Add support for distinct host and target character sets.

gdb/ChangeLog

@@ -1,3 +1,34 @@
+2002-09-19  Jim Blandy  <jimb@redhat.com>
+
+	Add support for distinct host and target character sets.
+	* charset.c, charset.h: New files.
+	* c-exp.y: #include "charset.h".
+	(yylex): Convert character and string literals to the target
+	character set, before returning them as the semantic value of the
+	token.
+	* c-lang.c: #include "charset.h".
+	(c_emit_char): Use charset-specific methods to recognize
+	characters with backslash escape forms, to decide which characters
+	to print literally and which to print using numeric escape
+	sequences, and to convert target characters to host characters
+	before printing.
+	* utils.c: #include "charset.h".
+	(no_control_char_error): New function.
+	(parse_escape): Use charset-specific methods to recognize
+	backslash escapes, parse `control character' notation, and convert
+	characters from the host character set to the target character set.
+	* configure.in: Set the default host character set.
+	Check where to find iconv, and what its argument types might be.
+	* acinclude.m4 (AM_ICONV): New macro, borrowed from GCC.
+	* Makefile.in (SFILES): List charset.c.
+	(COMMON_OBS): List charset.o.	
+	(charset.o): New rule.
+	(charset_h): New header dependency variable.
+	(c-lang.o, utils.o, c-exp.tab.o): Note dependency on $(charset_h).
+	(LIBICONV): New variable, set by configure.
+	(CLIBS): Include $(LIBICONV) here.
+	* aclocal.m4, config.in, configure: Regenerated.
+
 2002-09-19  Joel Brobecker  <brobecker@gnat.com>
 
 	* ada-exp.y: Add missing semicolons to end rules. Fixes a

gdb/Makefile.in

@@ -138,6 +138,9 @@ INTL_DEPS = @INTLDEPS@
 INTL_SRC = $(srcdir)/$(INTL_DIR)
 INTL_CFLAGS = -I$(INTL_DIR) -I$(INTL_SRC)
 
+# Where is the ICONV library?  This can be empty if libc has iconv.
+LIBICONV = @LIBICONV@
+
 #
 # CLI sub directory definitons
 #
@@ -369,6 +372,7 @@ INSTALLED_LIBS=-lbfd -lreadline -lopcodes -liberty \
 	-lmmalloc -lintl -liberty
 CLIBS = $(SIM) $(BFD) $(READLINE) $(OPCODES) $(INTL) $(LIBIBERTY) \
 	$(TERMCAP) $(XM_CLIBS) $(TM_CLIBS) $(NAT_CLIBS) $(GDBTKLIBS) @LIBS@ \
+	$(LIBICONV) \
 	$(MMALLOC) $(LIBIBERTY) $(WIN32LIBS)
 CDEPS = $(XM_CDEPS) $(TM_CDEPS) $(NAT_CDEPS) $(SIM) $(BFD) $(READLINE) \
 	$(OPCODES) $(MMALLOC) $(INTL_DEPS) $(LIBIBERTY) $(CONFIG_DEPS)
@@ -526,6 +530,7 @@ TARGET_FLAGS_TO_PASS = \
 
 SFILES = ada-exp.y ada-lang.c ada-typeprint.c ada-valprint.c ada-tasks.c \
 	ax-general.c ax-gdb.c bcache.c blockframe.c breakpoint.c \
+	charset.c \
 	buildsym.c c-exp.y c-lang.c c-typeprint.c c-valprint.c \
 	coffread.c \
 	complaints.c completer.c corefile.c cp-valprint.c dbxread.c \
@@ -767,6 +772,8 @@ tuiSourceWin_h = $(srcdir)/tui/tuiSourceWin.h
 tuiStack_h = $(srcdir)/tui/tuiStack.h
 tuiWin_h = $(srcdir)/tui/tuiWin.h
 
+charset_h =	charset.h
+
 # Header files that need to have srcdir added.  Note that in the cases
 # where we use a macro like $(gdbcmd_h), things are carefully arranged
 # so that each .h file is listed exactly once (M-x tags-search works
@@ -818,6 +825,7 @@ TAGFILES_NO_SRCDIR = $(SFILES) $(HFILES_NO_SRCDIR) $(ALLDEPFILES) \
 TAGFILES_WITH_SRCDIR = $(HFILES_WITH_SRCDIR)
 
