diff -Nurd cdb-0.75.orig/FILES cdb-0.75/FILES
--- cdb-0.75.orig/FILES	Sat Feb 19 20:42:05 2000
+++ cdb-0.75/FILES	Sun Oct 19 11:21:02 2003
@@ -1,4 +1,5 @@
 README
+README.cdbpatch
 TODO
 CHANGES
 VERSION
@@ -11,6 +12,7 @@
 Makefile
 cdbget.c
 cdbmake.c
+cdbpatch.c
 cdbdump.c
 cdbstats.c
 cdbtest.c
diff -Nurd cdb-0.75.orig/Makefile cdb-0.75/Makefile
--- cdb-0.75.orig/Makefile	Sat Feb 19 20:42:05 2000
+++ cdb-0.75/Makefile	Sun Oct 19 11:21:02 2003
@@ -142,6 +142,15 @@
 uint32.h cdb.h uint32.h
 	./compile cdbmake.c
 
+cdbpatch: \
+load cdbpatch.o cdb.a alloc.a buffer.a unix.a byte.a
+	./load cdbpatch cdb.a alloc.a buffer.a unix.a byte.a 
+
+cdbpatch.o: \
+compile cdbpatch.c error.h open.h strerr.h cdb_make.h buffer.h \
+uint32.h cdb.h uint32.h fmt.h alloc.h seek.h readwrite.h
+	./compile cdbpatch.c
+
 cdbstats: \
 load cdbstats.o cdb.a buffer.a unix.a byte.a
 	./load cdbstats cdb.a buffer.a unix.a byte.a 
@@ -243,7 +252,7 @@
 	./compile open_trunc.c
 
 prog: \
-cdbget cdbmake cdbdump cdbstats cdbtest cdbmake-12 cdbmake-sv rts \
+cdbget cdbmake cdbpatch cdbdump cdbstats cdbtest cdbmake-12 cdbmake-sv rts \
 testzero
 
 rts: \
diff -Nurd cdb-0.75.orig/README.cdbpatch cdb-0.75/README.cdbpatch
--- cdb-0.75.orig/README.cdbpatch	Thu Jan  1 01:00:00 1970
+++ cdb-0.75/README.cdbpatch	Sun Oct 19 11:21:02 2003
@@ -0,0 +1,59 @@
+
+Like cdbmake, the cdbpatch program makes changes to a cdb by rebuilding the
+database and renaming the new version into place.  The difference is the
+input format; cdbpatch reads the old version of the target cdb and a patch
+file, rather than a flat file in cdbmake format.  The intention is to allow
+a set of changes to be made to a large cdb as efficiently as possible.
+
+The patch file is itself a cdb, in a special format.  All values in the
+patch cdb must either be of zero length or start with an '=' character.
+
+The new target cdb is generated as follows.
+
+ First, entries are copied from the old target cdb to the new, skipping any
+ for which there is an entry in the patch cdb.
+
+ Next, entries are copied from the patch cdb to the new target cdb.  Entries
+ with zero length values are skipped, and the leading '=' is removed from
+ all values copied.
+
+In effect, entries with zero length values in the patch cdb are instructions
+to delete entries, while entries with nonempty values are instructions to
+add or replace entries.
