Subversion Repositories zipcpu

/*******************************************************************************
**
** Filename:    zpp.l
**
** Project:     Zip CPU -- a small, lightweight, RISC CPU core
**
** Purpose:     The preprocessor for the Zip Assembler.
**
**      This routine strips comments, handles #define's, #ifdef's, and
**      #include statements in a C fashion.
**
**      #define macro's are also defined in the language and therefore
**      supposed to be supported, but the support isn't there yet.
**
** Creator:     Dan Gisselquist, Ph.D.
**              Gisselquist Tecnology, LLC
**
********************************************************************************
**
** Copyright (C) 2015, Gisselquist Technology, LLC
**
** This program is free software (firmware): you can redistribute it and/or
** modify it under the terms of  the GNU General Public License as published
** by the Free Software Foundation, either version 3 of the License, or (at
** your option) any later version.
**
** This program is distributed in the hope that it will be useful, but WITHOUT
** ANY WARRANTY; without even the implied warranty of MERCHANTIBILITY or
** FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
** for more details.
**
** You should have received a copy of the GNU General Public License along
** with this program.  (It's in the $(ROOT)/doc directory, run make with no
** target there if the PDF file isn't present.)  If not, see
** <http://www.gnu.org/licenses/> for a copy.
**
** License:     GPL, v3, as defined and found on www.gnu.org,
**              http://www.gnu.org/licenses/gpl.html
**
**
*******************************************************************************/

%{
// #include <FlexLexer.h>
#include <string>
#include <ctype.h>
#include <stdio.h>
#include <list>
#include <vector>
#include <assert.h>

using namespace std;

int yylex();
void    mark_line(void);
int     end_of_file(void);
void    pushf(const char *fname);

// #include "zprepr.tab.h"
int     ndef = 0, structno = 0;
char    *structid = NULL;
void    stb_define(const char *str);
bool    stb_current(const char *str);
bool    stb_hasargs(const char *str);
void    stb_expand(FILE *fout, const char *str);
std::string     stb_expand(const char *str);
void    stb_args(const char *str);
void    stb_macro(const char *value);
void    stb_addmacro(const char *value);
bool    stb_isdefined(const char *str);
const char      *stb_getdefn(const char *str);
%}
%x DEF DFA DFV DFV_EOL INDEF IFDEFV INNOTDEF NODEF NVRDEF COMMENT INSTRUCT
%x INDEF_EOL INNOTDEF_EOL GETSTRUCTID
%option noyywrap
%option stack
ID [_:A-Za-z][_:A-Za-z0-9]*
IDDOT {ID}("."{ID})*

