenString = nullptr;
        switch (token) {
        case PpAtomIdentifier:
        case PpAtomConstInt:
        case PpAtomConstUint:
        case PpAtomConstFloat:
        case PpAtomConstDouble:
            tokenString = ppToken->name;
            break;
        case PpAtomConstString:
            parseContext.ppError(ppToken->loc, "string literals not supported", "\"\"", "");
            break;
        case '\'':
            parseContext.ppError(ppToken->loc, "character literals not supported", "\'", "");
            break;
        default:
            tokenString = GetAtomString(token);
            break;
        }

        if (tokenString) {
            if (tokenString[0] != 0)
                parseContext.tokensBeforeEOF = 1;

            return tokenString;
        }
    }
}

// Checks if we've seen balanced #if...#endif
void TPpContext::missingEndifCheck()
{
    if (ifdepth > 0)
        parseContext.ppError(parseContext.getCurrentLoc(), "missing #endif", "", "");
}

} // end namespace glslang