src/compiler/preprocessor/cpp.c

//
// Copyright (c) 2002-2010 The ANGLE Project Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//
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//
// cpp.c
//

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

#include "compiler/preprocessor/slglobals.h"

static int CPPif(yystypepp * yylvalpp);

/* Don't use memory.c's replacements, as we clean up properly here */
#undef malloc
#undef free

static int bindAtom = 0;
static int constAtom = 0;
static int defaultAtom = 0;
static int defineAtom = 0;
static int definedAtom = 0;
static int elseAtom = 0;
static int elifAtom = 0;
static int endifAtom = 0;
static int ifAtom = 0;
static int ifdefAtom = 0;
static int ifndefAtom = 0;
static int includeAtom = 0;
static int lineAtom = 0;
static int pragmaAtom = 0;
static int texunitAtom = 0;
static int undefAtom = 0;
static int errorAtom = 0;
static int __LINE__Atom = 0;
static int __FILE__Atom = 0;
static int __VERSION__Atom = 0;
static int gl_esAtom = 0;
static int versionAtom = 0;
static int extensionAtom = 0;

static Scope *macros = 0;
#define MAX_MACRO_ARGS  64
#define MAX_IF_NESTING  64

static SourceLoc ifloc; /* outermost #if */

int InitCPP(void)
{
    char        buffer[64], *t;
    const char  *f;

    SourceLoc location = {0};
    Symbol *symbol;
    MacroSymbol macro = {0};
    yystypepp one = {0};

    // Add various atoms needed by the CPP line scanner:
    bindAtom = LookUpAddString(atable, "bind");
    constAtom = LookUpAddString(atable, "const");
    defaultAtom = LookUpAddString(atable, "default");
    defineAtom = LookUpAddString(atable, "define");
    definedAtom = LookUpAddString(atable, "defined");
    elifAtom = LookUpAddString(atable, "elif");
    elseAtom = LookUpAddString(atable, "else");
    endifAtom = LookUpAddString(atable, "endif");
    ifAtom = LookUpAddString(atable, "if");
    ifdefAtom = LookUpAddString(atable, "ifdef");
    ifndefAtom = LookUpAddString(atable, "ifndef");
    includeAtom = LookUpAddString(atable, "include");
    lineAtom = LookUpAddString(atable, "line");
    pragmaAtom = LookUpAddString(atable, "pragma");
    texunitAtom = LookUpAddString(atable, "texunit");
    undefAtom = LookUpAddString(atable, "undef");
	errorAtom = LookUpAddString(atable, "error");
    __LINE__Atom = LookUpAddString(atable, "__LINE__");
    __FILE__Atom = LookUpAddString(atable, "__FILE__");
	__VERSION__Atom = LookUpAddString(atable, "__VERSION__");
    gl_esAtom = LookUpAddString(atable, "GL_ES");
    versionAtom = LookUpAddString(atable, "version");
    extensionAtom = LookUpAddString(atable, "extension");
    macros = NewScopeInPool(mem_CreatePool(0, 0));
    strcpy(buffer, "PROFILE_");
    t = buffer + strlen(buffer);
    f = cpp->options.profileString;
    while ((isalnum(*f) || *f == '_') && t < buffer + sizeof(buffer) - 1)
        *t++ = toupper(*f++);
    *t = 0;

    // #define GL_ES 1
    macro.body = NewTokenStream("GL_ES", macros->pool);
    one.sc_int = 1;
    strcpy(one.symbol_name, "1");
    RecordToken(macro.body, CPP_INTCONSTANT, &one);
    symbol = AddSymbol(&location, macros, gl_esAtom, MACRO_S);
    symbol->details.mac = macro;

	return 1;
} // InitCPP

int FreeCPP(void)
{
    if (macros)
    {
        mem_FreePool(macros->pool);
        macros = 0;
    }

    return 1;
}

int FinalCPP(void)
{
	if (cpp->ifdepth)
		CPPErrorToInfoLog("#if mismatch");
    return 1;
}

