diff --git a/CHANGES b/CHANGES
index ba07a6b..f08bfea 100644
--- a/CHANGES
+++ b/CHANGES
@@ -9,6 +9,7 @@
     that.
   implement Nikola's idea to remove limit number of strings in errmsg
   add taia_half
+  add cdb
 
 0.24:
   fix scan_to_sa (Tim Lorenz)
diff --git a/GNUmakefile b/GNUmakefile
index 712e5a9..3c5a82f 100644
--- a/GNUmakefile
+++ b/GNUmakefile
@@ -10,7 +10,8 @@ INCLUDEDIR=${prefix}/include
 MAN3DIR=${prefix}/man/man3
 
 LIBS=byte.a fmt.a scan.a str.a uint.a open.a stralloc.a unix.a socket.a \
-buffer.a mmap.a taia.a tai.a dns.a case.a mult.a array.a io.a textcode.a
+buffer.a mmap.a taia.a tai.a dns.a case.a mult.a array.a io.a \
+textcode.a cdb.a
 
 all: t $(LIBS) libowfat.a libsocket
 
@@ -53,7 +54,7 @@ endif
 # to build without diet libc support, use $ make DIET=
 # see http://www.fefe.de/dietlibc/ for details about the diet libc
 
-VPATH=str:byte:fmt:scan:uint:open:stralloc:unix:socket:buffer:mmap:textcode:taia:tai:dns:case:array:mult:io
+VPATH=str:byte:fmt:scan:uint:open:stralloc:unix:socket:buffer:mmap:textcode:taia:tai:dns:case:array:mult:io:cdb
 
 BYTE_OBJS=$(patsubst byte/%.c,%.o,$(wildcard byte/*.c))
 FMT_OBJS=$(patsubst fmt/%.c,%.o,$(wildcard fmt/*.c))
@@ -74,6 +75,7 @@ CASE_OBJS=$(patsubst case/%.c,%.o,$(wildcard case/*.c))
 ARRAY_OBJS=$(patsubst array/%.c,%.o,$(wildcard array/*.c))
 MULT_OBJS=$(patsubst mult/%.c,%.o,$(wildcard mult/*.c))
 IO_OBJS=$(patsubst io/%.c,%.o,$(wildcard io/*.c))
+CDB_OBJS=$(patsubst cdb/%.c,%.o,$(wildcard cdb/*.c))
 
 $(BYTE_OBJS): byte.h
 $(FMT_OBJS): fmt.h
@@ -92,6 +94,7 @@ $(CASE_OBJS): case.h
 $(ARRAY_OBJS): uint64.h array.h
 $(MULT_OBJS): uint64.h uint32.h uint16.h safemult.h
 $(IO_OBJS): uint64.h array.h io.h io_internal.h taia.h tai.h haveepoll.h havekqueue.h havesigio.h havebsdsf.h havedevpoll.h havesendfile.h
+$(CDB_OBJS): cdb.h uint32.h
 
 
 iob_addbuf.o iob_addfile.o iob_new.o iob_reset.o iob_send.o: iob_internal.h iob.h
@@ -120,6 +123,7 @@ case.a: $(CASE_OBJS)
 array.a: $(ARRAY_OBJS)
 mult.a: $(MULT_OBJS)
 io.a: $(IO_OBJS)
+cdb.a: $(CDB_OBJS)
 
 ALL_OBJS=$(DNS_OBJS) $(BYTE_OBJS) $(FMT_OBJS) $(SCAN_OBJS) \
 $(STR_OBJS) $(UINT_OBJS) $(OPEN_OBJS) $(STRALLOC_OBJS) $(UNIX_OBJS) \
@@ -155,7 +159,7 @@ dep libsocket havealloca.h
 INCLUDES=buffer.h byte.h fmt.h ip4.h ip6.h mmap.h scan.h socket.h str.h stralloc.h \
 uint16.h uint32.h uint64.h open.h textcode.h tai.h taia.h dns.h iopause.h case.h \
 openreadclose.h readclose.h ndelay.h array.h io.h safemult.h iob.h havealloca.h \
-errmsg.h
+errmsg.h cdb.h
 
 install: libowfat.a
 	install -d $(INCLUDEDIR) $(MAN3DIR) $(LIBDIR)
diff --git a/Makefile b/Makefile
index a3be572..214cb34 100644
--- a/Makefile
+++ b/Makefile
@@ -11,7 +11,8 @@ INCLUDEDIR=${prefix}/include
 MAN3DIR=${prefix}/man/man3
 