 COMMON_OBS = version.o blockframe.o breakpoint.o findvar.o regcache.o \
+	charset.o \
 	source.o values.o eval.o valops.o valarith.o valprint.o printcmd.o \
 	symtab.o symfile.o symmisc.o linespec.o infcmd.o infrun.o \
 	expprint.o environ.o stack.o thread.o \
@@ -1439,6 +1447,7 @@ z8k-tdep.o: $(srcdir)/z8k-tdep.c
 
 c-exp.tab.o: c-exp.tab.c $(defs_h) $(gdb_string_h) $(expression_h) \
 	$(value_h) $(parser_defs_h) $(language_h) $(c_lang_h) $(bfd_h) \
+	$(charset_h) \
 	$(symfile_h) $(objfiles_h)
 
 jv-exp.tab.o: jv-exp.tab.c jv-lang.h $(defs_h) $(expression_h) \
@@ -2578,4 +2587,8 @@ xdr_rdb.o: vx-share/xdr_rdb.c $(defs_h) vx-share/vxTypes.h \
 	vx-share/vxWorks.h vx-share/xdr_rdb.h
 	$(CC) -c $(INTERNAL_CFLAGS) $(srcdir)/vx-share/xdr_rdb.c
 
+charset.o: charset.c $(defs_h) $(charset_h) $(gdbcmd_h) gdb_assert.h
+
+c-lang.o: $(charset_h)
+utils.o: $(charset_h)
 ### end of the gdb Makefile.in.

gdb/acinclude.m4

@@ -976,3 +976,71 @@ case "x$am_cv_prog_cc_stdc" in
   *) CC="$CC $am_cv_prog_cc_stdc" ;;
 esac
 ])
+
+dnl From Bruno Haible.
+
+AC_DEFUN([AM_ICONV],
+[
+  dnl Some systems have iconv in libc, some have it in libiconv (OSF/1 and
+  dnl those with the standalone portable GNU libiconv installed).
+
+  AC_ARG_WITH([libiconv-prefix],
+[  --with-libiconv-prefix=DIR  search for libiconv in DIR/include and DIR/lib], [
+    for dir in `echo "$withval" | tr : ' '`; do
+      if test -d $dir/include; then CPPFLAGS="$CPPFLAGS -I$dir/include"; fi
+      if test -d $dir/lib; then LDFLAGS="$LDFLAGS -L$dir/lib"; fi
+    done
+   ])
+
+  AC_CACHE_CHECK(for iconv, am_cv_func_iconv, [
+    am_cv_func_iconv="no, consider installing GNU libiconv"
+    am_cv_lib_iconv=no
+    AC_TRY_LINK([#include <stdlib.h>
+#include <iconv.h>],
+      [iconv_t cd = iconv_open("","");
+       iconv(cd,NULL,NULL,NULL,NULL);
+       iconv_close(cd);],
+      am_cv_func_iconv=yes)
+    if test "$am_cv_func_iconv" != yes; then
+      am_save_LIBS="$LIBS"
+      LIBS="$LIBS -liconv"
+      AC_TRY_LINK([#include <stdlib.h>
+#include <iconv.h>],
+        [iconv_t cd = iconv_open("","");
+         iconv(cd,NULL,NULL,NULL,NULL);
+         iconv_close(cd);],
+        am_cv_lib_iconv=yes
+        am_cv_func_iconv=yes)
+      LIBS="$am_save_LIBS"
+    fi
+  ])
+  if test "$am_cv_func_iconv" = yes; then
+    AC_DEFINE(HAVE_ICONV, 1, [Define if you have the iconv() function.])
+    AC_MSG_CHECKING([for iconv declaration])
+    AC_CACHE_VAL(am_cv_proto_iconv, [
+      AC_TRY_COMPILE([
+#include <stdlib.h>
+#include <iconv.h>
+extern
+#ifdef __cplusplus
+"C"
+#endif
+#if defined(__STDC__) || defined(__cplusplus)
+size_t iconv (iconv_t cd, char * *inbuf, size_t *inbytesleft, char * *outbuf, size_t *outbytesleft);
+#else
+size_t iconv();
+#endif
+], [], am_cv_proto_iconv_arg1="", am_cv_proto_iconv_arg1="const")
+      am_cv_proto_iconv="extern size_t iconv (iconv_t cd, $am_cv_proto_iconv_arg1 char * *inbuf, size_t *inbytesleft, char * *outbuf, size_t *outbytesleft);"])
+    am_cv_proto_iconv=`echo "[$]am_cv_proto_iconv" | tr -s ' ' | sed -e 's/( /(/'`
+    AC_MSG_RESULT([$]{ac_t:-
+         }[$]am_cv_proto_iconv)
+    AC_DEFINE_UNQUOTED(ICONV_CONST, $am_cv_proto_iconv_arg1,
+      [Define as const if the declaration of iconv() needs const.])
+  fi
+  LIBICONV=
+  if test "$am_cv_lib_iconv" = yes; then
+    LIBICONV="-liconv"
+  fi
+  AC_SUBST(LIBICONV)
+])

