/src/racket/src/string.c

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/*
  Racket
  Copyright (c) 2004-2013 PLT Design Inc.
  Copyright (c) 1995-2001 Matthew Flatt

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Library General Public
    License as published by the Free Software Foundation; either
    version 2 of the License, or (at your option) any later version.

    This library 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
    Library General Public License for more details.

    You should have received a copy of the GNU Library General Public
    License along with this library; if not, write to the Free
    Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
    Boston, MA 02110-1301 USA.

  libscheme
  Copyright (c) 1994 Brent Benson
  All rights reserved.
*/

#include "schpriv.h"
#include "schvers.h"
#include <string.h>
#include <ctype.h>
#ifndef DONT_USE_LOCALE
# include <locale.h>
# ifdef MZ_NO_ICONV
#  define USE_ICONV_DLL
# endif
# ifndef USE_ICONV_DLL
#  include <iconv.h>
#  include <langinfo.h>
# endif
# include <wchar.h>
# include <wctype.h>
# include <errno.h>
# ifdef MACOS_UNICODE_SUPPORT
#  include <CoreFoundation/CFString.h>
#  include <CoreFoundation/CFLocale.h>
# endif
# ifdef WINDOWS_UNICODE_SUPPORT
#  include <windows.h>
# endif
#endif

#ifndef SCHEME_PLATFORM_LIBRARY_SUBPATH
# include "schsys.h"
#endif

#include "schustr.inc"

#ifdef USE_ICONV_DLL
typedef intptr_t iconv_t;
typedef int *(*errno_proc_t)();
typedef size_t (*iconv_proc_t)(iconv_t cd,
			       char **inbuf, size_t *inbytesleft,
			       char **outbuf, size_t *outbytesleft);
typedef iconv_t (*iconv_open_proc_t)(const char *tocode, const char *fromcode);
typedef void (*iconv_close_proc_t)(iconv_t cd);
typedef char *(*locale_charset_proc_t)();
static errno_proc_t iconv_errno;
static iconv_proc_t iconv;
static iconv_open_proc_t iconv_open;
static iconv_close_proc_t iconv_close;
static locale_charset_proc_t locale_charset; /* Not used, currently */
#define mzCHK_PROC(x) x
static int get_iconv_errno(void)
{
  int *a;
  a = iconv_errno();
  return *a;
}
# undef HAVE_CODESET
# define HAVE_CODESET 1
# define CODESET 0
# define ICONV_errno get_iconv_errno()
static int iconv_ready = 0;
static void init_iconv()
{
# ifdef MZ_NO_ICONV
# else
  HMODULE m;
  m = LoadLibraryW(scheme_get_dll_path(L"iconv.dll"));
  if (!m)
    m = LoadLibraryW(scheme_get_dll_path(L"libiconv.dll"));
  if (!m)
    m = LoadLibraryW(scheme_get_dll_path(L"libiconv-2.dll"));
  if (!m)
    m = LoadLibrary("iconv.dll");
  if (!m)
    m = LoadLibrary("libiconv.dll");
  if (!m)
    m = LoadLibrary("libiconv-2.dll");
  if (m) {
    iconv = (iconv_proc_t)GetProcAddress(m, "libiconv");
    iconv_open = (iconv_open_proc_t)GetProcAddress(m, "libiconv_open");
    iconv_close = (iconv_close_proc_t)GetProcAddress(m, "libiconv_close");
    locale_charset = (locale_charset_proc_t)GetProcAddress(m, "locale_charset");
    /* Make sure we have all of them or none: */
    if (!iconv || !iconv_open || !iconv_close) {
      iconv = NULL;
      iconv_open = NULL;
      iconv_close = NULL;
    }
  }
  if (iconv) {
    iconv_errno = (errno_proc_t)GetProcAddress(m, "_errno");
    if (!iconv_errno) {
      /* The iconv.dll distributed with Racket links to msvcrt.dll.
	 It's a slighly dangerous assumption that whatever iconv we
	 found also uses msvcrt.dll. */
      m = LoadLibrary("msvcrt.dll");
      if (m) {
	iconv_errno = (errno_proc_t)GetProcAddress(m, "_errno");
	if (!iconv_errno) {
	  iconv = NULL;
	  iconv_open = NULL;
	  iconv_close = NULL;
	}
      }
    }
  }
# endif
  iconv_ready = 1;
}
#else
# define ICONV_errno errno
# define iconv_ready 1
# define mzCHK_PROC(x) 1
static void init_iconv() { }
#endif

#ifdef MACOS_UNICODE_SUPPORT
# define mzLOCALE_IS_UTF_8(s) (!s || !(*s))
#endif
#ifdef WINDOWS_UNICODE_SUPPORT
# define mzLOCALE_IS_UTF_8(s) (!s || !(*s))
#endif
#ifndef mzLOCALE_IS_UTF_8
# define mzLOCALE_IS_UTF_8(s) !mzCHK_PROC(iconv_open)
#endif

#define mzICONV_KIND 0
#define mzUTF8_KIND 1
#define mzUTF8_TO_UTF16_KIND 2
#define mzUTF16_TO_UTF8_KIND 3

typedef struct Scheme_Converter {
  Scheme_Object so;
  short closed;
  short kind;
  iconv_t cd;
  int permissive;
  Scheme_Custodian_Reference *mref;
} Scheme_Converter;

/* locals */

/* These two locale variables are only valid when reset_locale()
   is called after continuation marks (and hence parameterization)
   may have changed. Similarly, setlocale() is only up-to-date
   when reset_locale() has been called. */
THREAD_LOCAL_DECL(static int locale_on);
THREAD_LOCAL_DECL(static void *current_locale_name_ptr);
static void reset_locale(void);

#define current_locale_name ((const mzchar *)current_locale_name_ptr)

#ifdef USE_ICONV_DLL
static char *nl_langinfo(int which)
{
  int i;

  reset_locale();
  if (!current_locale_name)
    current_locale_name_ptr = "\0\0\0\0";

  if ((current_locale_name[0] == 'C')
      && !current_locale_name[1])
    return "US-ASCII";

  for (i = 0; current_locale_name[i]; i++) {
    if (current_locale_name[i] == '.') {
      if (current_locale_name[i + 1]) {
	int len, j = 0;
	char *enc;
	i++;
	len = scheme_char_strlen(current_locale_name) - i;
	enc = (char *)scheme_malloc_atomic(len + 1);
	while (current_locale_name[i]) {
	  if (current_locale_name[i] > 127)
	    return "UTF-8";
	  enc[j++] = current_locale_name[i++];
	}
	enc[j] = 0;
	return enc;
      }
    }
  }

  return "UTF-8";
}
#endif

#ifdef DONT_USE_LOCALE
# define mz_iconv_nl_langinfo() ""
#else
static char *mz_iconv_nl_langinfo(){
  char *s;
# if HAVE_CODESET
  s = nl_langinfo(CODESET);
# else
  s = NULL;
# endif
  if (!s)
    return "";
  else
    return s;
}
#endif

