From d464704f111d211c1f1ff9ef23ef1d755054be00 Mon Sep 17 00:00:00 2001 From: shyouhei Date: Wed, 15 Aug 2007 19:08:43 +0000 Subject: add tag v1_8_5_54 git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/tags/v1_8_5_54@12952 b2dd03c8-39d4-4d8f-98ff-823fe69b080e --- ruby_1_8_5/ext/sdbm/_sdbm.c | 973 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 973 insertions(+) create mode 100644 ruby_1_8_5/ext/sdbm/_sdbm.c (limited to 'ruby_1_8_5/ext/sdbm/_sdbm.c') diff --git a/ruby_1_8_5/ext/sdbm/_sdbm.c b/ruby_1_8_5/ext/sdbm/_sdbm.c new file mode 100644 index 0000000000..11353e2345 --- /dev/null +++ b/ruby_1_8_5/ext/sdbm/_sdbm.c @@ -0,0 +1,973 @@ +/* + * sdbm - ndbm work-alike hashed database library + * based on Per-Aake Larson's Dynamic Hashing algorithms. BIT 18 (1978). + * author: oz@nexus.yorku.ca + * status: public domain. + * + * core routines + */ + +#ifndef lint +/*char sdbm_rcsid[] = "$Id: _sdbm.c,v 1.5.2.1 2005/09/08 05:59:41 matz Exp $";*/ +#endif + +#include "sdbm.h" +#include "config.h" + +/* + * sdbm - ndbm work-alike hashed database library + * tuning and portability constructs [not nearly enough] + * author: oz@nexus.yorku.ca + */ + +#define BYTESIZ 8 + +#ifdef HAVE_UNISTD_H +#include +#endif + +#ifdef BSD42 +#define SEEK_SET L_SET +#define memset(s,c,n) bzero(s, n) /* only when c is zero */ +#define memcpy(s1,s2,n) bcopy(s2, s1, n) +#define memcmp(s1,s2,n) bcmp(s1,s2,n) +#endif + +/* + * important tuning parms (hah) + */ + +#define SEEDUPS /* always detect duplicates */ +#define BADMESS /* generate a message for worst case: + cannot make room after SPLTMAX splits */ +/* + * misc + */ +#ifdef DEBUG +#define debug(x) printf x +#else +#define debug(x) +#endif + +#ifdef BIG_E +#define GET_SHORT(p, i) (((unsigned)((unsigned char *)(p))[(i)*2] << 8) + (((unsigned char *)(p))[(i)*2 + 1])) +#define PUT_SHORT(p, i, s) (((unsigned char *)(p))[(i)*2] = (unsigned char)((s) >> 8), ((unsigned char *)(p))[(i)*2 + 1] = (unsigned char)(s)) +#else +#define GET_SHORT(p, i) ((p)[i]) +#define PUT_SHORT(p, i, s) ((p)[i] = (s)) +#endif + +/*#include "pair.h"*/ +static int fitpair proto((char *, int)); +static void putpair proto((char *, datum, datum)); +static datum getpair proto((char *, datum)); +static int delpair proto((char *, datum)); +static int chkpage proto((char *)); +static datum getnkey proto((char *, int)); +static void splpage proto((char *, char *, long)); +#ifdef SEEDUPS +static int duppair proto((char *, datum)); +#endif + +#include +#include +#ifdef MSDOS +#include +#endif +#include +#include +#ifdef BSD42 +#include +#else +#include +/*#include */ +#endif +#ifndef O_BINARY +#define O_BINARY 0 +#endif + +#include +#ifndef EPERM +#define EPERM EACCES +#endif +#include + +#ifdef __STDC__ +#include +#endif + +#ifndef NULL +#define NULL 0 +#endif + +/* + * externals + */ +#if !defined sun && !defined MSDOS && !defined _WIN32 && !defined __CYGWIN__ && !defined(errno) +extern int errno; +#endif + +/* + * forward + */ +static int getdbit proto((DBM *, long)); +static int setdbit proto((DBM *, long)); +static int getpage proto((DBM *, long)); +static datum getnext proto((DBM *)); +static int makroom proto((DBM *, long, int)); + +/* + * useful macros + */ +#define bad(x) ((x).dptr == NULL || (x).dsize < 0) +#define exhash(item) sdbm_hash((item).dptr, (item).dsize) +#define ioerr(db) ((db)->flags |= DBM_IOERR) + +#define OFF_PAG(off) (long) (off) * PBLKSIZ +#define OFF_DIR(off) (long) (off) * DBLKSIZ + +static long masks[] = { + 000000000000L, 000000000001L, 000000000003L, + 000000000007L, 000000000017L, 000000000037L, + 