1 files changed, 94 insertions, 0 deletions
diff --git a/cdb_seek.c b/cdb_seek.c
new file mode 100644
index 0000000..f31b87d
--- /dev/null
+++ b/cdb_seek.c
@@ -0,0 +1,94 @@
+#include <sys/types.h>
+#include <errno.h>
+#include "cdb.h"
+
+#ifndef SEEK_SET
+#define SEEK_SET 0
+#endif
+
+int cdb_bread(fd,buf,len)
+int fd;
+char *buf;
+int len;
+{
+  int r;
+  while (len > 0) {
+    do
+      r = read(fd,buf,len);
+    while ((r == -1) && (errno == EINTR));
+    if (r == -1) return -1;
+    if (r == 0) { errno = EIO; return -1; }
+    buf += r;
+    len -= r;
+  }
+  return 0;
+}
+
+static int match(fd,key,len)
+int fd;
+char *key;
+unsigned int len;
+{
+  char buf[32];
+  int n;
+  int i;
+
+  while (len > 0) {
+    n = sizeof(buf);
+    if (n > len) n = len;
+    if (cdb_bread(fd,buf,n) == -1) return -1;
+    for (i = 0;i < n;++i) if (buf[i] != key[i]) return 0;
+    key += n;
+    len -= n;
+  }
+  return 1;
+}
+
+int cdb_seek(fd,key,len,dlen)
+int fd;
+char *key;
+unsigned int len;
+uint32 *dlen;
+{
+  char packbuf[8];
+  uint32 pos;
+  uint32 h;
+  uint32 lenhash;
+  uint32 h2;
+  uint32 loop;
+  uint32 poskd;
+
+  h = cdb_hash(key,len);
+
+  pos = 8 * (h & 255);
+  if (lseek(fd,(off_t) pos,SEEK_SET) == -1) return -1;
+
+  if (cdb_bread(fd,packbuf,8) == -1) return -1;
+
+  pos = cdb_unpack(packbuf);
+  lenhash = cdb_unpack(packbuf + 4);
+
+  if (!lenhash) return 0;
+  h2 = (h >> 8) % lenhash;
+
+  for (loop = 0;loop < lenhash;++loop) {
+    if (lseek(fd,(off_t) (pos + 8 * h2),SEEK_SET) == -1) return -1;
+    if (cdb_bread(fd,packbuf,8) == -1) return -1;
+    poskd = cdb_unpack(packbuf + 4);
+    if (!poskd) return 0;
+    if (cdb_unpack(packbuf) == h) {
+      if (lseek(fd,(off_t) poskd,SEEK_SET) == -1) return -1;
+      if (cdb_bread(fd,packbuf,8) == -1) return -1;
+      if (cdb_unpack(packbuf) == len)
+	switch(match(fd,key,len)) {
+	  case -1:
+	    return -1;
+	  case 1:
+	    *dlen = cdb_unpack(packbuf + 4);
+	    return 1;
+	}
+    }
+    if (++h2 == lenhash) h2 = 0;
+  }
+  return 0;
+}