Remove the "union pseudo_header" from the "frame_data" structure;

there's no need to keep it around in memory - when the frame data is
read in when handing a frame, read in the information, if any, necessary
to reconstruct the frame header, and reconstruct it.  This saves some
memory.

This requires that the seek-and-read function be implemented inside
Wiretap, and that the Wiretap handle remain open even after we've
finished reading the file sequentially.

This also points out that we can't really do X.25-over-Ethernet
correctly, as we don't know where the direction (DTE->DCE or DCE->DTE)
flag is stored; it's not clear how the Ethernet type 0x0805 for X.25
Layer 3 is supposed to be handled in any case.  We eliminate
X.25-over-Ethernet support (until we find out what we're supposed to
do).

svn path=/trunk/; revision=1975

1 files changed, 82 insertions, 27 deletions

diff --git a/wiretap/radcom.c b/wiretap/radcom.c
index ac378a2a83..ed168f417e 100644
--- a/wiretap/radcom.c
+++ b/wiretap/radcom.c
@@ -1,6 +1,6 @@
 /* radcom.c
  *
- * $Id: radcom.c,v 1.20 2000/04/15 21:12:37 guy Exp $
+ * $Id: radcom.c,v 1.21 2000/05/18 09:09:43 guy Exp $
  *
  * Wiretap Library
  * Copyright (c) 1998 by Gilbert Ramirez <gram@xiexie.org>
@@ -68,6 +68,11 @@ struct radcomrec_hdr {
 };
 
 static int radcom_read(wtap *wth, int *err);
+static int radcom_seek_read(wtap *wth, int seek_off,
+	union pseudo_header *pseudo_header, u_char *pd, int length);
+static int radcom_read_rec_header(FILE_T *fh, struct radcomrec_hdr *hdr,
+	int *err);
+static int radcom_read_rec_data(FILE_T *fh, char *pd, int length, int *err);
 
 int radcom_open(wtap *wth, int *err)
 {
@@ -134,6 +139,7 @@ int radcom_open(wtap *wth, int *err)
 	/* This is a radcom file */
 	wth->file_type = WTAP_FILE_RADCOM;
 	wth->subtype_read = radcom_read;
+	wth->subtype_seek_read = radcom_seek_read;
 	wth->snapshot_length = 16384;	/* not available in header, only in frame */
 
 	tm.tm_year = pletohs(&start_date.year)-1900;
@@ -218,26 +224,21 @@ read_error:
 /* Read the next packet */
 static int radcom_read(wtap *wth, int *err)
 {
-	int	bytes_read;
+	int	record_offset;
+	int	ret;
 	struct radcomrec_hdr hdr;
 	guint16 length;
 	guint32 sec;
+	int	bytes_read;
 	struct tm tm;
-	int	data_offset;
 	char	fcs[2];
 
 	/* Read record header. */
-	errno = WTAP_ERR_CANT_READ;
-	bytes_read = file_read(&hdr, 1, sizeof hdr, wth->fh);
-	if (bytes_read != sizeof hdr) {
-		*err = file_error(wth->fh);
-		if (*err != 0)
-			return -1;
-		if (bytes_read != 0) {
-			*err = WTAP_ERR_SHORT_READ;
-			return -1;
-		}
-		return 0;
+	record_offset = wth->data_offset;
+	ret = radcom_read_rec_header(wth->fh, &hdr, err);
+	if (ret <= 0) {
+		/* Read error or EOF */
+		return ret;
 	}
 	wth->data_offset += sizeof hdr;
 	length = pletohs(&hdr.length);
@@ -259,23 +260,15 @@ static int radcom_read(wtap *wth, int *err)
 	tm.tm_isdst = -1;
 	wth->phdr.ts.tv_sec = mktime(&tm);
 	wth->phdr.ts.tv_usec = pletohl(&hdr.date.usec);
-	wth->phdr.pseudo_header.x25.flags = (hdr.dce & 0x1) ? 0x00 : 0x80;
+	wth->pseudo_header.x25.flags = (hdr.dce & 0x1) ? 0x00 : 0x80;
 
 	/*
 	 * Read the packet data.
 	 */
 	buffer_assure_space(wth->frame_buffer, length);
-	data_offset = wth->data_offset;
-	errno = WTAP_ERR_CANT_READ;
-	bytes_read = file_read(buffer_start_ptr(wth->frame_buffer), 1,
-			length, wth->fh);
-
-	if (bytes_read != length) {
-		*err = file_error(wth->fh);
-		if (*err == 0)
-			*err = WTAP_ERR_SHORT_READ;
-		return -1;
-	}
+	if (radcom_read_rec_data(wth->fh,
+	    buffer_start_ptr(wth->frame_buffer), length, err) < 0)
+		return -1;	/* Read error */
 	wth->data_offset += length;
 
 	wth->phdr.pkt_encap = wth->file_encap;
@@ -294,5 +287,67 @@ static int radcom_read(wtap *wth, int *err)
 		wth->data_offset += sizeof fcs;
 	}
 
-	return data_offset;
+	return record_offset;
+}
+
+static int
+radcom_seek_read(wtap *wth, int seek_off,
+    union pseudo_header *pseudo_header, u_char *pd, int length)
+{
+	int	ret;
+	int	err;		/* XXX - return this */
+	struct radcomrec_hdr hdr;
+
+	file_seek(wth->random_fh, seek_off, SEEK_SET);
+
+	/* Read record header. */
+	ret = radcom_read_rec_header(wth->random_fh, &hdr, &err);
+	if (ret <= 0) {
+		/* Read error or EOF */
+		return ret;
+	}
+
+	pseudo_header->x25.flags = (hdr.dce & 0x1) ? 0x00 : 0x80;
+
+	/*
+	 * Read the packet data.
+	 */
+	return radcom_read_rec_data(wth->random_fh, pd, length, &err);
+}
+
+static int
+radcom_read_rec_header(FILE_T *fh, struct radcomrec_hdr *hdr, int *err)
+{
+	int	bytes_read;
+
+	errno = WTAP_ERR_CANT_READ;
+	bytes_read = file_read(hdr, 1, sizeof *hdr, fh);
+	if (bytes_read != sizeof *hdr) {
+		*err = file_error(fh);
+		if (*err != 0)
+			return -1;
+		if (bytes_read != 0) {
+			*err = WTAP_ERR_SHORT_READ;
+			return -1;
+		}
+		return 0;
+	}
+	return 1;
+}
+
+static int
+radcom_read_rec_data(FILE_T *fh, char *pd, int length, int *err)
+{
+	int	bytes_read;
+
+	errno = WTAP_ERR_CANT_READ;
+	bytes_read = file_read(pd, 1, length, fh);
+
+	if (bytes_read != length) {
+		*err = file_error(fh);
+		if (*err == 0)
+			*err = WTAP_ERR_SHORT_READ;
+		return -1;
+	}
+	return 0;
 }