static Scheme_Object *make_string (int argc, Scheme_Object *argv[]);
static Scheme_Object *string (int argc, Scheme_Object *argv[]);
static Scheme_Object *string_p (int argc, Scheme_Object *argv[]);
static Scheme_Object *string_length (int argc, Scheme_Object *argv[]);
static Scheme_Object *string_eq (int argc, Scheme_Object *argv[]);
static Scheme_Object *string_locale_eq (int argc, Scheme_Object *argv[]);
static Scheme_Object *string_ci_eq (int argc, Scheme_Object *argv[]);
static Scheme_Object *string_locale_ci_eq (int argc, Scheme_Object *argv[]);
static Scheme_Object *string_lt (int argc, Scheme_Object *argv[]);
static Scheme_Object *string_locale_lt (int argc, Scheme_Object *argv[]);
static Scheme_Object *string_gt (int argc, Scheme_Object *argv[]);
static Scheme_Object *string_locale_gt (int argc, Scheme_Object *argv[]);
static Scheme_Object *string_lt_eq (int argc, Scheme_Object *argv[]);
static Scheme_Object *string_gt_eq (int argc, Scheme_Object *argv[]);
static Scheme_Object *string_ci_lt (int argc, Scheme_Object *argv[]);
static Scheme_Object *string_locale_ci_lt (int argc, Scheme_Object *argv[]);
static Scheme_Object *string_ci_gt (int argc, Scheme_Object *argv[]);
static Scheme_Object *string_locale_ci_gt (int argc, Scheme_Object *argv[]);
static Scheme_Object *string_ci_lt_eq (int argc, Scheme_Object *argv[]);
static Scheme_Object *string_ci_gt_eq (int argc, Scheme_Object *argv[]);
static Scheme_Object *string_upcase (int argc, Scheme_Object *argv[]);
static Scheme_Object *string_downcase (int argc, Scheme_Object *argv[]);
static Scheme_Object *string_titlecase (int argc, Scheme_Object *argv[]);
static Scheme_Object *string_foldcase (int argc, Scheme_Object *argv[]);
static Scheme_Object *string_locale_upcase (int argc, Scheme_Object *argv[]);
static Scheme_Object *string_locale_downcase (int argc, Scheme_Object *argv[]);
static Scheme_Object *substring (int argc, Scheme_Object *argv[]);
static Scheme_Object *string_append (int argc, Scheme_Object *argv[]);
static Scheme_Object *string_to_list (int argc, Scheme_Object *argv[]);
static Scheme_Object *list_to_string (int argc, Scheme_Object *argv[]);
static Scheme_Object *string_copy (int argc, Scheme_Object *argv[]);
static Scheme_Object *string_copy_bang (int argc, Scheme_Object *argv[]);
static Scheme_Object *string_fill (int argc, Scheme_Object *argv[]);
static Scheme_Object *string_to_immutable (int argc, Scheme_Object *argv[]);
static Scheme_Object *string_normalize_c (int argc, Scheme_Object *argv[]);
static Scheme_Object *string_normalize_kc (int argc, Scheme_Object *argv[]);
static Scheme_Object *string_normalize_d (int argc, Scheme_Object *argv[]);
static Scheme_Object *string_normalize_kd (int argc, Scheme_Object *argv[]);

static Scheme_Object *make_shared_byte_string (int argc, Scheme_Object *argv[]);
static Scheme_Object *shared_byte_string (int argc, Scheme_Object *argv[]);

static Scheme_Object *make_byte_string (int argc, Scheme_Object *argv[]);
static Scheme_Object *byte_string (int argc, Scheme_Object *argv[]);
static Scheme_Object *byte_p (int argc, Scheme_Object *argv[]);
static Scheme_Object *byte_string_p (int argc, Scheme_Object *argv[]);
static Scheme_Object *byte_string_length (int argc, Scheme_Object *argv[]);
static Scheme_Object *byte_string_eq (int argc, Scheme_Object *argv[]);
static Scheme_Object *byte_string_lt (int argc, Scheme_Object *argv[]);
static Scheme_Object *byte_string_gt (int argc, Scheme_Object *argv[]);
static Scheme_Object *byte_substring (int argc, Scheme_Object *argv[]);
static Scheme_Object *byte_string_append (int argc, Scheme_Object *argv[]);
static Scheme_Object *byte_string_to_list (int argc, Scheme_Object *argv[]);
static Scheme_Object *list_to_byte_string (int argc, Scheme_Object *argv[]);
static Scheme_Object *byte_string_copy (int argc, Scheme_Object *argv[]);
static Scheme_Object *byte_string_copy_bang (int argc, Scheme_Object *argv[]);
static Scheme_Object *byte_string_fill (int argc, Scheme_Object *argv[]);
static Scheme_Object *byte_string_to_immutable (int argc, Scheme_Object *argv[]);

static Scheme_Object *byte_string_utf8_index (int argc, Scheme_Object *argv[]);
static Scheme_Object *byte_string_utf8_ref (int argc, Scheme_Object *argv[]);
static Scheme_Object *byte_string_utf8_length (int argc, Scheme_Object *argv[]);

static Scheme_Object *byte_string_to_char_string (int argc, Scheme_Object *argv[]);
static Scheme_Object *byte_string_to_char_string_locale (int argc, Scheme_Object *argv[]);
static Scheme_Object *byte_string_to_char_string_latin1 (int argc, Scheme_Object *argv[]);
static Scheme_Object *char_string_to_byte_string (int argc, Scheme_Object *argv[]);
static Scheme_Object *char_string_to_byte_string_locale (int argc, Scheme_Object *argv[]);
static Scheme_Object *char_string_to_byte_string_latin1 (int argc, Scheme_Object *argv[]);
static Scheme_Object *char_string_utf8_length (int argc, Scheme_Object *argv[]);

static Scheme_Object *version(int argc, Scheme_Object *argv[]);
static Scheme_Object *format(int argc, Scheme_Object *argv[]);
static Scheme_Object *sch_printf(int argc, Scheme_Object *argv[]);
static Scheme_Object *sch_eprintf(int argc, Scheme_Object *argv[]);
static Scheme_Object *sch_fprintf(int argc, Scheme_Object *argv[]);
static Scheme_Object *banner(int argc, Scheme_Object *argv[]);
static Scheme_Object *env_p(int argc, Scheme_Object *argv[]);
static Scheme_Object *sch_getenv(int argc, Scheme_Object *argv[]);
static Scheme_Object *sch_getenv_names(int argc, Scheme_Object *argv[]);
static Scheme_Object *sch_putenv(int argc, Scheme_Object *argv[]);
static Scheme_Object *env_copy(int argc, Scheme_Object *argv[]);
static Scheme_Object *env_make(int argc, Scheme_Object *argv[]);
static Scheme_Object *current_environment_variables(int argc, Scheme_Object *argv[]);
static Scheme_Object *system_type(int argc, Scheme_Object *argv[]);
static Scheme_Object *system_library_subpath(int argc, Scheme_Object *argv[]);
static Scheme_Object *cmdline_args(int argc, Scheme_Object *argv[]);
static Scheme_Object *current_locale(int argc, Scheme_Object *argv[]);
static Scheme_Object *locale_string_encoding(int argc, Scheme_Object *argv[]);
static Scheme_Object *system_language_country(int argc, Scheme_Object *argv[]);

static Scheme_Object *byte_string_open_converter(int argc, Scheme_Object *argv[]);
static Scheme_Object *byte_string_close_converter(int argc, Scheme_Object *argv[]);
static Scheme_Object *byte_string_convert(int argc, Scheme_Object *argv[]);
static Scheme_Object *byte_string_convert_end(int argc, Scheme_Object *argv[]);
static Scheme_Object *byte_converter_p(int argc, Scheme_Object *argv[]);