 LIBS=byte.a fmt.a scan.a str.a uint.a open.a stralloc.a unix.a socket.a \
-buffer.a mmap.a taia.a tai.a dns.a case.a mult.a array.a io.a textcode.a
+buffer.a mmap.a taia.a tai.a dns.a case.a mult.a array.a io.a \
+textcode.a cdb.a
 
 all: t $(LIBS) libowfat.a libsocket
 
@@ -116,6 +117,10 @@ case_diffs.o: case/case_diffs.c case.h
 case_lowerb.o: case/case_lowerb.c case.h
 case_lowers.o: case/case_lowers.c case.h
 case_starts.o: case/case_starts.c case.h
+cdb.o: cdb/cdb.c byte.h cdb.h uint32.h
+cdb_hash.o: cdb/cdb_hash.c cdb.h uint32.h
+cdb_make.o: cdb/cdb_make.c cdb.h uint32.h cdb_make.h buffer.h
+cdb_traverse.o: cdb/cdb_traverse.c cdb.h uint32.h
 dns_dfd.o: dns/dns_dfd.c byte.h dns.h stralloc.h iopause.h taia.h tai.h \
   uint64.h
 dns_domain.o: dns/dns_domain.c case.h byte.h dns.h stralloc.h iopause.h \
@@ -523,6 +528,7 @@ MULT_OBJS=imult16.o imult32.o imult64.o umult16.o umult32.o umult64.o
 ARRAY_OBJS=array_allocate.o array_bytes.o array_cat.o array_cat0.o array_catb.o array_cate.o array_cats.o array_cats0.o array_equal.o array_fail.o array_get.o array_length.o array_reset.o array_start.o array_trunc.o array_truncate.o 
 IO_OBJS=io_appendfile.o io_canread.o io_canwrite.o io_check.o io_close.o io_closeonexec.o io_createfile.o io_dontwantread.o io_dontwantwrite.o io_eagain.o io_fd.o io_finishandshutdown.o io_getcookie.o io_mmapwritefile.o io_nonblock.o io_passfd.o io_pipe.o io_readfile.o io_readwritefile.o io_receivefd.o io_sendfile.o io_setcookie.o io_sigpipe.o io_socketpair.o io_timeout.o io_timeouted.o io_tryread.o io_tryreadtimeout.o io_trywrite.o io_trywritetimeout.o io_wait.o io_waitread.o io_waituntil.o io_waituntil2.o io_waitwrite.o io_wantread.o io_wantwrite.o iob_addbuf.o iob_addbuf_free.o iob_addbuf_internal.o iob_addfile.o iob_addfile_close.o iob_adds.o iob_adds_free.o iob_free.o iob_new.o iob_prefetch.o iob_reset.o iob_send.o iob_write.o 
 TEXTCODE_OBJS=base64.o fmt_base64.o fmt_cescape.o fmt_foldwhitespace.o fmt_hexdump.o fmt_html.o fmt_quotedprintable.o fmt_to_array.o fmt_to_sa.o fmt_tofrom_array.o fmt_urlencoded.o fmt_uuencoded.o fmt_yenc.o scan_base64.o scan_cescape.o scan_hexdump.o scan_html.o scan_quotedprintable.o scan_to_array.o scan_to_sa.o scan_tofrom_array.o scan_urlencoded.o scan_uuencoded.o scan_yenc.o 
+CDB_OBJS=cdb.o cdb_hash.o cdb_make.o cdb_traverse.o 
 
 byte.a: $(BYTE_OBJS)
 fmt.a: $(FMT_OBJS)
@@ -543,6 +549,7 @@ case.a: $(CASE_OBJS)
 array.a: $(ARRAY_OBJS)
 mult.a: $(MULT_OBJS)
 io.a: $(IO_OBJS)
+cdb.a: $(CDB_OBJS)
 
