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authormatz <matz@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>1999-05-07 08:23:32 +0000
committermatz <matz@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>1999-05-07 08:23:32 +0000
commit3383b32856a3da7e74964402d4d8f7bac1bc1801 (patch)
treea5a088961c2eed137043d2e24f00f27221f6f714
parente8505b64725b10f92e828d289ad0995bb23c1c8a (diff)
sdbm module
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_3@458 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
-rw-r--r--ext/sdbm/MANIFEST5
-rw-r--r--ext/sdbm/_sdbm.c977
-rw-r--r--ext/sdbm/extconf.rb3
-rw-r--r--ext/sdbm/init.c585
-rw-r--r--ext/sdbm/sdbm.h84
5 files changed, 1654 insertions, 0 deletions
diff --git a/ext/sdbm/MANIFEST b/ext/sdbm/MANIFEST
new file mode 100644
index 0000000..d0ed99b
--- /dev/null
+++ b/ext/sdbm/MANIFEST
@@ -0,0 +1,5 @@
+MANIFEST
+_sdbm.c
+extconf.rb
+init.c
+sdbm.h
diff --git a/ext/sdbm/_sdbm.c b/ext/sdbm/_sdbm.c
new file mode 100644
index 0000000..8a40fb3
--- /dev/null
+++ b/ext/sdbm/_sdbm.c
@@ -0,0 +1,977 @@
+/*
+ * 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[] = "$Id$";*/
+#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 <unistd.h>
+#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 <stdio.h>
+#include <stdlib.h>
+#ifdef MSDOS
+#include <io.h>
+#endif
+#include <sys/types.h>
+#include <sys/stat.h>
+#ifdef BSD42
+#include <sys/file.h>
+#else
+#include <fcntl.h>
+/*#include <memory.h>*/
+#endif
+#ifndef O_BINARY
+#define O_BINARY 0
+#endif
+
+#include <errno.h>
+#ifndef EPERM
+#define EPERM EACCES
+#endif
+#include <string.h>
+
+#ifdef __STDC__
+#include <stddef.h>
+#endif
+
+#ifndef NULL
+#define NULL 0
+#endif
+
+/*
+ * externals
+ */
+#ifndef sun
+#ifndef MSDOS
+extern int errno;
+#endif
+#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.
+ */
+#ifdef MSDOS
+ flags |= O_BINARY;
+#endif
+ 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];
+#ifdef MSDOS
+ char zer[PBLKSIZ];
+#endif
+ char *pag = db->pagbuf;
+ char *new = twin;
+ register int smax = SPLTMAX;
+ long oldtail;
+
+ 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.
+ */
+
+#ifdef MSDOS
+ /*
+ * 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[] = "$Id$";*/
+#endif
+
+#ifndef BSD42
+/*#include <memory.h>*/
+#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;
+}
diff --git a/ext/sdbm/extconf.rb b/ext/sdbm/extconf.rb
new file mode 100644
index 0000000..cc6c8ce
--- /dev/null
+++ b/ext/sdbm/extconf.rb
@@ -0,0 +1,3 @@
+require 'mkmf'
+
+create_makefile("sdbm")
diff --git a/ext/sdbm/init.c b/ext/sdbm/init.c
new file mode 100644
index 0000000..9ae2161
--- /dev/null
+++ b/ext/sdbm/init.c
@@ -0,0 +1,585 @@
+/************************************************
+
+ sdbminit.c -
+
+ $Author$
+ $Date$
+ created at: Fri May 7 08:34:24 JST 1999
+