#ifdef MZ_PRECISE_GC
static void register_traversers(void);
#endif

static int mz_char_strcmp(const char *who, const mzchar *str1, intptr_t l1, const mzchar *str2, intptr_t l2, int locale, int size_shortcut);
static int mz_char_strcmp_ci(const char *who, const mzchar *str1, intptr_t l1, const mzchar *str2, intptr_t l2, int locale, int size_shortcut);
static int mz_strcmp(const char *who, unsigned char *str1, intptr_t l1, unsigned char *str2, intptr_t l2);

XFORM_NONGCING static intptr_t utf8_decode_x(const unsigned char *s, intptr_t start, intptr_t end,
					unsigned int *us, intptr_t dstart, intptr_t dend,
					intptr_t *ipos, intptr_t *jpos,
					char compact, char utf16,
					int *state, int might_continue, int permissive);
XFORM_NONGCING static intptr_t utf8_encode_x(const unsigned int *us, intptr_t start, intptr_t end,
					unsigned char *s, intptr_t dstart, intptr_t dend,
					intptr_t *_ipos, intptr_t *_opos, char utf16);

static char *string_to_from_locale(int to_bytes,
				   char *in, intptr_t delta, intptr_t len,
				   intptr_t *olen, int perm,
				   int *no_cvt);

#define portable_isspace(x) (((x) < 128) && isspace(x))

ROSYM static Scheme_Object *sys_symbol;
ROSYM static Scheme_Object *link_symbol, *machine_symbol, *gc_symbol;
ROSYM static Scheme_Object *so_suffix_symbol, *so_mode_symbol, *word_symbol;
ROSYM static Scheme_Object *os_symbol;
ROSYM static Scheme_Object *platform_3m_path, *platform_cgc_path;
READ_ONLY static Scheme_Object *zero_length_char_string;
READ_ONLY static Scheme_Object *zero_length_byte_string;

SHARED_OK static Scheme_Hash_Table *putenv_str_table;

SHARED_OK static char *embedding_banner;
SHARED_OK static Scheme_Object *vers_str;
SHARED_OK static Scheme_Object *banner_str;

READ_ONLY static Scheme_Object *complete_symbol, *continues_symbol, *aborts_symbol, *error_symbol;

void
scheme_init_string (Scheme_Env *env)
{
  Scheme_Object *p;

  REGISTER_SO(sys_symbol);
  sys_symbol = scheme_intern_symbol(SYSTEM_TYPE_NAME);

  REGISTER_SO(link_symbol);
  REGISTER_SO(machine_symbol);
  REGISTER_SO(gc_symbol);
  REGISTER_SO(so_suffix_symbol);
  REGISTER_SO(so_mode_symbol);
  REGISTER_SO(word_symbol);
  REGISTER_SO(os_symbol);
  link_symbol = scheme_intern_symbol("link");
  machine_symbol = scheme_intern_symbol("machine");
  gc_symbol = scheme_intern_symbol("gc");
  so_suffix_symbol = scheme_intern_symbol("so-suffix");
  so_mode_symbol = scheme_intern_symbol("so-mode");
  word_symbol = scheme_intern_symbol("word");
  os_symbol = scheme_intern_symbol("os");

  REGISTER_SO(zero_length_char_string);
  REGISTER_SO(zero_length_byte_string);
  zero_length_char_string = scheme_alloc_char_string(0, 0);
  zero_length_byte_string = scheme_alloc_byte_string(0, 0);

  REGISTER_SO(complete_symbol);
  REGISTER_SO(continues_symbol);
  REGISTER_SO(aborts_symbol);
  REGISTER_SO(error_symbol);
  complete_symbol = scheme_intern_symbol("complete");
  continues_symbol = scheme_intern_symbol("continues");
  aborts_symbol = scheme_intern_symbol("aborts");
  error_symbol = scheme_intern_symbol("error");

  REGISTER_SO(platform_3m_path);
#ifdef UNIX_FILE_SYSTEM
# define MZ3M_SUBDIR "/3m"
#else
# ifdef DOS_FILE_SYSTEM
#  define MZ3M_SUBDIR "\\3m"
# else
#  define MZ3M_SUBDIR ":3m"
# endif
#endif
  REGISTER_SO(platform_3m_path);
  REGISTER_SO(platform_cgc_path);
  platform_cgc_path = scheme_make_path(SCHEME_PLATFORM_LIBRARY_SUBPATH);
  platform_3m_path = scheme_make_path(SCHEME_PLATFORM_LIBRARY_SUBPATH MZ3M_SUBDIR);

  REGISTER_SO(putenv_str_table);

  REGISTER_SO(embedding_banner);
  REGISTER_SO(vers_str);
  REGISTER_SO(banner_str);

  vers_str = scheme_make_utf8_string(scheme_version());
  SCHEME_SET_CHAR_STRING_IMMUTABLE(vers_str);
  banner_str = scheme_make_utf8_string(scheme_banner());
  SCHEME_SET_CHAR_STRING_IMMUTABLE(banner_str);

  p = scheme_make_folding_prim(string_p, "string?", 1, 1, 1);
  SCHEME_PRIM_PROC_FLAGS(p) |= scheme_intern_prim_opt_flags(SCHEME_PRIM_IS_UNARY_INLINED
                                                            | SCHEME_PRIM_IS_OMITABLE);
  scheme_add_global_constant("string?", p, env);

  scheme_add_global_constant("make-string",
			     scheme_make_immed_prim(make_string,
						    "make-string",
						    1, 2),
			     env);
  scheme_add_global_constant("string",
			     scheme_make_immed_prim(string,
						    "string",
						    0, -1),
			     env);
  
  p = scheme_make_folding_prim(string_length, "string-length", 1, 1, 1);
  SCHEME_PRIM_PROC_FLAGS(p) |= scheme_intern_prim_opt_flags(SCHEME_PRIM_PRODUCES_FIXNUM);
  scheme_add_global_constant("string-length", p,
			     env);

  p = scheme_make_immed_prim(scheme_checked_string_ref, "string-ref", 2, 2);
  SCHEME_PRIM_PROC_FLAGS(p) |= scheme_intern_prim_opt_flags(SCHEME_PRIM_IS_BINARY_INLINED);
  scheme_add_global_constant("string-ref", p, env);


  p = scheme_make_immed_prim(scheme_checked_string_set, "string-set!", 3, 3);
  SCHEME_PRIM_PROC_FLAGS(p) |= scheme_intern_prim_opt_flags(SCHEME_PRIM_IS_NARY_INLINED);
  scheme_add_global_constant("string-set!", p, env);