 ALL_OBJS=$(DNS_OBJS) $(BYTE_OBJS) $(FMT_OBJS) $(SCAN_OBJS) \
 $(STR_OBJS) $(UINT_OBJS) $(OPEN_OBJS) $(STRALLOC_OBJS) $(UNIX_OBJS) \
@@ -578,7 +585,7 @@ dep libsocket havealloca.h
 INCLUDES=buffer.h byte.h fmt.h ip4.h ip6.h mmap.h scan.h socket.h str.h stralloc.h \
 uint16.h uint32.h uint64.h open.h textcode.h tai.h taia.h dns.h iopause.h case.h \
 openreadclose.h readclose.h ndelay.h array.h io.h safemult.h iob.h havealloca.h \
-errmsg.h
+errmsg.h cdb.h
 
 install: libowfat.a
 	install -d $(INCLUDEDIR) $(MAN3DIR) $(LIBDIR)
diff --git a/cdb.h b/cdb.h
new file mode 100644
index 0000000..9080bad
--- /dev/null
+++ b/cdb.h
@@ -0,0 +1,37 @@
+/* Public domain. */
+
+#ifndef CDB_H
+#define CDB_H
+
+#include "uint32.h"
+
+#define CDB_HASHSTART 5381
+extern uint32 cdb_hashadd(uint32 h,unsigned char c);
+extern uint32 cdb_hash(const unsigned char *buf,unsigned long int len);
+
+struct cdb {
+  char *map; /* 0 if no map is available */
+  int fd;
+  uint32 size; /* initialized if map is nonzero */
+  uint32 loop; /* number of hash slots searched under this key */
+  uint32 khash; /* initialized if loop is nonzero */
+  uint32 kpos; /* initialized if loop is nonzero */
+  uint32 hpos; /* initialized if loop is nonzero */
+  uint32 hslots; /* initialized if loop is nonzero */
+  uint32 dpos; /* initialized if cdb_findnext() returns 1 */
+  uint32 dlen; /* initialized if cdb_findnext() returns 1 */
+} ;
+
+extern void cdb_free(struct cdb *);
+extern void cdb_init(struct cdb *,int fd);
+
+extern int cdb_read(struct cdb *,unsigned char *,unsigned long int,uint32);
+
+extern void cdb_findstart(struct cdb *);
+extern int cdb_findnext(struct cdb *,const unsigned char *,unsigned long int);
+extern int cdb_find(struct cdb *,const unsigned char *,unsigned long int);
+
+#define cdb_datapos(c) ((c)->dpos)
+#define cdb_datalen(c) ((c)->dlen)
+
+#endif
diff --git a/cdb/cdb.c b/cdb/cdb.c
new file mode 100644
index 0000000..fb5740c
--- /dev/null
+++ b/cdb/cdb.c
@@ -0,0 +1,128 @@
+#define _FILE_OFFSET_BITS 64
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+#include <unistd.h>
+#include <errno.h>
+#include "byte.h"
+#include "cdb.h"
+
+void cdb_free(struct cdb *c) {
+  if (c->map) {
+    munmap(c->map,c->size);
+    c->map = 0;
+  }
+}
+
+void cdb_findstart(struct cdb *c) {
+  c->loop = 0;
+}
+
+void cdb_init(struct cdb *c,int fd) {
+  struct stat st;
+  char *x;
+
+  cdb_free(c);
+  cdb_findstart(c);
+  c->fd = fd;
+
+  if (fstat(fd,&st) == 0)
+    if (st.st_size <= 0xffffffff) {
+      x = mmap(0,st.st_size,PROT_READ,MAP_SHARED,fd,0);
+      if (x + 1) {
+	c->size = st.st_size;
+	c->map = x;
+      }
+    }
+}
+
+int cdb_read(struct cdb *c,unsigned char *buf,unsigned long len,uint32 pos) {
+  if (c->map) {
+    if ((pos > c->size) || (c->size - pos < len)) goto FORMAT;
+    byte_copy(buf,len,c->map + pos);
+  }
+  else {
+    if (lseek(c->fd,pos,SEEK_SET) == -1) return -1;
+    while (len > 0) {
+      int r;
+      do
+        r = read(c->fd,buf,len);
+      while ((r == -1) && (errno == EINTR));
+      if (r == -1) return -1;
+      if (r == 0) goto FORMAT;
+      buf += r;
+      len -= r;
+    }
+  }
+  return 0;
+
+  FORMAT:
+  errno = EPROTO;
+  return -1;
+}
+
+static int match(struct cdb *c,const unsigned char *key,unsigned long int len,uint32 pos) {
+  unsigned char buf[32];
+  unsigned long n;
+
+  while (len > 0) {
+    n = sizeof buf;
+    if (n > len) n = len;
+    if (cdb_read(c,buf,n,pos) == -1) return -1;
+    if (byte_diff(buf,n,key)) return 0;
+    pos += n;
+    key += n;
+    len -= n;
+  }
+  return 1;
+}
+
+int cdb_findnext(struct cdb *c,const unsigned char *key,unsigned long int len) {
+  unsigned char buf[8];
+  uint32 pos;
+  uint32 u;
+
+  if (!c->loop) {
+    u = cdb_hash(key,len);
+    if (cdb_read(c,buf,8,(u << 3) & 2047) == -1) return -1;
+    uint32_unpack(buf + 4,&c->hslots);
+    if (!c->hslots) return 0;
+    uint32_unpack(buf,&c->hpos);
+    c->khash = u;
+    u >>= 8;
+    u %= c->hslots;
+    u <<= 3;
+    c->kpos = c->hpos + u;
+  }
+
+  while (c->loop < c->hslots) {
+    if (cdb_read(c,buf,8,c->kpos) == -1) return -1;
+    uint32_unpack(buf + 4,&pos);
+    if (!pos) return 0;
+    c->loop += 1;
+    c->kpos += 8;
+    if (c->kpos == c->hpos + (c->hslots << 3)) c->kpos = c->hpos;
+    uint32_unpack(buf,&u);
+    if (u == c->khash) {
+      if (cdb_read(c,buf,8,pos) == -1) return -1;
+      uint32_unpack(buf,&u);
+      if (u == len)
+	switch(match(c,key,len,pos + 8)) {
+	  case -1:
+	    return -1;
+	  case 1:
+	    uint32_unpack(buf + 4,&c->dlen);
+	    c->dpos = pos + 8 + len;
+	    return 1;
+	}
+    }
+  }
+
+  return 0;
+}
+
+int cdb_find(struct cdb *c,const unsigned char *key,unsigned long int len) {
+  cdb_findstart(c);
+  return cdb_findnext(c,key,len);
+}
diff --git a/cdb/cdb_datalen.3 b/cdb/cdb_datalen.3
new file mode 100644
index 0000000..3b0f0f7
--- /dev/null
+++ b/cdb/cdb_datalen.3
@@ -0,0 +1,17 @@
+.TH cdb_datalen 3
+.SH NAME
+cdb_datalen \- get length of data
+.SH SYNTAX
+.B #include <cdb.h>
+
+unsigned int cdb_datalen(struct cdb *\fIc\fR);
+
+.SH DESCRIPTION
+.B cdb_datalen
+returns the length of the data associated with the last key you looked
+up with cdb_find or cdb_findnext.
+
+Use cdb_datapos to get the position of the data.
+
+.SH "SEE ALSO"
+cdb_datapos(3), cdb_keylen(3), cdb_keypos(3)
diff --git a/cdb/cdb_datapos.3 b/cdb/cdb_datapos.3
new file mode 100644
index 0000000..e679795
--- /dev/null
+++ b/cdb/cdb_datapos.3
@@ -0,0 +1,17 @@
+.TH cdb_datapos 3
+.SH NAME
+cdb_datapos \- get position of data
+.SH SYNTAX
+.B #include <cdb.h>
+
+uint32 cdb_datapos(struct cdb *\fIc\fR);
+
+.SH DESCRIPTION
+.B cdb_datapos
+returns the position of the data associated with the last key you looked
+up using cdb_find or cdb_findnext.
+
+Use cdb_datalen to get the length of the data.
+
+.SH "SEE ALSO"
+cdb_datalen(3), cdb_keypos(3), cdb_keylen(3)
diff --git a/cdb/cdb_find.3 b/cdb/cdb_find.3
new file mode 100644
index 0000000..5e9dfe6
--- /dev/null
+++ b/cdb/cdb_find.3
@@ -0,0 +1,42 @@
+.TH cdb_find 3
+.SH NAME
+cdb_find \- look up a key in a constant database
+.SH SYNTAX
+.B #include <cdb.h>
+.br
+.B #include <uint32.h>
+
+int cdb_find(struct cdb *\fIc\fR,char *\fIkey\fR,unsigned int \fIkeylen\fR);
+.br
+int cdb_datalen(struct cdb *\fIc\fR);
+.br
+int cdb_datapos(struct cdb *\fIc\fR);
+.br