%%
<COMMENT>"*/"           { yy_pop_state(); }
<COMMENT>[^*]+          { /* Ignore comments */ }
<COMMENT>"*"+[^/]       { /* Ignore comments */ }
<INITIAL,INDEF>^"#include"[ \t]+\"[^\"]+\"      {
                char *ptr = &yytext[9], *start, *end, *str;
                while(isspace(*ptr))
                        ptr++;
                start = ++ptr;
                ptr++;
                while((*ptr)&&(*ptr != '\"'))
                        ptr++;
                *ptr = '\0';
                pushf(start);
                // push_file_state(yylineno); // and filename ...
                mark_line();
        }
<INITIAL,INDEF>^"#define"[ \t]+ { yy_push_state(DEF); }
 /* <*>^"#line"[ \t]+(0-9)+[ \t]+["][^"]*["][ \t]*\n    { } */
<DEF>{IDDOT}/[^(]       {
                // fprintf(stderr, "Defining \'%s\'\n", yytext);
                stb_define(yytext);
                BEGIN DFV;
        }
<DEF>{IDDOT}/[(]        { stb_define(yytext); BEGIN DFA; }
<DFA>"("[^)]+")"                                {
                /* Process macro arguments */
                stb_args(yytext);
                BEGIN DFV;
        }
<DFV>^[ \t]+    { stb_macro(yytext); /* Replicate initial spaces */ }
<DFV>[ \t]+     { stb_macro(" "); /* Ignore all  but one internal space */ }
<DFV>{ID}       {/* Parse to end of line, get value for our define */
                // fprintf(stderr, "%s may be a macro, line %d\n", yytext, yylineno);
                if ((!stb_current(yytext))&&(stb_isdefined(yytext))) {
                        // fprintf(stderr, "Recursive MACRO!\n");
                        stb_macro(stb_getdefn(yytext));
                } else {
                        // fprintf(stderr, "But it is not defined\n");
                        stb_macro(yytext);
                }
        }
<DFV>{ID}[ \t]*[(][ \t]*{ID}[ \t]*(,[ \t]*{ID}[ \t]*)*[)]       { 
                // fprintf(stderr, "%s may be a macro within a macro!\n", yytext);
                if ((!stb_current(yytext))&&(stb_isdefined(yytext))) {
                        if (stb_hasargs(yytext)) {
                                std::string str = stb_expand(yytext);
                                stb_macro(str.c_str());
                        } else {
                                char *dup = strdup(yytext), *ptr;
                                ptr = strchr(dup, '(');
                                *ptr = '\0';
                                stb_macro(stb_getdefn(dup));
                                free(dup);
                                yyless(strchr(yytext,'(')-yytext);
                        }
                } else {
                        char *dup = strdup(yytext), *ptr;
                        ptr = strchr(dup, '(');
                        *ptr = '\0';
                        stb_macro(stb_getdefn(dup));
                        free(dup);
                        yyless(strchr(yytext,'(')-yytext);
                }
        }
<DFV>[^a-zA-Z_0-9 \t\n]+        {/* Parse to end of line, get value for our define */
                // fprintf(stderr, "A: Adding to macro %s\n", yytext);
                stb_macro(yytext);
        }
<DFV>0[xX][0-9A-Fa-f]+  {/* Get any hexadecimal constants */
                // fprintf(stderr, "B: Adding to macro %s\n", yytext);
                stb_macro(yytext);
        }
<DFV>[0-9A-Fa-f]+[hH]   {/* Get any hexadecimal constants */
                // fprintf(stderr, "C: Adding to macro %s\n", yytext);
                stb_macro(yytext);
        }
<DFV>[0-7]+[oO] {/* Get any hexadecimal constants */
                // fprintf(stderr, "D: Adding to macro %s\n", yytext);
                stb_macro(yytext);
        }
<DFV>[0-9]+     {/* Get any hexadecimal constants */
                // fprintf(stderr, "E: Adding to macro %s\n", yytext);
                stb_macro(yytext);
        }
<DFV>[ \t]*((;|"//").*)?$       {/* Parse to end of line, get value for our define */
                yy_pop_state();
        }
<DFV>[ \t]*"\\"[ \t]*((;|"//").*)?\n    {/* Continue onto next line */
                fprintf(yyout, "\n"); mark_line(); yylineno++;
                stb_macro("\n");
        }
<INITIAL,INDEF>^[ \t]+.[dD][aA][tT][aA]?        { fprintf(yyout, "\tWORD"); }
<INITIAL,INDEF>^"#defcont"[ \t]+        { yy_push_state(DFV); }
<INITIAL,INDEF>^"#ifdef"[ \t]*  { ndef = 0; yy_push_state(IFDEFV); }
<INITIAL,INDEF>^"#ifndef"[ \t]* { ndef = 1; yy_push_state(IFDEFV); }
<IFDEFV>{IDDOT} {
                bool    known = stb_isdefined(yytext);
                if ( ((known)&&(ndef==0)) || ((!known)&&(ndef!=0)) ) {