  scheme_add_global_constant("string=?",
			     scheme_make_immed_prim(string_eq,
						    "string=?",
						    2, -1),
			     env);
  scheme_add_global_constant("string-locale=?",
			     scheme_make_immed_prim(string_locale_eq,
						    "string-locale=?",
						    2, -1),
			     env);
  scheme_add_global_constant("string-ci=?",
			     scheme_make_immed_prim(string_ci_eq,
						    "string-ci=?",
						    2, -1),
			     env);
  scheme_add_global_constant("string-locale-ci=?",
			     scheme_make_immed_prim(string_locale_ci_eq,
						    "string-locale-ci=?",
						    2, -1),
			     env);
  scheme_add_global_constant("string<?",
			     scheme_make_immed_prim(string_lt,
						    "string<?",
						    2, -1),
			     env);
  scheme_add_global_constant("string-locale<?",
			     scheme_make_immed_prim(string_locale_lt,
						    "string-locale<?",
						    2, -1),
			     env);
  scheme_add_global_constant("string>?",
			     scheme_make_immed_prim(string_gt,
						    "string>?",
						    2, -1),
			     env);
  scheme_add_global_constant("string-locale>?",
			     scheme_make_immed_prim(string_locale_gt,
						    "string-locale>?",
						    2, -1),
			     env);
  scheme_add_global_constant("string<=?",
			     scheme_make_immed_prim(string_lt_eq,
						    "string<=?",
						    2, -1),
			     env);
  scheme_add_global_constant("string>=?",
			     scheme_make_immed_prim(string_gt_eq,
						    "string>=?",
						    2, -1),
			     env);
  scheme_add_global_constant("string-ci<?",
			     scheme_make_immed_prim(string_ci_lt,
						    "string-ci<?",
						    2, -1),
			     env);
  scheme_add_global_constant("string-locale-ci<?",
			     scheme_make_immed_prim(string_locale_ci_lt,
						    "string-locale-ci<?",
						    2, -1),
			     env);
  scheme_add_global_constant("string-ci>?",
			     scheme_make_immed_prim(string_ci_gt,
						    "string-ci>?",
						    2, -1),
			     env);
  scheme_add_global_constant("string-locale-ci>?",
			     scheme_make_immed_prim(string_locale_ci_gt,
						    "string-locale-ci>?",
						    2, -1),
			     env);
  scheme_add_global_constant("string-ci<=?",
			     scheme_make_immed_prim(string_ci_lt_eq,
						    "string-ci<=?",
						    2, -1),
			     env);
  scheme_add_global_constant("string-ci>=?",
			     scheme_make_immed_prim(string_ci_gt_eq,
						    "string-ci>=?",
						    2, -1),
			     env);

  scheme_add_global_constant("substring",
			     scheme_make_immed_prim(substring,
						    "substring",
						    2, 3),
			     env);
  scheme_add_global_constant("string-append",
			     scheme_make_immed_prim(string_append,
						    "string-append",
						    0, -1),
			     env);
  scheme_add_global_constant("string->list",
			     scheme_make_immed_prim(string_to_list,
						    "string->list",
						    1, 1),
			     env);
  scheme_add_global_constant("list->string",
			     scheme_make_immed_prim(list_to_string,
						    "list->string",
						    1, 1),
			     env);
  scheme_add_global_constant("string-copy",
			     scheme_make_immed_prim(string_copy,
						    "string-copy",
						    1, 1),
			     env);
  scheme_add_global_constant("string-copy!",
			     scheme_make_immed_prim(string_copy_bang,
						    "string-copy!",
						    3, 5),
			     env);
  scheme_add_global_constant("string-fill!",
			     scheme_make_immed_prim(string_fill,
						    "string-fill!",
						    2, 2),
			     env);
  scheme_add_global_constant("string->immutable-string",
			     scheme_make_immed_prim(string_to_immutable,
						    "string->immutable-string",
						    1, 1),
			     env);
  scheme_add_global_constant("string-normalize-nfc",
			     scheme_make_immed_prim(string_normalize_c,
						    "string-normalize-nfc",
						    1, 1),
			     env);
  scheme_add_global_constant("string-normalize-nfkc",
			     scheme_make_immed_prim(string_normalize_kc,
						    "string-normalize-nfkc",
						    1, 1),
			     env);
  scheme_add_global_constant("string-normalize-nfd",
			     scheme_make_immed_prim(string_normalize_d,
						    "string-normalize-nfd",
						    1, 1),
			     env);
  scheme_add_global_constant("string-normalize-nfkd",
			     scheme_make_immed_prim(string_normalize_kd,
						    "string-normalize-nfkd",
						    1, 1),
			     env);

  scheme_add_global_constant("string-upcase",
			     scheme_make_immed_prim(string_upcase,
						    "string-upcase",
						    1, 1),
			     env);
  scheme_add_global_constant("string-downcase",
			     scheme_make_immed_prim(string_downcase,
						    "string-downcase",
						    1, 1),
			     env);
  scheme_add_global_constant("string-titlecase",
			     scheme_make_immed_prim(string_titlecase,
						    "string-titlecase",
						    1, 1),
			     env);
  scheme_add_global_constant("string-foldcase",
			     scheme_make_immed_prim(string_foldcase,
						    "string-foldcase",
						    1, 1),
			     env);

  scheme_add_global_constant("string-locale-upcase",
			     scheme_make_immed_prim(string_locale_upcase,
						    "string-locale-upcase",
						    1, 1),
			     env);
  scheme_add_global_constant("string-locale-downcase",
			     scheme_make_immed_prim(string_locale_downcase,
						    "string-locale-downcase",
						    1, 1),
			     env);

  scheme_add_global_constant("current-locale",
			     scheme_register_parameter(current_locale,
						       "current-locale",
						       MZCONFIG_LOCALE),
			     env);
  scheme_add_global_constant("locale-string-encoding",
			     scheme_make_immed_prim(locale_string_encoding,
						    "locale-string-encoding",
						    0, 0),
			     env);
  scheme_add_global_constant("system-language+country",
			     scheme_make_immed_prim(system_language_country,
						    "system-language+country",
						    0, 0),
			     env);

  scheme_add_global_constant("bytes-converter?",
			     scheme_make_immed_prim(byte_converter_p,
						    "bytes-converter?",
						    1, 1),
			     env);
  scheme_add_global_constant("bytes-convert",
			     scheme_make_prim_w_arity2(byte_string_convert,
						       "bytes-convert",
						       1, 7,
						       3, 3),
			     env);
  scheme_add_global_constant("bytes-convert-end",
			     scheme_make_prim_w_arity2(byte_string_convert_end,
						       "bytes-convert-end",
						       0, 3,
						       2, 2),
			     env);
  scheme_add_global_constant("bytes-open-converter",
			     scheme_make_immed_prim(byte_string_open_converter,
						    "bytes-open-converter",
						    2, 2),
			     env);
  scheme_add_global_constant("bytes-close-converter",
			     scheme_make_immed_prim(byte_string_close_converter,
						    "bytes-close-converter",
						    1, 1),
			     env);

  scheme_add_global_constant("format",
			     scheme_make_noncm_prim(format,
                                                    "format",
                                                    1, -1),
			     env);
  scheme_add_global_constant("printf",
			     scheme_make_noncm_prim(sch_printf,
                                                    "printf",
                                                    1, -1),
			     env);
  scheme_add_global_constant("eprintf",
			     scheme_make_noncm_prim(sch_eprintf,
                                                    "eprintf",
                                                    1, -1),
			     env);
  scheme_add_global_constant("fprintf",
			     scheme_make_noncm_prim(sch_fprintf,
                                                    "fprintf",
                                                    2, -1),
			     env);

  scheme_add_global_constant("byte?",
			     scheme_make_folding_prim(byte_p,
						      "byte?",
						      1, 1, 1),
			     env);

  p = scheme_make_folding_prim(byte_string_p, "bytes?", 1, 1, 1);
  SCHEME_PRIM_PROC_FLAGS(p) |= scheme_intern_prim_opt_flags(SCHEME_PRIM_IS_NARY_INLINED
                                                            | SCHEME_PRIM_IS_OMITABLE);
  scheme_add_global_constant("bytes?", p, env);

  scheme_add_global_constant("make-bytes",
			     scheme_make_immed_prim(make_byte_string,
						    "make-bytes",
						    1, 2),
			     env);
  scheme_add_global_constant("bytes",
			     scheme_make_immed_prim(byte_string,
						    "bytes",
						    0, -1),
			     env);