+ Copyright (C) 1995-1998 Yukihiro Matsumoto
+
+************************************************/
+
+#include "ruby.h"
+
+#include "sdbm.h"
+#include <fcntl.h>
+#include <errno.h>
+#ifdef USE_CWGUSI
+# include <sys/errno.h>
+#endif
+
+VALUE cSDBM;
+
+struct dbmdata {
+ int di_size;
+ DBM *di_dbm;
+};
+
+static void
+closed_sdbm()
+{
+ rb_raise(rb_eRuntimeError, "closed SDBM file");
+}
+
+#define GetDBM(obj, dbmp) {\
+ Data_Get_Struct(obj, struct dbmdata, dbmp);\
+ if (dbmp->di_dbm == 0) closed_sdbm();\
+}
+
+static void
+free_sdbm(dbmp)
+ struct dbmdata *dbmp;
+{
+
+ if (dbmp->di_dbm) sdbm_close(dbmp->di_dbm);
+ free(dbmp);
+}
+
+static VALUE
+fsdbm_s_open(argc, argv, klass)
+ int argc;
+ VALUE *argv;
+ VALUE klass;
+{
+ VALUE file, vmode;
+ DBM *dbm;
+ struct dbmdata *dbmp;
+ int mode;
+ VALUE obj;
+
+ if (rb_scan_args(argc, argv, "11", &file, &vmode) == 1) {
+ mode = 0666; /* default value */
+ }
+ else if (NIL_P(vmode)) {
+ mode = -1; /* return nil if DB not exist */
+ }
+ else {
+ mode = NUM2INT(vmode);
+ }
+ Check_SafeStr(file);
+
+ dbm = 0;
+ if (mode >= 0)
+ dbm = sdbm_open(RSTRING(file)->ptr, O_RDWR|O_CREAT, mode);
+ if (!dbm)
+ dbm = sdbm_open(RSTRING(file)->ptr, O_RDWR, mode);
+ if (!dbm)
+ dbm = sdbm_open(RSTRING(file)->ptr, O_RDONLY, mode);
+
+ if (!dbm) {
+ if (mode == -1) return Qnil;
+ rb_sys_fail(RSTRING(file)->ptr);
+ }
+
+ obj = Data_Make_Struct(klass,struct dbmdata,0,free_sdbm,dbmp);
+ dbmp->di_dbm = dbm;
+ dbmp->di_size = -1;
+ rb_obj_call_init(obj, argc, argv);
+
+ return obj;
+}
+
+static VALUE
+fsdbm_close(obj)
+ VALUE obj;
+{
+ struct dbmdata *dbmp;
+
+ Data_Get_Struct(obj, struct dbmdata, dbmp);
+ if (dbmp->di_dbm == 0) closed_sdbm();
+ sdbm_close(dbmp->di_dbm);
+ dbmp->di_dbm = 0;
+
+ return Qnil;
+}
+
+static VALUE
+fsdbm_fetch(obj, keystr)
+ VALUE obj, keystr;
+{
+ datum key, value;
+ struct dbmdata *dbmp;
+ DBM *dbm;
+
+ Check_Type(keystr, T_STRING);
+ key.dptr = RSTRING(keystr)->ptr;
+ key.dsize = RSTRING(keystr)->len;
+
+ GetDBM(obj, dbmp);
+ dbm = dbmp->di_dbm;
+ value = sdbm_fetch(dbm, key);
+ if (value.dptr == 0) {
+ return Qnil;
+ }
+ return rb_tainted_str_new(value.dptr, value.dsize);
+}
+
+static VALUE
+fsdbm_indexes(argc, argv, obj)
+ int argc;
+ VALUE *argv;
+ VALUE obj;
+{
+ VALUE new;
+ int i;
+
+ new = rb_ary_new2(argc);
+ for (i=0; i<argc; i++) {
+ rb_ary_push(new, fsdbm_fetch(obj, argv[i]));
+ }
+
+ return new;
+}
+
+static VALUE
+fsdbm_delete(obj, keystr)
+ VALUE obj, keystr;
+{
+ datum key, value;
+ struct dbmdata *dbmp;
+ DBM *dbm;
+
+ rb_secure(4);
+ Check_Type(keystr, T_STRING);
+ key.dptr = RSTRING(keystr)->ptr;
+ key.dsize = RSTRING(keystr)->len;
+
+ GetDBM(obj, dbmp);
+ dbm = dbmp->di_dbm;
+
+ value = sdbm_fetch(dbm, key);
+ if (value.dptr == 0) {
+ if (rb_iterator_p()) rb_yield(keystr);
+ return Qnil;
+ }
+
+ if (sdbm_delete(dbm, key)) {
+ dbmp->di_size = -1;