gdb/aclocal.m4

@@ -879,6 +879,74 @@ ifelse(yes,no,[
 AC_DEFUN([CY_GNU_GETTEXT],)
 ])
 
+dnl From Bruno Haible.
+
+AC_DEFUN([AM_ICONV],
+[
+  dnl Some systems have iconv in libc, some have it in libiconv (OSF/1 and
+  dnl those with the standalone portable GNU libiconv installed).
+
+  AC_ARG_WITH([libiconv-prefix],
+[  --with-libiconv-prefix=DIR  search for libiconv in DIR/include and DIR/lib], [
+    for dir in `echo "$withval" | tr : ' '`; do
+      if test -d $dir/include; then CPPFLAGS="$CPPFLAGS -I$dir/include"; fi
+      if test -d $dir/lib; then LDFLAGS="$LDFLAGS -L$dir/lib"; fi
+    done
+   ])
+
+  AC_CACHE_CHECK(for iconv, am_cv_func_iconv, [
+    am_cv_func_iconv="no, consider installing GNU libiconv"
+    am_cv_lib_iconv=no
+    AC_TRY_LINK([#include <stdlib.h>
+#include <iconv.h>],
+      [iconv_t cd = iconv_open("","");
+       iconv(cd,NULL,NULL,NULL,NULL);
+       iconv_close(cd);],
+      am_cv_func_iconv=yes)
+    if test "$am_cv_func_iconv" != yes; then
+      am_save_LIBS="$LIBS"
+      LIBS="$LIBS -liconv"
+      AC_TRY_LINK([#include <stdlib.h>
+#include <iconv.h>],
+        [iconv_t cd = iconv_open("","");
+         iconv(cd,NULL,NULL,NULL,NULL);
+         iconv_close(cd);],
+        am_cv_lib_iconv=yes
+        am_cv_func_iconv=yes)
+      LIBS="$am_save_LIBS"
+    fi
+  ])
+  if test "$am_cv_func_iconv" = yes; then
+    AC_DEFINE(HAVE_ICONV, 1, [Define if you have the iconv() function.])
+    AC_MSG_CHECKING([for iconv declaration])
+    AC_CACHE_VAL(am_cv_proto_iconv, [
+      AC_TRY_COMPILE([
+#include <stdlib.h>
+#include <iconv.h>
+extern
+#ifdef __cplusplus
+"C"
+#endif
+#if defined(__STDC__) || defined(__cplusplus)
+size_t iconv (iconv_t cd, char * *inbuf, size_t *inbytesleft, char * *outbuf, size_t *outbytesleft);
+#else
+size_t iconv();
+#endif
+], [], am_cv_proto_iconv_arg1="", am_cv_proto_iconv_arg1="const")
+      am_cv_proto_iconv="extern size_t iconv (iconv_t cd, $am_cv_proto_iconv_arg1 char * *inbuf, size_t *inbytesleft, char * *outbuf, size_t *outbytesleft);"])
+    am_cv_proto_iconv=`echo "[$]am_cv_proto_iconv" | tr -s ' ' | sed -e 's/( /(/'`
+    AC_MSG_RESULT([$]{ac_t:-
+         }[$]am_cv_proto_iconv)
+    AC_DEFINE_UNQUOTED(ICONV_CONST, $am_cv_proto_iconv_arg1,
+      [Define as const if the declaration of iconv() needs const.])
+  fi
+  LIBICONV=
+  if test "$am_cv_lib_iconv" = yes; then
+    LIBICONV="-liconv"
+  fi
+  AC_SUBST(LIBICONV)
+])
+
 