  GLOBAL_PRIM_W_ARITY("make-shared-bytes", make_shared_byte_string, 1, 2, env);
  GLOBAL_PRIM_W_ARITY("shared-bytes", shared_byte_string, 0, -1, env);

  p = scheme_make_folding_prim(byte_string_length, "bytes-length", 1, 1, 1);
  SCHEME_PRIM_PROC_FLAGS(p) |= scheme_intern_prim_opt_flags(SCHEME_PRIM_PRODUCES_FIXNUM);
  scheme_add_global_constant("bytes-length", p, env);

  p = scheme_make_immed_prim(scheme_checked_byte_string_ref, "bytes-ref", 2, 2);
  SCHEME_PRIM_PROC_FLAGS(p) |= scheme_intern_prim_opt_flags(SCHEME_PRIM_IS_BINARY_INLINED
                                                            | SCHEME_PRIM_PRODUCES_FIXNUM);
  scheme_add_global_constant("bytes-ref", p, env);

  p = scheme_make_immed_prim(scheme_checked_byte_string_set, "bytes-set!", 3, 3);
  SCHEME_PRIM_PROC_FLAGS(p) |= scheme_intern_prim_opt_flags(SCHEME_PRIM_IS_NARY_INLINED);
  scheme_add_global_constant("bytes-set!", p, env);

  scheme_add_global_constant("bytes=?",
			     scheme_make_immed_prim(byte_string_eq,
						    "bytes=?",
						    2, -1),
			     env);
  scheme_add_global_constant("bytes<?",
			     scheme_make_immed_prim(byte_string_lt,
						    "bytes<?",
						    2, -1),
			     env);
  scheme_add_global_constant("bytes>?",
			     scheme_make_immed_prim(byte_string_gt,
						    "bytes>?",
						    2, -1),
			     env);

  scheme_add_global_constant("subbytes",
			     scheme_make_immed_prim(byte_substring,
						    "subbytes",
						    2, 3),
			     env);
  scheme_add_global_constant("bytes-append",
			     scheme_make_immed_prim(byte_string_append,
						    "bytes-append",
						    0, -1),
			     env);
  scheme_add_global_constant("bytes->list",
			     scheme_make_immed_prim(byte_string_to_list,
						    "bytes->list",
						    1, 1),
			     env);
  scheme_add_global_constant("list->bytes",
			     scheme_make_immed_prim(list_to_byte_string,
						    "list->bytes",
						    1, 1),
			     env);
  scheme_add_global_constant("bytes-copy",
			     scheme_make_immed_prim(byte_string_copy,
						    "bytes-copy",
						    1, 1),
			     env);
  scheme_add_global_constant("bytes-copy!",
			     scheme_make_immed_prim(byte_string_copy_bang,
						    "bytes-copy!",
						    3, 5),
			     env);
  scheme_add_global_constant("bytes-fill!",
			     scheme_make_immed_prim(byte_string_fill,
						    "bytes-fill!",
						    2, 2),
			     env);
  scheme_add_global_constant("bytes->immutable-bytes",
			     scheme_make_immed_prim(byte_string_to_immutable,
						    "bytes->immutable-bytes",
						    1, 1),
			     env);

  p = scheme_make_immed_prim(byte_string_utf8_index, "bytes-utf-8-index", 2, 4);
  SCHEME_PRIM_PROC_FLAGS(p) |= scheme_intern_prim_opt_flags(SCHEME_PRIM_PRODUCES_FIXNUM);
  scheme_add_global_constant("bytes-utf-8-index", p, env);

  p = scheme_make_immed_prim(byte_string_utf8_length, "bytes-utf-8-length", 1, 4);
  SCHEME_PRIM_PROC_FLAGS(p) |= scheme_intern_prim_opt_flags(SCHEME_PRIM_PRODUCES_FIXNUM);
  scheme_add_global_constant("bytes-utf-8-length", p, env);

  scheme_add_global_constant("bytes-utf-8-ref",
			     scheme_make_immed_prim(byte_string_utf8_ref,
						    "bytes-utf-8-ref",
						    2, 4),
			     env);

  scheme_add_global_constant("bytes->string/utf-8",
			     scheme_make_immed_prim(byte_string_to_char_string,
						    "bytes->string/utf-8",
						    1, 4),
			     env);
  scheme_add_global_constant("bytes->string/locale",
			     scheme_make_immed_prim(byte_string_to_char_string_locale,
						    "bytes->string/locale",
						    1, 4),
			     env);
  scheme_add_global_constant("bytes->string/latin-1",
			     scheme_make_immed_prim(byte_string_to_char_string_latin1,
						    "bytes->string/latin-1",
						    1, 4),
			     env);
  scheme_add_global_constant("string->bytes/utf-8",
			     scheme_make_immed_prim(char_string_to_byte_string,
						    "string->bytes/utf-8",
						    1, 4),
			     env);
  scheme_add_global_constant("string->bytes/locale",
			     scheme_make_immed_prim(char_string_to_byte_string_locale,
						    "string->bytes/locale",
						    1, 4),
			     env);
  scheme_add_global_constant("string->bytes/latin-1",
			     scheme_make_immed_prim(char_string_to_byte_string_latin1,
						    "string->bytes/latin-1",
						    1, 4),
			     env);

  scheme_add_global_constant("string-utf-8-length",
			     scheme_make_immed_prim(char_string_utf8_length,
						    "string-utf-8-length",
						    1, 3),
			     env);


  /* In principle, `version' could be foldable, but it invites
     more problems than it solves... */

  scheme_add_global_constant("version",
			     scheme_make_immed_prim(version,
						    "version",
						    0, 0),
			     env);
  scheme_add_global_constant("banner",
			     scheme_make_immed_prim(banner,
						    "banner",
						    0, 0),
			     env);

  /* Environment variables */

  scheme_add_global_constant("environment-variables?",
			     scheme_make_folding_prim(env_p,
                                                      "environment-variables?",
                                                      1, 1, 1),
			     env);

  scheme_add_global_constant("current-environment-variables",
			     scheme_register_parameter(current_environment_variables,
						       "current-environment-variables",
						       MZCONFIG_CURRENT_ENV_VARS),
			     env);  

  scheme_add_global_constant("environment-variables-ref",
			     scheme_make_immed_prim(sch_getenv,
						    "environment-variables-ref",
						    2, 2),
			     env);

  scheme_add_global_constant("environment-variables-set!",
			     scheme_make_prim_w_arity(sch_putenv,
                                                      "environment-variables-set!",
                                                      3, 4),
			     env);

  scheme_add_global_constant("environment-variables-names",
			     scheme_make_immed_prim(sch_getenv_names,
						    "environment-variables-names",
						    1, 1),
			     env);

  scheme_add_global_constant("environment-variables-copy",
			     scheme_make_immed_prim(env_copy,
						    "environment-variables-copy",
						    1, 1),
			     env);

  scheme_add_global_constant("make-environment-variables",
			     scheme_make_immed_prim(env_make,
						    "make-environment-variables",
						    0, -1),
			     env);