+int cdb_findnext(struct cdb *\fIc\fR,char *\fIkey\fR,unsigned int \fIkeylen\fR);
+
+.SH DESCRIPTION
+\fBcdb_find\fR looks for \fIkey\fR. If cdb_find returns 0, the database
+does not contain that key; stop. If cdb_find returns -1, there was a
+read error; abort.
+
+\fBcdb_datalen\fR returns the length of the data associated with the
+\fIkey\fR.  Use it to allocate a pointer \fIp\fR with enough space to
+hold the data.
+
+\fBcdb_datapos\fR returns the position of the data inside the file.  Use
+it as argument to cdb_read to retrieve the data.
+
+There may be several records under a single key. You can use
+\fBcdb_findnext\fR to find the next record under this key.
+
+.SH EXAMPLE
+static struct cdb;
+
+if (cdb_find(&c,key,strlen(key)>0) {
+  char *buf=alloca(cdb_datalen(&c));
+  cdb_read(&c,buf,cdb_datalen(&c),cdb_datapos(&c));
+  write(1,buf,cdb_datalen(&c));
+.br
+}
+.SH "SEE ALSO"
+cdb_read(3), cdb_init(3), cdb_free(3), cdbmake(1)
diff --git a/cdb/cdb_firstkey.3 b/cdb/cdb_firstkey.3
new file mode 100644
index 0000000..6f34234
--- /dev/null
+++ b/cdb/cdb_firstkey.3
@@ -0,0 +1,19 @@
+.TH cdb_firstkey 3
+.SH NAME
+cdb_firstkey \- find first physical record in constant database
+.SH SYNTAX
+.B #include <cdb.h>
+.br
+.B #include <uint32.h>
+
+int cdb_firstkey(struct cdb *\fIc\fR,uint32 *\fIkpos\fR);
+
+.SH DESCRIPTION
+\fBcdb_firstkey\fR finds the physically first record in the constant
+database.
+
+You can use cdb_datapos or cdb_keypos to get \fIposition\fR and
+cdb_datalen and cdb_keylen to get \fIlen\fR.
+
+.SH "SEE ALSO"
+cdb_nextkey(3), cdb_successor(3)
diff --git a/cdb/cdb_free.3 b/cdb/cdb_free.3
new file mode 100644
index 0000000..f901b77
--- /dev/null
+++ b/cdb/cdb_free.3
@@ -0,0 +1,17 @@
+.TH cdb_free 3
+.SH NAME
+cdb_free \- close a constant databased
+.SH SYNTAX
+.B #include <cdb.h>
+
+int cdb_free(struct cdb *\fIc\fR);
+
+.SH DESCRIPTION
+.B cdb_free
+removes any memory mapping that cdb_init might have established.
+
+It will not close the file descriptor that you passed to cdb_init or
+attempt to call free() on the struct cdb pointer.
+
+.SH "SEE ALSO"
+cdb_free(3), cdb_read(3), cdb_find(3), cdbmake(1)
diff --git a/cdb/cdb_hash.c b/cdb/cdb_hash.c
new file mode 100644
index 0000000..4211486
--- /dev/null
+++ b/cdb/cdb_hash.c
@@ -0,0 +1,19 @@
+
+#include "cdb.h"
+
+uint32 cdb_hashadd(uint32 h,unsigned char c) {
+  h += (h << 5);
+  return h ^ c;
+}
+
+uint32 cdb_hash(const unsigned char *buf,unsigned long int len) {
+  uint32 h;
+
+  h = CDB_HASHSTART;
+  while (len) {
+    h = cdb_hashadd(h,*buf);
+    ++buf;
+    --len;
+  }
+  return h;
+}
diff --git a/cdb/cdb_init.3 b/cdb/cdb_init.3
new file mode 100644
index 0000000..69a8850
--- /dev/null
+++ b/cdb/cdb_init.3
@@ -0,0 +1,20 @@
+.TH cdb_init 3
+.SH NAME
+cdb_init \- open a constant database
+.SH SYNTAX
+.B #include <cdb.h>
+
+int cdb_init(struct cdb *\fIc\fR,int \fIfd\fR);
+
+.SH DESCRIPTION
+.B cdb_init
+places information about \fIfd\fR into a struct cdb variable \fIc\fR.
+\fIfd\fR has to be a seekable file previously opened for reading.
+
+On systems that support mmap, cdb_init will try to map the whole
+constant database into memory.
+
+The inverse operation to cdb_init is cdb_free.