+ rb_raise(rb_eRuntimeError, "dbm_delete failed");
+ }
+ else if (dbmp->di_size >= 0) {
+ dbmp->di_size--;
+ }
+ return obj;
+}
+
+static VALUE
+fsdbm_shift(obj)
+ VALUE obj;
+{
+ datum key, val;
+ struct dbmdata *dbmp;
+ DBM *dbm;
+ VALUE keystr, valstr;
+
+ rb_secure(4);
+ GetDBM(obj, dbmp);
+ dbm = dbmp->di_dbm;
+
+ key = sdbm_firstkey(dbm);
+ if (!key.dptr) return Qnil;
+ val = sdbm_fetch(dbm, key);
+ sdbm_delete(dbm, key);
+
+ keystr = rb_tainted_str_new(key.dptr, key.dsize);
+ valstr = rb_tainted_str_new(val.dptr, val.dsize);
+ return rb_assoc_new(keystr, valstr);
+}
+
+static VALUE
+fsdbm_delete_if(obj)
+ VALUE obj;
+{
+ datum key, val;
+ struct dbmdata *dbmp;
+ DBM *dbm;
+ VALUE keystr, valstr;
+
+ rb_secure(4);
+ GetDBM(obj, dbmp);
+ dbm = dbmp->di_dbm;
+ for (key = sdbm_firstkey(dbm); key.dptr; key = sdbm_nextkey(dbm)) {
+ val = sdbm_fetch(dbm, key);
+ keystr = rb_tainted_str_new(key.dptr, key.dsize);
+ valstr = rb_tainted_str_new(val.dptr, val.dsize);
+ if (RTEST(rb_yield(rb_assoc_new(keystr, valstr)))) {
+ if (sdbm_delete(dbm, key)) {
+ rb_raise(rb_eRuntimeError, "sdbm_delete failed");
+ }
+ }
+ }
+ return obj;
+}
+
+static VALUE
+fsdbm_clear(obj)
+ VALUE obj;
+{
+ datum key;
+ struct dbmdata *dbmp;
+ DBM *dbm;
+
+ rb_secure(4);
+ GetDBM(obj, dbmp);
+ dbm = dbmp->di_dbm;
+ dbmp->di_size = -1;
+ for (key = sdbm_firstkey(dbm); key.dptr; key = sdbm_nextkey(dbm)) {
+ if (sdbm_delete(dbm, key)) {
+ rb_raise(rb_eRuntimeError, "sdbm_delete failed");
+ }
+ }
+ return obj;
+}
+
+static VALUE
+fsdbm_invert(obj)
+ VALUE obj;
+{
+ datum key, val;
+ struct dbmdata *dbmp;
+ DBM *dbm;
+ VALUE keystr, valstr;
+ VALUE hash = rb_hash_new();
+
+ GetDBM(obj, dbmp);
+ dbm = dbmp->di_dbm;
+ for (key = sdbm_firstkey(dbm); key.dptr; key = sdbm_nextkey(dbm)) {
+ val = sdbm_fetch(dbm, key);
+ keystr = rb_tainted_str_new(key.dptr, key.dsize);
+ valstr = rb_tainted_str_new(val.dptr, val.dsize);
+ rb_hash_aset(hash, valstr, keystr);
+ }
+ return obj;
+}
+
+static VALUE
+each_pair(obj)
+ VALUE obj;
+{
+ return rb_funcall(obj, rb_intern("each_pair"), 0, 0);
+}
+
+static VALUE fsdbm_store _((VALUE,VALUE,VALUE));
+
+static VALUE
+update_i(pair, dbm)
+ VALUE pair, dbm;
+{
+ Check_Type(pair, T_ARRAY);
+ if (RARRAY(pair)->len < 2) {
+ rb_raise(rb_eArgError, "pair must be [key, value]");
+ }
+ fsdbm_store(dbm, RARRAY(pair)->ptr[0], RARRAY(pair)->ptr[1]);
+ return Qnil;
+}
+
+static VALUE
+fsdbm_update(obj, other)
+ VALUE obj, other;
+{
+ rb_iterate(each_pair, other, update_i, obj);
+ return obj;
+}
+
+static VALUE
+fsdbm_replace(obj, other)
+ VALUE obj, other;
+{
+ fsdbm_clear(obj);
+ rb_iterate(each_pair, other, update_i, obj);
+ return obj;
+}
+
+static VALUE
+fsdbm_store(obj, keystr, valstr)
+ VALUE obj, keystr, valstr;
+{
+ datum key, val;
+ struct dbmdata *dbmp;
+ DBM *dbm;
+
+ if (valstr == Qnil) {
+ fsdbm_delete(obj, keystr);