 # Copyright 1996, 1997, 1999, 2000, 2001 Free Software Foundation, Inc.
 

gdb/c-exp.y

@@ -49,6 +49,7 @@ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
 #include "bfd.h" /* Required by objfiles.h.  */
 #include "symfile.h" /* Required by objfiles.h.  */
 #include "objfiles.h" /* For have_full_symbols and have_partial_symbols */
+#include "charset.h"
 
 /* Flag indicating we're dealing with HP-compiled objects */ 
 extern int hp_som_som_object_present;
@@ -1314,6 +1315,15 @@ yylex ()
 	c = parse_escape (&lexptr);
       else if (c == '\'')
 	error ("Empty character constant.");
+      else if (! host_char_to_target (c, &c))
+        {
+          int toklen = lexptr - tokstart + 1;
+          char *tok = alloca (toklen + 1);
+          memcpy (tok, tokstart, toklen);
+          tok[toklen] = '\0';
+          error ("There is no character corresponding to %s in the target "
+                 "character set `%s'.", tok, target_charset ());
+        }
 
       yylval.typed_val_int.val = c;
       yylval.typed_val_int.type = builtin_type_char;
@@ -1464,6 +1474,8 @@ yylex ()
       tempbufindex = 0;
 
       do {
+        char *char_start_pos = tokptr;
+
 	/* Grow the static temp buffer if necessary, including allocating
 	   the first one on demand. */
 	if (tempbufindex + 1 >= tempbufsize)
@@ -1486,7 +1498,19 @@ yylex ()
 	    tempbuf[tempbufindex++] = c;
 	    break;
 	  default:
-	    tempbuf[tempbufindex++] = *tokptr++;
+	    c = *tokptr++;
+            if (! host_char_to_target (c, &c))
+              {
+                int len = tokptr - char_start_pos;
+                char *copy = alloca (len + 1);
+                memcpy (copy, char_start_pos, len);
+                copy[len] = '\0';
+
+                error ("There is no character corresponding to `%s' "
+                       "in the target character set `%s'.",
+                       copy, target_charset ());
+              }
+            tempbuf[tempbufindex++] = c;
 	    break;
 	  }
       } while ((*tokptr != '"') && (*tokptr != '\0'));

gdb/c-lang.c

@@ -29,6 +29,7 @@
 #include "valprint.h"
 #include "macroscope.h"
 #include "gdb_assert.h"
+#include "charset.h"
 
 extern void _initialize_c_language (void);
 static void c_emit_char (int c, struct ui_file * stream, int quoter);
@@ -40,55 +41,30 @@ static void c_emit_char (int c, struct ui_file * stream, int quoter);
 static void
 c_emit_char (register int c, struct ui_file *stream, int quoter)
 {
+  const char *escape;
+  int host_char;
+
   c &= 0xFF;			/* Avoid sign bit follies */
 
-  if (PRINT_LITERAL_FORM (c))
+  escape = c_target_char_has_backslash_escape (c);
+  if (escape)
     {
-      if (c == '\\' || c == quoter)
-	{
-	  fputs_filtered ("\\", stream);
-	}
-      fprintf_filtered (stream, "%c", c);
+      if (quoter == '"' && strcmp (escape, "0") == 0)
+	/* Print nulls embedded in double quoted strings as \000 to
+	   prevent ambiguity.  */
+	fprintf_filtered (stream, "\\000");
+      else
+	fprintf_filtered (stream, "\\%s", escape);
+    }
+  else if (target_char_to_host (c, &host_char)
+           && host_char_print_literally (host_char))
+    {
+      if (host_char == '\\' || host_char == quoter)
+        fputs_filtered ("\\", stream);
+      fprintf_filtered (stream, "%c", host_char);
     }
   else
-    {
-      switch (c)
-	{
-	case '\n':
-	  fputs_filtered ("\\n", stream);
-	  break;
-	case '\b':
-	  fputs_filtered ("\\b", stream);
-	  break;
-	case '\t':
-	  fputs_filtered ("\\t", stream);
-	  break;
-	case '\f':
-	  fputs_filtered ("\\f", stream);
-	  break;
-	case '\r':
-	  fputs_filtered ("\\r", stream);
-	  break;
-        case '\013':
-          fputs_filtered ("\\v", stream);
-          break;
-	case '\033':
-	  fputs_filtered ("\\e", stream);
-	  break;
-	case '\007':
-	  fputs_filtered ("\\a", stream);
-	  break;
-	case '\0':
-	  if (quoter == '\'')
-	    fputs_filtered ("\\0", stream);
-	  else
-	    fprintf_filtered (stream, "\\%.3o", (unsigned int) c);
-	  break;
-	default:
-	  fprintf_filtered (stream, "\\%.3o", (unsigned int) c);
-	  break;
-	}
-    }
+    fprintf_filtered (stream, "\\%.3o", (unsigned int) c);
 }
 