+
+For example, if the old target cdb contains:
+
++5,4:hello->wooo
++3,3:foo->foo
++3,1:foo->x
++3,3:bar->bar
++2,2:oh->ho
++2,2:hi->ho
+
+
+and we wish to change it to:
+
++3,3:foo->foo
++3,0:bar->
++4,1:woot:x
++2,2:oh->ho
++2,2:hi->ho
+
+
+then we would run this through cdbmake to build a patch cdb:
+
++3,4:foo->=foo
++3,1:bar->=
++5,0:hello->
++4,2:woot->=x
+
+
+The cdbpatch program expects to read the old target cdb from fd 0 and the
+patch cdb from fd 6.  Both must be seekable.  For example:
+
+   cdbpatch <bigtable.cdb 6<patch.cdb bigtable.cdb tmp
+
+
+--
+Nick Cleaton
+catnick@cleaton.net (remove "cat")
diff -Nurd cdb-0.75.orig/TARGETS cdb-0.75/TARGETS
--- cdb-0.75.orig/TARGETS	Sat Feb 19 20:42:05 2000
+++ cdb-0.75/TARGETS	Sun Oct 19 11:21:02 2003
@@ -37,9 +37,11 @@
 byte.a
 cdbget
 cdbmake.o
+cdbpatch.o
 alloc.o
 alloc.a
 cdbmake
+cdbpatch
 cdbdump.o
 cdbdump
 cdbstats.o
diff -Nurd cdb-0.75.orig/cdbpatch.c cdb-0.75/cdbpatch.c
--- cdb-0.75.orig/cdbpatch.c	Thu Jan  1 01:00:00 1970
+++ cdb-0.75/cdbpatch.c	Sun Oct 19 11:21:02 2003
@@ -0,0 +1,225 @@
+#include "uint32.h"
+#include "fmt.h"
+#include "error.h"
+#include "open.h"
+#include "buffer.h"
+#include "alloc.h"
+#include "seek.h"
+#include "readwrite.h"
+#include "strerr.h"
+#include "cdb_make.h"
+#include "cdb.h"
+
+#define FATAL "cdbpatch: fatal: "
+
+#define ORIG_CDB_FD  0
+#define PATCH_CDB_FD 6
+
+char *fn;
+char *fntmp;
+
+void die_usage(void)
+{
+  strerr_die1x(100,"cdbpatch: usage: cdbpatch f ftmp");
+}
+void die_write(void)
+{
+  strerr_die4sys(111,FATAL,"unable to create ",fntmp,": ");
+}
+void die_read(void)
+{
+  strerr_die2sys(111,FATAL,"unable to read input: ");
+}
+void die_trunc(void)
+{
+  strerr_die2x(111,FATAL,"unable to read input: truncated file");
+}
+void die_nomem(void)
+{
+  strerr_die2x(111,FATAL,"out of memory");
+}
+void die_notpatch(void)
+{
+  strerr_die2x(111,FATAL,"invalid cdb patch");
+}
+
+char buffer_in_space[BUFFER_INSIZE];
+static buffer buffer_in;
+int buffer_in_read(fd,buf,len) int fd; char *buf; int len;
+{
+  if (buffer_flush(&buffer_in) == -1) return -1;
+  return read(fd,buf,len);
+}
+uint32 input_pos; 
+uint32 input_eod; 
+
+static struct cdb_make cdbout;
+
+void copy(unsigned int len)
+{
+  unsigned int r;
+  char *x;
+
+  input_pos += len;
+  while (len) {
+    r = buffer_feed(&buffer_in);
+    if (r == -1) die_read();
+    if (r == 0)  die_trunc();
+    if (r > len) r = len;
+    x = buffer_peek(&buffer_in);
+    if (buffer_put(&cdbout.b,x,r) == -1) die_write();
+    buffer_seek(&buffer_in,r);
+    len -= r;
+  }
+}
+
+uint32 copyh(unsigned int len)
+{
+  uint32 h = CDB_HASHSTART;
+  unsigned int i;
+  unsigned int r;
+  char *x;
+
+  input_pos += len;
+  while (len) {
+    r = buffer_feed(&buffer_in);
+    if (r == -1) die_read();
+    if (r == 0)  die_trunc();
+    if (r > len) r = len;
+    x = buffer_peek(&buffer_in);
+    for (i = 0;i < r;++i)
+      h = cdb_hashadd(h,x[i]);
+    if (buffer_put(&cdbout.b,x,r) == -1) die_write();
+    buffer_seek(&buffer_in,r);
+    len -= r;
+  }
+  return h;
+}
+
+void get(char *buf,unsigned int len)
+{
+  unsigned int r;
+
+  input_pos += len;