+ return Qnil;
+ }
+
+ rb_secure(4);
+ keystr = rb_obj_as_string(keystr);
+
+ key.dptr = RSTRING(keystr)->ptr;
+ key.dsize = RSTRING(keystr)->len;
+
+ if (NIL_P(valstr)) return fsdbm_delete(obj, keystr);
+
+ valstr = rb_obj_as_string(valstr);
+ val.dptr = RSTRING(valstr)->ptr;
+ val.dsize = RSTRING(valstr)->len;
+
+ Data_Get_Struct(obj, struct dbmdata, dbmp);
+ dbmp->di_size = -1;
+ dbm = dbmp->di_dbm;
+ if (sdbm_store(dbm, key, val, DBM_REPLACE)) {
+#ifdef HAVE_DBM_CLAERERR
+ sdbm_clearerr(dbm);
+#endif
+ if (errno == EPERM) rb_sys_fail(0);
+ rb_raise(rb_eRuntimeError, "sdbm_store failed");
+ }
+
+ return valstr;
+}
+
+static VALUE
+fsdbm_length(obj)
+ VALUE obj;
+{
+ datum key;
+ struct dbmdata *dbmp;
+ DBM *dbm;
+ int i = 0;
+
+ Data_Get_Struct(obj, struct dbmdata, dbmp);
+ if (dbmp->di_size > 0) return INT2FIX(dbmp->di_size);
+ dbm = dbmp->di_dbm;
+
+ for (key = sdbm_firstkey(dbm); key.dptr; key = sdbm_nextkey(dbm)) {
+ i++;
+ }
+ dbmp->di_size = i;
+
+ return INT2FIX(i);
+}
+
+static VALUE
+fsdbm_empty_p(obj)
+ VALUE obj;
+{
+ datum key;
+ struct dbmdata *dbmp;
+ DBM *dbm;
+ int i = 0;
+
+ Data_Get_Struct(obj, struct dbmdata, dbmp);
+ if (dbmp->di_size < 0) {
+ dbm = dbmp->di_dbm;
+
+ for (key = sdbm_firstkey(dbm); key.dptr; key = sdbm_nextkey(dbm)) {
+ i++;
+ }
+ }
+ else {
+ i = dbmp->di_size;
+ }
+ if (i == 0) return Qtrue;
+ return Qfalse;
+}
+
+static VALUE
+fsdbm_each_value(obj)
+ VALUE obj;
+{
+ datum key, val;
+ struct dbmdata *dbmp;
+ DBM *dbm;
+
+ GetDBM(obj, dbmp);
+ dbm = dbmp->di_dbm;
+ for (key = sdbm_firstkey(dbm); key.dptr; key = sdbm_nextkey(dbm)) {
+ val = sdbm_fetch(dbm, key);
+ rb_yield(rb_tainted_str_new(val.dptr, val.dsize));
+ }
+ return obj;
+}
+
+static VALUE
+fsdbm_each_key(obj)
+ VALUE obj;
+{
+ datum key;
+ struct dbmdata *dbmp;
+ DBM *dbm;
+
+ GetDBM(obj, dbmp);
+ dbm = dbmp->di_dbm;
+ for (key = sdbm_firstkey(dbm); key.dptr; key = sdbm_nextkey(dbm)) {
+ rb_yield(rb_tainted_str_new(key.dptr, key.dsize));
+ }
+ return obj;
+}
+
+static VALUE
+fsdbm_each_pair(obj)
+ VALUE obj;
+{
+ datum key, val;
+ DBM *dbm;
+ struct dbmdata *dbmp;
+ VALUE keystr, valstr;
+
+ GetDBM(obj, dbmp);
+ dbm = dbmp->di_dbm;
+
+ for (key = sdbm_firstkey(dbm); key.dptr; key = sdbm_nextkey(dbm)) {
+ val = sdbm_fetch(dbm, key);
+ keystr = rb_tainted_str_new(key.dptr, key.dsize);
+ valstr = rb_tainted_str_new(val.dptr, val.dsize);
+ rb_yield(rb_assoc_new(keystr, valstr));
+ }
+
+ return obj;
+}
+
+static VALUE
+fsdbm_keys(obj)
+ VALUE obj;
+{
+ datum key;
+ struct dbmdata *dbmp;
+ DBM *dbm;
+ VALUE ary;
+
+ GetDBM(obj, dbmp);
+ dbm = dbmp->di_dbm;
+
+ ary = rb_ary_new();
+ for (key = sdbm_firstkey(dbm); key.dptr; key = sdbm_nextkey(dbm)) {
+ rb_ary_push(ary, rb_tainted_str_new(key.dptr, key.dsize));
+ }
+
+ return ary;
+}
+
+static VALUE
+fsdbm_values(obj)
+ VALUE obj;
+{
+ datum key, val;