000000000077L, 000000000177L, 000000000377L, + 000000000777L, 000000001777L, 000000003777L, + 000000007777L, 000000017777L, 000000037777L, + 000000077777L, 000000177777L, 000000377777L, + 000000777777L, 000001777777L, 000003777777L, + 000007777777L, 000017777777L, 000037777777L, + 000077777777L, 000177777777L, 000377777777L, + 000777777777L, 001777777777L, 003777777777L, + 007777777777L, 017777777777L +}; + +datum nullitem = {NULL, 0}; + +DBM * +sdbm_open(file, flags, mode) +register char *file; +register int flags; +register int mode; +{ + register DBM *db; + register char *dirname; + register char *pagname; + register int n; + + if (file == NULL || !*file) + return errno = EINVAL, (DBM *) NULL; +/* + * need space for two seperate filenames + */ + n = strlen(file) * 2 + strlen(DIRFEXT) + strlen(PAGFEXT) + 2; + + if ((dirname = malloc((unsigned) n)) == NULL) + return errno = ENOMEM, (DBM *) NULL; +/* + * build the file names + */ + dirname = strcat(strcpy(dirname, file), DIRFEXT); + pagname = strcpy(dirname + strlen(dirname) + 1, file); + pagname = strcat(pagname, PAGFEXT); + + db = sdbm_prep(dirname, pagname, flags, mode); + free((char *) dirname); + return db; +} + +DBM * +sdbm_prep(dirname, pagname, flags, mode) +char *dirname; +char *pagname; +int flags; +int mode; +{ + register DBM *db; + struct stat dstat; + + if ((db = (DBM *) malloc(sizeof(DBM))) == NULL) + return errno = ENOMEM, (DBM *) NULL; + + db->flags = 0; + db->hmask = 0; + db->blkptr = 0; + db->keyptr = 0; +/* + * adjust user flags so that WRONLY becomes RDWR, + * as required by this package. Also set our internal + * flag for RDONLY. + */ + if (flags & O_WRONLY) + flags = (flags & ~O_WRONLY) | O_RDWR; + if (flags & O_RDONLY) + db->flags = DBM_RDONLY; +/* + * open the files in sequence, and stat the dirfile. + * If we fail anywhere, undo everything, return NULL. + */ + flags |= O_BINARY; + if ((db->pagf = open(pagname, flags, mode)) > -1) { + if ((db->dirf = open(dirname, flags, mode)) > -1) { +/* + * need the dirfile size to establish max bit number. + */ + if (fstat(db->dirf, &dstat) == 0) { +/* + * zero size: either a fresh database, or one with a single, + * unsplit data page: dirpage is all zeros. + */ + db->dirbno = (!dstat.st_size) ? 0 : -1; + db->pagbno = -1; + db->maxbno = dstat.st_size * (long) BYTESIZ; + + (void) memset(db->pagbuf, 0, PBLKSIZ); + (void) memset(db->dirbuf, 0, DBLKSIZ); + /* + * success + */ + return db; + } + (void) close(db->dirf); + } + (void) close(db->pagf); + } + free((char *) db); + return (DBM *) NULL; +} + +void +sdbm_close(db) +register DBM *db; +{ + if (db == NULL) + errno = EINVAL; + else { + (void) close(db->dirf); + (void) close(db->pagf); + free((char *) db); + } +} + +datum +sdbm_fetch(db, key) +register DBM *db; +datum key; +{ + if (db == NULL || bad(key)) + return errno = EINVAL, nullitem; + + if (getpage(db, exhash(key))) + return getpair(db->pagbuf, key); + + return ioerr(db), nullitem; +} + +int +sdbm_delete(db, key) +register DBM *db; +datum key; +{ + if (db == NULL || bad(key)) + return errno = EINVAL, -1; + if (sdbm_rdonly(db)) + return errno = EPERM, -1; + + if (getpage(db, exhash(key))) { + if (!delpair(db->pagbuf, key)) + return -1; +/* + * update the page file + */ + if (lseek(db->pagf, OFF_PAG(db->pagbno), SEEK_SET) < 0 + || write(db->pagf, db->pagbuf, PBLKSIZ) < 0) + return ioerr(db), -1; + + return 0; + } + + return ioerr(db), -1; +} + +int +sdbm_store(db, key, val, flags) +register DBM *db; +datum key; +datum val; +int flags; +{ + int need; + register long hash; + + if (db == NULL || bad(key)) + return