 void

gdb/charset.h

@@ -0,0 +1,120 @@
+/* Character set conversion support for GDB.
+   Copyright 2001 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   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 of the License, 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 CHARSET_H
+#define CHARSET_H
+
+
+/* If the target program uses a different character set than the host,
+   GDB has some support for translating between the two; GDB converts
+   characters and strings to the host character set before displaying
+   them, and converts characters and strings appearing in expressions
+   entered by the user to the target character set.
+
+   At the moment, GDB only supports single-byte, stateless character
+   sets.  This includes the ISO-8859 family (ASCII extended with
+   accented characters, and (I think) Cyrillic, for European
+   languages), and the EBCDIC family (used on IBM's mainframes).
+   Unfortunately, it excludes many Asian scripts, the fixed- and
+   variable-width Unicode encodings, and other desireable things.
+   Patches are welcome!  (For example, it would be nice if the Java
+   string support could simply get absorbed into some more general
+   multi-byte encoding support.)
+
+   Furthermore, GDB's code pretty much assumes that the host character
+   set is some superset of ASCII; there are plenty if ('0' + n)
+   expressions and the like.
+
+   When the `iconv' library routine supports a character set meeting
+   the requirements above, it's easy to plug an entry into GDB's table
+   that uses iconv to handle the details.  */
+
+
+/* Set the host character set to CHARSET.  CHARSET must be a superset
+   of ASCII, since GDB's code assumes this.  */
+void set_host_charset (const char *charset);
+
+
+/* Set the target character set to CHARSET.  */
+void set_target_charset (const char *charset);
+
+
+/* Return the name of the current host/target character set.  The
+   result is owned by the charset module; the caller should not free
+   it.  */
+const char *host_charset (void);
+const char *target_charset (void);
+
+
+/* In general, the set of C backslash escapes (\n, \f) is specific to
+   the character set.  Not all character sets will have form feed
+   characters, for example.
+
+   The following functions allow GDB to parse and print control
+   characters in a character-set-independent way.  They are both
+   language-specific (to C and C++) and character-set-specific.
+   Putting them here is a compromise.  */
+
+
+/* If the target character TARGET_CHAR have a backslash escape in the
+   C language (i.e., a character like 'n' or 't'), return the host
+   character string that should follow the backslash.  Otherwise,
+   return zero.
+
+   When this function returns non-zero, the string it returns is
+   statically allocated; the caller is not responsible for freeing it.  */
+const char *c_target_char_has_backslash_escape (int target_char);
+
+
+/* If the host character HOST_CHAR is a valid backslash escape in the
+   C language for the target character set, return non-zero, and set
+   *TARGET_CHAR to the target character the backslash escape represents.
+   Otherwise, return zero.  */
+int c_parse_backslash (int host_char, int *target_char);
+
+
+/* Return non-zero if the host character HOST_CHAR can be printed
+   literally --- that is, if it can be readably printed as itself in a
+   character or string constant.  Return zero if it should be printed
+   using some kind of numeric escape, like '\031' in C, '^(25)' in
+   Chill, or #25 in Pascal.  */
+int host_char_print_literally (int host_char);
+
+
+/* If the host character HOST_CHAR has an equivalent in the target
+   character set, set *TARGET_CHAR to that equivalent, and return
+   non-zero.  Otherwise, return zero.  */
+int host_char_to_target (int host_char, int *target_char);
+
+
+/* If the target character TARGET_CHAR has an equivalent in the host
+   character set, set *HOST_CHAR to that equivalent, and return
+   non-zero.  Otherwise, return zero.  */
+int target_char_to_host (int target_char, int *host_char);
+
+
+/* If the target character TARGET_CHAR has a corresponding control
+   character (also in the target character set), set *TARGET_CTRL_CHAR
+   to the control character, and return non-zero.  Otherwise, return
+   zero.  */
+int target_char_to_control_char (int target_char, int *target_ctrl_char);
+
+
+#endif /* CHARSET_H */

gdb/configure.in

@@ -1362,6 +1362,18 @@ AC_LINK_FILES($files, $links)
 dnl Check for exe extension set on certain hosts (e.g. Win32)
 AC_EXEEXT
 