+
+.SH "SEE ALSO"
+cdb_free(3), cdb_read(3), cdb_find(3), cdbmake(1)
diff --git a/cdb/cdb_keylen.3 b/cdb/cdb_keylen.3
new file mode 100644
index 0000000..203af9e
--- /dev/null
+++ b/cdb/cdb_keylen.3
@@ -0,0 +1,16 @@
+.TH cdb_keylen 3
+.SH NAME
+cdb_keylen \- get length of key
+.SH SYNTAX
+.B #include <cdb.h>
+
+unsigned int cdb_keylen(struct cdb *\fIc\fR);
+
+.SH DESCRIPTION
+.B cdb_keylen
+returns the length of the key cdb_firstkey or cdb_nextkey found.
+
+Use cdb_keypos to get the position of the key.
+
+.SH "SEE ALSO"
+cdb_keypos(3), cdb_datalen(3), cdb_datapos(3)
diff --git a/cdb/cdb_keypos.3 b/cdb/cdb_keypos.3
new file mode 100644
index 0000000..06f4c34
--- /dev/null
+++ b/cdb/cdb_keypos.3
@@ -0,0 +1,16 @@
+.TH cdb_keypos 3
+.SH NAME
+cdb_keypos \- get position of key
+.SH SYNTAX
+.B #include <cdb.h>
+
+uint32 cdb_keypos(struct cdb *\fIc\fR);
+
+.SH DESCRIPTION
+.B cdb_keypos
+returns the position of the key cdb_firstkey or cdb_nextkey found.
+
+Use cdb_keylen to get the length of the key.
+
+.SH "SEE ALSO"
+cdb_keylen(3), cdb_datapos(3), cdb_datalen(3)
diff --git a/cdb/cdb_make.c b/cdb/cdb_make.c
new file mode 100644
index 0000000..fe94af1
--- /dev/null
+++ b/cdb/cdb_make.c
@@ -0,0 +1,148 @@
+#define _FILE_OFFSET_BITS 64
+
+#include <unistd.h>
+#include <stdlib.h>
+#include <errno.h>
+#include "cdb.h"
+#include "cdb_make.h"
+
+int cdb_make_start(struct cdb_make *c,int fd) {
+  c->head = 0;
+  c->split = 0;
+  c->hash = 0;
+  c->numentries = 0;
+  c->fd = fd;
+  c->pos = sizeof c->final;
+  buffer_init(&c->b,(void*)write,fd,c->bspace,sizeof c->bspace);
+  return lseek(fd,c->pos,SEEK_SET);
+}
+
+static int posplus(struct cdb_make *c,uint32 len) {
+  uint32 newpos = c->pos + len;
+  if (newpos < len) { errno = ENOMEM; return -1; }
+  c->pos = newpos;
+  return 0;
+}
+
+int cdb_make_addend(struct cdb_make *c,unsigned long int keylen,unsigned long int datalen,uint32 h) {
+  struct cdb_hplist *head;
+
+  head = c->head;
+  if (!head || (head->num >= CDB_HPLIST)) {
+    head = (struct cdb_hplist *) malloc(sizeof(struct cdb_hplist));
+    if (!head) return -1;
+    head->num = 0;
+    head->next = c->head;
+    c->head = head;
+  }
+  head->hp[head->num].h = h;
+  head->hp[head->num].p = c->pos;
+  ++head->num;
+  ++c->numentries;
+  if (posplus(c,8) == -1) return -1;
+  if (posplus(c,keylen) == -1) return -1;
+  if (posplus(c,datalen) == -1) return -1;
+  return 0;
+}
+
+int cdb_make_addbegin(struct cdb_make *c,unsigned long int keylen,unsigned long int datalen) {
+  char buf[8];
+
+  if (keylen > 0xffffffff) { errno = ENOMEM; return -1; }
+  if (datalen > 0xffffffff) { errno = ENOMEM; return -1; }
+
+  uint32_pack(buf,keylen);
+  uint32_pack(buf + 4,datalen);
+  if (buffer_putalign(&c->b,buf,8) == -1) return -1;
+  return 0;
+}
+
+int cdb_make_add(struct cdb_make *c,const unsigned char *key,unsigned long int keylen,const unsigned char *data,unsigned long int datalen)
+{
+  if (cdb_make_addbegin(c,keylen,datalen) == -1) return -1;
+  if (buffer_putalign(&c->b,(char*)key,keylen) == -1) return -1;
+  if (buffer_putalign(&c->b,(char*)data,datalen) == -1) return -1;
+  return cdb_make_addend(c,keylen,datalen,cdb_hash(key,keylen));