errno = EINVAL, -1; + if (sdbm_rdonly(db)) + return errno = EPERM, -1; + + need = key.dsize + val.dsize; +/* + * is the pair too big (or too small) for this database ?? + */ + if (need < 0 || need > PAIRMAX) + return errno = EINVAL, -1; + + if (getpage(db, (hash = exhash(key)))) { +/* + * if we need to replace, delete the key/data pair + * first. If it is not there, ignore. + */ + if (flags == DBM_REPLACE) + (void) delpair(db->pagbuf, key); +#ifdef SEEDUPS + else if (duppair(db->pagbuf, key)) + return 1; +#endif +/* + * if we do not have enough room, we have to split. + */ + if (!fitpair(db->pagbuf, need)) + if (!makroom(db, hash, need)) + return ioerr(db), -1; +/* + * we have enough room or split is successful. insert the key, + * and update the page file. + */ + (void) putpair(db->pagbuf, key, val); + + if (lseek(db->pagf, OFF_PAG(db->pagbno), SEEK_SET) < 0 + || write(db->pagf, db->pagbuf, PBLKSIZ) < 0) + return ioerr(db), -1; + /* + * success + */ + return 0; + } + + return ioerr(db), -1; +} + +/* + * makroom - make room by splitting the overfull page + * this routine will attempt to make room for SPLTMAX times before + * giving up. + */ +static int +makroom(db, hash, need) +register DBM *db; +long hash; +int need; +{ + long newp; + char twin[PBLKSIZ]; +#if defined MSDOS || (defined _WIN32 && !defined __CYGWIN__) + char zer[PBLKSIZ]; + long oldtail; +#endif + char *pag = db->pagbuf; + char *new = twin; + register int smax = SPLTMAX; + + do { +/* + * split the current page + */ + (void) splpage(pag, new, db->hmask + 1); +/* + * address of the new page + */ + newp = (hash & db->hmask) | (db->hmask + 1); + debug(("newp: %ld\n", newp)); +/* + * write delay, read avoidence/cache shuffle: + * select the page for incoming pair: if key is to go to the new page, + * write out the previous one, and copy the new one over, thus making + * it the current page. If not, simply write the new page, and we are + * still looking at the page of interest. current page is not updated + * here, as sdbm_store will do so, after it inserts the incoming pair. + */ + +#if defined MSDOS || (defined _WIN32 && !defined __CYGWIN__) + /* + * Fill hole with 0 if made it. + * (hole is NOT read as 0) + */ + oldtail = lseek(db->pagf, 0L, SEEK_END); + memset(zer, 0, PBLKSIZ); + while (OFF_PAG(newp) > oldtail) { + if (lseek(db->pagf, 0L, SEEK_END) < 0 || + write(db->pagf, zer, PBLKSIZ) < 0) { + + return 0; + } + oldtail += PBLKSIZ; + } +#endif + + if (hash & (db->hmask + 1)) { + if (lseek(db->pagf, OFF_PAG(db->pagbno), SEEK_SET) < 0 + || write(db->pagf, db->pagbuf, PBLKSIZ) < 0) + return 0; + db->pagbno = newp; + (void) memcpy(pag, new, PBLKSIZ); + } + else if (lseek(db->pagf, OFF_PAG(newp), SEEK_SET) < 0 + || write(db->pagf, new, PBLKSIZ) < 0) + return 0; + + if (!setdbit(db, db->curbit)) + return 0; +/* + * see if we have enough room now + */ + if (fitpair(pag, need)) + return 1; +/* + * try again... update curbit and hmask as getpage would have + * done. because of our update of the current page, we do not + * need to read in anything. BUT we have to write the current + * [deferred] page out, as the window of failure is too great. + */ + db->curbit = 2 * db->curbit + + ((hash & (db->hmask + 1)) ? 2 : 1); + db->hmask |= (db->hmask + 1); + + if (lseek(db->pagf, OFF_PAG(db->pagbno), SEEK_SET) < 0 + || write(db->pagf, db->pagbuf, PBLKSIZ) < 0) + return 0; + + } while (--smax); +/* + * if we are here, this is real bad news. After SPLTMAX splits, + * we still cannot fit the key. say goodnight. + */ +#ifdef BADMESS + (void) write(2, "sdbm: cannot insert after SPLTMAX attempts.