                        BEGIN INDEF_EOL;
                } else {
                        BEGIN INNOTDEF_EOL;
                }
        }
        /* Not yet: <INITIAL,INDEF>^"#if"[ \t]*         { yy_push_state(IFDEFE); }
        /* Not yet: <INITIAL,INDEF>^"#if"[ \t]*         { yy_push_state(IFDEFE); }
        /* Not yet: <IFDEFE><expr> { yy_push_state(IFDEFE); } */
        /* <INNOTDEF>^"#elsif"[ \t]*    { yy_pop_state(); yy_push_state(IFDEFE); } */
<INDEF_EOL>[ \t]*$              { BEGIN INDEF; }
<INDEF_EOL>(;|"//").*$          { BEGIN INDEF; }
<INNOTDEF_EOL>[ \t]*$           { BEGIN INNOTDEF; }
<INNOTDEF_EOL>(;|"//").*$       { BEGIN INNOTDEF; }
<INDEF_EOL>[^ \t\n].*$          { BEGIN INDEF; fprintf(stderr, "WARNING! Unexpected characters on IFDEF line, \'%s\'\n", yytext); mark_line(); }
<INNOTDEF_EOL>[^ \t\n].*$       { BEGIN INNOTDEF; fprintf(stderr, "WARNING! Unexpected characters on IFNDEF line, %s\n", yytext); mark_line(); }
<INDEF,NVRDEF>^"#else"[ \t]*((;|"//").*)?$      { BEGIN NODEF; }
<INNOTDEF>^"#else"[ \t]*((;|"//").*)?$          { BEGIN INDEF; }
<INNOTDEF>(.*)                  { }
<INDEF>^"#elsif"[ \t]*          { BEGIN NVRDEF; }
<NVRDEF,NODEF,INDEF,INNOTDEF>^"#endif"[ \t]*((;|"//").*)?$      { yy_pop_state(); }
<NVRDEF,NODEF,INDEF,INNOTDEF>^"#endif"[ \t]*"/*"        { BEGIN COMMENT; }
<*>^"#endif"[ \t]*              { fprintf(stderr, "ERR: Unknown endif!!\n");}
<INITIAL,INDEF>^"#struct"[ \t]* {
                yy_push_state(GETSTRUCTID); structno  = 0; }
<*>^"#"{ID}[ \t]*               { fprintf(stderr, "ERR: Unrecognized preprocessor instruction, %s\n", yytext);}
<GETSTRUCTID>{ID}/[ \t\n;/]     { BEGIN INSTRUCT;
                structid = strdup(yytext);
                }
<INSTRUCT>{ID}("."{ID})*        { 
                fprintf(yyout, "\t%s.%s\tequ\t%d", structid, yytext, structno++); }
<INSTRUCT>^"#endstruct".*$      { yy_pop_state(); }
        /* Not yet: ^"#struct"[ \t]*    {}      */
        /* Not yet: ^"#endstruct"[ \t]* {}      */
        /* Not yet: ^"#seg"[ \t]*       {}      */
<NODEF,NVRDEF>.*                { /* Ignore everything in these states*/ }
<INITIAL,INDEF>{ID}/[^(]        { 
                if (stb_isdefined(yytext))
                        fprintf(yyout, "%s", stb_getdefn(yytext));
                else
                        fprintf(yyout, "%s", yytext);
        }
<INITIAL,INDEF>{ID}([ \t]*)     { 
                if (stb_isdefined(yytext))
                        fprintf(yyout, "%s", stb_getdefn(yytext));
                else
                        fprintf(yyout, "%s", yytext);
        }
<INITIAL,INDEF>{ID}[ \t]*[(][ \t]*{ID}[ \t]*(,[ \t]*{ID}[ \t]*)*[)]     { 
                // fprintf(stderr, "%s may be a macro!\n", yytext);
                if (stb_isdefined(yytext)) {
                        if (stb_hasargs(yytext)) {
                                stb_expand(yyout, yytext);
                        } else {
                                fprintf(yyout, "%s", stb_getdefn(yytext));
                                yyless(strchr(yytext,'(')-yytext);
                        }
                } else {
                        // fprintf(stderr, "But it is not defined\n");
                        fprintf(yyout, "%s", yytext);
                }
        }
<*>[ \t]*"//".*$        { /* Ignore (trailing) comment only lines */ }
<*>[ \t]*";".*$         { /* Ignore (trailing) comment only lines */ }
<*>"#warning".*$        { fprintf(stderr, "WARNING: %s\n", &yytext[8]); }
<*>"#error".*$          { fprintf(stderr, "ERROR: %s\n", &yytext[8]); exit(-1); }
<*>"/*"                 { yy_push_state(COMMENT); }
<*>[ \t]+               { ECHO; }
<*>\n                   { ECHO; yylineno++; mark_line(); }
        /* <*>.                 { printf("Unmatched \'%c\'\n", yytext[0]); } */
<NVRDEF,NODEF,INDEF,INNOTDEF><<EOF>>    { fprintf(stderr, "Unexpected EOF!  Expecting #endif\n"); }
<IFDEFV><<EOF>>         { fprintf(stderr, "Unexpected EOF!  Expecting #endif\n"); }
<COMMENT><<EOF>>        { fprintf(stderr, "Unexpected EOF!  Expecting */\n"); }
<INSTRUCT><<EOF>>       { fprintf(stderr, "Unexpected EOF!  Expecting #endstruct\n"); }
<GETSTRUCTID><<EOF>>    { fprintf(stderr, "Unexpected EOF!  Expecting #struct ID, then #endstruct\n"); }
<DFA,DFV,DFV_EOL><<EOF>> { fprintf(stderr, "Unexpected EOF!  Expecting end of line\n"); }
<INDEF_EOL,INNOTDEF_EOL><<EOF>  { fprintf(stderr, "Unexpected EOF  Expecting end of line, then #endif\n"); }
<INITIAL><<EOF>>        { if (end_of_file()) yyterminate(); }