+ struct dbmdata *dbmp;
+ DBM *dbm;
+ VALUE ary;
+
+ GetDBM(obj, dbmp);
+ dbm = dbmp->di_dbm;
+
+ ary = rb_ary_new();
+ for (key = sdbm_firstkey(dbm); key.dptr; key = sdbm_nextkey(dbm)) {
+ val = sdbm_fetch(dbm, key);
+ rb_ary_push(ary, rb_tainted_str_new(val.dptr, val.dsize));
+ }
+
+ return ary;
+}
+
+static VALUE
+fsdbm_has_key(obj, keystr)
+ VALUE obj, keystr;
+{
+ datum key, val;
+ struct dbmdata *dbmp;
+ DBM *dbm;
+
+ Check_Type(keystr, T_STRING);
+ key.dptr = RSTRING(keystr)->ptr;
+ key.dsize = RSTRING(keystr)->len;
+
+ GetDBM(obj, dbmp);
+ dbm = dbmp->di_dbm;
+ val = sdbm_fetch(dbm, key);
+ if (val.dptr) return Qtrue;
+ return Qfalse;
+}
+
+static VALUE
+fsdbm_has_value(obj, valstr)
+ VALUE obj, valstr;
+{
+ datum key, val;
+ struct dbmdata *dbmp;
+ DBM *dbm;
+
+ Check_Type(valstr, T_STRING);
+ val.dptr = RSTRING(valstr)->ptr;
+ val.dsize = RSTRING(valstr)->len;
+
+ GetDBM(obj, dbmp);
+ dbm = dbmp->di_dbm;
+ for (key = sdbm_firstkey(dbm); key.dptr; key = sdbm_nextkey(dbm)) {
+ val = sdbm_fetch(dbm, key);
+ if (val.dsize == RSTRING(valstr)->len &&
+ memcmp(val.dptr, RSTRING(valstr)->ptr, val.dsize) == 0)
+ return Qtrue;
+ }
+ return Qfalse;
+}
+
+static VALUE
+fsdbm_to_a(obj)
+ VALUE obj;
+{
+ datum key, val;
+ struct dbmdata *dbmp;
+ DBM *dbm;
+ VALUE ary;
+
+ GetDBM(obj, dbmp);
+ dbm = dbmp->di_dbm;
+
+ ary = rb_ary_new();
+ for (key = sdbm_firstkey(dbm); key.dptr; key = sdbm_nextkey(dbm)) {
+ val = sdbm_fetch(dbm, key);
+ rb_ary_push(ary, rb_assoc_new(rb_tainted_str_new(key.dptr, key.dsize),
+ rb_tainted_str_new(val.dptr, val.dsize)));
+ }
+
+ return ary;
+}
+
+void
+Init_sdbm()
+{
+ cSDBM = rb_define_class("SDBM", rb_cObject);
+ rb_include_module(cSDBM, rb_mEnumerable);
+
+ rb_define_singleton_method(cSDBM, "open", fsdbm_s_open, -1);
+ rb_define_singleton_method(cSDBM, "new", fsdbm_s_open, -1);
+ rb_define_method(cSDBM, "close", fsdbm_close, 0);
+ rb_define_method(cSDBM, "[]", fsdbm_fetch, 1);
+ rb_define_method(cSDBM, "[]=", fsdbm_store, 2);
+ rb_define_method(cSDBM, "indexes", fsdbm_indexes, -1);
+ rb_define_method(cSDBM, "indices", fsdbm_indexes, -1);
+ rb_define_method(cSDBM, "length", fsdbm_length, 0);
+ rb_define_alias(cSDBM, "size", "length");
+ rb_define_method(cSDBM, "empty?", fsdbm_empty_p, 0);
+ rb_define_method(cSDBM, "each", fsdbm_each_pair, 0);
+ rb_define_method(cSDBM, "each_value", fsdbm_each_value, 0);
+ rb_define_method(cSDBM, "each_key", fsdbm_each_key, 0);
+ rb_define_method(cSDBM, "each_pair", fsdbm_each_pair, 0);
+ rb_define_method(cSDBM, "keys", fsdbm_keys, 0);
+ rb_define_method(cSDBM, "values", fsdbm_values, 0);
+ rb_define_method(cSDBM, "shift", fsdbm_shift, 1);
+ rb_define_method(cSDBM, "delete", fsdbm_delete, 1);
+ rb_define_method(cSDBM, "delete_if", fsdbm_delete_if, 0);
+ rb_define_method(cSDBM, "clear", fsdbm_clear, 0);
+ rb_define_method(cSDBM,"invert", fsdbm_invert, 0);