\n", 44); +#endif + return 0; + +} + +/* + * the following two routines will break if + * deletions aren't taken into account. (ndbm bug) + */ +datum +sdbm_firstkey(db) +register DBM *db; +{ + if (db == NULL) + return errno = EINVAL, nullitem; +/* + * start at page 0 + */ + (void) memset(db->pagbuf, 0, PBLKSIZ); + if (lseek(db->pagf, OFF_PAG(0), SEEK_SET) < 0 + || read(db->pagf, db->pagbuf, PBLKSIZ) < 0) + return ioerr(db), nullitem; + db->pagbno = 0; + db->blkptr = 0; + db->keyptr = 0; + + return getnext(db); +} + +datum +sdbm_nextkey(db) +register DBM *db; +{ + if (db == NULL) + return errno = EINVAL, nullitem; + return getnext(db); +} + +/* + * all important binary trie traversal + */ +static int +getpage(db, hash) +register DBM *db; +register long hash; +{ + register int hbit; + register long dbit; + register long pagb; + + dbit = 0; + hbit = 0; + while (dbit < db->maxbno && getdbit(db, dbit)) + dbit = 2 * dbit + ((hash & ((long) 1 << hbit++)) ? 2 : 1); + + debug(("dbit: %d...", dbit)); + + db->curbit = dbit; + db->hmask = masks[hbit]; + + pagb = hash & db->hmask; +/* + * see if the block we need is already in memory. + * note: this lookaside cache has about 10% hit rate. + */ + if (pagb != db->pagbno) { +/* + * note: here, we assume a "hole" is read as 0s. + * if not, must zero pagbuf first. + */ + (void) memset(db->pagbuf, 0, PBLKSIZ); + + if (lseek(db->pagf, OFF_PAG(pagb), SEEK_SET) < 0 + || read(db->pagf, db->pagbuf, PBLKSIZ) < 0) + return 0; + if (!chkpage(db->pagbuf)) { + return 0; + } + db->pagbno = pagb; + + debug(("pag read: %d\n", pagb)); + } + return 1; +} + +static int +getdbit(db, dbit) +register DBM *db; +register long dbit; +{ + register long c; + register long dirb; + + c = dbit / BYTESIZ; + dirb = c / DBLKSIZ; + + if (dirb != db->dirbno) { + if (lseek(db->dirf, OFF_DIR(dirb), SEEK_SET) < 0 + || read(db->dirf, db->dirbuf, DBLKSIZ) < 0) + return 0; + db->dirbno = dirb; + + debug(("dir read: %d\n", dirb)); + } + + return db->dirbuf[c % DBLKSIZ] & (1 << (dbit % BYTESIZ)); +} + +static int +setdbit(db, dbit) +register DBM *db; +register long dbit; +{ + register long c; + register long dirb; + + c = dbit / BYTESIZ; + dirb = c / DBLKSIZ; + + if (dirb != db->dirbno) { + if (lseek(db->dirf, OFF_DIR(dirb), SEEK_SET) < 0 + || read(db->dirf, db->dirbuf, DBLKSIZ) < 0) + return 0; + db->dirbno = dirb; + + debug(("dir read: %d\n", dirb)); + } + + db->dirbuf[c % DBLKSIZ] |= (1 << (dbit % BYTESIZ)); + + if (dbit >= db->maxbno) + db->maxbno += (long) DBLKSIZ * BYTESIZ; + + if (lseek(db->dirf, OFF_DIR(dirb), SEEK_SET) < 0 + || write(db->dirf, db->dirbuf, DBLKSIZ) < 0) + return 0; + + return 1; +} + +/* + * getnext - get the next key in the page, and if done with + * the page, try the next page in sequence + */ +static datum +getnext(db) +register DBM *db; +{ + datum key; + + for (;;) { + db->keyptr++; + key = getnkey(db->pagbuf, db->keyptr); + if (key.dptr != NULL) + return key; +/* + * we either run out, or there is nothing on this page.. + * try the next one... If we lost our position on the + * file, we will have to seek. + */ + db->keyptr = 0; + if (db->pagbno != db->blkptr++) + if (lseek(db->pagf, OFF_PAG(db->blkptr), SEEK_SET) < 0) + break; + db->pagbno = db->blkptr; + if (read(db->pagf, db->pagbuf, PBLKSIZ) <= 0) + break; + if (!chkpage(db->pagbuf)) { + break; + } + } + + return ioerr(db), nullitem; +} + +/* pair.c */ +/* + * sdbm - ndbm work-alike hashed database library + * based on Per-Aake Larson's Dynamic Hashing algorithms. BIT 18 (1978). + * author: oz@nexus.yorku.ca + * status: public