  /* Don't make these folding, since they're platform-specific: */

  scheme_add_global_constant("system-type",
			     scheme_make_immed_prim(system_type,
						    "system-type",
						    0, 1),
			     env);
  scheme_add_global_constant("system-library-subpath",
			     scheme_make_immed_prim(system_library_subpath,
						    "system-library-subpath",
						    0, 1),
			     env);

  scheme_add_global_constant("current-command-line-arguments",
			     scheme_register_parameter(cmdline_args,
						       "current-command-line-arguments",
						       MZCONFIG_CMDLINE_ARGS),
			     env);

#ifdef MZ_PRECISE_GC
  register_traversers();
#endif
}

void scheme_init_string_places(void) {
  REGISTER_SO(current_locale_name_ptr);
  current_locale_name_ptr = "xxxx\0\0\0\0";
}

/**********************************************************************/
/*                     UTF-8 char constructors                        */
/**********************************************************************/

Scheme_Object *scheme_make_sized_offset_utf8_string(char *chars, intptr_t d, intptr_t len)
{
  intptr_t ulen;
  mzchar *us;

  if (len) {
    ulen = scheme_utf8_decode((unsigned char *)chars, d, d + len,
			      NULL, 0, -1,
			      NULL, 0 /* not UTF-16 */, 0xFFFD);
    us = scheme_malloc_atomic(sizeof(mzchar) * (ulen + 1));
    scheme_utf8_decode((unsigned char *)chars, d, d + len,
                       us, 0, -1,
                       NULL, 0 /* not UTF-16 */, 0xFFFD);
    us[ulen] = 0;
  } else {
    us = (mzchar *)"\0\0\0";
    ulen = 0;
  }
  return scheme_make_sized_offset_char_string(us, 0, ulen, 0);
}

Scheme_Object *
scheme_make_sized_utf8_string(char *chars, intptr_t len)
{
  return scheme_make_sized_offset_utf8_string(chars, 0, len);
}

Scheme_Object *
scheme_make_immutable_sized_utf8_string(char *chars, intptr_t len)
{
  Scheme_Object *s;

  s = scheme_make_sized_offset_utf8_string(chars, 0, len);
  if (len)
    SCHEME_SET_CHAR_STRING_IMMUTABLE(s);

  return s;
}

Scheme_Object *
scheme_make_utf8_string(const char *chars)
{
  return scheme_make_sized_offset_utf8_string((char *)chars, 0, -1);
}

Scheme_Object *
scheme_make_locale_string(const char *chars)
{
  return scheme_byte_string_to_char_string_locale(scheme_make_byte_string((char *)chars));
}

/**********************************************************************/
/*                         index helpers                              */
/**********************************************************************/

intptr_t scheme_extract_index(const char *name, int pos, int argc, Scheme_Object **argv, intptr_t top, int false_ok)
{
  intptr_t i;
  int is_top = 0;

  if (SCHEME_INTP(argv[pos])) {
    i = SCHEME_INT_VAL(argv[pos]);
  } else if (SCHEME_BIGNUMP(argv[pos])) {
    if (SCHEME_BIGPOS(argv[pos])) {
      i = top; /* out-of-bounds */
      is_top = 1;
    } else
      i = -1; /* negative */
  } else
    i = -1;

  if (!is_top && (i < 0))
    scheme_wrong_contract(name,
                          (false_ok ? "(or/c exact-nonnegative-integer? #f)" : "exact-nonnegative-integer?"),
                          pos, argc, argv);

  return i;
}

void scheme_get_substring_indices(const char *name, Scheme_Object *str,
                                  int argc, Scheme_Object **argv,
                                  int spos, int fpos, intptr_t *_start, intptr_t *_finish)
{
  intptr_t len;
  intptr_t start, finish;

  if (SCHEME_CHAPERONE_VECTORP(str))
    len = SCHEME_VEC_SIZE(str);
  else if (SCHEME_CHAR_STRINGP(str))
    len = SCHEME_CHAR_STRTAG_VAL(str);
  else
    len = SCHEME_BYTE_STRTAG_VAL(str);

  if (argc > spos)
    start = scheme_extract_index(name, spos, argc, argv, len + 1, 0);
  else
    start = 0;
  if (argc > fpos)
    finish = scheme_extract_index(name, fpos, argc, argv, len + 1, 0);
  else
    finish = len;

  if (!(start <= len)) {
    scheme_out_of_range(name, NULL, (fpos < 100) ? "starting " : "", argv[spos], str, 0, len);
  }
  if (!(finish >= start && finish <= len)) {
    scheme_out_of_range(name, NULL, "ending ", argv[fpos], str, start, len);
  }

  *_start = start;
  *_finish = finish;
}

void scheme_do_get_substring_indices(const char *name, Scheme_Object *str,
                                     int argc, Scheme_Object **argv,
                                     int spos, int fpos, intptr_t *_start, intptr_t *_finish, intptr_t len)
{
  if (argc > spos) {
    if (SCHEME_INTP(argv[spos])) {
      intptr_t start = SCHEME_INT_VAL(argv[spos]);
      if ((start >= 0) && (start < len)) {
        *_start = start;
        if (argc > fpos) {
          intptr_t finish = SCHEME_INT_VAL(argv[fpos]);
          if ((finish >= start) && (finish <= len)) {
            *_finish = finish;
            return;
          }
        } else {
          *_finish = len;
          return;
        }
      }
    }
  } else {
    *_start = 0;
    *_finish = len;
    return;
  }

  scheme_get_substring_indices(name, str, argc, argv, spos, fpos, _start, _finish);
}

/**********************************************************************/
/*                          char strings                              */
/**********************************************************************/

#define SCHEME_X_STR_VAL(x) SCHEME_CHAR_STR_VAL(x)
#define SCHEME_X_STRTAG_VAL(x) SCHEME_CHAR_STRTAG_VAL(x)
#define SCHEME_X_STRINGP(x) SCHEME_CHAR_STRINGP(x)
#define SCHEME_MUTABLE_X_STRINGP(x) SCHEME_MUTABLE_CHAR_STRINGP(x)
#define SCHEME_SET_X_STRING_IMMUTABLE(x) SCHEME_SET_CHAR_STRING_IMMUTABLE(x)
#define scheme_x_string_type scheme_char_string_type
#define X(a, b) a##_char##b
#define X_(a, b) a##_##b
#define X__(a) a
#define EMPTY (mzchar *)"\0\0\0"
#define Xchar mzchar
#define uXchar mzchar
#define XSTR ""
#define IS_STR "string?"
#define XSTRINGSTR "string"
#define SUBXSTR "substring"
#define CHARP(x) SCHEME_CHARP(x)
#define CHAR_VAL(x) SCHEME_CHAR_VAL(x)
#define CHAR_STR "char?"
#define MAKE_CHAR(x) _scheme_make_char(x)
#define xstrlen scheme_char_strlen
#include "strops.inc"

#define GEN_STRING_COMP(name, scheme_name, comp, op, ul, size_shortcut)     \
static Scheme_Object * name (int argc, Scheme_Object *argv[]) \
{  mzchar *s, *prev; int i, sl, pl; int falz = 0;\
   if (!SCHEME_CHAR_STRINGP(argv[0])) \
    scheme_wrong_contract(scheme_name, "string?", 0, argc, argv); \
   prev = SCHEME_CHAR_STR_VAL(argv[0]); pl = SCHEME_CHAR_STRTAG_VAL(argv[0]); \
   for (i = 1; i < argc; i++) { \
     if (!SCHEME_CHAR_STRINGP(argv[i])) \
      scheme_wrong_contract(scheme_name, "string?", i, argc, argv); \
     s = SCHEME_CHAR_STR_VAL(argv[i]); sl = SCHEME_CHAR_STRTAG_VAL(argv[i]); \
     if (!falz) if (!(comp(scheme_name, \
                           prev, pl, \
                           s, sl, ul, size_shortcut) op 0)) falz = 1; \
     prev = s; pl = sl; \
  } \
  return falz ? scheme_false : scheme_true; \
}

