add scm_{to,from}_{utf8,latin1}_string{n,}

* libguile/strings.h:
* libguile/strings.c (scm_from_latin1_string, scm_to_latin1_string): New
  functions, in terms of the latin1_stringn variants.
  (scm_from_utf8_string, scm_from_utf8_stringn)
  (scm_to_utf8_string, scm_to_utf8_stringn): New functions.
  (scm_i_from_utf8_string, scm_i_to_utf8_string): Removed these internal
  functions.
  (scm_from_stringn): Handle -1 as a length. Unlike the previous
  behavior of scm_from_locale_string (NULL), which returned the empty
  string, we now raise an error.  The null pointer is not the same as
  the empty string.

* libguile/stime.c (scm_strftime, scm_strptime): Adapt to publishing of
  utf8 functions.

libguile/stime.c

@@ -1,4 +1,4 @@
-/* Copyright (C) 1995,1996,1997,1998,1999,2000,2001, 2003, 2004, 2005, 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
+/* Copyright (C) 1995,1996,1997,1998,1999,2000,2001, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2011 Free Software Foundation, Inc.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public License
@@ -625,11 +625,11 @@ SCM_DEFINE (scm_strftime, "strftime", 2, 0, 0,
 {
   struct tm t;
 
-  scm_t_uint8 *tbuf;
+  char *tbuf;
   int size = 50;
-  scm_t_uint8 *fmt;
+  char *fmt;
-  scm_t_uint8 *myfmt;
+  char *myfmt;
-  int len;
+  size_t len;
   SCM result;
 
   SCM_VALIDATE_STRING (1, format);
@@ -637,8 +637,7 @@ SCM_DEFINE (scm_strftime, "strftime", 2, 0, 0,
 
   /* Convert string to UTF-8 so that non-ASCII characters in the
      format are passed through unchanged.  */
-  fmt = scm_i_to_utf8_string (format);
+  fmt = scm_to_utf8_stringn (format, &len);
-  len = strlen ((const char *) fmt);
 
   /* Ugly hack: strftime can return 0 if its buffer is too small,
      but some valid time strings (e.g. "%p") can sometimes produce
@@ -647,7 +646,7 @@ SCM_DEFINE (scm_strftime, "strftime", 2, 0, 0,
      nonzero. */
   myfmt = scm_malloc (len+2);
   *myfmt = (scm_t_uint8) 'x';
-  strncpy ((char *) myfmt + 1, (const char *) fmt, len);
+  strncpy (myfmt + 1, fmt, len);
   myfmt[len + 1] = 0;
   scm_remember_upto_here_1 (format);
   free (fmt);
@@ -685,8 +684,7 @@ SCM_DEFINE (scm_strftime, "strftime", 2, 0, 0,
 
     /* Use `nstrftime ()' from Gnulib, which supports all GNU extensions
        supported by glibc.  */
-    while ((len = nstrftime ((char *) tbuf, size, 
+    while ((len = nstrftime (tbuf, size, myfmt, &t, 0, 0)) == 0)
-			     (const char *) myfmt, &t, 0, 0)) == 0)
       {
 	free (tbuf);
 	size *= 2;
@@ -702,7 +700,7 @@ SCM_DEFINE (scm_strftime, "strftime", 2, 0, 0,
 #endif
     }
 
-  result = scm_i_from_utf8_string ((const scm_t_uint8 *) tbuf + 1);
+  result = scm_from_utf8_string (tbuf + 1);
   free (tbuf);
   free (myfmt);
 #if HAVE_STRUCT_TM_TM_ZONE
@@ -728,7 +726,7 @@ SCM_DEFINE (scm_strptime, "strptime", 2, 0, 0,
 #define FUNC_NAME s_scm_strptime
 {
   struct tm t;
-  scm_t_uint8 *fmt, *str, *rest;
+  char *fmt, *str, *rest;
   size_t used_len;
   long zoff;
 
@@ -737,8 +735,8 @@ SCM_DEFINE (scm_strptime, "strptime", 2, 0, 0,
 
   /* Convert strings to UTF-8 so that non-ASCII characters are passed
      through unchanged.  */
-  fmt = scm_i_to_utf8_string (format);
+  fmt = scm_to_utf8_string (format);
-  str = scm_i_to_utf8_string (string);
+  str = scm_to_utf8_string (string);
 
