Instead of converting between 802.11 frequencies and channels umpteen

different ways, add a set of common conversion routines.  Add a
"Frequency/Channel" column and fill it in where we can.  Fix RSSI column
printing in PPI.

Fix up whitespace along the way.


git-svn-id: http://anonsvn.wireshark.org/wireshark/trunk@22538 f5534014-38df-0310-8fa8-9805f1628bb7

1 files changed, 110 insertions, 0 deletions

diff --git a/epan/frequency-utils.c b/epan/frequency-utils.c
new file mode 100644
index 0000000000..aa04f1d4cf
--- /dev/null
+++ b/epan/frequency-utils.c
@@ -0,0 +1,110 @@
+/* frequency-utils.c
+ * Frequency conversion utility definitions
+ *
+ * $Id$
+ *
+ * Wireshark - Network traffic analyzer
+ * By Gerald Combs <gerald@wireshark.org>
+ * Copyright 2007 Gerald Combs
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#include <glib.h>
+
+#include "frequency-utils.h"
+
+typedef struct freq_cvt_s {
+    guint fmin;         /* Minimum frequency in MHz */
+    guint fmax;         /* Maximum frequency in MHz */
+    gint cmin;          /* Minimum/base channel */
+    gboolean is_bg;     /* B/G channel? */
+} freq_cvt_t;
+
+#define FREQ_STEP 5     /* MHz. This seems to be consistent, thankfully */
+
+static freq_cvt_t freq_cvt[] = {
+    { 2412, 2472,   1, TRUE },
+    { 2484, 2484,  14, TRUE },
+    { 5000, 5995,   0, FALSE },
+    { 4920, 4995, 240, FALSE }
+};
+
+#define NUM_FREQ_CVT (sizeof(freq_cvt) / sizeof(freq_cvt_t))
+#define MAX_CHANNEL(fc) ( (gint) ((fc.fmax - fc.fmin) / FREQ_STEP) + fc.cmin )
+
+/*
+ * Get channel number given a Frequency
+ */
+gint
+ieee80211_mhz_to_chan(guint freq) {
+    int i;
+
+    for (i = 0; i < NUM_FREQ_CVT; i++) {
+        if (freq >= freq_cvt[i].fmin && freq <= freq_cvt[i].fmax) {
+            return ((freq - freq_cvt[i].fmin) / FREQ_STEP) + freq_cvt[i].cmin;
+        }
+    }
+    return -1;
+}
+
+/*
+ * Get Frequency given a Channel number
+ */
+guint
+ieee80211_chan_to_mhz(gint chan, gboolean is_bg) {
+    int i;
+
+    for (i = 0; i < NUM_FREQ_CVT; i++) {
+        if (is_bg == freq_cvt[i].is_bg &&
+                chan >= freq_cvt[i].cmin && chan <= MAX_CHANNEL(freq_cvt[i])) {
+            return ((chan - freq_cvt[i].cmin) * FREQ_STEP) + freq_cvt[i].fmin;
+        }
+    }
+    return 0;
+}
+
+/*
+ * Get channel representation string given a Frequency
+ */
+gchar*
+ieee80211_mhz_to_str(guint freq){
+    gint chan = ieee80211_mhz_to_chan(freq);
+    gboolean is_bg = FREQ_IS_BG(freq);
+
+    if (chan < 0) {
+        return g_strdup_printf("%u", freq);
+    } else {
+        return g_strdup_printf("%u [%s %u]", freq, is_bg ? "BG" : "A",
+            chan);
+    }
+}
+
+/*
+ * Editor modelines
+ *
+ * Local Variables:
+ * c-basic-offset: 4
+ * tab-width: 8
+ * indent-tabs-mode: nil
+ * End:
+ *
+ * ex: set shiftwidth=4 tabstop=8 expandtab
+ * :indentSize=4:tabSize=8:noTabs=true:
+ */