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/* classes: h_files */
#ifndef SCM_STRINGS_H
#define SCM_STRINGS_H
/* Copyright (C) 1995,1996,1997,1998,2000,2001, 2004, 2005, 2006, 2008, 2009 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 as published by the Free Software Foundation; either
* version 2.1 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser 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
*/
#include "libguile/__scm.h"
/* String representation.
A string is a piece of a stringbuf. A stringbuf can be used by
more than one string. When a string is written to and the
stringbuf of that string is used by more than one string, a new
stringbuf is created. That is, strings are copy-on-write. This
behavior can be used to make the substring operation quite
efficient.
The implementation is tuned so that mutating a string is costly,
but just reading it is cheap and lock-free.
There are also mutation-sharing strings. They refer to a part of
an ordinary string. Writing to a mutation-sharing string just
writes to the ordinary string.
Internal, low level interface to the character arrays
- Use scm_i_string_chars to get a pointer to the byte array of a
string for reading. Use scm_i_string_length to get the number of
bytes in that array. The array is not null-terminated.
- The array is valid as long as the corresponding SCM object is
protected but only until the next SCM_TICK. During such a 'safe
point', strings might change their representation.
- Use scm_i_string_writable_chars to get the same pointer as with
scm_i_string_chars, but for reading and writing. This is a
potentially costly operation since it implements the
copy-on-write behavior. When done with the writing, call
scm_i_string_stop_writing. You must do this before the next
SCM_TICK. (This means, before calling almost any other scm_
function and you can't allow throws, of course.)
- New strings can be created with scm_i_make_string. This gives
access to a writable pointer that remains valid as long as nobody
else makes a copy-on-write substring of the string. Do not call
scm_i_string_stop_writing for this pointer.
Legacy interface
- SCM_STRINGP is just scm_is_string.
- SCM_STRING_CHARS uses scm_i_string_writable_chars and immediately
calls scm_i_stop_writing, hoping for the best. SCM_STRING_LENGTH
is the same as scm_i_string_length. SCM_STRING_CHARS will throw
an error for for strings that are not null-terminated.
*/
SCM_API SCM scm_string_p (SCM x);
SCM_API SCM scm_string (SCM chrs);
SCM_API SCM scm_make_string (SCM k, SCM chr);
SCM_API SCM scm_string_length (SCM str);
SCM_API SCM scm_string_ref (SCM str, SCM k);
SCM_API SCM scm_string_set_x (SCM str, SCM k, SCM chr);
SCM_API SCM scm_substring (SCM str, SCM start, SCM end);
SCM_API SCM scm_substring_read_only (SCM str, SCM start, SCM end);
SCM_API SCM scm_substring_shared (SCM str, SCM start, SCM end);
SCM_API SCM scm_substring_copy (SCM str, SCM start, SCM end);
SCM_API SCM scm_string_append (SCM args);
SCM_API SCM scm_c_make_string (size_t len, SCM chr);
SCM_API size_t scm_c_string_length (SCM str);
SCM_API size_t scm_c_symbol_length (SCM sym);
SCM_API SCM scm_c_string_ref (SCM str, size_t pos);
SCM_API void scm_c_string_set_x (SCM str, size_t pos, SCM chr);
SCM_API SCM scm_c_substring (SCM str, size_t start, size_t end);
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 int scm_is_string (SCM x);
SCM_API SCM scm_from_locale_string (const char *str);
SCM_API SCM scm_from_locale_stringn (const char *str, size_t len);
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_locale_string (SCM str);
SCM_API char *scm_to_locale_stringn (SCM str, size_t *lenp);
SCM_API size_t scm_to_locale_stringbuf (SCM str, char *buf, size_t max_len);
SCM_API SCM scm_makfromstrs (int argc, char **argv);
/* internal constants */
/* Type tag for read-only strings. */
#define scm_tc7_ro_string (scm_tc7_string + 0x200)
/* Flags for shared and inline strings. */
#define SCM_I_STRINGBUF_F_SHARED 0x100
#define SCM_I_STRINGBUF_F_INLINE 0x200
/* internal accessor functions. Arguments must be valid. */
SCM_INTERNAL SCM scm_i_make_string (size_t len, char **datap);
SCM_INTERNAL SCM scm_i_substring (SCM str, size_t start, size_t end);
SCM_INTERNAL SCM scm_i_substring_read_only (SCM str, size_t start, size_t end);
SCM_INTERNAL SCM scm_i_substring_shared (SCM str, size_t start, size_t end);
SCM_INTERNAL SCM scm_i_substring_copy (SCM str, size_t start, size_t end);
SCM_INTERNAL size_t scm_i_string_length (SCM str);
SCM_API /* FIXME: not internal */ const char *scm_i_string_chars (SCM str);
SCM_API /* FIXME: not internal */ char *scm_i_string_writable_chars (SCM str);
SCM_INTERNAL void scm_i_string_stop_writing (void);
/* internal functions related to symbols. */
SCM_INTERNAL SCM scm_i_make_symbol (SCM name, scm_t_bits flags,
unsigned long hash, SCM props);
SCM_INTERNAL SCM
scm_i_c_make_symbol (const char *name, size_t len,
scm_t_bits flags, unsigned long hash, SCM props);
SCM_INTERNAL SCM
scm_i_c_take_symbol (char *name, size_t len,
scm_t_bits flags, unsigned long hash, SCM props);
SCM_INTERNAL const char *scm_i_symbol_chars (SCM sym);
SCM_INTERNAL size_t scm_i_symbol_length (SCM sym);
SCM_INTERNAL SCM scm_i_symbol_substring (SCM sym, size_t start, size_t end);
/* internal utility functions. */
SCM_INTERNAL char **scm_i_allocate_string_pointers (SCM list);
SCM_INTERNAL void scm_i_get_substring_spec (size_t len,
SCM start, size_t *cstart,
SCM end, size_t *cend);
SCM_INTERNAL SCM scm_i_take_stringbufn (char *str, size_t len);
/* deprecated stuff */
#if SCM_ENABLE_DEPRECATED
SCM_API int scm_i_deprecated_stringp (SCM obj);
SCM_API char *scm_i_deprecated_string_chars (SCM str);
SCM_API size_t scm_i_deprecated_string_length (SCM str);
#define SCM_STRINGP(x) scm_i_deprecated_stringp(x)
#define SCM_STRING_CHARS(x) scm_i_deprecated_string_chars(x)
#define SCM_STRING_LENGTH(x) scm_i_deprecated_string_length(x)
#define SCM_STRING_UCHARS(str) ((unsigned char *)SCM_STRING_CHARS (str))
#endif
SCM_INTERNAL void scm_init_strings (void);
#endif /* SCM_STRINGS_H */
/*
Local Variables:
c-file-style: "gnu"
End:
*/
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