static int CPPdefine(yystypepp * yylvalpp)
{
    int token, name, args[MAX_MACRO_ARGS], argc;
    const char *message;
    MacroSymbol mac;
    Symbol *symb;
    SourceLoc dummyLoc;
    memset(&mac, 0, sizeof(mac));
    token = cpp->currentInput->scan(cpp->currentInput, yylvalpp);
    if (token != CPP_IDENTIFIER) {
        CPPErrorToInfoLog("#define");
        return token;
    }
    name = yylvalpp->sc_ident;
    token = cpp->currentInput->scan(cpp->currentInput, yylvalpp);
    if (token == '(' && !yylvalpp->sc_int) {
        // gather arguments
        argc = 0;
        do {
            token = cpp->currentInput->scan(cpp->currentInput, yylvalpp);
            if (argc == 0 && token == ')') break;
            if (token != CPP_IDENTIFIER) {
				CPPErrorToInfoLog("#define");
                return token;
            }
            if (argc < MAX_MACRO_ARGS)
                args[argc++] = yylvalpp->sc_ident;
            token = cpp->currentInput->scan(cpp->currentInput, yylvalpp);
        } while (token == ',');
        if (token != ')') {
            CPPErrorToInfoLog("#define");
            return token;
        }
        mac.argc = argc;
        mac.args = mem_Alloc(macros->pool, argc * sizeof(int));
        memcpy(mac.args, args, argc * sizeof(int));
        token = cpp->currentInput->scan(cpp->currentInput, yylvalpp);
	}
    mac.body = NewTokenStream(GetAtomString(atable, name), macros->pool);
    while (token != '\n') {
        if (token == '\\') {
            CPPErrorToInfoLog("The line continuation character (\\) is not part of the OpenGL ES Shading Language");
            return token;
        }
        RecordToken(mac.body, token, yylvalpp);
        token = cpp->currentInput->scan(cpp->currentInput, yylvalpp);
    };

    symb = LookUpSymbol(macros, name);
    if (symb) {
        if (!symb->details.mac.undef) {
            // already defined -- need to make sure they are identical
            if (symb->details.mac.argc != mac.argc) goto error;
            for (argc=0; argc < mac.argc; argc++)
                if (symb->details.mac.args[argc] != mac.args[argc])
                    goto error;
            RewindTokenStream(symb->details.mac.body);
            RewindTokenStream(mac.body);
            do {
                int old_lval, old_token;
                old_token = ReadToken(symb->details.mac.body, yylvalpp);
                old_lval = yylvalpp->sc_int;
                token = ReadToken(mac.body, yylvalpp);
                if (token != old_token || yylvalpp->sc_int != old_lval) { 
                error:
                    StoreStr("Macro Redefined");
                    StoreStr(GetStringOfAtom(atable,name));
                    message=GetStrfromTStr();
                    DecLineNumber();
                    CPPShInfoLogMsg(message);
                    IncLineNumber();
                    ResetTString();
                    break; }
            } while (token > 0);
        }
        //FreeMacro(&symb->details.mac);
    } else {
        dummyLoc.file = 0;
        dummyLoc.line = 0;
        symb = AddSymbol(&dummyLoc, macros, name, MACRO_S);
    }
    symb->details.mac = mac;
    return '\n';
} // CPPdefine

static int CPPundef(yystypepp * yylvalpp)
{
    int token = cpp->currentInput->scan(cpp->currentInput, yylvalpp);
    Symbol *symb;
	if(token == '\n'){
		CPPErrorToInfoLog("#undef");
	    return token;
    }
    if (token != CPP_IDENTIFIER)
          goto error;
    symb = LookUpSymbol(macros, yylvalpp->sc_ident);
    if (symb) {
        symb->details.mac.undef = 1;
    }
    token = cpp->currentInput->scan(cpp->currentInput, yylvalpp);
    if (token != '\n') {
    error:
        CPPErrorToInfoLog("#undef");
    }
    return token;
} // CPPundef

/* CPPelse -- skip forward to appropriate spot.  This is actually used
** to skip to and #endif after seeing an #else, AND to skip to a #else,
** #elif, or #endif after a #if/#ifdef/#ifndef/#elif test was false
*/

static int CPPelse(int matchelse, yystypepp * yylvalpp)
{
    int atom,depth=0;
    int token = cpp->currentInput->scan(cpp->currentInput, yylvalpp);
	
	while (token > 0) {
        if (token != '#') {
		    while (token != '\n')
                token = cpp->currentInput->scan(cpp->currentInput, yylvalpp);
            