GEN_STRING_COMP(string_eq, "string=?", mz_char_strcmp, ==, 0, 1)
GEN_STRING_COMP(string_lt, "string<?", mz_char_strcmp, <, 0, 0)
GEN_STRING_COMP(string_gt, "string>?", mz_char_strcmp, >, 0, 0)
GEN_STRING_COMP(string_lt_eq, "string<=?", mz_char_strcmp, <=, 0, 0)
GEN_STRING_COMP(string_gt_eq, "string>=?", mz_char_strcmp, >=, 0, 0)

GEN_STRING_COMP(string_ci_eq, "string-ci=?", mz_char_strcmp_ci, ==, 0, 0)
GEN_STRING_COMP(string_ci_lt, "string-ci<?", mz_char_strcmp_ci, <, 0, 0)
GEN_STRING_COMP(string_ci_gt, "string-ci>?", mz_char_strcmp_ci, >, 0, 0)
GEN_STRING_COMP(string_ci_lt_eq, "string-ci<=?", mz_char_strcmp_ci, <=, 0, 0)
GEN_STRING_COMP(string_ci_gt_eq, "string-ci>=?", mz_char_strcmp_ci, >=, 0, 0)

GEN_STRING_COMP(string_locale_eq, "string-locale=?", mz_char_strcmp, ==, 1, 0)
GEN_STRING_COMP(string_locale_lt, "string-locale<?", mz_char_strcmp, <, 1, 0)
GEN_STRING_COMP(string_locale_gt, "string-locale>?", mz_char_strcmp, >, 1, 0)
GEN_STRING_COMP(string_locale_ci_eq, "string-locale-ci=?", mz_char_strcmp_ci, ==, 1, 0)
GEN_STRING_COMP(string_locale_ci_lt, "string-locale-ci<?", mz_char_strcmp_ci, <, 1, 0)
GEN_STRING_COMP(string_locale_ci_gt, "string-locale-ci>?", mz_char_strcmp_ci, >, 1, 0)

/**********************************************************************/
/*                         byte strings                               */
/**********************************************************************/

#define SCHEME_BYTEP(x) ((SCHEME_INTP(x)) && (SCHEME_INT_VAL(x) >= 0) && (SCHEME_INT_VAL(x) <= 255))

static Scheme_Object *
byte_p(int argc, Scheme_Object *argv[])
{
  return (SCHEME_BYTEP(argv[0]) ? scheme_true : scheme_false);
}

#define SCHEME_X_STR_VAL(x) SCHEME_BYTE_STR_VAL(x)
#define SCHEME_X_STRTAG_VAL(x) SCHEME_BYTE_STRTAG_VAL(x)
#define SCHEME_X_STRINGP(x) SCHEME_BYTE_STRINGP(x)
#define SCHEME_MUTABLE_X_STRINGP(x) SCHEME_MUTABLE_BYTE_STRINGP(x)
#define SCHEME_SET_X_STRING_IMMUTABLE(x) SCHEME_SET_BYTE_STRING_IMMUTABLE(x)
#define scheme_x_string_type scheme_byte_string_type
#define X(a, b) a##_byte##b
#define X_(a, b) a##_byte_##b
#define X__(a) byte_##a
#define EMPTY ""
#define Xchar char
#define uXchar unsigned char
#define XSTR "byte "
#define IS_STR "bytes?"
#define XSTRINGSTR "bytes"
#define SUBXSTR "subbytes"
#define CHARP(x) SCHEME_BYTEP(x)
#define CHAR_VAL(x) SCHEME_INT_VAL(x)
#define CHAR_STR "byte?"
#define MAKE_CHAR(x) scheme_make_integer_value(x)
#define xstrlen strlen
#define GENERATING_BYTE
#include "strops.inc"
#undef GENERATING_BYTE

/* comparisons */

#define GEN_BYTE_STRING_COMP(name, scheme_name, comp, op) \
static Scheme_Object * name (int argc, Scheme_Object *argv[]) \
{  char *s, *prev; int i, sl, pl; int falz = 0;\
   if (!SCHEME_BYTE_STRINGP(argv[0])) \
    scheme_wrong_contract(scheme_name, "bytes?", 0, argc, argv); \
   prev = SCHEME_BYTE_STR_VAL(argv[0]); pl = SCHEME_BYTE_STRTAG_VAL(argv[0]); \
   for (i = 1; i < argc; i++) { \
     if (!SCHEME_BYTE_STRINGP(argv[i])) \
      scheme_wrong_contract(scheme_name, "bytes?", i, argc, argv); \
     s = SCHEME_BYTE_STR_VAL(argv[i]); sl = SCHEME_BYTE_STRTAG_VAL(argv[i]); \
     if (!falz) if (!(comp(scheme_name, \
                           (unsigned char *)prev, pl, \
                           (unsigned char *)s, sl) op 0)) falz = 1; \
     prev = s; pl = sl; \
  } \
  return falz ? scheme_false : scheme_true; \
}

GEN_BYTE_STRING_COMP(byte_string_eq, "bytes=?", mz_strcmp, ==)
GEN_BYTE_STRING_COMP(byte_string_lt, "bytes<?", mz_strcmp, <)
GEN_BYTE_STRING_COMP(byte_string_gt, "bytes>?", mz_strcmp, >)

/**********************************************************************/
/*                   byte string <-> char string                      */
/**********************************************************************/

/************************* bytes->string *************************/

static Scheme_Object *
do_byte_string_to_char_string(const char *who,
			      Scheme_Object *bstr,
			      intptr_t istart, intptr_t ifinish,
			      int perm, int as_locale)
{
  int i, ulen;
  char *chars;
  unsigned int *v;

  chars = SCHEME_BYTE_STR_VAL(bstr);

  ulen = utf8_decode_x((unsigned char *)chars, istart, ifinish,
		       NULL, 0, -1,
		       NULL, NULL, 0, 0,
		       NULL, 0, 
		       (perm > -1) ? 0xD800 : 0);
  if (ulen < 0) {
    scheme_contract_error(who,
                          "string is not a well-formed UTF-8 encoding",
                          "string", 1, bstr,
                          NULL);
  }

  v = (unsigned int *)scheme_malloc_atomic((ulen + 1) * sizeof(unsigned int));
  utf8_decode_x((unsigned char *)chars, istart, ifinish,
		v, 0, -1,
		NULL, NULL, 0, 0,
		NULL, 0, 
		(perm > -1) ? 0xD800 : 0);
  
  if (perm > -1) {
    for (i = 0; i < ulen; i++) {
      if (v[i] == 0xD800)
	v[i] = perm;
    }
  }
  v[ulen] = 0;

  return scheme_make_sized_char_string(v, ulen, 0);
}

static Scheme_Object *
do_byte_string_to_char_string_locale(const char *who,
				     Scheme_Object *bstr,
				     intptr_t istart, intptr_t ifinish,
				     int perm)
{
  char *us;
  intptr_t olen;

