6 /* Copyright (C) 1995,1996,1997,1998,2000,2001, 2004, 2005, 2006, 2008 Free Software Foundation, Inc.
8 * This library is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public License
10 * as published by the Free Software Foundation; either version 3 of
11 * the License, or (at your option) any later version.
13 * This library is distributed in the hope that it will be useful, but
14 * WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with this library; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
26 #include "libguile/__scm.h"
30 /* String representation.
32 A string is a piece of a stringbuf. A stringbuf can be used by
33 more than one string. When a string is written to and the
34 stringbuf of that string is used by more than one string, a new
35 stringbuf is created. That is, strings are copy-on-write. This
36 behavior can be used to make the substring operation quite
39 The implementation is tuned so that mutating a string is costly,
40 but just reading it is cheap and lock-free.
42 There are also mutation-sharing strings. They refer to a part of
43 an ordinary string. Writing to a mutation-sharing string just
44 writes to the ordinary string.
47 Internal, low level interface to the character arrays
49 - Use scm_i_string_chars to get a pointer to the byte array of a
50 string for reading. Use scm_i_string_length to get the number of
51 bytes in that array. The array is not null-terminated.
53 - The array is valid as long as the corresponding SCM object is
54 protected but only until the next SCM_TICK. During such a 'safe
55 point', strings might change their representation.
57 - Use scm_i_string_writable_chars to get the same pointer as with
58 scm_i_string_chars, but for reading and writing. This is a
59 potentially costly operation since it implements the
60 copy-on-write behavior. When done with the writing, call
61 scm_i_string_stop_writing. You must do this before the next
62 SCM_TICK. (This means, before calling almost any other scm_
63 function and you can't allow throws, of course.)
65 - New strings can be created with scm_i_make_string. This gives
66 access to a writable pointer that remains valid as long as nobody
67 else makes a copy-on-write substring of the string. Do not call
68 scm_i_string_stop_writing for this pointer.
72 - SCM_STRINGP is just scm_is_string.
74 - SCM_STRING_CHARS uses scm_i_string_writable_chars and immediately
75 calls scm_i_stop_writing, hoping for the best. SCM_STRING_LENGTH
76 is the same as scm_i_string_length. SCM_STRING_CHARS will throw
77 an error for for strings that are not null-terminated.
80 SCM_API SCM
scm_string_p (SCM x
);
81 SCM_API SCM
scm_string (SCM chrs
);
82 SCM_API SCM
scm_make_string (SCM k
, SCM chr
);
83 SCM_API SCM
scm_string_length (SCM str
);
84 SCM_API SCM
scm_string_ref (SCM str
, SCM k
);
85 SCM_API SCM
scm_string_set_x (SCM str
, SCM k
, SCM chr
);
86 SCM_API SCM
scm_substring (SCM str
, SCM start
, SCM end
);
87 SCM_API SCM
scm_substring_read_only (SCM str
, SCM start
, SCM end
);
88 SCM_API SCM
scm_substring_shared (SCM str
, SCM start
, SCM end
);
89 SCM_API SCM
scm_substring_copy (SCM str
, SCM start
, SCM end
);
90 SCM_API SCM
scm_string_append (SCM args
);
92 SCM_API SCM
scm_c_make_string (size_t len
, SCM chr
);
93 SCM_API
size_t scm_c_string_length (SCM str
);
94 SCM_API
size_t scm_c_symbol_length (SCM sym
);
95 SCM_API SCM
scm_c_string_ref (SCM str
, size_t pos
);
96 SCM_API
void scm_c_string_set_x (SCM str
, size_t pos
