[bug-gnulib] Re: iconv made easy

[Simon Josefsson]

Here is an updated version; now indented, works when iconv is not
available, and has a function comment.

Index: lib/iconvme.c
===================================================================
RCS file: lib/iconvme.c
diff -N lib/iconvme.c
--- /dev/null   1 Jan 1970 00:00:00 -0000
+++ lib/iconvme.c       12 Dec 2004 23:33:48 -0000
@@ -0,0 +1,149 @@
+/* Recode strings between character sets, using iconv.
+   Copyright (C) 2002, 2003, 2004 Free Software Foundation, Inc.
+
+   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, 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
+
+/* Get prototype. */
+#include "iconvme.h"
+
+/* Get malloc. */
+#include <stdlib.h>
+
+/* Get strcmp. */
+#include <string.h>
+
+/* Get errno. */
+#include <errno.h>
+
+#if HAVE_ICONV
+/* Get iconv etc. */
+# include <iconv.h>
+#endif
+
+/* Convert a zero-terminated string from one code set to another.  The
+   returned string is allocated using malloc, and must be dellocated
+   by the caller using free.  On failure, NULL is returned and errno
+   holds the error reason.  Note that this function does not handle
+   embedded zero's in the output well.  */
+char *
+iconv_z (const char *to_codeset, const char *from_codeset, const char *str)
+{
+  char *dest = NULL;
+#if HAVE_ICONV
+  iconv_t cd;
+  char *outp;
+  ICONV_CONST char *p;
+  size_t inbytes_remaining;
+  size_t outbytes_remaining;
+  size_t err;
+  size_t outbuf_size;
+  int have_error = 0;
+#endif
+
+  if (strcmp (to_codeset, from_codeset) == 0)
+    {
+      char *q;
+
+      q = malloc (strlen (str) + 1);
+      if (!q)
+       return NULL;
+
+      return strcpy (q, str);
+    }
+
+#if HAVE_ICONV
+  cd = iconv_open (to_codeset, from_codeset);
+
+  if (cd == (iconv_t) - 1)
+    return NULL;
+
+  p = (ICONV_CONST char *) str;
+
+  inbytes_remaining = strlen (p);
+  /* Guess the maximum length the output string can have.  */
+  outbuf_size = (inbytes_remaining + 1) * 5;
+
+  outp = dest = malloc (outbuf_size);
+  if (dest == NULL)
+    goto out;
+  outbytes_remaining = outbuf_size - 1;        /* -1 for NUL */
+
+again:
+
+  err = iconv (cd, (ICONV_CONST char **) &p, &inbytes_remaining,
+              &outp, &outbytes_remaining);
+
+  if (err == (size_t) - 1)
+    {
+      switch (errno)
+       {
+       case EINVAL:
+         /* Incomplete text, do not report an error */
+         break;
+
+       case E2BIG:
+         {
+           size_t used = outp - dest;
+           char *newdest;
+
+           outbuf_size *= 2;
+           newdest = realloc (dest, outbuf_size);
+           if (newdest == NULL)
+             {
+               have_error = 1;
+               goto out;
+             }
+           dest = newdest;
+
+           outp = dest + used;
+           outbytes_remaining = outbuf_size - used - 1;        /* -1 for NUL */
+
+           goto again;
+         }
+         break;
+
+       case EILSEQ:
+         have_error = 1;
+         break;
+
+       default:
+         have_error = 1;
+         break;
+       }
+    }
+
+  *outp = '\0';
+
+  if (*p != '\0')
+    have_error = 1;
+
+out:
+  iconv_close (cd);
+
+  if (have_error)
+    {
+      free (dest);
+      dest = NULL;
+    }
+#else
+  errno = ENOSYS;
+#endif
+
+  return dest;
+}
Index: lib/iconvme.h
===================================================================
RCS file: lib/iconvme.h
diff -N lib/iconvme.h
--- /dev/null   1 Jan 1970 00:00:00 -0000
+++ lib/iconvme.h       12 Dec 2004 23:33:48 -0000
@@ -0,0 +1,25 @@
+/* Recode strings between character sets, using iconv.
+   Copyright (C) 2004 Free Software Foundation, Inc.
+   Written by Simon Josefsson.
+
+   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, 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.  */
+
+#ifndef ICONVME_H
+# define ICONVME_H
+
+extern char *iconv_z (const char *to_codeset, const char *from_codeset,
+                     const char *str);
+
+#endif /* ICONVME_H */
Index: m4/iconvme.m4
===================================================================
