/*
 * addfile(), nextfile(): maintain a circular buffer of file names
 */

#include "m.h"

#ifdef __unix__
# define LIBRARY "/usr/local/lib/m/"
#endif

#ifdef vms
# define LIBRARY "esl$dir:[lib.m]"
#endif

#ifdef MSDOS
# define LIBRARY "C:\\m\\lib\\"		/* not used anymore */
#endif

#ifndef LIBRARY
# define LIBRARY ""
#endif

#define MAXFILES 128

static char *files[MAXFILES];
static char **start = files;	/* location to return for nextfile */
static char **stop = files;	/* next free location for addfile() */
static int nfiles = 0;		/* number of file names in buffer */

#define inc(p) if( ++p >= files + MAXFILES) p = files

void addfile( char *name)
{
    if( nfiles == MAXFILES) {
	yyerror("file list overflow in addfile()");
	return;
    }

    if( (*stop = strdup(name)) == NULL)
	yyerror("strdup() failed in addfile()");
    else {
	inc( stop);
	++nfiles;
    }
}

/*
 * I think this routine is no longer needed.
 * load is handled by #include in scan.l
 */
FILE *nextfile( void)
{
    FILE *f = NULL;
    char name[BUFSIZ];

    while( nfiles > 0) {
#ifdef DEBUG
	if( prog_debug)
	    dprint("nextfile: %s\n", *start);
#endif
	--nfiles;
	if( (f = fopen( *start, "r")) == NULL) {
#ifdef MSDOS
	    (void) strcat( strcat( strcpy( name, exedir), "lib\\"), *start);
#else
	    (void) strcat( strcpy( name, LIBRARY), *start);
#endif
	    if( (f = fopen( name, "r")) == NULL)
		dprint("nextfile: could not open %s or %s\n", *start, name);
	}
	free( *start);
	inc(start);
	if( f)
	    break;
    }

    return (f == NULL) ? stdin : f;
}

/*
 * include_name will contain no ' ', '\t', or '\n' when open_include is called
 * from yylex.  It should be in one of the forms: name, <name>, "name"
 */
FILE *open_include( const char *include_name)
{
    char name[BUFSIZ];		/* copy of include_name for strtok() */
    char *cwd_name;		/* strtok'd name */
    char lib_name[BUFSIZ];	/* Library path + cwd_name */
    char *p1, *p2;		/* paths to check first and second */
    FILE *f;			/* fopen() result */

#ifdef DEBUG
    if( prog_debug)
	dprint("open_include: %s\n", include_name);
#endif

    strcpy( name, include_name);
    cwd_name = strtok( name, "\"<>");

    if( cwd_name == NULL) { /* bad name, like "" or <> */
	yyerror( "open_include: bad file name");
	return NULL;
    }

#ifdef MSDOS
    strcat( strcat( strcpy( lib_name, exedir), "lib\\"), cwd_name);
#else
    strcat( strcpy( lib_name, LIBRARY), cwd_name);
#endif

    if( *include_name == '<') {	/* search M library first */
	p1 = lib_name;
	p2 = cwd_name;
    } else {			/* search cwd first */
	p1 = cwd_name;
	p2 = lib_name;
    }

#ifdef DEBUG
    if( prog_debug)
	dprint("open_include: trying %s then %s\n", p1, p2);
#endif

    if( (f = fopen( p1, "r")) == NULL && (f = fopen( p2, "r")) == NULL)
	dprint("could not open %s or %s\n", p1, p2);

    return f;
}