, SCM chr
);
97 SCM_API SCM
scm_c_substring (SCM str
, size_t start
, size_t end
);
98 SCM_API SCM
scm_c_substring_read_only (SCM str
, size_t start
, size_t end
);
99 SCM_API SCM
scm_c_substring_shared (SCM str
, size_t start
, size_t end
);
100 SCM_API SCM
scm_c_substring_copy (SCM str
, size_t start
, size_t end
);
102 SCM_API
int scm_is_string (SCM x
);
103 SCM_API SCM
scm_from_locale_string (const char *str
);
104 SCM_API SCM
scm_from_locale_stringn (const char *str
, size_t len
);
105 SCM_API SCM
scm_take_locale_string (char *str
);
106 SCM_API SCM
scm_take_locale_stringn (char *str
, size_t len
);
107 SCM_API
char *scm_to_locale_string (SCM str
);
108 SCM_API
char *scm_to_locale_stringn (SCM str
, size_t *lenp
);
109 SCM_API
size_t scm_to_locale_stringbuf (SCM str
, char *buf
, size_t max_len
);
111 SCM_API SCM
scm_makfromstrs (int argc
, char **argv
);
113 /* internal accessor functions. Arguments must be valid. */
115 SCM_INTERNAL SCM
scm_i_make_string (size_t len
, char **datap
);
116 SCM_INTERNAL SCM
scm_i_substring (SCM str
, size_t start
, size_t end
);
117 SCM_INTERNAL SCM
scm_i_substring_read_only (SCM str
, size_t start
, size_t end
);
118 SCM_INTERNAL SCM
scm_i_substring_shared (SCM str
, size_t start
, size_t end
);
119 SCM_INTERNAL SCM
scm_i_substring_copy (SCM str
, size_t start
, size_t end
);
120 SCM_INTERNAL
size_t scm_i_string_length (SCM str
);
121 SCM_API
/* FIXME: not internal */ const char *scm_i_string_chars (SCM str
);
122 SCM_API
/* FIXME: not internal */ char *scm_i_string_writable_chars (SCM str
);
123 SCM_INTERNAL
void scm_i_string_stop_writing (void);
125 /* internal functions related to symbols. */
127 SCM_INTERNAL SCM
scm_i_make_symbol (SCM name
, scm_t_bits flags
,
128 unsigned long hash
, SCM props
);
130 scm_i_c_make_symbol (const char *name
, size_t len
,
131 scm_t_bits flags
, unsigned long hash
, SCM props
);
133 scm_i_c_take_symbol (char *name
, size_t len
,
134 scm_t_bits flags
, unsigned long hash
, SCM props
);
135 SCM_INTERNAL
const char *scm_i_symbol_chars (SCM sym
);
136 SCM_INTERNAL
size_t scm_i_symbol_length (SCM sym
);
137 SCM_INTERNAL SCM
scm_i_symbol_substring (SCM sym
, size_t start
, size_t end
);
139 /* internal GC functions. */
141 SCM_INTERNAL SCM
scm_i_string_mark (SCM str
);
142 SCM_INTERNAL SCM
scm_i_stringbuf_mark (SCM buf
);
143 SCM_INTERNAL SCM
scm_i_symbol_mark (SCM buf
);
144 SCM_INTERNAL
void scm_i_string_free (SCM str
);
145 SCM_INTERNAL
void scm_i_stringbuf_free (SCM buf
);
146 SCM_INTERNAL
void scm_i_symbol_free (SCM sym
);
148 /* internal utility functions. */
150 SCM_INTERNAL
char **scm_i_allocate_string_pointers (SCM list
);
151 SCM_INTERNAL
void scm_i_free_string_pointers (char **pointers
);
152 SCM_INTERNAL
void scm_i_get_substring_spec (size_t len
,
153 SCM start
, size_t *cstart
,
154 SCM end
, size_t *cend
);
155 SCM_INTERNAL SCM
scm_i_take_stringbufn (char *str
, size_t len
);
157 /* deprecated stuff */
159 #if SCM_ENABLE_DEPRECATED
161 SCM_API
int scm_i_deprecated_stringp (SCM obj
);
162 SCM_API
char *scm_i_deprecated_string_chars (SCM str
);
163 SCM_API
size_t scm_i_deprecated_string_length (SCM str
);
165 #define SCM_STRINGP(x) scm_i_deprecated_stringp(x)
166 #define SCM_STRING_CHARS(x) scm_i_deprecated_string_chars(x)
167 #define SCM_STRING_LENGTH(x) scm_i_deprecated_string_length(x)
168 #define SCM_STRING_UCHARS(str) ((unsigned char *)SCM_STRING_CHARS (str))
172 SCM_INTERNAL
void scm_init_strings (void);
174 #endif /* SCM_STRINGS_H */