/* * compress routines: * zmagic() - returns 0 if not recognized, uncompresses and prints * information if recognized * uncompress(method, old, n, newch) - uncompress old into new, * using method, return sizeof new * $Id: compress.c,v 1.1.1.1 1994/09/03 19:16:22 csgr Exp $ */ #include #include #include #include #include #include "file.h" static struct { char *magic; int maglen; char *argv[3]; int silent; } compr[] = { { "\037\235", 2, { "uncompress", "-c", NULL }, 0 }, { "\037\213", 2, { "gzip", "-dq", NULL }, 1 }, /* * XXX pcat does not work, cause I don't know how to make it read stdin, * so we use gzip */ { "\037\036", 2, { "gzip", "-dq", NULL }, 0 }, }; static int ncompr = sizeof(compr) / sizeof(compr[0]); static int uncompress __P((int, const unsigned char *, unsigned char **, int)); int zmagic(buf, nbytes) unsigned char *buf; int nbytes; { unsigned char *newbuf; int newsize; int i; for (i = 0; i < ncompr; i++) { if (nbytes < compr[i].maglen) continue; if (memcmp(buf, compr[i].magic, compr[i].maglen) == 0) break; } if (i == ncompr) return 0; if ((newsize = uncompress(i, buf, &newbuf, nbytes)) != 0) { tryit(newbuf, newsize, 1); free(newbuf); printf(" ("); tryit(buf, nbytes, 0); printf(")"); } return 1; } static int uncompress(method, old, newch, n) int method; const unsigned char *old; unsigned char **newch; int n; { int fdin[2], fdout[2]; if (pipe(fdin) == -1 || pipe(fdout) == -1) { error("cannot create pipe (%s).\n", strerror(errno)); /*NOTREACHED*/ } switch (fork()) { case 0: /* child */ (void) close(0); (void) dup(fdin[0]); (void) close(fdin[0]); (void) close(fdin[1]); (void) close(1); (void) dup(fdout[1]); (void) close(fdout[0]); (void) close(fdout[1]); if (compr[method].silent) (void) close(2); execvp(compr[method].argv[0], compr[method].argv); error("could not execute `%s' (%s).\n", compr[method].argv[0], strerror(errno)); /*NOTREACHED*/ case -1: error("could not fork (%s).\n", strerror(errno)); /*NOTREACHED*/ default: /* parent */ (void) close(fdin[0]); (void) close(fdout[1]); if (write(fdin[1], old, n) != n) { error("write failed (%s).\n", strerror(errno)); /*NOTREACHED*/ } (void) close(fdin[1]); if ((*newch = (unsigned char *) malloc(n)) == NULL) { error("out of memory.\n"); /*NOTREACHED*/ } if ((n = read(fdout[0], *newch, n)) <= 0) { free(*newch); error("read failed (%s).\n", strerror(errno)); /*NOTREACHED*/ } (void) close(fdout[0]); (void) wait(NULL); return n; } }