RCS file: m4/iconvme.m4
diff -N m4/iconvme.m4
--- /dev/null   1 Jan 1970 00:00:00 -0000
+++ m4/iconvme.m4       12 Dec 2004 23:33:48 -0000
@@ -0,0 +1,17 @@
+# iconvme.m4 serial 1
+dnl Copyright (C) 2004 Free Software Foundation, Inc.
+dnl This file is free software, distributed under the terms of the GNU
+dnl General Public License.  As a special exception to the GNU General
+dnl Public License, this file may be distributed as part of a program
+dnl that contains a configuration script generated by Autoconf, under
+dnl the same distribution terms as the rest of that program.
+
+AC_DEFUN([gl_ICONVME],
+[
+  gl_PREREQ_ICONVME
+])
+
+# Prerequisites of lib/iconvme.c.
+AC_DEFUN([gl_PREREQ_ICONVME], [
+  AC_REQUIRE([AM_ICONV])
+])
Index: gnulib-tool
===================================================================
RCS file: /cvsroot/gnulib/gnulib/gnulib-tool,v
retrieving revision 1.36
diff -u -p -r1.36 gnulib-tool
--- gnulib-tool 17 Oct 2004 17:50:25 -0000      1.36
+++ gnulib-tool 12 Dec 2004 23:33:48 -0000
@@ -455,7 +455,7 @@ func_emit_lib_Makefile_am ()
     func_verify_module
     if test -n "$module"; then
       {
-        func_get_automake_snippet "$module" | sed -e 
"s,lib_SOURCES,${libname}_${libext}_SOURCES,g" -e 
"s,lib_OBJECTS,${libname}_${libext}_OBJECTS,g"
+        func_get_automake_snippet "$module" | sed -e 
"s,lib_SOURCES,${libname}_${libext}_SOURCES,g" -e 
"s,lib_OBJECTS,${libname}_${libext}_OBJECTS,g" -e 
"s,lib_LIBADD,${libname}_${libext}_LIBADD,g"
         if test "$module" = 'alloca'; then
           echo "${libname}_${libext}_LIBADD += @${perhapsLT}ALLOCA@"
         fi
Index: modules/iconvme
===================================================================
RCS file: modules/iconvme
diff -N modules/iconvme
--- /dev/null   1 Jan 1970 00:00:00 -0000
+++ modules/iconvme     12 Dec 2004 23:33:48 -0000
@@ -0,0 +1,26 @@
+Description:
+Character set conversion of strings made easy, uses iconv.
+
+Files:
+lib/iconvme.h
+lib/iconvme.c
+m4/iconvme.m4
+
+Depends-on:
+iconv
+
+configure.ac:
+gl_ICONVME
+
+Makefile.am:
+lib_SOURCES += iconvme.h iconvme.c
+lib_LIBADD += $(LTLIBICONV)
+
+Include:
+"iconvme.h"
+
+License:
+LGPL
+
+Maintainer:
+Simon Josefsson
Index: tests/test-iconvme.c
===================================================================
RCS file: tests/test-iconvme.c
diff -N tests/test-iconvme.c
--- /dev/null   1 Jan 1970 00:00:00 -0000
+++ tests/test-iconvme.c        12 Dec 2004 23:33:48 -0000
@@ -0,0 +1,81 @@
+/* Recode strings between character sets, using iconv.
+   Copyright (C) 2004 Free Software Foundation, Inc.
+   Written by Simon Josefsson.
+
+   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, 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.  */
+
+#include <stdlib.h>
+#include <stdio.h>
+
+#include "iconvme.h"
+
+int main (int ac, char *av[])
+{
+  char *in = NULL, *out = NULL;
+  char *to = NULL, *from = NULL;
+
+  if (ac > 1)
+    from = av[1];
+
+  if (ac > 2)
+    to = av[2];
+
+  if (ac > 3)
+    in = av[3];
+
+  if (!in)
+    {
+      size_t len = 0;
+      printf ("Enter string to convert:\n\t> ");
+      if (getline (&in, &len, stdin) < 0)
+       perror ("getline");
+      if (in[strlen (in) - 1] == '\n')
+       in[strlen (in) - 1] = '\0';
+    }
+
+  if (!to)
+    {
+      size_t len = 0;
+      printf ("Enter destination code set:\n\t> ");
+      if (getline (&to, &len, stdin) < 0)
+       perror ("getline");
+      if (to[strlen (to) - 1] == '\n')
+       to[strlen (to) - 1] = '\0';
+    }
+
+  if (!from)
+    {
+      size_t len = 0;
+      printf ("Enter source code set:\n\t> ");
+      if (getline (&from, &len, stdin) < 0)
+       perror ("getline");
+      if (from[strlen (from) - 1] == '\n')
+       from[strlen (from) - 1] = '\0';
+    }
+
+  printf (" Input string: `%s'\n"
+         "From code set: `%s'\n"
+         "  To code set: `%s'\n",
+         in, from, to);
+
+  out = iconv_z (to, from, in);
+
+  if (out == NULL)
+    perror ("iconv");
+  else
+    printf ("\nOutput: `%s'\n", out);
+
+  return EXIT_SUCCESS;
+}