            token = cpp->currentInput->scan(cpp->currentInput, yylvalpp);
            continue;
        }
		if ((token = cpp->currentInput->scan(cpp->currentInput, yylvalpp)) != CPP_IDENTIFIER)
			continue;
        atom = yylvalpp->sc_ident;
        if (atom == ifAtom || atom == ifdefAtom || atom == ifndefAtom){
            depth++; cpp->ifdepth++; cpp->elsetracker++;
            cpp->elsedepth[cpp->elsetracker] = 0;
		}
		else if (atom == endifAtom) {
            if(--depth<0){
			    --cpp->elsetracker;
                if (cpp->ifdepth) 
                    --cpp->ifdepth;
                break;
            }             
                --cpp->elsetracker;
                --cpp->ifdepth;
            }
        else if (((int)(matchelse) != 0)&& depth==0) {
			if (atom == elseAtom ) {
                token = cpp->currentInput->scan(cpp->currentInput, yylvalpp);
                if (token != '\n') {
                    CPPWarningToInfoLog("unexpected tokens following #else preprocessor directive - expected a newline");
                    while (token != '\n')
                        token = cpp->currentInput->scan(cpp->currentInput, yylvalpp);
                } 
				break;
			} 
			else if (atom == elifAtom) {
                /* we decrement cpp->ifdepth here, because CPPif will increment
                 * it and we really want to leave it alone */
				if (cpp->ifdepth){
					--cpp->ifdepth;
				    --cpp->elsetracker;
				}
                return CPPif(yylvalpp);
            }
		}
        else if((atom==elseAtom) && (!ChkCorrectElseNesting())){
            CPPErrorToInfoLog("#else after a #else");
            cpp->CompileError=1;
        }
	};
    return token;
}

enum eval_prec {
    MIN_PREC,
    COND, LOGOR, LOGAND, OR, XOR, AND, EQUAL, RELATION, SHIFT, ADD, MUL, UNARY,
    MAX_PREC
};

static int op_logor(int a, int b) { return a || b; }
static int op_logand(int a, int b) { return a && b; }
static int op_or(int a, int b) { return a | b; }
static int op_xor(int a, int b) { return a ^ b; }
static int op_and(int a, int b) { return a & b; }
static int op_eq(int a, int b) { return a == b; }
static int op_ne(int a, int b) { return a != b; }
static int op_ge(int a, int b) { return a >= b; }
static int op_le(int a, int b) { return a <= b; }
static int op_gt(int a, int b) { return a > b; }
static int op_lt(int a, int b) { return a < b; }
static int op_shl(int a, int b) { return a << b; }
static int op_shr(int a, int b) { return a >> b; }
static int op_add(int a, int b) { return a + b; }
static int op_sub(int a, int b) { return a - b; }
static int op_mul(int a, int b) { return a * b; }
static int op_div(int a, int b) { return a / b; }
static int op_mod(int a, int b) { return a % b; }
static int op_pos(int a) { return a; }
static int op_neg(int a) { return -a; }
static int op_cmpl(int a) { return ~a; }
static int op_not(int a) { return !a; }

struct {
    int token, prec, (*op)(int, int);
} binop[] = {
    { CPP_OR_OP, LOGOR, op_logor },
    { CPP_AND_OP, LOGAND, op_logand },
    { '|', OR, op_or },
    { '^', XOR, op_xor },
    { '&', AND, op_and },
    { CPP_EQ_OP, EQUAL, op_eq },
    { CPP_NE_OP, EQUAL, op_ne },
    { '>', RELATION, op_gt },
    { CPP_GE_OP, RELATION, op_ge },
    { '<', RELATION, op_lt },
    { CPP_LE_OP, RELATION, op_le },
    { CPP_LEFT_OP, SHIFT, op_shl },
    { CPP_RIGHT_OP, SHIFT, op_shr },
    { '+', ADD, op_add },
    { '-', ADD, op_sub },
    { '*', MUL, op_mul },
    { '/', MUL, op_div },
    { '%', MUL, op_mod },
};

struct {
    int token, (*op)(int);
} unop[] = {
    { '+', op_pos },
    { '-', op_neg },
    { '~', op_cmpl },
    { '!', op_not },
};

#define ALEN(A) (sizeof(A)/sizeof(A[0]))

