shithub: sdbm

ref: 64e312636599ea2c86f21dc1176dca7da77bd74a
dir: /dbd.c/

/*
 * dbd - dump a dbm data file
 */

#include <u.h>
#include <libc.h>
#include <stdio.h>

#include "sdbm.h"

char *progname;
extern void oops(char *, char *);
extern int okpage(char *);

void sdump(int);
void dispage(char *);

#define empty(page)	(((short *) page)[0] == 0)

void
main(int argc, char ** argv)
{
	int n;
	char *p;
	char *name;
	int pagf;

	progname = argv[0];

    if (argc != 2) oops("usage: %s dbname\n", progname); /* keeps compiler quiet */

	if (p = argv[1]) {
		name = (char *) malloc((n = strlen(p)) + 5);
		strcpy(name, p);
		strcpy(name + n, ".pag");

		if ((pagf = open(name, OREAD)) < 0)
			oops("cannot open %s.", name);

		sdump(pagf);
	}
	else
		oops("usage: %s dbname\n", progname);
	exits(0);
}

void
sdump(int pagf)
{
	int r;
	int n = 0;
	int o = 0;
	char pag[PBLKSIZ];
	char num[16];

	while ((r = read(pagf, pag, PBLKSIZ)) > 0) {
		if (!okpage(pag))
			fprintf(stderr, "%d: bad page.\n", n);
		else if (empty(pag))
			o++;
		else
			dispage(pag);
		n++;
	}

	if (r == 0)
		fprintf(stderr, "%d pages (%d holes).\n", n, o);
	else 
	{
		snprint(num, 15, "%d", n);
		oops("read failed: block %d", num);
	}
}

void
dispage(char *pag){
	int i, n;
	int off;
	short *ino = (short *) pag;

	off = PBLKSIZ;
	for (i = 1; i < ino[0]; i += 2) {
		for (n = ino[i]; n < off; n++)
			if (pag[n] != 0)
				putchar(pag[n]);
		putchar('\t');
		off = ino[i];
		for (n = ino[i + 1]; n < off; n++)
			if (pag[n] != 0)
				putchar(pag[n]);
		putchar('\n');
		off = ino[i + 1];
	}
}