--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/cdb.c	Fri Oct 19 11:01:15 2007 +0200
@@ -0,0 +1,136 @@
+/* Public domain. */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+#include "readwrite.h"
+#include "error.h"
+#include "seek.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,char *buf,unsigned int 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 (seek_set(c->fd,pos) == -1) return -1;
+    while (len > 0) {
+      int r;
+      do
+        r = read(c->fd,buf,len);
+      while ((r == -1) && (errno == error_intr));
+      if (r == -1) return -1;
+      if (r == 0) goto FORMAT;
+      buf += r;
+      len -= r;
+    }
+  }
+  return 0;
+
+  FORMAT:
+  errno = error_proto;
+  return -1;
+}
+
+static int match(struct cdb *c,char *key,unsigned int len,uint32 pos)
+{
+  char buf[32];
+  int 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,char *key,unsigned int len)
+{
+  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,char *key,unsigned int len)
+{
+  cdb_findstart(c);
+  return cdb_findnext(c,key,len);
+}