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/* Copyright (C) 1995,1996,1997,1998,2000,2001, 2004, 2005, 2006 Free Software Foundation, Inc.
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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#include "libguile/__scm.h"
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/* String representation.
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A string is a piece of a stringbuf. A stringbuf can be used by
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more than one string. When a string is written to and the
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stringbuf of that string is used by more than one string, a new
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stringbuf is created. That is, strings are copy-on-write. This
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behavior can be used to make the substring operation quite
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The implementation is tuned so that mutating a string is costly,
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but just reading it is cheap and lock-free.
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There are also mutation-sharing strings. They refer to a part of
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an ordinary string. Writing to a mutation-sharing string just
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writes to the ordinary string.
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Internal, low level interface to the character arrays
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- Use scm_i_string_chars to get a pointer to the byte array of a
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string for reading. Use scm_i_string_length to get the number of
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bytes in that array. The array is not null-terminated.
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- The array is valid as long as the corresponding SCM object is
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protected but only until the next SCM_TICK. During such a 'safe
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point', strings might change their representation.
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- Use scm_i_string_writable_chars to get the same pointer as with
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scm_i_string_chars, but for reading and writing. This is a
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potentially costly operation since it implements the
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copy-on-write behavior. When done with the writing, call
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scm_i_string_stop_writing. You must do this before the next
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SCM_TICK. (This means, before calling almost any other scm_
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function and you can't allow throws, of course.)
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- New strings can be created with scm_i_make_string. This gives
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access to a writable pointer that remains valid as long as nobody
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else makes a copy-on-write substring of the string. Do not call
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scm_i_string_stop_writing for this pointer.
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- SCM_STRINGP is just scm_is_string.
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- SCM_STRING_CHARS uses scm_i_string_writable_chars and immediately
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calls scm_i_stop_writing, hoping for the best. SCM_STRING_LENGTH
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is the same as scm_i_string_length. SCM_STRING_CHARS will throw
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an error for for strings that are not null-terminated.
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SCM_API SCM scm_string_p (SCM x);
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SCM_API SCM scm_string (SCM chrs);
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SCM_API SCM scm_make_string (SCM k, SCM chr);
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SCM_API SCM scm_string_length (SCM str);
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SCM_API SCM scm_string_ref (SCM str, SCM k);
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SCM_API SCM scm_string_set_x (SCM str, SCM k, SCM chr);
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SCM_API SCM scm_substring (SCM str, SCM start, SCM end);
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SCM_API SCM scm_substring_read_only (SCM str, SCM start, SCM end);
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SCM_API SCM scm_substring_shared (SCM str, SCM start, SCM end);
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SCM_API SCM scm_substring_copy (SCM str, SCM start, SCM end);
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SCM_API SCM scm_string_append (SCM args);
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SCM_API SCM scm_c_make_string (size_t len, SCM chr);
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SCM_API size_t scm_c_string_length (SCM str);
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SCM_API SCM scm_c_string_ref (SCM str, size_t pos);
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SCM_API void scm_c_string_set_x (SCM str, size_t pos, SCM chr);
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SCM_API SCM scm_c_substring (SCM str, size_t start, size_t end);
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SCM_API SCM scm_c_substring_read_only (SCM str, size_t start, size_t end);
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SCM_API SCM scm_c_substring_shared (SCM str, size_t start, size_t end);
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SCM_API SCM scm_c_substring_copy (SCM str, size_t start, size_t end);
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SCM_API int scm_is_string (SCM x);
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SCM_API SCM scm_from_locale_string (const char *str);
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SCM_API SCM scm_from_locale_stringn (const char *str, size_t len);
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SCM_API SCM scm_take_locale_string (char *str);
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SCM_API SCM scm_take_locale_stringn (char *str, size_t len);
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SCM_API char *scm_to_locale_string (SCM str);
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SCM_API char *scm_to_locale_stringn (SCM str, size_t *lenp);
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SCM_API size_t scm_to_locale_stringbuf (SCM str, char *buf, size_t max_len);
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SCM_API SCM scm_makfromstrs (int argc, char **argv);
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/* internal accessor functions. Arguments must be valid. */
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SCM_API SCM scm_i_make_string (size_t len, char **datap);
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SCM_API SCM scm_i_substring (SCM str, size_t start, size_t end);
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SCM_API SCM scm_i_substring_read_only (SCM str, size_t start, size_t end);
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SCM_API SCM scm_i_substring_shared (SCM str, size_t start, size_t end);
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SCM_API SCM scm_i_substring_copy (SCM str, size_t start, size_t end);
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SCM_API size_t scm_i_string_length (SCM str);
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SCM_API const char *scm_i_string_chars (SCM str);
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SCM_API char *scm_i_string_writable_chars (SCM str);
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SCM_API void scm_i_string_stop_writing (void);
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/* internal functions related to symbols. */
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SCM_API SCM scm_i_make_symbol (SCM name, scm_t_bits flags,
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unsigned long hash, SCM props);
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scm_i_c_make_symbol (const char *name, size_t len,
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scm_t_bits flags, unsigned long hash, SCM props);
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scm_i_c_take_symbol (char *name, size_t len,
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scm_t_bits flags, unsigned long hash, SCM props);
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SCM_API const char *scm_i_symbol_chars (SCM sym);
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SCM_API size_t scm_i_symbol_length (SCM sym);
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SCM_API SCM scm_i_symbol_substring (SCM sym, size_t start, size_t end);
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/* internal GC functions. */
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SCM_API SCM scm_i_string_mark (SCM str);
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SCM_API SCM scm_i_stringbuf_mark (SCM buf);
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SCM_API SCM scm_i_symbol_mark (SCM buf);
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SCM_API void scm_i_string_free (SCM str);
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SCM_API void scm_i_stringbuf_free (SCM buf);
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SCM_API void scm_i_symbol_free (SCM sym);
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/* internal utility functions. */
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SCM_API char **scm_i_allocate_string_pointers (SCM list);
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SCM_API void scm_i_free_string_pointers (char **pointers);
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SCM_API void scm_i_get_substring_spec (size_t len,
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SCM start, size_t *cstart,
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SCM end, size_t *cend);
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SCM_API SCM scm_i_take_stringbufn (char *str, size_t len);
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/* deprecated stuff */
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#if SCM_ENABLE_DEPRECATED
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SCM_API int scm_i_deprecated_stringp (SCM obj);
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SCM_API char *scm_i_deprecated_string_chars (SCM str);
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SCM_API size_t scm_i_deprecated_string_length (SCM str);
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#define SCM_STRINGP(x) scm_i_deprecated_stringp(x)
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#define SCM_STRING_CHARS(x) scm_i_deprecated_string_chars(x)
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#define SCM_STRING_LENGTH(x) scm_i_deprecated_string_length(x)
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#define SCM_STRING_UCHARS(str) ((unsigned char *)SCM_STRING_CHARS (str))
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SCM_API void scm_init_strings (void);
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#endif /* SCM_STRINGS_H */
added
removed
libguile/strings.h