static int eval(int token, int prec, int *res, int *err, yystypepp * yylvalpp)
{
    int         i, val;
    Symbol      *s;
    if (token == CPP_IDENTIFIER) {
        if (yylvalpp->sc_ident == definedAtom) {
            int needclose = 0;
            token = cpp->currentInput->scan(cpp->currentInput, yylvalpp);
            if (token == '(') {
                needclose = 1;
                token = cpp->currentInput->scan(cpp->currentInput, yylvalpp);
            }
            if (token != CPP_IDENTIFIER)
                goto error;
            *res = (s = LookUpSymbol(macros, yylvalpp->sc_ident))
                        ? !s->details.mac.undef : 0;
            token = cpp->currentInput->scan(cpp->currentInput, yylvalpp);
            if (needclose) {
                if (token != ')')
                    goto error;
                token = cpp->currentInput->scan(cpp->currentInput, yylvalpp);
            }
		} else if (MacroExpand(yylvalpp->sc_ident, yylvalpp)) {
			token = cpp->currentInput->scan(cpp->currentInput, yylvalpp);
            return eval(token, prec, res, err, yylvalpp);
        } else {
            goto error;
        }
	} else if (token == CPP_INTCONSTANT) {
        *res = yylvalpp->sc_int;
        token = cpp->currentInput->scan(cpp->currentInput, yylvalpp);
    } else if (token == '(') {
        token = cpp->currentInput->scan(cpp->currentInput, yylvalpp);
        token = eval(token, MIN_PREC, res, err, yylvalpp);
        if (!*err) {
            if (token != ')')
                goto error;
            token = cpp->currentInput->scan(cpp->currentInput, yylvalpp);
        }
    } else {
        for (i = ALEN(unop) - 1; i >= 0; i--) {
            if (unop[i].token == token)
                break;
        }
        if (i >= 0) {
            token = cpp->currentInput->scan(cpp->currentInput, yylvalpp);
            token = eval(token, UNARY, res, err, yylvalpp);
            *res = unop[i].op(*res);
        } else {
            goto error;
        }
    }
    while (!*err) {
        if (token == ')' || token == '\n') break;
        for (i = ALEN(binop) - 1; i >= 0; i--) {
            if (binop[i].token == token)
                break;
        }
        if (i < 0 || binop[i].prec <= prec)
            break;
        val = *res;
        token = cpp->currentInput->scan(cpp->currentInput, yylvalpp);
        token = eval(token, binop[i].prec, res, err, yylvalpp);
        *res = binop[i].op(val, *res);
    }
    return token;
error:
    CPPErrorToInfoLog("incorrect preprocessor directive");
    *err = 1;
    *res = 0;
    return token;
} // eval

static int CPPif(yystypepp * yylvalpp) {
    int token = cpp->currentInput->scan(cpp->currentInput, yylvalpp);
    int res = 0, err = 0;
	cpp->elsetracker++;
    cpp->elsedepth[cpp->elsetracker] = 0;
    if (!cpp->ifdepth++)
        ifloc = *cpp->tokenLoc;
	if(cpp->ifdepth >MAX_IF_NESTING){
        CPPErrorToInfoLog("max #if nesting depth exceeded");
		return 0;
	}
	token = eval(token, MIN_PREC, &res, &err, yylvalpp);
    if (token != '\n') {
        CPPWarningToInfoLog("unexpected tokens following the preprocessor directive - expected a newline");
        while (token != '\n')
            token = cpp->currentInput->scan(cpp->currentInput, yylvalpp);
    } 
    if (!res && !err) {
        token = CPPelse(1, yylvalpp);
    }

    return token;
} // CPPif

static int CPPifdef(int defined, yystypepp * yylvalpp)
{
    int token = cpp->currentInput->scan(cpp->currentInput, yylvalpp);
    int name = yylvalpp->sc_ident;
	if(++cpp->ifdepth >MAX_IF_NESTING){
	    CPPErrorToInfoLog("max #if nesting depth exceeded");
		return 0;
	}
	cpp->elsetracker++;
    cpp->elsedepth[cpp->elsetracker] = 0;
    if (token != CPP_IDENTIFIER) {
            defined ? CPPErrorToInfoLog("ifdef"):CPPErrorToInfoLog("ifndef");
    } else {
        Symbol *s = LookUpSymbol(macros, name);
        token = cpp->currentInput->scan(cpp->currentInput, yylvalpp);
        if (token != '\n') {
            CPPWarningToInfoLog("unexpected tokens following #ifdef preprocessor directive - expected a newline");
            while (token != '\n')
                token = cpp->currentInput->scan(cpp->currentInput, yylvalpp);
        }
        if (((s && !s->details.mac.undef) ? 1 : 0) != defined)
            token = CPPelse(1, yylvalpp);
    }
    return token;
} // CPPifdef

static int CPPline(yystypepp * yylvalpp) 
{
    int token = cpp->currentInput->scan(cpp->currentInput, yylvalpp);
	if(token=='\n'){
		DecLineNumber();
        CPPErrorToInfoLog("#line");
        IncLineNumber();
		return token;
	}
	else if (token == CPP_INTCONSTANT) {
		yylvalpp->sc_int=atoi(yylvalpp->symbol_name);
		SetLineNumber(yylvalpp->sc_int);
        token = cpp->currentInput->scan(cpp->currentInput, yylvalpp);
        
