/* C language support routines for GDB, the GNU debugger.
Copyright (C) 1992, 1993, 1994, 1995, 1996, 1998, 1999, 2000, 2002, 2003,
- 2004, 2005, 2007, 2008 Free Software Foundation, Inc.
+ 2004, 2005, 2007, 2008, 2009 Free Software Foundation, Inc.
This file is part of GDB.
if (force_ellipses || i < length)
fputs_filtered ("...", stream);
}
+
+/* Obtain a C string from the inferior storing it in a newly allocated
+ buffer in BUFFER, which should be freed by the caller. The string is
+ read until a null character is found. If VALUE is an array with known
+ length, the function will not read past the end of the array. LENGTH
+ will contain the size of the string in bytes (not counting the null
+ character).
+
+ Assumes strings are terminated by a null character. The size of a character
+ is determined by the length of the target type of the pointer or array.
+ This means that a null byte present in a multi-byte character will not
+ terminate the string unless the whole character is null.
+
+ CHARSET is always set to the target charset. */
+
+void
+c_get_string (struct value *value, gdb_byte **buffer, int *length,
+ const char **charset)
+{
+ int err, width;
+ unsigned int fetchlimit;
+ struct type *type = check_typedef (value_type (value));
+ struct type *element_type = TYPE_TARGET_TYPE (type);
+
+ if (element_type == NULL)
+ goto error;
+
+ if (TYPE_CODE (type) == TYPE_CODE_ARRAY)
+ {
+ /* If we know the size of the array, we can use it as a limit on the
+ number of characters to be fetched. */
+ if (TYPE_NFIELDS (type) == 1
+ && TYPE_CODE (TYPE_FIELD_TYPE (type, 0)) == TYPE_CODE_RANGE)
+ {
+ LONGEST low_bound, high_bound;
+
+ get_discrete_bounds (TYPE_FIELD_TYPE (type, 0),
+ &low_bound, &high_bound);
+ fetchlimit = high_bound - low_bound + 1;
+ }
+ else
+ fetchlimit = UINT_MAX;
+ }
+ else if (TYPE_CODE (type) == TYPE_CODE_PTR)
+ fetchlimit = UINT_MAX;
+ else
+ /* We work only with arrays and pointers. */
+ goto error;
+
+ element_type = check_typedef (element_type);
+ if (TYPE_CODE (element_type) != TYPE_CODE_INT
+ && TYPE_CODE (element_type) != TYPE_CODE_CHAR)
+ /* If the elements are not integers or characters, we don't consider it
+ a string. */
+ goto error;
+
+ width = TYPE_LENGTH (element_type);
+
+ /* If the string lives in GDB's memory intead of the inferior's, then we
+ just need to copy it to BUFFER. Also, since such strings are arrays
+ with known size, FETCHLIMIT will hold the size of the array. */
+ if ((VALUE_LVAL (value) == not_lval
+ || VALUE_LVAL (value) == lval_internalvar)
+ && fetchlimit != UINT_MAX)
+ {
+ int i;
+ const gdb_byte *contents = value_contents (value);
+
+ /* Look for a null character. */
+ for (i = 0; i < fetchlimit; i++)
+ if (extract_unsigned_integer (contents + i * width, width) == 0)
+ break;
+
+ /* I is now either the number of non-null characters, or FETCHLIMIT. */
+ *length = i * width;
+ *buffer = xmalloc (*length);
+ memcpy (*buffer, contents, *length);
+ err = 0;
+ }
+ else
+ {
+ err = read_string (value_as_address (value), -1, width, fetchlimit,
+ buffer, length);
+ if (err)
+ {
+ xfree (buffer);
+ error (_("Error reading string from inferior: %s"),
+ safe_strerror (err));
+ }
+ }
+
+ /* If the last character is null, subtract it from LENGTH. */
+ if (*length > 0
+ && extract_unsigned_integer (*buffer + *length - width, width) == 0)
+ *length -= width;
+
+ *charset = target_charset ();
+
+ return;
+
+ error:
+ {
+ char *type_str;
+
+ type_str = type_to_string (type);
+ if (type_str)
+ {
+ make_cleanup (xfree, type_str);
+ error (_("Trying to read string with inappropriate type `%s'."),
+ type_str);
+ }
+ else
+ error (_("Trying to read string with inappropriate type."));
+ }
+}
+
\f
/* Preprocessing and parsing C and C++ expressions. */
c_language_arch_info,
default_print_array_index,
default_pass_by_reference,
+ c_get_string,
LANG_MAGIC
};
cplus_language_arch_info,
default_print_array_index,
cp_pass_by_reference,
+ c_get_string,
LANG_MAGIC
};
c_language_arch_info, /* FIXME: la_language_arch_info. */
default_print_array_index,
default_pass_by_reference,
+ c_get_string,
LANG_MAGIC
};
c_language_arch_info,
default_print_array_index,
default_pass_by_reference,
+ c_get_string,
LANG_MAGIC
};