+}
+
+int cdb_make_finish(struct cdb_make *c)
+{
+  char buf[8];
+  int i;
+  uint32 len;
+  uint32 u;
+  uint32 memsize;
+  uint32 count;
+  uint32 where;
+  struct cdb_hplist *x;
+  struct cdb_hp *hp;
+
+  for (i = 0;i < 256;++i)
+    c->count[i] = 0;
+
+  for (x = c->head;x;x = x->next) {
+    i = x->num;
+    while (i--)
+      ++c->count[255 & x->hp[i].h];
+  }
+
+  memsize = 1;
+  for (i = 0;i < 256;++i) {
+    u = c->count[i] * 2;
+    if (u > memsize)
+      memsize = u;
+  }
+
+  memsize += c->numentries; /* no overflow possible up to now */
+  u = (uint32) 0 - (uint32) 1;
+  u /= sizeof(struct cdb_hp);
+  if (memsize > u) { errno = ENOMEM; return -1; }
+
+  c->split = (struct cdb_hp *) malloc(memsize * sizeof(struct cdb_hp));
+  if (!c->split) return -1;
+
+  c->hash = c->split + c->numentries;
+
+  u = 0;
+  for (i = 0;i < 256;++i) {
+    u += c->count[i]; /* bounded by numentries, so no overflow */
+    c->start[i] = u;
+  }
+
+  for (x = c->head;x;x = x->next) {
+    i = x->num;
+    while (i--)
+      c->split[--c->start[255 & x->hp[i].h]] = x->hp[i];
+  }
+
+  for (i = 0;i < 256;++i) {
+    count = c->count[i];
+
+    len = count + count; /* no overflow possible */
+    uint32_pack(c->final + 8 * i,c->pos);
+    uint32_pack(c->final + 8 * i + 4,len);
+
+    for (u = 0;u < len;++u)
+      c->hash[u].h = c->hash[u].p = 0;
+
+    hp = c->split + c->start[i];
+    for (u = 0;u < count;++u) {
+      where = (hp->h >> 8) % len;
+      while (c->hash[where].p)
+	if (++where == len)
+	  where = 0;
+      c->hash[where] = *hp++;
+    }
+
+    for (u = 0;u < len;++u) {
+      uint32_pack(buf,c->hash[u].h);
+      uint32_pack(buf + 4,c->hash[u].p);
+      if (buffer_putalign(&c->b,buf,8) == -1) return -1;
+      if (posplus(c,8) == -1) return -1;
+    }
+  }
+
+  if (buffer_flush(&c->b) == -1) return -1;
+  if (lseek(c->fd,0,SEEK_SET) == -1) return -1;
+  return buffer_putflush(&c->b,c->final,sizeof c->final);
+}
diff --git a/cdb/cdb_nextkey.3 b/cdb/cdb_nextkey.3
new file mode 100644
index 0000000..7dbf846
--- /dev/null
+++ b/cdb/cdb_nextkey.3
@@ -0,0 +1,19 @@
+.TH cdb_nextkey 3
+.SH NAME
+cdb_nextkey \- find next physical record in constant database
+.SH SYNTAX
+.B #include <cdb.h>
+.br
+.B #include <uint32.h>
+
+int cdb_nextkey(struct cdb *\fIc\fR,uint32 *\fIkpos\fR);
+
+.SH DESCRIPTION
+\fBcdb_nextkey\fR finds the next physical record in the constant
+database.
+
+You can use cdb_datapos or cdb_keypos to get \fIposition\fR and
+cdb_datalen and cdb_keylen to get \fIlen\fR.
+
+.SH "SEE ALSO"
+cdb_firstkey(3), cdb_successor(3)
diff --git a/cdb/cdb_read.3 b/cdb/cdb_read.3
new file mode 100644
index 0000000..2dd8451
--- /dev/null
+++ b/cdb/cdb_read.3
@@ -0,0 +1,20 @@
+.TH cdb_read 3
+.SH NAME
+cdb_read \- read bytes from a constant database
+.SH SYNTAX
+.B #include <cdb.h>
+.br
+.B #include <uint32.h>
+
+int cdb_read(struct cdb *\fIc\fR,char *\fIbuf\fR,unsigned int \fIlen\fR,uint32 \fIposition\fR);
+
+.SH DESCRIPTION
+\fBcdb_read\fR reads \fIlen\fR bytes starting at \fIposition\fR from
+\fIc\fR to buf.  You can use cdb_datapos or cdb_keypos to get
+\fIposition\fR and cdb_datalen and cdb_keylen to get \fIlen\fR.