+dnl  Detect the character set used by this host.
+
+dnl  At the moment, we just assume it's ISO-8859-1 (which is a
+dnl  superset of ASCII containing the characters needed for French,
+dnl  German, Spanish, Italian, and possibly others), but if were
+dnl  *were* to support any host character sets other than ISO-8859-1,
+dnl  here's where we'd detect it.
+AC_DEFINE(GDB_DEFAULT_HOST_CHARSET, "ISO-8859-1",
+          [Define to be a string naming the default host character set.])
+
+AM_ICONV
+
 AC_CONFIG_SUBDIRS($configdirs)
 AC_OUTPUT(Makefile .gdbinit:gdbinit.in,
 [

gdb/utils.c

@@ -60,6 +60,7 @@
 #include "demangle.h"
 #include "expression.h"
 #include "language.h"
+#include "charset.h"
 #include "annotate.h"
 #include "filenames.h"
 
@@ -1362,6 +1363,23 @@ query (const char *ctlstr,...)
 }
 
 
+/* Print an error message saying that we couldn't make sense of a
+   \^mumble sequence in a string or character constant.  START and END
+   indicate a substring of some larger string that contains the
+   erroneous backslash sequence, missing the initial backslash.  */
+static NORETURN int
+no_control_char_error (const char *start, const char *end)
+{
+  int len = end - start;
+  char *copy = alloca (end - start + 1);
+
+  memcpy (copy, start, len);
+  copy[len] = '\0';
+
+  error ("There is no control character `\\%s' in the `%s' character set.",
+         copy, target_charset ());
+}
+
 /* Parse a C escape sequence.  STRING_PTR points to a variable
    containing a pointer to the string to parse.  That pointer
    should point to the character after the \.  That pointer
@@ -1380,37 +1398,55 @@ query (const char *ctlstr,...)
 int
 parse_escape (char **string_ptr)
 {
+  int target_char;
   register int c = *(*string_ptr)++;
-  switch (c)
+  if (c_parse_backslash (c, &target_char))
+    return target_char;
+  else switch (c)
     {
-    case 'a':
-      return 007;		/* Bell (alert) char */
-    case 'b':
-      return '\b';
-    case 'e':			/* Escape character */
-      return 033;
-    case 'f':
-      return '\f';
-    case 'n':
-      return '\n';
-    case 'r':
-      return '\r';
-    case 't':
-      return '\t';
-    case 'v':
-      return '\v';
     case '\n':
       return -2;
     case 0:
       (*string_ptr)--;
       return 0;
     case '^':
-      c = *(*string_ptr)++;
-      if (c == '\\')
-	c = parse_escape (string_ptr);
-      if (c == '?')
-	return 0177;
-      return (c & 0200) | (c & 037);
+      {
+        /* Remember where this escape sequence started, for reporting
+           errors.  */
+        char *sequence_start_pos = *string_ptr - 1;
+
+        c = *(*string_ptr)++;
+
+        if (c == '?')
+          {
+            /* XXXCHARSET: What is `delete' in the host character set?  */
+            c = 0177;
+
+            if (! host_char_to_target (c, &target_char))
+              error ("There is no character corresponding to `Delete' "
+                     "in the target character set `%s'.",
+                     host_charset ());
+
+            return target_char;
+          }
+        else if (c == '\\')
+          target_char = parse_escape (string_ptr);
+        else
+          {
+            if (! host_char_to_target (c, &target_char))
+              no_control_char_error (sequence_start_pos, *string_ptr);
+          }          
+
+        /* Now target_char is something like `c', and we want to find
+           its control-character equivalent.  */
+        if (! target_char_to_control_char (target_char, &target_char))
+          no_control_char_error (sequence_start_pos, *string_ptr);
+
+        return target_char;
+      }
+
+      /* XXXCHARSET: we need to use isdigit and value-of-digit
+         methods of the host character set here.  */
 
     case '0':
     case '1':
@@ -1439,7 +1475,12 @@ parse_escape (char **string_ptr)
 	return i;
       }
     default:
-      return c;
+      if (! host_char_to_target (c, &target_char))
+        error ("The escape sequence `\%c' is equivalent to plain `%c', which"
+               " has no equivalent\n"
+               "in the `%s' character set.",
+               c, c, target_charset ());
+      return target_char;
     }
 }