%%

class   SYMTABLE_ACTION {
public:
        // Types: 0 (end of actions), 1-X, argument number, <0 raw string
        int             m_type;
        std::string     m_str;          // if m_type < 0, have m_str
};

class   SYMTABLE_ENTRY {
private:
        bool    m_reduced;
        std::string     &trim(std::string &s) {
                std::string::iterator   ptr = s.end();

                while((ptr >= s.begin())&&(isspace(*ptr)))
                        *ptr-- = '\0';

                return s;
        }

public:
        std::string     m_name, m_value, m_args;
        std::vector<SYMTABLE_ACTION>    m_actions;
        SYMTABLE_ENTRY(const char *str) : m_name(str) {
                trim(m_name);
                m_reduced = false;
        }
        SYMTABLE_ENTRY &operator+=(const char *str) {
                const char      *start = str;

                while(isspace(*start))
                        start++;
                if (m_value.length()!=0)
                        m_value += " ";

                m_value += str;

                /*
                printf("ENTRY::SYMBOL \'%s\' NOW = \'%s\'\n",
                        m_name.c_str(), m_value.c_str());
                */
                return *this;
        }
        SYMTABLE_ENTRY &setargs(const char *str) {
                m_args += str;
                return *this;
        }

        const std::string &getdefn(void) {
                return m_value;
        }

        bool    hasargs(void) {
                return (m_args.size()>0);
        }

        void    reduce(void) {
                if (m_reduced)
                        return;

                // fprintf(stderr, "Reducing %s ( %s ) \n", m_name.c_str(), m_args.c_str());
                std::vector<std::string>        alist;
                int i=0, bg, en;
                do {
                        if ((m_args[i] == ',')||(m_args[i] == '('))
                                i++;
                        while((m_args[i])&&(isspace(m_args[i])))
                                i++;
                        bg = i;
                        while((m_args[i])&&(
                                (isalpha(m_args[i]))
                                ||(m_args[i]==':')
                                ||(m_args[i]=='_')
                                ||(isdigit(m_args[i]))))
                                i++;
                        en = i;
                        while((m_args[i])&&(isspace(m_args[i])))
                                i++;

                        alist.push_back(m_args.substr(bg,en-bg));
                        // printf("Found argument %2ld of %s: \'%s\'\n",
                                // alist.size(),
                                // m_name.c_str(),
                                // m_args.substr(bg,en-bg).c_str());
                } while((m_args[i])&&(m_args[i] == ','));

                assert(m_args[i] == ')');

                // Now that we know our arguments, lets look for these
                // arguments in our macro definition
                std::string     building;
                i = 0;
                while(m_value[i]) {
                        int     nxti = m_value.size(), nxtv;
                        for(int a=0; a<alist.size(); a++) {
                                const char *ptr;
                                ptr = strstr(m_value.c_str()+i, alist[a].c_str());
                                while((ptr)&&(ptr-m_value.c_str() < nxti)) {
                                        int loc = ptr-m_value.c_str();
                                        const char *pre = ptr-1;
                                        const char *pst = ptr+alist[a].size();
                                        if ((loc < nxti)&&(
                                                (loc == i)
                                                ||((!isalpha(*pre)
                                                        &&(*pre != '_')
                                                        &&(*pre != ':')
                                                        &&(!isdigit(*pre)))))
                                                &&((*pst=='\0')
                                                ||(     (!isalpha(*pst))
                                                        &&(*pst != '_')
                                                        &&(*pst != ':')
                                                        &&(!isdigit(*pst)))))
                                        {
                                                        nxti = loc;
                                                        nxtv = a;
                                                        break;
                                        } else {
                                                ptr = strstr(m_value.c_str()+loc, alist[a].c_str());
                                                loc = ptr-m_value.c_str();
                                        }
                                }
                        }