+  while (len) {
+    r = buffer_get(&buffer_in,buf,len);
+    if (r == -1) die_read();
+    if (r == 0)  die_trunc();
+    buf += r;
+    len -= r;
+  }
+}
+
+char buf[512];
+
+void skip(unsigned int bytes) {
+  while(bytes > sizeof buf) {
+    get(buf,sizeof buf);
+    bytes -= sizeof buf;
+  }
+  get(buf,bytes);
+}
+
+void getnum(uint32 *num)
+{
+  get(buf,4);
+  uint32_unpack(buf,num);
+}
+
+void buffer_in_init(int fd)
+{
+  input_pos = 0;
+  buffer_init(&buffer_in,buffer_in_read,fd,
+                       buffer_in_space,sizeof buffer_in_space);
+
+  getnum(&input_eod);
+  skip(2048 - input_pos);
+}
+
+static struct cdb pcdb;
+
+#define KCAP 8192
+main(int argc,char **argv)
+{
+  int fd;
+  uint32 klen;
+  uint32 dlen;
+  uint32 h;
+  unsigned int i;
+  char ch;
+  unsigned int kcap;
+  char *kstore;
+
+  if (!*argv) die_usage();
+  
+  if (!*++argv) die_usage();
+  fn = *argv;
+
+  if (!*++argv) die_usage();
+  fntmp = *argv;
+
+  fd = open_trunc(fntmp);
+  if (fd == -1) die_write();
+
+  if (cdb_make_start(&cdbout,fd) == -1) die_write();
+
+  /* Copy any keys that aren't in the patch from old to new */
+  kcap = KCAP;
+  kstore = alloc(kcap);
+  if (!kstore) die_nomem();
+  cdb_init(&pcdb,PATCH_CDB_FD);
+  buffer_in_init(ORIG_CDB_FD);
+  while (input_pos < input_eod) {
+    getnum(&klen);
+    getnum(&dlen);
+    if (klen > kcap) {
+      while (klen > kcap) kcap *= 2;
+      alloc_free(kstore);
+      kstore = alloc(kcap);
+      if (!kstore) die_nomem();
+    }
+    get(kstore, klen);
+    switch (cdb_find(&pcdb,kstore,klen)) {
+      case -1:
+        die_write();
+      case 0:
+        h = cdb_hash(kstore,klen);
+        if (cdb_make_addbegin(&cdbout,klen,dlen) == -1) die_write();
+        if (buffer_put(&cdbout.b,kstore,klen)    == -1) die_write();
+        copy(dlen);
+        if (cdb_make_addend(&cdbout,klen,dlen,h) == -1) die_write();
+        break;
+      default:
+        skip(dlen);
+    }
+  }
+  cdb_free(&pcdb);
+
+  /* Copy keys from patch to new */
+  seek_begin(PATCH_CDB_FD);
+  buffer_in_init(PATCH_CDB_FD);
+  while (input_pos < input_eod) {
+    getnum(&klen);
+    getnum(&dlen);
+    if (dlen == 0)
+      skip(klen);
+    else {
+      --dlen;
+      if (cdb_make_addbegin(&cdbout,klen,dlen) == -1) die_write();
+      h = copyh(klen);
+      get(&ch,1);
+      if (ch != '=') die_notpatch();
+      copy(dlen);
+      if (cdb_make_addend(&cdbout,klen,dlen,h) == -1) die_write();
+    }
+  }
+
+  if (cdb_make_finish(&cdbout) == -1) die_write();
+  if (fsync(fd) == -1) die_write();
+  if (close(fd) == -1) die_write(); /* NFS silliness */
+  if (rename(fntmp,fn) == -1)
+    strerr_die6sys(111,FATAL,"unable to rename ",fntmp," to ",fn,": ");
+
+  _exit(0);
+}
+
diff -Nurd cdb-0.75.orig/hier.c cdb-0.75/hier.c
--- cdb-0.75.orig/hier.c	Sat Feb 19 20:42:05 2000
+++ cdb-0.75/hier.c	Sun Oct 19 11:21:02 2003
@@ -7,6 +7,7 @@
 
   c(auto_home,"bin","cdbget",-1,-1,0755);
   c(auto_home,"bin","cdbmake",-1,-1,0755);
+  c(auto_home,"bin","cdbpatch",-1,-1,0755);
   c(auto_home,"bin","cdbdump",-1,-1,0755);
   c(auto_home,"bin","cdbstats",-1,-1,0755);
   c(auto_home,"bin","cdbtest",-1,-1,0755);