		if (token == CPP_INTCONSTANT) {
            yylvalpp->sc_int=atoi(yylvalpp->symbol_name);
			SetStringNumber(yylvalpp->sc_int);
            token = cpp->currentInput->scan(cpp->currentInput, yylvalpp);
			if(token!='\n')
				CPPErrorToInfoLog("#line");
        }
		else if (token == '\n'){
			return token;
		}
		else{
            CPPErrorToInfoLog("#line");
		}
	}
	else{
          CPPErrorToInfoLog("#line");
	}
    return token;
}

static int CPPerror(yystypepp * yylvalpp) {

	int token = cpp->currentInput->scan(cpp->currentInput, yylvalpp);
    const char *message;
	
    while (token != '\n') {
		if (token == CPP_FLOATCONSTANT || token == CPP_INTCONSTANT){
            StoreStr(yylvalpp->symbol_name);
		}else if(token == CPP_IDENTIFIER || token == CPP_STRCONSTANT){
			StoreStr(GetStringOfAtom(atable,yylvalpp->sc_ident));
		}else {
		    StoreStr(GetStringOfAtom(atable,token));
		}
		token = cpp->currentInput->scan(cpp->currentInput, yylvalpp);
	}
	DecLineNumber();
	//store this msg into the shader's information log..set the Compile Error flag!!!!
	message=GetStrfromTStr();
    CPPShInfoLogMsg(message);
    ResetTString();
    cpp->CompileError=1;
    IncLineNumber();
    return '\n';
}//CPPerror

static int CPPpragma(yystypepp * yylvalpp)
{
	char SrcStrName[2];
	char** allTokens;
	int tokenCount = 0;
	int maxTokenCount = 10;
	const char* SrcStr;
	int i;

	int token = cpp->currentInput->scan(cpp->currentInput, yylvalpp);
	
	if (token=='\n') {
		DecLineNumber();
        CPPErrorToInfoLog("#pragma");
        IncLineNumber();
	    return token;
	}
	
	allTokens = (char**)malloc(sizeof(char*) * maxTokenCount);	

	while (token != '\n') {
		if (tokenCount >= maxTokenCount) {
			maxTokenCount *= 2;
			allTokens = (char**)realloc((char**)allTokens, sizeof(char*) * maxTokenCount);
		}
		switch (token) {
		case CPP_IDENTIFIER:
			SrcStr = GetAtomString(atable, yylvalpp->sc_ident);
			allTokens[tokenCount] = (char*)malloc(strlen(SrcStr) + 1);
			strcpy(allTokens[tokenCount++], SrcStr);
			break;
		case CPP_INTCONSTANT:
			SrcStr = yylvalpp->symbol_name;
			allTokens[tokenCount] = (char*)malloc(strlen(SrcStr) + 1);
			strcpy(allTokens[tokenCount++], SrcStr);
			break;
		case CPP_FLOATCONSTANT:
			SrcStr = yylvalpp->symbol_name;
			allTokens[tokenCount] = (char*)malloc(strlen(SrcStr) + 1);
			strcpy(allTokens[tokenCount++], SrcStr);
			break;
		case -1:
            // EOF
            CPPShInfoLogMsg("#pragma directive must end with a newline");			
			return token;
		default:
			SrcStrName[0] = token;
			SrcStrName[1] = '\0';
			allTokens[tokenCount] = (char*)malloc(2);
			strcpy(allTokens[tokenCount++], SrcStrName);
		}
		token = cpp->currentInput->scan(cpp->currentInput, yylvalpp);
	}

	cpp->currentInput->ungetch(cpp->currentInput, token, yylvalpp);
	HandlePragma((const char**)allTokens, tokenCount);
	token = cpp->currentInput->scan(cpp->currentInput, yylvalpp);
	
	for (i = 0; i < tokenCount; ++i) {
		free (allTokens[i]);
	}
	free (allTokens);	

	return token;    
} // CPPpragma

#define ESSL_VERSION_NUMBER 100
#define ESSL_VERSION_STRING "100"

static int CPPversion(yystypepp * yylvalpp)
{

    int token = cpp->currentInput->scan(cpp->currentInput, yylvalpp);

