From RobiOneKenobi via https://bugs.wireshark.org/bugzilla/show_bug.cgi?id=9229

Add a new strutil function format_text_chr that replaces unprintable characters
with a single passed-in char (eg a '.' or a '-') instead of a C-style escape.
This is useful for displaying binary data that frequently but not always
contains text; otherwise the number of C escape codes makes it unreadable.

svn path=/trunk/; revision=52563

1 files changed, 65 insertions, 0 deletions

diff --git a/epan/strutil.c b/epan/strutil.c
index 4446a45979..1265f9f89e 100644
--- a/epan/strutil.c
+++ b/epan/strutil.c
@@ -355,6 +355,71 @@ format_text_wsp(const guchar *string, size_t len)
     return fmtbuf[idx];
 }
 
+/*
+ * Given a string, generate a string from it that shows non-printable
+ * characters as the chr parameter passed, except a whitespace character
+ * (space, tab, carriage return, new line, vertical tab, or formfeed)
+ * which will be replaced by a space, and return a pointer to it.
+ */
+gchar *
+format_text_chr(const guchar *string, const size_t len, const guchar chr)
+{
+    static gchar *fmtbuf[3];
+    static int fmtbuf_len[3];
+    static int idx;
+    int column;
+    const guchar *stringend = string + len;
+    guchar c;
+
+    idx = (idx + 1) % 3;
+
+    /*
+     * Allocate the buffer if it's not already allocated.
+     */
+    if (fmtbuf[idx] == NULL) {
+        fmtbuf[idx] = (gchar *)g_malloc(INITIAL_FMTBUF_SIZE);
+        fmtbuf_len[idx] = INITIAL_FMTBUF_SIZE;
+    }
+    column = 0;
+    while (string < stringend) 
+    {
+        /*
+         * Is there enough room for this character, 
+         * and also enough room for a terminating '\0'?
+         */
+        if (column+1 >= fmtbuf_len[idx]) 
+        {
+            /*
+             * Double the buffer's size if it's not big enough.
+             * The size of the buffer starts at 128, so doubling its size
+             * adds at least another 128 bytes, which is more than enough
+             * for one more character plus a terminating '\0'.
+             */
+            fmtbuf_len[idx] = fmtbuf_len[idx] * 2;
+            fmtbuf[idx] = (gchar *)g_realloc(fmtbuf[idx], fmtbuf_len[idx]);
+        }
+        c = *string++;
+
+        if (isprint(c)) 
+        {
+            fmtbuf[idx][column] = c;
+            column++;
+        } 
+        else if  (isspace(c)) 
+        {
+            fmtbuf[idx][column] = ' ';
+            column++;
+        } 
+        else 
+        {
+            fmtbuf[idx][column] =  chr;
+            column++;
+        }
+    }
+    fmtbuf[idx][column] = '\0';
+    return fmtbuf[idx];
+}
+
 static gboolean
 is_byte_sep(guint8 c)
 {