                        if (nxti < m_value.size()) {
                                // Found an argument!!
                                SYMTABLE_ACTION act;
                                if (nxti > i) {
                                        act.m_type = -1;
                                        act.m_str = m_value.substr(i,nxti-i);
                                        // printf("ACTION: \'%s\'\n", act.m_str.c_str());
                                        m_actions.push_back(act);
                                }
                                act.m_type = nxtv;
                                act.m_str = "";
                                m_actions.push_back(act);
                                // printf("ACTION[%2d]: \'%s\'\n", nxtv, alist[nxtv].c_str());
                                
                                i = nxti+alist[nxtv].size();
                        } else break; // No more arguments
                } if (i<m_value.size()) {
                        SYMTABLE_ACTION act;
                        act.m_type = -1;
                        act.m_str = m_value.substr(i);
                        // printf("ACTION: \'%s\'\n", act.m_str.c_str());
                        m_actions.push_back(act);
                }
                m_reduced = true;
        }

        std::string expand(std::string args) {
                if (!m_reduced)
                        reduce();
                std::vector<std::string>        alist;
                std::string     result;

                // printf("Expanding %s\n", args.c_str());
                int i=0, bg, en, nest=-1;
                do {
                        if ((args[i] == '(')||(args[i] == ',')) {
                                if (args[i] =='(')
                                        nest++;
                                i++;
                        }
                        while((args[i])&&(isspace(args[i])))
                                i++;
                        bg = i;
                        while((args[i])&&(args[i] != ',')&&((args[i] != ')')||(nest != 0))) {
                                if (args[i] == '(')
                                        nest++;
                                else if (args[i] == ')')
                                        nest--;
                                i++;
                        } en = i-1;
                        while((en>0)&&(isspace(args[en])))
                                en--;
                        alist.push_back(args.substr(bg,en+1-bg));
                        // printf("Argument %2ld of %s maps to \'%s\'\n",
                                // alist.size(),
                                // m_name.c_str(),
                                // args.substr(bg,en+1-bg).c_str());
                } while((args[i])&&(args[i] == ','));

                // printf("At end, args[i] = \'%s\'\n", &args[i]);
                assert(args[i] == ')');

                // printf("Filling in %ld actions\n", m_actions.size());
                for(i=0; i<m_actions.size(); i++) {
                        if((m_actions[i].m_type >= 0)&&(m_actions[i].m_type < alist.size()))
                                result += alist[m_actions[i].m_type].c_str();
                        else if (m_actions[i].m_type < 0)
                                result += m_actions[i].m_str.c_str();
                        // else {
                                // fprintf(fout, "m_type = %d, size = %ld\n", m_actions[i].m_type, alist.size());
                        // }
                }

                return result;
        }
};

class   SYMBOL_TABLE {
private:
        typedef SYMTABLE_ENTRY  *TBLV;
        typedef std::list<TBLV> TBLT;

        TBLT    m_tbl;
        TBLT::iterator  lookup(const char *str) {
                TBLT::iterator  i = m_tbl.begin();
                for(; (i!= m_tbl.end())&&(strcmp(str, (*i)->m_name.c_str())>0); i++)
                        ;
                if ((i != m_tbl.end())&&(strcmp(str, (*i)->m_name.c_str())==0))
                        return i;
                return m_tbl.end();
        }

public:
        SYMBOL_TABLE(void) {}

        void define(const char *str) {
                SYMTABLE_ENTRY  *v = new SYMTABLE_ENTRY(str);
                TBLT::iterator  i = m_tbl.begin();
                for(; (i!= m_tbl.end())&&(strcmp(str, (*i)->m_name.c_str())>0); i++)
                        ;
                m_tbl.insert(i, v);

                // fprintf(stderr, "SYMS::Defining SYMBOL: \'%s\'\n", str);
        }

        bool defined(const char *str) {
                TBLT::iterator  i = lookup(str);
                if (i==m_tbl.end())
                        return false;
                else
                        return true;
        }


        void    undefine(const char *str) {
                TBLT::iterator  i = lookup(str);
                if (i == m_tbl.end())
                        return;
                TBLV    v = (*i);
                m_tbl.erase(i);
                delete  v;
        }

        void    addmacro(const char *name, const char *str) {
                TBLT::iterator i = lookup(name);
                if (i == m_tbl.end()) {
                        fprintf(stderr, "INTERNAL ERR, %s NOT DEFINED!\n", name);
                } *(*i) += str;
        }
                                
