/*- * Copyright (c) 1980, 1993 *	The Regents of the University of California.  All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright *    notice, this list of conditions and the following disclaimer. * 2. 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. * 3. All advertising materials mentioning features or use of this software *    must display the following acknowledgement: *	This product includes software developed by the University of *	California, Berkeley and its contributors. * 4. Neither the name of the University nor the names of its contributors *    may be used to endorse or promote products derived from this software *    without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */#ifndef lintstatic char sccsid[] = "@(#)source.c	8.1 (Berkeley) 6/6/93";#endif /* not lint *//* * Source file management. */#include "defs.h"#include "source.h"/* * Seektab is the data structure used for indexing source * seek addresses by line number. * * The constraints are: * *  we want an array so indexing is fast and easy *  we don't want to waste space for small files *  we don't want an upper bound on # of lines in a file *  we don't know how many lines there are * * The solution is a sparse array. We have NSLOTS pointers to * arrays of NLINESPERSLOT addresses.  To find the source address of * a particular line we find the slot, allocate space if necessary, * and then find its location within the pointed to array. * * As a result, there is a limit of NSLOTS*NLINESPERSLOT lines per file * but this is plenty high and still fairly inexpensive. * * This implementation maintains only one source file at any given * so as to avoid consuming too much memory.  In an environment where * memory is less constrained and one expects to be changing between * files often enough, it would be reasonable to have multiple seek tables. */typedef int SEEKADDR;#define NSLOTS 40#define NLINESPERSLOT 500#define slotno(line)	((line)/NLINESPERSLOT)#define index(line)	((line)%NLINESPERSLOT)#define slot_alloc()	alloc(NLINESPERSLOT, SEEKADDR)#define srcaddr(line)	seektab[(line)/NLINESPERSLOT][(line)%NLINESPERSLOT]LOCAL SEEKADDR *seektab[NSLOTS];LOCAL FILE *srcfp;/* * check to make sure a source line number is valid */chkline(linenum)register LINENO linenum;{    if (linenum < 1) {	error("line number must be positive");    }    if (linenum > lastlinenum) {	error("not that many lines");    }}/* * print out the given lines from the source */printlines(l1, l2)LINENO l1, l2;{    register int c;    register LINENO i;    register FILE *fp;    chkline(l1);    chkline(l2);    if (l2 < l1) {	error("second line number less than first");    }    fp = srcfp;    fseek(fp, (long) srcaddr(l1), 0);    for (i = l1; i <= l2; i++) {	printf("%5d   ", i);	while ((c = getc(fp)) != '\n') {	    putchar(c);	}	putchar('\n');    }}/* * read the source file getting seek pointers for each line */skimsource(file)char *file;{    register int c;    register SEEKADDR count;    register FILE *fp;    register LINENO linenum;    register SEEKADDR lastaddr;    register int slot;    if (file == NIL || file == cursource) {	return;    }    if ((fp = fopen(file, "r")) == NULL) {	panic("can't open \"%s\"", file);    }    if (cursource != NIL) {	free_seektab();    }    cursource = file;    linenum = 0, count = 0, lastaddr = 0;    while ((c = getc(fp)) != EOF) {	count++;	if (c == '\n') {	    slot = slotno(++linenum);	    if (slot >= NSLOTS) {		panic("skimsource: too many lines");	    }	    if (seektab[slot] == NIL) {		seektab[slot] = slot_alloc();	    }	    seektab[slot][index(linenum)] = lastaddr;	    lastaddr = count;	}    }    lastlinenum = linenum;    srcfp = fp;}/* * Erase information and release space in the current seektab. * This is in preparation for reading in seek pointers for a * new file.  It is possible that seek pointers for all files * should be kept around, but the current concern is space. */LOCAL free_seektab(){    register int slot;    for (slot = 0; slot < NSLOTS; slot++) {	if (seektab[slot] != NIL) {	    free(seektab[slot]);	    seektab[slot] = NIL;	}    }}