   /* initialize the struct tm */
 #define tm_init(field) t.field = 0
@@ -760,8 +758,7 @@ SCM_DEFINE (scm_strptime, "strptime", 2, 0, 0,
      fields, hence the use of SCM_CRITICAL_SECTION_START.  */
   t.tm_isdst = -1;
   SCM_CRITICAL_SECTION_START;
-  rest = (scm_t_uint8 *) strptime ((const char *) str, 
+  rest = strptime (str, fmt, &t);
-                                   (const char *) fmt, &t);
   SCM_CRITICAL_SECTION_END;
   if (rest == NULL)
     {
@@ -784,7 +781,7 @@ SCM_DEFINE (scm_strptime, "strptime", 2, 0, 0,
 #endif
 
   /* Compute the number of UTF-8 characters.  */
-  used_len = u8_strnlen (str, rest-str);
+  used_len = u8_strnlen ((scm_t_uint8*) str, rest-str);
   scm_remember_upto_here_2 (format, string);
   free (str);
   free (fmt);

libguile/strings.c

@@ -1,4 +1,4 @@
-/* Copyright (C) 1995,1996,1998,2000,2001, 2004, 2006, 2008, 2009, 2010 Free Software Foundation, Inc.
+/* Copyright (C) 1995,1996,1998,2000,2001, 2004, 2006, 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
  * 
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public License
@@ -1437,8 +1437,13 @@ scm_from_stringn (const char *str, size_t len, const char *encoding,
   int wide = 0;
   SCM res;
 
+  /* The order of these checks is important. */
   if (len == 0)
     return scm_nullstr;
+  if (!str)
+    scm_misc_error ("scm_from_stringn", "NULL string pointer", SCM_EOL);
+  if (len == (size_t) -1)
+    len = strlen (str);
 
   if (encoding == NULL)
     {
@@ -1502,9 +1507,9 @@ scm_from_stringn (const char *str, size_t len, const char *encoding,
 }
 
 SCM
-scm_from_latin1_stringn (const char *str, size_t len)
+scm_from_locale_string (const char *str)
 {
-  return scm_from_stringn (str, len, NULL, SCM_FAILED_CONVERSION_ERROR);
+  return scm_from_locale_stringn (str, -1);
 }
 
 SCM
@@ -1515,11 +1520,6 @@ scm_from_locale_stringn (const char *str, size_t len)
   SCM inport;
   scm_t_port *pt;
 
-  if (len == (size_t) -1)
-    len = strlen (str);
-  if (len == 0)
-    return scm_nullstr;
-
   inport = scm_current_input_port ();
   if (!SCM_UNBNDP (inport) && SCM_OPINPORTP (inport))
     {
@@ -1537,20 +1537,27 @@ scm_from_locale_stringn (const char *str, size_t len)
 }
 
 SCM
-scm_from_locale_string (const char *str)
+scm_from_latin1_string (const char *str)
 {
-  if (str == NULL)
+  return scm_from_latin1_stringn (str, -1);
-    return scm_nullstr;
-
-  return scm_from_locale_stringn (str, -1);
 }
 
 SCM
-scm_i_from_utf8_string (const scm_t_uint8 *str)
+scm_from_latin1_stringn (const char *str, size_t len)
 {
-  return scm_from_stringn ((const char *) str,
+  return scm_from_stringn (str, len, NULL, SCM_FAILED_CONVERSION_ERROR);
-                           strlen ((char *) str), "UTF-8",
+}
-                           SCM_FAILED_CONVERSION_ERROR);
+
+SCM
+scm_from_utf8_string (const char *str)
+{
+  return scm_from_utf8_stringn (str, -1);
+}
+
+SCM
+scm_from_utf8_stringn (const char *str, size_t len)
+{
+  return scm_from_stringn (str, len, "UTF-8", SCM_FAILED_CONVERSION_ERROR);
 }
 
 /* Create a new scheme string from the C string STR.  The memory of
@@ -1707,9 +1714,9 @@ scm_i_unistring_escapes_to_r6rs_escapes (char *buf, size_t *lenp)
 }
 
 char *
-scm_to_latin1_stringn (SCM str, size_t *lenp)
+scm_to_locale_string (SCM str)
 {
-  return scm_to_stringn (str, lenp, NULL, SCM_FAILED_CONVERSION_ERROR);
+  return scm_to_locale_stringn (str, NULL);
 }
 
 char *
@@ -1733,6 +1740,30 @@ scm_to_locale_stringn (SCM str, size_t *lenp)
                          scm_i_get_conversion_strategy (SCM_BOOL_F));
 }
 