        void    addargs(const char *name, const char *str) {
                TBLT::iterator i = lookup(name);
                if (i == m_tbl.end()) {
                        fprintf(stderr, "INTERNAL ERR, %s NOT DEFINED!\n", name);
                } (*i)->setargs(str);
        }
        bool    hasargs(const char *name) {
                TBLT::iterator i = lookup(name);
                if (i == m_tbl.end()) {
                        return false;
                } return (*i)->hasargs();
        }
        const   char *getdefn(const char *name) {
                TBLT::iterator i = lookup(name);
                if (i == m_tbl.end()) {
                        fprintf(stderr, "INTERNAL ERR, %s NOT DEFINED!\n", name);
                        return NULL;
                } (*i)->getdefn().c_str();
        }

        std::string     expand(const char *name, const char *ptr) {
                TBLT::iterator  i = lookup(name);
                if (i==m_tbl.end())
                        return std::string("");
                return (*i)->expand(std::string(ptr));
        }
                                
};

SYMTABLE_ENTRY  *last = NULL;
SYMBOL_TABLE    syms;
std::string     last_define;

void    stb_define(const char *str) {
        /*
        if (last_define.size()>0) {
                fprintf(stderr, "LAST-DEFINE(%s): %s\n", last_define.c_str(),
                        stb_getdefn(last_define.c_str()));
        } */

        if (syms.defined(str)) {
                fprintf(stderr, "WARNING!  Symbol \'%s\' is already defined!\n", str);
                syms.undefine(str);
        }

        syms.define(str);
        last_define = str;
}

void    stb_args(const char *args) {
        syms.addargs(last_define.c_str(), args);
}

void    stb_macro(const char *value) {
        syms.addmacro(last_define.c_str(), value);
}

void    stb_addmacro(const char *value) {
        syms.addmacro(last_define.c_str(),value);
}

bool    stb_isdefined(const char *str) {
        const char *ptr;
        if ((ptr = strchr(str, '('))!=NULL) {
                // fprintf(stderr, "Checking whether %s needs to be expanded\n",str);
                char *dup = strdup(str), *chr;
                chr = strchr(dup, '(');
                *chr = '\0';
                // fprintf(stderr, "\tLooking it up by the name \'%s\'\n", dup);
                bool r = (syms.defined(dup));
                free(dup);
                return r;
        } else {
                return syms.defined(str);
        }
}

const char *stb_getdefn(const char *str) {
        return syms.getdefn(str);
}

bool    stb_current(const char *str) {
        return (strcmp(str, last_define.c_str())==0);
}

bool    stb_hasargs(const char *str) {
        const char *ptr;
        if ((ptr = strchr(str, '('))!=NULL) {
                char *dup = strdup(str), *chr;
                chr = strchr(dup, '(');
                *chr = '\0';
                bool r = (syms.hasargs(dup));
                // fprintf(stderr, "\t%s has %sarguments\n", dup, (r)?"":"no ");
                free(dup);
                return r;
        } else {
                return syms.hasargs(str);
        }
}

std::string     stb_expand(const char *macro) {
        const   char    *ptr;
        std::string     str;
        ptr = strchr(macro, '(');
        assert(ptr);
        ptr--;
        while((ptr>macro)&&(isspace(*ptr)))
                ptr--;
        char *nam = strndup(macro, ptr+1-macro);
        ptr = strchr(ptr, '(');
        // fprintf(stderr, "Requesting an expansion of %s -- %s\n", nam, ptr);
        str = syms.expand(nam, ptr);
        free(nam);

        return str;
}

void    stb_expand(FILE *fout, const char *macro) {
        std::string     str = stb_expand(macro);
        fprintf(fout, "%s", str.c_str());
}

class   BUFSTACK {
public:
        FILE            *m_fp;
        char            *m_fname;
        int             m_lineno;
        BUFSTACK        *m_prev;
        YY_BUFFER_STATE m_bs;

        static  BUFSTACK        *curbs;
        static  const char      *curfilename;

