Fix scm_to_utf8_stringn once and for all; optimize; add tests

* libguile/strings.c (scm_to_utf8_stringn): Fix another new bug in this
  recent comedy of errors: pass the size of the preallocated buffer to
  u32_to_u8.  Arrange to call 'scm_i_string_wide_chars' and
  'scm_i_string_length' only once each.  Rename local variables for
  improved code clarity.

* test-suite/standalone/test-conversion.c (test_to_utf8_stringn): New
  function to test scm_to_utf8_stringn.

diff --git a/libguile/strings.c b/libguile/strings.c
index ec55c50..07356fc 100644 (file)
--- a/libguile/strings.c
+++ b/libguile/strings.c
@@ -1929,28 +1929,28 @@ scm_to_utf8_stringn (SCM str, size_t *lenp)
                                   NULL, lenp);
   else
     {
+      scm_t_uint32 *chars = (scm_t_uint32 *) scm_i_string_wide_chars (str);
       scm_t_uint8 *buf, *ret;
-      size_t predicted_len, actual_len;  /* length in bytes */
+      size_t num_chars = scm_i_string_length (str);
+      size_t num_bytes_predicted, num_bytes_actual;
 
-      predicted_len = u32_u8_length_in_bytes
-        ((scm_t_uint32 *) scm_i_string_wide_chars (str),
-         scm_i_string_length (str));
+      num_bytes_predicted = u32_u8_length_in_bytes (chars, num_chars);
 
       if (lenp)
         {
-          *lenp = predicted_len;
-          buf = scm_malloc (predicted_len);
+          *lenp = num_bytes_predicted;
+          buf = scm_malloc (num_bytes_predicted);
         }
       else
         {
-          buf = scm_malloc (predicted_len + 1);
-          buf[predicted_len] = 0;
+          buf = scm_malloc (num_bytes_predicted + 1);
+          buf[num_bytes_predicted] = 0;
         }
 
-      ret = u32_to_u8 ((scm_t_uint32 *) scm_i_string_wide_chars (str),
-                       scm_i_string_length (str), buf, &actual_len);
+      num_bytes_actual = num_bytes_predicted;
+      ret = u32_to_u8 (chars, num_chars, buf, &num_bytes_actual);
 
-      if (SCM_LIKELY (ret == buf && actual_len == predicted_len))
+      if (SCM_LIKELY (ret == buf && num_bytes_actual == num_bytes_predicted))
         return (char *) ret;
 
       /* An error: a bad codepoint.  */

diff --git a/test-suite/standalone/test-conversion.c b/test-suite/standalone/test-conversion.c
index 09b74bf..700e5b3 100644 (file)
--- a/test-suite/standalone/test-conversion.c
+++ b/test-suite/standalone/test-conversion.c
@@ -1078,6 +1078,74 @@ test_locale_strings ()
   test_11 ("(string #\\f #\\nul)", NULL, 1, 0);
 }
 
+static void
+test_to_utf8_stringn ()
+{
+  scm_t_wchar wstr[] = { 0x20,      /* 0x20 */
+                         0xDF,      /* 0xC3, 0x9F */
+                         0x65E5,    /* 0xE6, 0x97, 0xA5 */
+                         0x1D400 }; /* 0xF0, 0x9D, 0x90, 0x80 */
+
+  SCM str0 = scm_from_utf32_stringn (wstr, 1); /* ASCII */
+  SCM str1 = scm_from_utf32_stringn (wstr, 2); /* Narrow */
+  SCM str2 = scm_from_utf32_stringn (wstr, 4); /* Wide */
+
+  char cstr0[] = { 0x20, 0 };
+  char cstr1[] = { 0x20, 0xC3, 0x9F, 0 };
+  char cstr2[] = { 0x20, 0xC3, 0x9F, 0xE6, 0x97, 0xA5,
+                   0xF0, 0x9D, 0x90, 0x80, 0 };
+  char *cstr;
+  size_t len;
+
+  /* Test conversion of ASCII string */
+  cstr = scm_to_utf8_stringn (str0, &len);
+  if (len + 1 != sizeof (cstr0) || memcmp (cstr, cstr0, len))
+    {
+      fprintf (stderr, "fail: scm_to_utf8_stringn (<ASCII>, &len)");
+      exit (EXIT_FAILURE);
+    }
+  free (cstr);
+  cstr = scm_to_utf8_stringn (str0, NULL);
+  if (memcmp (cstr, cstr0, len + 1))
+    {
+      fprintf (stderr, "fail: scm_to_utf8_stringn (<ASCII>, NULL)");
+      exit (EXIT_FAILURE);
+    }
+  free (cstr);
+
+  /* Test conversion of narrow string */
+  cstr = scm_to_utf8_stringn (str1, &len);
+  if (len + 1 != sizeof (cstr1) || memcmp (cstr, cstr1, len))
+    {
+      fprintf (stderr, "fail: scm_to_utf8_stringn (<NARROW>, &len)");
+      exit (EXIT_FAILURE);
+    }
+  free (cstr);
+  cstr = scm_to_utf8_stringn (str1, NULL);
+  if (memcmp (cstr, cstr1, len + 1))
+    {
+      fprintf (stderr, "fail: scm_to_utf8_stringn (<NARROW>, NULL)");
+      exit (EXIT_FAILURE);
+    }
+  free (cstr);
+
+  /* Test conversion of wide string */
+  cstr = scm_to_utf8_stringn (str2, &len);
+  if (len + 1 != sizeof (cstr2) || memcmp (cstr, cstr2, len))
+    {
+      fprintf (stderr, "fail: scm_to_utf8_stringn (<WIDE>, &len)");
+      exit (EXIT_FAILURE);
+    }
+  free (cstr);
+  cstr = scm_to_utf8_stringn (str2, NULL);
+  if (memcmp (cstr, cstr2, len + 1))
+    {
+      fprintf (stderr, "fail: scm_to_utf8_stringn (<WIDE>, NULL)");
+      exit (EXIT_FAILURE);
+    }
+  free (cstr);
+}
+
 static void
 test_is_exact ()
 {
@@ -1122,6 +1190,7 @@ tests (void *data, int argc, char **argv)
   test_from_double ();
   test_to_double ();
   test_locale_strings ();
+  test_to_utf8_stringn ();
   test_is_exact ();
   test_is_inexact ();
 }