    if (cpp->pastFirstStatement == 1)
        CPPShInfoLogMsg("#version must occur before any other statement in the program");

    if(token=='\n'){
		DecLineNumber();
        CPPErrorToInfoLog("#version");
        IncLineNumber();
		return token;
	}
    if (token != CPP_INTCONSTANT)
        CPPErrorToInfoLog("#version");
	
    yylvalpp->sc_int=atoi(yylvalpp->symbol_name);
	//SetVersionNumber(yylvalpp->sc_int);
    
    if (yylvalpp->sc_int != ESSL_VERSION_NUMBER)
        CPPShInfoLogMsg("Version number not supported by ESSL");

    token = cpp->currentInput->scan(cpp->currentInput, yylvalpp);
    
	if (token == '\n'){
		return token;
	}
	else{
        CPPErrorToInfoLog("#version");
	}
    return token;
} // CPPversion

static int CPPextension(yystypepp * yylvalpp)
{

    int token = cpp->currentInput->scan(cpp->currentInput, yylvalpp);
    char extensionName[80];

    if(token=='\n'){
		DecLineNumber();
        CPPShInfoLogMsg("extension name not specified");
        IncLineNumber();
		return token;
	}

    if (token != CPP_IDENTIFIER)
        CPPErrorToInfoLog("#extension");
    
    strcpy(extensionName, GetAtomString(atable, yylvalpp->sc_ident));
	    
    token = cpp->currentInput->scan(cpp->currentInput, yylvalpp);
    if (token != ':') {
        CPPShInfoLogMsg("':' missing after extension name");
        return token;
    }
    
    token = cpp->currentInput->scan(cpp->currentInput, yylvalpp);
    if (token != CPP_IDENTIFIER) {
        CPPShInfoLogMsg("behavior for extension not specified");
        return token;
    }

    updateExtensionBehavior(extensionName, GetAtomString(atable, yylvalpp->sc_ident));

    token = cpp->currentInput->scan(cpp->currentInput, yylvalpp);
	if (token == '\n'){
		return token;
	}
	else{
        CPPErrorToInfoLog("#extension");
	}
    return token;
} // CPPextension

int readCPPline(yystypepp * yylvalpp)
{
    int token = cpp->currentInput->scan(cpp->currentInput, yylvalpp);
    const char *message;
    int isVersion = 0;

    if (token == CPP_IDENTIFIER) {
        if (yylvalpp->sc_ident == defineAtom) {
             token = CPPdefine(yylvalpp);
        } else if (yylvalpp->sc_ident == elseAtom) {
			 if(ChkCorrectElseNesting()){
                 if (!cpp->ifdepth ){
                     CPPErrorToInfoLog("#else mismatch");
                     cpp->CompileError=1;
                 }
                 token = cpp->currentInput->scan(cpp->currentInput, yylvalpp);
                 if (token != '\n') {
                     CPPWarningToInfoLog("unexpected tokens following #else preprocessor directive - expected a newline");
                     while (token != '\n')
                         token = cpp->currentInput->scan(cpp->currentInput, yylvalpp);
                 }
			     token = CPPelse(0, yylvalpp);
             }else{
                 CPPErrorToInfoLog("#else after a #else");
                 cpp->ifdepth=0;
                 cpp->pastFirstStatement = 1;
                 return 0;
             }
		} else if (yylvalpp->sc_ident == elifAtom) {
            if (!cpp->ifdepth){
                 CPPErrorToInfoLog("#elif mismatch");
                 cpp->CompileError=1;
            } 
            // this token is really a dont care, but we still need to eat the tokens
            token = cpp->currentInput->scan(cpp->currentInput, yylvalpp); 
            while (token != '\n')
                token = cpp->currentInput->scan(cpp->currentInput, yylvalpp);
		    token = CPPelse(0, yylvalpp);
        } else if (yylvalpp->sc_ident == endifAtom) {
		     --cpp->elsetracker;
             if (!cpp->ifdepth){
                 CPPErrorToInfoLog("#endif mismatch");
                 cpp->CompileError=1;
             }
             else
			  	 --cpp->ifdepth;
	    } else if (yylvalpp->sc_ident == ifAtom) {
             token = CPPif(yylvalpp);
        } else if (yylvalpp->sc_ident == ifdefAtom) {
             token = CPPifdef(1, yylvalpp);
        } else if (yylvalpp->sc_ident == ifndefAtom) {
             token = CPPifdef(0, yylvalpp);
        } else if (yylvalpp->sc_ident == lineAtom) {
             token = CPPline(yylvalpp);
        } else if (yylvalpp->sc_ident == pragmaAtom) {
             token = CPPpragma(yylvalpp);
        } else if (yylvalpp->sc_ident == undefAtom) {
             token = CPPundef(yylvalpp);
        } else if (yylvalpp->sc_ident == errorAtom) {
             token = CPPerror(yylvalpp);
        } else if (yylvalpp->sc_ident == versionAtom) {
            token = CPPversion(yylvalpp);
            isVersion = 1;
        } else if (yylvalpp->sc_ident == extensionAtom) {
            token = CPPextension(yylvalpp);
        } else {
            StoreStr("Invalid Directive");
            StoreStr(GetStringOfAtom(atable,yylvalpp->sc_ident));
            message=GetStrfromTStr();
            CPPShInfoLogMsg(message);
            ResetTString();
        }
    }
    while (token != '\n' && token != 0 && token != EOF) {
		token = cpp->currentInput->scan(cpp->currentInput, yylvalpp);
	}
        