+ rb_define_method(cSDBM,"update", fsdbm_update, 1);
+ rb_define_method(cSDBM,"replace", fsdbm_replace, 1);
+
+ rb_define_method(cSDBM, "include?", fsdbm_has_key, 1);
+ rb_define_method(cSDBM, "has_key?", fsdbm_has_key, 1);
+ rb_define_method(cSDBM, "has_value?", fsdbm_has_value, 1);
+ rb_define_method(cSDBM, "key?", fsdbm_has_key, 1);
+ rb_define_method(cSDBM, "value?", fsdbm_has_value, 1);
+
+ rb_define_method(cSDBM, "to_a", fsdbm_to_a, 0);
+}
diff --git a/ext/sdbm/sdbm.h b/ext/sdbm/sdbm.h
new file mode 100644
index 0000000..ce8f54c
--- /dev/null
+++ b/ext/sdbm/sdbm.h
@@ -0,0 +1,84 @@
+/*
+ * sdbm - ndbm work-alike hashed database library
+ * based on Per-Ake Larson's Dynamic Hashing algorithms. BIT 18 (1978).
+ * author: oz@nexus.yorku.ca
+ * status: public domain.
+ */
+#ifndef _SDBM_H_
+#define _SDBM_H_
+
+#define DBLKSIZ 4096
+#define PBLKSIZ 1024
+#define PAIRMAX 1008 /* arbitrary on PBLKSIZ-N */
+#define SPLTMAX 10 /* maximum allowed splits */
+ /* for a single insertion */
+#define DIRFEXT ".dir"
+#define PAGFEXT ".pag"
+
+typedef struct {
+ int dirf; /* directory file descriptor */
+ int pagf; /* page file descriptor */
+ int flags; /* status/error flags, see below */
+ long maxbno; /* size of dirfile in bits */
+ long curbit; /* current bit number */
+ long hmask; /* current hash mask */
+ long blkptr; /* current block for nextkey */
+ int keyptr; /* current key for nextkey */
+ long blkno; /* current page to read/write */
+ long pagbno; /* current page in pagbuf */
+ char pagbuf[PBLKSIZ]; /* page file block buffer */
+ long dirbno; /* current block in dirbuf */
+ char dirbuf[DBLKSIZ]; /* directory file block buffer */
+} DBM;
+
+#define DBM_RDONLY 0x1 /* data base open read-only */
+#define DBM_IOERR 0x2 /* data base I/O error */
+
+/*
+ * utility macros
+ */
+#define sdbm_rdonly(db) ((db)->flags & DBM_RDONLY)
+#define sdbm_error(db) ((db)->flags & DBM_IOERR)
+
+#define sdbm_clearerr(db) ((db)->flags &= ~DBM_IOERR) /* ouch */
+
+#define sdbm_dirfno(db) ((db)->dirf)
+#define sdbm_pagfno(db) ((db)->pagf)
+
+typedef struct {
+ char *dptr;
+ int dsize;
+} datum;
+
+extern datum nullitem;
+
+#if defined(__STDC__) || defined(MSDOS)
+#define proto(p) p
+#else
+#define proto(p) ()
+#endif
+
+/*
+ * flags to sdbm_store
+ */
+#define DBM_INSERT 0
+#define DBM_REPLACE 1
+
+/*
+ * ndbm interface
+ */
+extern DBM *sdbm_open proto((char *, int, int));
+extern void sdbm_close proto((DBM *));
+extern datum sdbm_fetch proto((DBM *, datum));
+extern int sdbm_delete proto((DBM *, datum));
+extern int sdbm_store proto((DBM *, datum, datum, int));
+extern datum sdbm_firstkey proto((DBM *));
+extern datum sdbm_nextkey proto((DBM *));
+
+/*
+ * other
+ */
+extern DBM *sdbm_prep proto((char *, char *, int, int));
+extern long sdbm_hash proto((char *, int));
+
+#endif /* _SDBM_H_ */