+
+\fIbuf\fR needs to point to a memory region large enough to hold
+\fIlen\fR bytes.
+
+.SH "SEE ALSO"
+cdb_find(3), cdb_init(3), cdb_free(3), cdbmake(1)
diff --git a/cdb/cdb_successor.3 b/cdb/cdb_successor.3
new file mode 100644
index 0000000..28c9626
--- /dev/null
+++ b/cdb/cdb_successor.3
@@ -0,0 +1,21 @@
+.TH cdb_successor 3
+.SH NAME
+cdb_successor \- find next record
+.SH SYNTAX
+.B #include <cdb.h>
+
+int cdb_successor(struct cdb *\fIc\fR,char *\fIkey\fR,unsigned int \fIklen\fR);
+
+.SH DESCRIPTION
+\fBcdb_successor\fR finds the record that follows \fIkey\fR.  If
+\fIkey\fR is NULL, cdb_successor finds the first record.
+
+\fBNOTE!\fR  The database must not contain keys with more than one
+associated record or this API will lead to infinite loops!  Use
+cdb_firstkey and cdb_nextkey instead.
+
+You can use cdb_datapos or cdb_keypos to get \fIposition\fR and
+cdb_datalen and cdb_keylen to get \fIlen\fR.
+
+.SH "SEE ALSO"
+cdb_firstkey(3), cdb_nextkey(3)
diff --git a/cdb/cdb_traverse.c b/cdb/cdb_traverse.c
new file mode 100644
index 0000000..81bfd50
--- /dev/null
+++ b/cdb/cdb_traverse.c
@@ -0,0 +1,40 @@
+#include "cdb.h"
+
+static int doit(struct cdb *c,uint32 *kpos) {
+  unsigned char buf[8];
+  uint32 eod,klen;
+  if (cdb_read(c,buf,4,0)) return -1;
+  uint32_unpack(buf,&eod);
+  if (eod<8 || eod-8<*kpos) return 0;
+  c->kpos=*kpos+8;
+  if (c->kpos<*kpos) return -1; /* wraparound */
+  cdb_findstart(c);
+  c->hslots=1;
+  if (cdb_read(c,buf,8,*kpos) == -1) return -1;
+  uint32_unpack(buf,&klen);
+  uint32_unpack(buf+4,&c->dlen);
+  c->dpos=c->kpos+klen;
+  *kpos+=8+klen+c->dlen;
+  return 1;
+}
+
+int cdb_firstkey(struct cdb *c,uint32 *kpos) {
+  *kpos=2048;
+  return doit(c,kpos);
+}
+
+int cdb_nextkey(struct cdb *c,uint32 *kpos) {
+  return doit(c,kpos);
+}
+
+int cdb_successor(struct cdb *c,unsigned char *key,unsigned long int klen) {
+  int r;
+  uint32 kpos;
+  if (key) {
+    r=cdb_find(c,key,klen);
+    if (r<1) return r;
+    kpos=c->dpos+c->dlen;
+  } else
+    kpos=2048;
+  return doit(c,&kpos);
+}
diff --git a/cdb_make.h b/cdb_make.h
new file mode 100644
index 0000000..961b10b
--- /dev/null
+++ b/cdb_make.h
@@ -0,0 +1,39 @@
+/* Public domain. */
+
+#ifndef CDB_MAKE_H
+#define CDB_MAKE_H
+
+#include "buffer.h"
+#include "uint32.h"
+
+#define CDB_HPLIST 1000
+
+struct cdb_hp { uint32 h; uint32 p; } ;
+
+struct cdb_hplist {
+  struct cdb_hp hp[CDB_HPLIST];
+  struct cdb_hplist *next;
+  int num;
+} ;
+
+struct cdb_make {
+  char bspace[8192];
+  char final[2048];
+  uint32 count[256];
+  uint32 start[256];
+  struct cdb_hplist *head;
+  struct cdb_hp *split; /* includes space for hash */
+  struct cdb_hp *hash;
+  uint32 numentries;
+  buffer b;
+  uint32 pos;
+  int fd;
+} ;
+
+extern int cdb_make_start(struct cdb_make *,int);
+extern int cdb_make_addbegin(struct cdb_make *,unsigned long int,unsigned long int);
+extern int cdb_make_addend(struct cdb_make *,unsigned long int,unsigned long int,uint32);
+extern int cdb_make_add(struct cdb_make *,const unsigned char *,unsigned long int,const unsigned char *,unsigned long int);
+extern int cdb_make_finish(struct cdb_make *);
+
+#endif