    cpp->pastFirstStatement = 1;

    return token;
} // readCPPline

void FreeMacro(MacroSymbol *s) {
    DeleteTokenStream(s->body);
}

static int eof_scan(InputSrc *in, yystypepp * yylvalpp) { return -1; }
static void noop(InputSrc *in, int ch, yystypepp * yylvalpp) { }

static void PushEofSrc() {
    InputSrc *in = malloc(sizeof(InputSrc));
    memset(in, 0, sizeof(InputSrc));
    in->scan = eof_scan;
    in->getch = eof_scan;
    in->ungetch = noop;
    in->prev = cpp->currentInput;
    cpp->currentInput = in;
}

static void PopEofSrc() {
    if (cpp->currentInput->scan == eof_scan) {
        InputSrc *in = cpp->currentInput;
        cpp->currentInput = in->prev;
        free(in);
    }
}

static TokenStream *PrescanMacroArg(TokenStream *a, yystypepp * yylvalpp) {
    int token;
    TokenStream *n;
    RewindTokenStream(a);
    do {
        token = ReadToken(a, yylvalpp);
        if (token == CPP_IDENTIFIER && LookUpSymbol(macros, yylvalpp->sc_ident))
            break;
    } while (token > 0);
    if (token <= 0) return a;
    n = NewTokenStream("macro arg", 0);
    PushEofSrc();
    ReadFromTokenStream(a, 0, 0);
    while ((token = cpp->currentInput->scan(cpp->currentInput, yylvalpp)) > 0) {
        if (token == CPP_IDENTIFIER && MacroExpand(yylvalpp->sc_ident, yylvalpp))
            continue;
        RecordToken(n, token, yylvalpp);
    }
    PopEofSrc();
    DeleteTokenStream(a);
    return n;
} // PrescanMacroArg

typedef struct MacroInputSrc {
    InputSrc    base;
    MacroSymbol *mac;
    TokenStream **args;
} MacroInputSrc;

/* macro_scan ---
** return the next token for a macro expanion, handling macro args 
*/
static int macro_scan(MacroInputSrc *in, yystypepp * yylvalpp) {
    int i;
    int token = ReadToken(in->mac->body, yylvalpp);
    if (token == CPP_IDENTIFIER) {
        for (i = in->mac->argc-1; i>=0; i--)
            if (in->mac->args[i] == yylvalpp->sc_ident) break;
        if (i >= 0) {
            ReadFromTokenStream(in->args[i], yylvalpp->sc_ident, 0);
            return cpp->currentInput->scan(cpp->currentInput, yylvalpp);
        }
    }
    if (token > 0) return token;
    in->mac->busy = 0;
    cpp->currentInput = in->base.prev;
    if (in->args) {
        for (i=in->mac->argc-1; i>=0; i--)
            DeleteTokenStream(in->args[i]);
        free(in->args);
    }
    free(in);
    return cpp->currentInput->scan(cpp->currentInput, yylvalpp);
} // macro_scan