domain. + * + * page-level routines + */ + +#ifndef lint +/*char pair_rcsid[] = "$Id: _sdbm.c,v 1.5.2.1 2005/09/08 05:59:41 matz Exp $";*/ +#endif + +#ifndef BSD42 +/*#include */ +#endif + +#define exhash(item) sdbm_hash((item).dptr, (item).dsize) + +/* + * forward + */ +static int seepair proto((char *, int, char *, int)); + +/* + * page format: + * +------------------------------+ + * ino | n | keyoff | datoff | keyoff | + * +------------+--------+--------+ + * | datoff | - - - ----> | + * +--------+---------------------+ + * | F R E E A R E A | + * +--------------+---------------+ + * | <---- - - - | data | + * +--------+-----+----+----------+ + * | key | data | key | + * +--------+----------+----------+ + * + * calculating the offsets for free area: if the number + * of entries (ino[0]) is zero, the offset to the END of + * the free area is the block size. Otherwise, it is the + * nth (ino[ino[0]]) entry's offset. + */ + +static int +fitpair(pag, need) +char *pag; +int need; +{ + register int n; + register int off; + register int free; + register short *ino = (short *) pag; + + off = ((n = GET_SHORT(ino,0)) > 0) ? GET_SHORT(ino,n) : PBLKSIZ; + free = off - (n + 1) * sizeof(short); + need += 2 * sizeof(short); + + debug(("free %d need %d\n", free, need)); + + return need <= free; +} + +static void +putpair(pag, key, val) +char *pag; +datum key; +datum val; +{ + register int n; + register int off; + register short *ino = (short *) pag; + + off = ((n = GET_SHORT(ino,0)) > 0) ? GET_SHORT(ino,n) : PBLKSIZ; +/* + * enter the key first + */ + off -= key.dsize; + if (key.dsize) + (void) memcpy(pag + off, key.dptr, key.dsize); + PUT_SHORT(ino,n + 1,off); +/* + * now the data + */ + off -= val.dsize; + if (val.dsize) + (void) memcpy(pag + off, val.dptr, val.dsize); + PUT_SHORT(ino,n + 2,off); +/* + * adjust item count + */ + PUT_SHORT(ino,0,GET_SHORT(ino,0) + 2); +} + +static datum +getpair(pag, key) +char *pag; +datum key; +{ + register int i; + register int n; + datum val; + register short *ino = (short *) pag; + + if ((n = GET_SHORT(ino,0)) == 0) + return nullitem; + + if ((i = seepair(pag, n, key.dptr, key.dsize)) == 0) + return nullitem; + + val.dptr = pag + GET_SHORT(ino,i + 1); + val.dsize = GET_SHORT(ino,i) - GET_SHORT(ino,i + 1); + return val; +} + +#ifdef SEEDUPS +static int +duppair(pag, key) +char *pag; +datum key; +{ + register short *ino = (short *) pag; + return GET_SHORT(ino,0) > 0 && + seepair(pag, GET_SHORT(ino,0), key.dptr, key.dsize) > 0; +} +#endif + +static datum +getnkey(pag, num) +char *pag; +int num; +{ + datum key; + register int off; + register short *ino = (short *) pag; + + num = num * 2 - 1; + if (GET_SHORT(ino,0) == 0 || num > GET_SHORT(ino,0)) + return nullitem; + + off = (num > 1) ? GET_SHORT(ino,num - 1) : PBLKSIZ; + + key.dptr = pag + GET_SHORT(ino,num); + key.dsize = off - GET_SHORT(ino,num); + + return key; +} + +static int +delpair(pag, key) +char *pag; +datum key; +{ + register int n; + register int i; + register short *ino = (short *) pag; + + if ((n = GET_SHORT(ino,0)) == 0) + return 0; + + if ((i = seepair(pag, n, key.dptr, key.dsize)) == 0) + return 0; +/* + * found the key. if it is the last entry + * [i.e. i == n - 1] we just adjust the entry count. + * hard case: move all data down onto the deleted pair, + * shift offsets onto deleted offsets, and adjust them. + * [note: 0 < i < n] + */ + if (i < n - 1) { + register int m; + register char *dst = pag + (i == 1 ? PBLKSIZ : GET_SHORT(ino,i - 1)); + register char *src = pag + GET_SHORT(ino,i + 1); + register int zoo = dst - src; + + debug(("free-up %d ", zoo)); +/* + * shift data/keys down + */ + m = GET_SHORT(ino,i + 1) - GET_SHORT(ino,n); +#ifdef DUFF +#define MOVB *--dst = *--src + + if (m > 0) { + register int loop = (m + 8 - 1) >> 3; + + switch (m & (8 - 1)) { + case 0: do { + MOVB; case 7: MOVB; + case 6: MOVB; case 5: MOVB; + case 4: MOVB; case 3: MOVB; + case 2: MOVB; case 1: MOVB; + } while (--loop); + } + } +#else +#ifdef MEMMOVE + memmove(dst, src, m); +#else + while (m--) + *--dst = *--src; +#endif +#endif +/* + * adjust offset index up + */ + while (i < n - 1) { + PUT_SHORT(ino,i, GET_SHORT(ino,i + 2) + zoo); + i++; + } + } + PUT_SHORT(ino, 0, GET_SHORT(ino, 0) - 2); + return 1; +} + +/* + * search for the key in the page. + * return offset index in the range 0 < i < n. + * return 0 if not found. + */ +static int +seepair(pag, n, key, siz) +char *pag; +register int n; +register char *key; +register int siz; +{ + register int i; + register int off = PBLKSIZ; + register short *ino = (short *) pag; + + for (i = 1; i < n; i += 2) { + if (siz == off - GET_SHORT(ino,i) && + memcmp(key, pag + GET_SHORT(ino,i), siz) == 0) + return i; + off = GET_SHORT(ino,i + 1); + } + return 0; +} + +static void +splpage(pag, new, sbit) +char *pag; +char *new; +long sbit; +{ + datum key; + datum val; + + register int n; + register int off = PBLKSIZ; + char cur[PBLKSIZ]; + register short *ino = (short *) cur; + + (void) memcpy(cur, pag, PBLKSIZ); + (void) memset(pag, 0, PBLKSIZ); + (void) memset(new, 0, PBLKSIZ); + + n = GET_SHORT(ino,0); + for (ino++; n > 0; ino += 2) { + key.dptr = cur + GET_SHORT(ino,0); + key.dsize = off - GET_SHORT(ino,0); + val.dptr = cur + GET_SHORT(ino,1); + val.dsize = GET_SHORT(ino,0) - GET_SHORT(ino,1); +/* + * select the page pointer (by looking at sbit) and insert + */ + (void) putpair((exhash(key) & sbit) ? new : pag, key, val); + + off = GET_SHORT(ino,1); + n -= 2; + } + + debug(("%d split %d/%d\n", ((short *) cur)[0] / 2, + ((short *) new)[0] / 2, + ((short *) pag)[0] / 2)); +} + +/* + * check page sanity: + * number of entries should be something + * reasonable, and all offsets in the index should be in order. + * this could be made more rigorous. + */ +static int +chkpage(pag) +char *pag; +{ + register int n; + register int off; + register short *ino = (short *) pag; + + if ((n = GET_SHORT(ino,0)) < 0 || n > PBLKSIZ / sizeof(short)) + return 0; + + if (n > 0) { + off = PBLKSIZ; + for (ino++; n > 0; ino += 2) { + if (GET_SHORT(ino,0) > off || GET_SHORT(ino,1) > off || + GET_SHORT(ino,1) > GET_SHORT(ino,0)) + return 0; + off = GET_SHORT(ino,1); + n -= 2; + } + } + return 1; +} + +/* hash.c */ +/* + * sdbm - ndbm work-alike hashed database library + * based on Per-Aake Larson's Dynamic Hashing algorithms. BIT 18 (1978). + * author: oz@nexus.yorku.ca + * status: public domain. keep it that way. + * + * hashing routine + */ + +/* + * polynomial conversion ignoring overflows + * [this seems to work remarkably well, in fact better + * then the ndbm hash function. Replace at your own risk] + * use: 65599 nice. + * 65587 even better. + */ +long +sdbm_hash(str, len) +register char *str; +register int len; +{ + register unsigned long n = 0; + +#ifdef DUFF + +#define HASHC n = *str++ + 65599 * n + + if (len > 0) { + register int loop = (len + 8 - 1) >> 3; + + switch(len & (8 - 1)) { + case 0: do { + HASHC; case 7: HASHC; + case 6: HASHC; case 5: HASHC; + case 4: HASHC; case 3: HASHC; + case 2: HASHC; case 1: HASHC; + } while (--loop); + } + + } +#else + while (len--) + n = ((*str++) & 255) + 65587L * n; +#endif + return n; +} -- cgit v1.2.3