charset: change GSM unpack to take number of characters rather than octets

Change interface to take the number of GSM characters
rather than the number of octets, so that it is possible to
distinguish the 7-character and 8-character cases.

3 files changed, 8 insertions, 10 deletions

diff --git a/src/mm-charsets.c b/src/mm-charsets.c
index d2b9a667..dd1ae087 100644
--- a/src/mm-charsets.c
+++ b/src/mm-charsets.c
@@ -427,14 +427,13 @@ mm_charset_utf8_to_unpacked_gsm (const char *utf8, guint32 *out_len)
 
 guint8 *
 gsm_unpack (const guint8 *gsm,
-            guint32 gsm_len,
+            guint32 nchars,
             guint8 start_offset,  /* in _bits_ */
             guint32 *out_unpacked_len)
 {
     GByteArray *unpacked;
-    int i, nchars;
+    int i;
 
-    nchars = ((gsm_len * 8) - start_offset) / 7;
     unpacked = g_byte_array_sized_new (nchars + 1);
 
     for (i = 0; i < nchars; i++) {
diff --git a/src/mm-charsets.h b/src/mm-charsets.h
index 661052da..efd89f3c 100644
--- a/src/mm-charsets.h
+++ b/src/mm-charsets.h
@@ -53,7 +53,7 @@ guint8 *mm_charset_utf8_to_unpacked_gsm (const char *utf8, guint32 *out_len);
 guint8 *mm_charset_gsm_unpacked_to_utf8 (const guint8 *gsm, guint32 len);
 
 guint8 *gsm_unpack (const guint8 *gsm,
-                    guint32 gsm_len,
+                    guint32 nchars, /* number of gsm characters, not octets */
                     guint8 start_offset,  /* in bits */
                     guint32 *out_unpacked_len);
 
diff --git a/src/tests/test-charsets.c b/src/tests/test-charsets.c
index 656b80ca..70c796ab 100644
--- a/src/tests/test-charsets.c
+++ b/src/tests/test-charsets.c
@@ -98,7 +98,7 @@ test_unpack_gsm7 (void *f, gpointer d)
     guint8 *unpacked;
     guint32 unpacked_len = 0;
 
-    unpacked = gsm_unpack (gsm, sizeof (gsm), 0, &unpacked_len);
+    unpacked = gsm_unpack (gsm, (sizeof (gsm) * 8) / 7, 0, &unpacked_len);
     g_assert (unpacked);
     g_assert_cmpint (unpacked_len, ==, sizeof (expected));
     g_assert_cmpint (memcmp (unpacked, expected, unpacked_len), ==, 0);
@@ -110,17 +110,16 @@ static void
 test_unpack_gsm7_7_chars (void *f, gpointer d)
 {
     static const guint8 gsm[] = { 0xF1, 0x7B, 0x59, 0x4E, 0xCF, 0xD7, 0x01 };
-    static const guint8 expected[] = { 0x71, 0x77, 0x65, 0x72, 0x74, 0x79, 0x75, 0x00 };
+    static const guint8 expected[] = { 0x71, 0x77, 0x65, 0x72, 0x74, 0x79, 0x75};
     guint8 *unpacked;
     guint32 unpacked_len = 0;
 
     /* Tests the edge case where there are 7 bits left in the packed
      * buffer but those 7 bits do not contain a character.  In this case
-     * we expect a trailing NULL byte and the caller must know enough about
-     * the intended message to remove it when required.
+     * we expect to get the number of characters that were specified.
      */
 
-    unpacked = gsm_unpack (gsm, sizeof (gsm), 0, &unpacked_len);
+    unpacked = gsm_unpack (gsm, 7 , 0, &unpacked_len);
     g_assert (unpacked);
     g_assert_cmpint (unpacked_len, ==, sizeof (expected));
     g_assert_cmpint (memcmp (unpacked, expected, unpacked_len), ==, 0);
@@ -153,7 +152,7 @@ test_unpack_gsm7_all_chars (void *f, gpointer d)
     guint32 unpacked_len = 0;
     int i;
 
-    unpacked = gsm_unpack (gsm, sizeof (gsm), 0, &unpacked_len);
+    unpacked = gsm_unpack (gsm, (sizeof (gsm) * 8) / 7, 0, &unpacked_len);
     g_assert (unpacked);
     g_assert_cmpint (unpacked_len, ==, 148);