/* MacroExpand
** check an identifier (atom) to see if it a macro that should be expanded.
** If it is, push an InputSrc that will produce the appropriate expansion
** and return TRUE.  If not, return FALSE.
*/

int MacroExpand(int atom, yystypepp * yylvalpp)
{
    Symbol              *sym = LookUpSymbol(macros, atom);
    MacroInputSrc       *in;
    int i,j, token, depth=0;
    const char *message;
	if (atom == __LINE__Atom) {
        yylvalpp->sc_int = GetLineNumber();
        sprintf(yylvalpp->symbol_name,"%d",yylvalpp->sc_int);
        UngetToken(CPP_INTCONSTANT, yylvalpp);
        return 1;
    }
    if (atom == __FILE__Atom) {
        yylvalpp->sc_int = GetStringNumber();
        sprintf(yylvalpp->symbol_name,"%d",yylvalpp->sc_int);
        UngetToken(CPP_INTCONSTANT, yylvalpp);
        return 1;
    }
	if (atom == __VERSION__Atom) {
        strcpy(yylvalpp->symbol_name,ESSL_VERSION_STRING);
        yylvalpp->sc_int = atoi(yylvalpp->symbol_name);
        UngetToken(CPP_INTCONSTANT, yylvalpp);
        return 1;
    }
    if (!sym || sym->details.mac.undef) return 0;
    if (sym->details.mac.busy) return 0;        // no recursive expansions
    in = malloc(sizeof(*in));
    memset(in, 0, sizeof(*in));
    in->base.scan = (void *)macro_scan;
    in->base.line = cpp->currentInput->line;
    in->base.name = cpp->currentInput->name;
    in->mac = &sym->details.mac;
    if (sym->details.mac.args) {
        token = cpp->currentInput->scan(cpp->currentInput, yylvalpp);
		if (token != '(') {
            UngetToken(token, yylvalpp);
            yylvalpp->sc_ident = atom;
            return 0;
        }
        in->args = malloc(in->mac->argc * sizeof(TokenStream *));
        for (i=0; i<in->mac->argc; i++)
            in->args[i] = NewTokenStream("macro arg", 0);
		i=0;j=0;
        do{
            depth = 0;
			while(1) {
                token = cpp->currentInput->scan(cpp->currentInput, yylvalpp);
                if (token <= 0) {
                    StoreStr("EOF in Macro ");
                    StoreStr(GetStringOfAtom(atable,atom));
                    message=GetStrfromTStr();
                    CPPShInfoLogMsg(message);
                    ResetTString();
                    return 1;
                }
                if((in->mac->argc==0) && (token!=')')) break;
                if (depth == 0 && (token == ',' || token == ')')) break;
                if (token == '(') depth++;
                if (token == ')') depth--;
                RecordToken(in->args[i], token, yylvalpp);
                j=1;
			}
            if (token == ')') {
                if((in->mac->argc==1) &&j==0)
                    break;
                i++;
                break;
            }
            i++;
		}while(i < in->mac->argc);

        if (i < in->mac->argc) {
            StoreStr("Too few args in Macro ");
            StoreStr(GetStringOfAtom(atable,atom));
            message=GetStrfromTStr();
            CPPShInfoLogMsg(message);
            ResetTString();
        } else if (token != ')') {
            depth=0;
			while (token >= 0 && (depth > 0 || token != ')')) {
                if (token == ')') depth--;
                token = cpp->currentInput->scan(cpp->currentInput, yylvalpp);
                if (token == '(') depth++;
            }
			
            if (token <= 0) {
                StoreStr("EOF in Macro ");
                StoreStr(GetStringOfAtom(atable,atom));
                message=GetStrfromTStr();
                CPPShInfoLogMsg(message);
                ResetTString();
                return 1;
            }
            StoreStr("Too many args in Macro ");
            StoreStr(GetStringOfAtom(atable,atom));
            message=GetStrfromTStr();
            CPPShInfoLogMsg(message);
            ResetTString();
		}
		for (i=0; i<in->mac->argc; i++) {
            in->args[i] = PrescanMacroArg(in->args[i], yylvalpp);
        }
    }
#if 0
    printf("  <%s:%d>found macro %s\n", GetAtomString(atable, loc.file),
           loc.line, GetAtomString(atable, atom));
    for (i=0; i<in->mac->argc; i++) {
        printf("\targ %s = '", GetAtomString(atable, in->mac->args[i]));
        DumpTokenStream(stdout, in->args[i]);
        printf("'\n");
    }
#endif
	/*retain the input source*/
    in->base.prev = cpp->currentInput;
    sym->details.mac.busy = 1;
    RewindTokenStream(sym->details.mac.body);
    cpp->currentInput = &in->base;
    return 1;
} // MacroExpand

int ChkCorrectElseNesting(void)
{
    if(cpp->elsedepth[cpp->elsetracker]==0){
	  cpp->elsedepth[cpp->elsetracker]=1;
      return 1;          
    }
    return 0;
}