+char *
+scm_to_latin1_string (SCM str)
+{
+  return scm_to_latin1_stringn (str, NULL);
+}
+
+char *
+scm_to_latin1_stringn (SCM str, size_t *lenp)
+{
+  return scm_to_stringn (str, lenp, NULL, SCM_FAILED_CONVERSION_ERROR);
+}
+
+char *
+scm_to_utf8_string (SCM str)
+{
+  return scm_to_utf8_stringn (str, NULL);
+}
+
+char *
+scm_to_utf8_stringn (SCM str, size_t *lenp)
+{
+  return scm_to_stringn (str, lenp, "UTF-8", SCM_FAILED_CONVERSION_ERROR);
+}
+
 /* Return a malloc(3)-allocated buffer containing the contents of STR encoded
    according to ENCODING.  If LENP is non-NULL, set it to the size in bytes of
    the returned buffer.  If the conversion to ENCODING fails, apply the strategy
@@ -1845,20 +1876,6 @@ scm_to_stringn (SCM str, size_t *lenp, const char *encoding,
   return buf;
 }
 
-char *
-scm_to_locale_string (SCM str)
-{
-  return scm_to_locale_stringn (str, NULL);
-}
-
-scm_t_uint8 *
-scm_i_to_utf8_string (SCM str)
-{
-  char *u8str;
-  u8str = scm_to_stringn (str, NULL, "UTF-8", SCM_FAILED_CONVERSION_ERROR);
-  return (scm_t_uint8 *) u8str;
-}
-
 size_t
 scm_to_locale_stringbuf (SCM str, char *buf, size_t max_len)
 {

libguile/strings.h

@@ -3,7 +3,7 @@
 #ifndef SCM_STRINGS_H
 #define SCM_STRINGS_H
 
-/* Copyright (C) 1995,1996,1997,1998,2000,2001, 2004, 2005, 2006, 2008, 2009, 2010 Free Software Foundation, Inc.
+/* Copyright (C) 1995,1996,1997,1998,2000,2001, 2004, 2005, 2006, 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public License
@@ -125,18 +125,31 @@ SCM_API SCM scm_c_substring_read_only (SCM str, size_t start, size_t end);
 SCM_API SCM scm_c_substring_shared (SCM str, size_t start, size_t end);
 SCM_API SCM scm_c_substring_copy (SCM str, size_t start, size_t end);
 
-SCM_API SCM scm_from_latin1_stringn (const char *str, size_t len);
+/* Use locale encoding for user input, user output, or interacting with
+   the C library.  Use latin1 for ASCII, and for literals in source
+   code.  Use utf8 for interaction with modern libraries which deal in
+   UTF-8.  Otherwise use scm_to_stringn or scm_from_stringn with a
+   specific encoding. */
+
 SCM_API SCM scm_from_locale_string (const char *str);
 SCM_API SCM scm_from_locale_stringn (const char *str, size_t len);
-SCM_INTERNAL SCM scm_i_from_utf8_string (const scm_t_uint8 *str);
 SCM_API SCM scm_take_locale_string (char *str);
 SCM_API SCM scm_take_locale_stringn (char *str, size_t len);
-SCM_API char *scm_to_latin1_stringn (SCM str, size_t *lenp);
 SCM_API char *scm_to_locale_string (SCM str);
 SCM_API char *scm_to_locale_stringn (SCM str, size_t *lenp);
+
+SCM_API SCM scm_from_latin1_string (const char *str);
+SCM_API SCM scm_from_latin1_stringn (const char *str, size_t len);
+SCM_API char *scm_to_latin1_string (SCM str);
+SCM_API char *scm_to_latin1_stringn (SCM str, size_t *lenp);
+
+SCM_API char *scm_to_utf8_string (SCM str);
+SCM_API char *scm_to_utf8_stringn (SCM str, size_t *lenp);
+SCM_API SCM scm_from_utf8_string (const char *str);
+SCM_API SCM scm_from_utf8_stringn (const char *str, size_t len);
+
 SCM_API char *scm_to_stringn (SCM str, size_t *lenp, const char *encoding,
                               scm_t_string_failed_conversion_handler handler);
-SCM_INTERNAL scm_t_uint8 *scm_i_to_utf8_string (SCM str);
 SCM_API size_t scm_to_locale_stringbuf (SCM str, char *buf, size_t max_len);
 
 SCM_API SCM scm_string_normalize_nfd (SCM str);