  reset_locale();
  if (!iconv_ready) init_iconv();

  if (mzLOCALE_IS_UTF_8(current_locale_name) || !locale_on || !mzCHK_PROC(iconv_open))
    return do_byte_string_to_char_string(who, bstr, istart, ifinish, perm, 1);

  if (istart < ifinish) {
    int no_cvt;

    us = string_to_from_locale(0, SCHEME_BYTE_STR_VAL(bstr),
			       istart, ifinish - istart,
			       &olen, perm, &no_cvt);

    if (!us) {
      if (no_cvt) {
	return do_byte_string_to_char_string(who, bstr, istart, ifinish, perm, 1);
      } else {
	scheme_contract_error(who,
                              "byte string is not a valid encoding for the current locale",
                              "byte string", 1, bstr,
                              NULL);
      }
    }
    ((mzchar *)us)[olen] = 0;
  } else {
    us = "\0\0\0";
    olen = 0;
  }

  return scheme_make_sized_char_string((mzchar *)us, olen, 0);
}

static Scheme_Object *
do_string_to_vector(const char *who, int mode, int argc, Scheme_Object *argv[])
{
  int permc;
  intptr_t istart, ifinish;

  if (!SCHEME_BYTE_STRINGP(argv[0]))
    scheme_wrong_contract(who, "bytes?", 0, argc, argv);

  if ((argc < 2) || SCHEME_FALSEP(argv[1]))
    permc = -1;
  else {
    if (!SCHEME_CHARP(argv[1]))
      scheme_wrong_contract(who, "(or/c char? #f)", 1, argc, argv);
    permc = SCHEME_CHAR_VAL(argv[1]);
  }

  scheme_get_substring_indices(who, argv[0], argc, argv,
			       2, 3,
			       &istart, &ifinish);

  if (mode == 0)
    return do_byte_string_to_char_string(who, argv[0], istart, ifinish, permc, 0);
  else if (mode == 1)
    return do_byte_string_to_char_string_locale(who, argv[0], istart, ifinish, permc);
  else {
    /* Latin-1 */
    mzchar *us;
    unsigned char *s;
    intptr_t i, len;
    len = ifinish - istart;
    s = (unsigned char *)SCHEME_BYTE_STR_VAL(argv[0]);
    us = (mzchar *)scheme_malloc_atomic((len + 1) * sizeof(mzchar));
    for (i = istart; i < ifinish; i++) {
      us[i - istart] = s[i];
    }
    us[len] = 0;

    return scheme_make_sized_char_string(us, len, 0);
  }
}


static Scheme_Object *
byte_string_to_char_string (int argc, Scheme_Object *argv[])
{
  return do_string_to_vector("bytes->string/utf-8", 0, argc, argv);
}

static Scheme_Object *
byte_string_to_char_string_locale (int argc, Scheme_Object *argv[])
{
  return do_string_to_vector("bytes->string/locale", 1, argc, argv);
}

static Scheme_Object *
byte_string_to_char_string_latin1 (int argc, Scheme_Object *argv[])
{
  return do_string_to_vector("bytes->string/latin-1", 2, argc, argv);
}

Scheme_Object *scheme_byte_string_to_char_string(Scheme_Object *o)
{
  return do_byte_string_to_char_string("s->s", o, 0, SCHEME_BYTE_STRLEN_VAL(o), 0xFFFD, 0);
}

Scheme_Object *scheme_byte_string_to_char_string_locale(Scheme_Object *o)
{
  return do_byte_string_to_char_string_locale("s->s", o, 0, SCHEME_BYTE_STRLEN_VAL(o), 0xFFFD);
}

/************************* string->bytes *************************/

static Scheme_Object *do_char_string_to_byte_string(Scheme_Object *s, intptr_t istart, intptr_t ifinish, 
						    int as_locale)
{
  char *bs;
  int slen;

  slen = scheme_utf8_encode(SCHEME_CHAR_STR_VAL(s), istart, ifinish,
			    NULL, 0,
			    0 /* UTF-16 */);
  bs = (char *)scheme_malloc_atomic(slen + 1);
  scheme_utf8_encode(SCHEME_CHAR_STR_VAL(s), istart, ifinish,
		     (unsigned char *)bs, 0,
		     0 /* UTF-16 */);
  bs[slen] = 0;

  return scheme_make_sized_byte_string(bs, slen, 0);
}

static Scheme_Object *
do_char_string_to_byte_string_locale(const char *who,
				     Scheme_Object *cstr,
				     intptr_t istart, intptr_t ifinish,
				     int perm)
{
  char *s;
  intptr_t olen;

  reset_locale();
  if (!iconv_ready) init_iconv();

  if (mzLOCALE_IS_UTF_8(current_locale_name) || !locale_on || !mzCHK_PROC(iconv_open))
    return do_char_string_to_byte_string(cstr, istart, ifinish, 1);

  if (istart < ifinish) {
    int no_cvt;

    s = string_to_from_locale(1, (char *)SCHEME_CHAR_STR_VAL(cstr),
			      istart, ifinish - istart,
			      &olen, perm, &no_cvt);

    if (!s) {
      if (no_cvt) {
	return do_char_string_to_byte_string(cstr, istart, ifinish, 1);
      } else {
	scheme_contract_error(who,
                              "string cannot be encoded for the current locale",
                              "string", 1, cstr, 
                              NULL);
      }
    }
    s[olen] = 0;
  } else {
    s = "";
    olen = 0;
  }

  return scheme_make_sized_byte_string(s, olen, 0);
}


Scheme_Object *scheme_char_string_to_byte_string(Scheme_Object *s)
{
  return do_char_string_to_byte_string(s, 0, SCHEME_CHAR_STRLEN_VAL(s), 0);
}

Scheme_Object *scheme_char_string_to_byte_string_locale(Scheme_Object *s)
{
  return do_char_string_to_byte_string_locale("s->s", s, 0, SCHEME_CHAR_STRLEN_VAL(s), '?');
}

static Scheme_Object *do_chars_to_bytes(const char *who, int mode,
					int argc, Scheme_Object *argv[])
{
  intptr_t istart, ifinish;
  int permc;

  if (!SCHEME_CHAR_STRINGP(argv[0]))
    scheme_wrong_contract(who, "string?", 0, argc, argv);

  if ((argc < 2) || SCHEME_FALSEP(argv[1]))
    permc = -1;
  else {
    if (!SCHEME_BYTEP(argv[1]))
      scheme_wrong_contract(who, "(or/c byte? #f)", 1, argc, argv);
    permc = SCHEME_INT_VAL(argv[1]);
  }

  scheme_get_substring_indices(who, argv[0], argc, argv,
			       2, 3, &istart, &ifinish);

  if (mode == 1)
    return do_char_string_to_byte_string_locale(who, argv[0], istart, ifinish, permc);
  else if (mode == 0)
    return do_char_string_to_byte_string(argv[0], istart, ifinish, 0);
  else {
    /* Latin-1 */
    mzchar *us;
    unsigned char *s;
    intptr_t i, len;
    len = ifinish - istart;
    us = SCHEME_CHAR_STR_VAL(argv[0]);
    s = (unsigned char *)scheme_malloc_atomic(len + 1);
    for (i = istart; i < ifinish; i++) {
      if (us[i] < 256)
	s[i - istart] = us[i];
      else if (permc >= 0) {
	s[i - istart] = permc;
      } else {
	scheme_contract_error(who,
                              "string cannot be encoded in …