        BUFSTACK(void) {
                m_fp = stdin;

                if (curbs)
                        curbs->m_lineno = yylineno;
                m_prev = curbs;
                // m_bs = yy_create_buffer(fp, YY_BUF_SIZE);
                m_fname = strdup("(stdin)");
                // yy_switch_to_buffer(m_bs);
                m_bs = NULL;
                curbs = this;
                m_lineno = 1;
                curfilename = m_fname;

                yyrestart(m_fp);
                yylineno = 1;
        }

        BUFSTACK(const char *fname) {
                m_fp = fopen(fname, "r");
                if (!m_fp) {
                        char *pathptr = getenv("ZIPINC");
                        if (!pathptr) {
                                fprintf(stderr, "Cannot open %s\n", fname);
                                perror("O/S Err:");
                                exit(-1);
                        } else {
                                char    *dptr, *colonp;
                                char *pathcpy = new char[strlen(pathptr)+8192];
                                strcpy(pathcpy, pathptr);

                                fprintf(stderr, "ZIPINC := %s\n", pathptr);
                                dptr = pathptr;
                                while((!m_fp)&&(NULL != (colonp = strchr(dptr, ':')))) {
                                        strncpy(pathcpy, dptr, colonp-pathptr);
                                        strcat(pathcpy, "/");
                                        strcat(pathcpy, fname);
                                        fprintf(stderr, "Looking for include file, %s\n", pathcpy);
                                        if (access(fname, R_OK)==0)
                                                m_fp = fopen(pathcpy, "r");
                                        dptr = colonp+1;
                                } if ((!m_fp)&&(*dptr)) {
                                        strcpy(pathcpy, dptr);
                                        strcat(pathcpy, "/");
                                        strcat(pathcpy, fname);
                                        fprintf(stderr, "Looking for include file, %s\n", pathcpy);
                                        m_fp = fopen(pathcpy, "r");
                                } if (!m_fp) {
                                        fprintf(stderr, "Cannot open %s\n", fname);
                                        perror("O/S Err:");
                                        exit(-1);
                                }

                                delete[] pathcpy;
                        }
                }

                if (curbs)
                        curbs->m_lineno = yylineno;
                m_prev = curbs;
                m_bs = yy_create_buffer(m_fp, YY_BUF_SIZE);
                m_fname = strdup(fname);
                yy_switch_to_buffer(m_bs);
                curbs = this;
                m_lineno = 1;
                curfilename = m_fname;

                yyrestart(m_fp);
                yylineno = 1;
        }

        ~BUFSTACK(void) {
                // fprintf(stderr, "DELETING(%s)\n", m_fname);
                fclose(m_fp);
                free(m_fname);
                if (m_bs)
                        yy_delete_buffer(m_bs);
                curbs = m_prev;

                if (curbs) {
                        yy_switch_to_buffer(curbs->m_bs);
                        yylineno = curbs->m_lineno;
                        curfilename = curbs->m_fname;
                }
        }

        void    mark(void) {
                FILE    *fp = yyout;
                if (!fp) fp = stdout;
                fprintf(fp, "#line %d \"%s\"\n", yylineno, m_fname);
        }

        void    markline(void) {
                FILE    *fp = yyout;
                if (!fp) fp = stdout;
                fprintf(fp, "#line %d\n", yylineno);
        }

        static  void pop(void) {
                // fprintf(stderr, "POP! (%s)\n", curbs->m_fname);
                if (curbs)
                        delete curbs;
        }
};

BUFSTACK *BUFSTACK::curbs = NULL;
const char *BUFSTACK::curfilename = NULL;

int             last_marked_line = -1;
const char      *last_marked_file = NULL;
void    mark_line(void) {
        if ((yylineno != last_marked_line+1)||(BUFSTACK::curfilename != last_marked_file))
                if (BUFSTACK::curfilename == last_marked_file)
                        BUFSTACK::curbs->markline();
                else BUFSTACK::curbs->mark();
        last_marked_line = yylineno;
        last_marked_file = BUFSTACK::curfilename;
}

int     end_of_file(void) {
        BUFSTACK::pop();
        return (BUFSTACK::curbs == NULL);
}

void    pushf(const char *fname) {
        BUFSTACK        *bs = new BUFSTACK(fname);
}

int main(int argc, char **argv) {
        yylineno = 1;
        if (argc < 2) { // Stdin only
                BUFSTACK::curbs = new BUFSTACK();
                yylex();
        } else {
                for(int argn=1; argn<argc; argn++) {
                        BUFSTACK        *bs = new BUFSTACK(argv[argn]);
                        mark_line();
                        yylex();
                        // delete       bs;
                }
        }

        return 0;
}