--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/srvrlib/read_rcd.c	Tue Mar 10 13:49:58 2009 +0100
@@ -0,0 +1,190 @@
+/* Distributed Checksum Clearinghouse
+ *
+ * Copyright (c) 2008 by Rhyolite Software, LLC
+ *
+ * This agreement is not applicable to any entity which sells anti-spam
+ * solutions to others or provides an anti-spam solution as part of a
+ * security solution sold to other entities, or to a private network
+ * which employs the DCC or uses data provided by operation of the DCC
+ * but does not provide corresponding data to other users.
+ *
+ * Permission to use, copy, modify, and distribute this software without
+ * changes for any purpose with or without fee is hereby granted, provided
+ * that the above copyright notice and this permission notice appear in all
+ * copies and any distributed versions or copies are either unchanged
+ * or not called anything similar to "DCC" or "Distributed Checksum
+ * Clearinghouse".
+ *
+ * Parties not eligible to receive a license under this agreement can
+ * obtain a commercial license to use DCC by contacting Rhyolite Software
+ * at sales@rhyolite.com.
+ *
+ * A commercial license would be for Distributed Checksum and Reputation
+ * Clearinghouse software.  That software includes additional features.  This
+ * free license for Distributed ChecksumClearinghouse Software does not in any
+ * way grant permision to use Distributed Checksum and Reputation Clearinghouse
+ * software
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND RHYOLITE SOFTWARE, LLC DISCLAIMS ALL
+ * WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL RHYOLITE SOFTWARE, LLC
+ * BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES
+ * OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
+ * WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
+ * ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
+ * SOFTWARE.
+ *
+ * Rhyolite Software DCC 1.3.103-1.24 $Revision$
+ */
+
+#include "srvr_defs.h"
+
+static int read_rcd_fd = -1;
+#define BUF_SIZE    (64*1024)
+static u_char read_rcd_buf[BUF_SIZE];
+static u_int read_rcd_bufsize = BUF_SIZE;
+static off_t read_rcd_base;
+static u_int read_rcd_buflen;
+
+static int system_pagesize;
+
+
+
+int
+read_db(DCC_EMSG emsg, void *buf, u_int buf_len,
+	int fd, off_t pos, const char *file_nm)
+{
+	int i;
+
+	if (-1 == lseek(fd, pos, SEEK_SET)) {
+		dcc_pemsg(EX_IOERR, emsg, "lseek(%s, 0): %s",
+			  DB_NM2PATH_ERR(file_nm), ERROR_STR());
+		return -1;
+	}
+
+	i = read(fd, buf, buf_len);
+	if (i >= 0)
+		return i;
+
+	dcc_pemsg(EX_IOERR, emsg, "read(%s): %s",
+		  DB_NM2PATH_ERR(file_nm), ERROR_STR());
+	return -1;
+}
+
+
+
+u_char
+read_db_hdr(DCC_EMSG emsg, DB_HDR *hdrp,
+	   int fd, const char *file_nm)
+{
+	return (sizeof(*hdrp) == read_db(emsg, hdrp, sizeof(*hdrp),
+					  fd, 0, file_nm));
+}
+
+
+
+/* invalidate the read_rcd() read-ahead cache */
+void
+read_rcd_invalidate(u_int bufsize)
+{
+	read_rcd_fd = -1;
+
+	if (system_pagesize == 0)
+		system_pagesize = getpagesize();
+	bufsize = ((bufsize + system_pagesize-1) / system_pagesize
+		   * system_pagesize);
+	if (bufsize == 0 || bufsize > BUF_SIZE)
+		bufsize = BUF_SIZE;
+	read_rcd_bufsize = bufsize;
+}
+
+
+
+static int
+read_rcd_sub(DCC_EMSG emsg, void *buf, u_int buflen,
+	     int fd, off_t pos, const char *file_nm)
+{
+	int i;
+
+	if (fd == read_rcd_fd
+	    && pos >= read_rcd_base
+	    && pos+buflen <= read_rcd_base+read_rcd_buflen) {
+		memcpy(buf, &read_rcd_buf[pos-read_rcd_base], buflen);
+		return buflen;
+	}
+
+	if (system_pagesize == 0)
+		system_pagesize = getpagesize();
+	read_rcd_base = pos - (pos % system_pagesize);
+
+	i = read_db(emsg, read_rcd_buf, read_rcd_bufsize,
+		    read_rcd_fd = fd,
+		    read_rcd_base, file_nm);
+	if (i <= 0) {
+		read_rcd_fd = -1;
+		return i;
+	}
+	read_rcd_buflen = i;
+	if (buflen > read_rcd_buflen)
+		buflen = read_rcd_buflen;
+	memcpy(buf, &read_rcd_buf[pos-read_rcd_base], buflen);
+	return buflen;
+}
+
+
+
+int					/* -1=error 0=eof >0=record length */
+read_rcd(DCC_EMSG emsg, DB_RCD *rcd,
+	 int fd, off_t pos, const char *file_nm)
+{
+	int i, cks_len, num_cks;
+
+	/* read a record, starting with its beginning */
+	i = read_rcd_sub(emsg, rcd, DB_RCD_HDR_LEN,
+			 fd, pos, file_nm);
+	if (DB_RCD_HDR_LEN != i) {
+		if (i == 0)
+			return 0;
+		if (i > 0) {
+			dcc_pemsg(EX_DATAERR, emsg,
+				  "header of record at "OFF_HPAT" of %s"
+				  " truncated by %d bytes",
+				  lseek(fd, 0, SEEK_CUR) - i,
+				  DB_NM2PATH_ERR(file_nm), DB_RCD_HDR_LEN-i);
+		}
+		return -1;
+	}
+
+	num_cks = DB_NUM_CKS(rcd);
+	if (num_cks > DIM(rcd->cks)) {
+		dcc_pemsg(EX_DATAERR, emsg,
+			  "bogus checksum count %#x at "OFF_HPAT" of %s",
+			  rcd->fgs_num_cks, lseek(fd, 0, SEEK_CUR),
+			  DB_NM2PATH_ERR(file_nm));
+		return -1;
+	}
+	cks_len = num_cks * sizeof(rcd->cks[0]);
+	if (cks_len != 0) {
+		i = read_rcd_sub(emsg, rcd->cks, cks_len,
+				 fd, pos+DB_RCD_HDR_LEN, file_nm);
+		if (i != cks_len) {
+			if (i < 0)
+				return -1;
+			if (!i)
+				dcc_pemsg(EX_DATAERR, emsg,
+					  "record at "OFF_HPAT" of %s"
+					  " truncated after header",
+					  lseek(fd, 0, SEEK_CUR),
+					  DB_NM2PATH_ERR(file_nm));
+			else
+				dcc_pemsg(EX_DATAERR, emsg,
+					  "record at "OFF_HPAT" of %s"
+					  " truncated by %d bytes",
+					  lseek(fd, 0, SEEK_CUR),
+					  DB_NM2PATH_ERR(file_nm), cks_len-i);
+			return 0;
+		}
+	}
+
+	return DB_RCD_HDR_LEN+cks_len;
+}