libguile/strings.h

   1 /* classes: h_files */
   2
   3 #ifndef SCM_STRINGS_H
   4 #define SCM_STRINGS_H
   5
   6 /* Copyright (C) 1995,1996,1997,1998,2000,2001, 2004 Free Software Foundation, Inc.
   7  *
   8  * This library is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; either
  11  * version 2.1 of the License, or (at your option) any later version.
  12  *
  13  * This library is distributed in the hope that it will be useful,
  14  * but 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.
  17  *
  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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  21  */
  22
  23 \f
  24
  25 #include "libguile/__scm.h"
  26
  27 \f
  28
  29 /* String representation.
  30
  31    A string is a piece of a stringbuf.  A stringbuf can be used by
  32    more than one string.  When a string is written to and the
  33    stringbuf of that string is used by more than one string, a new
  34    stringbuf is created.  That is, strings are copy-on-write.  This
  35    behavior can be used to make the substring operation quite
  36    efficient.
  37
  38    The implementation is tuned so that mutating a string is costly,
  39    but just reading it is cheap and lock-free.
  40
  41    There are also mutation-sharing strings.  They refer to a part of
  42    an ordinary string.  Writing to a mutation-sharing string just
  43    writes to the ordinary string.
  44
  45
  46    Internal, low level interface to the character arrays
  47
  48    - Use scm_i_string_chars to get a pointer to the byte array of a
  49      string for reading.  Use scm_i_string_length to get the number of
  50      bytes in that array.  The array is not null-terminated.
  51
  52    - The array is valid as long as the corresponding SCM object is
  53      protected but only until the next SCM_TICK.  During such a 'safe
  54      point', strings might change their representation.
  55
  56    - Use scm_i_string_writable_chars to get the same pointer as with
  57      scm_i_string_chars, but for reading and writing.  This is a
  58      potentially costly operation since it implements the
  59      copy-on-write behavior.  When done with the writing, call
  60      scm_i_string_stop_writing.  You must do this before the next
  61      SCM_TICK.  (This means, before calling almost any other scm_
  62      function and you can't allow throws, of course.)
  63
  64    - New strings can be created with scm_i_make_string.  This gives
  65      access to a writable pointer that remains valid as long as nobody
  66      else makes a copy-on-write substring of the string.  Do not call
  67      scm_i_string_stop_writing for this pointer.
  68
  69    Legacy interface
  70
  71    - SCM_STRINGP returns false for sh-strings.
  72
  73    - SCM_STRING_CHARS uses scm_i_string_writable_chars and immediately
  74      calls scm_i_stop_writing, hoping for the best.  SCM_STRING_LENGTH
  75      is the same as scm_i_string_length.  SCM_STRINGP will only return
  76      true for strings that are null-terminated when accessed with
  77      SCM_STRING_CHARS.
  78 */
  79
  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_shared (SCM str, SCM start, SCM end);
  88 SCM_API SCM scm_substring_copy (SCM str, SCM start, SCM end);
  89 SCM_API SCM scm_string_append (SCM args);
  90
  91 SCM_API SCM scm_c_make_string (size_t len, SCM chr);
  92 SCM_API size_t scm_c_string_length (SCM str);
  93 SCM_API SCM scm_c_string_ref (SCM str, size_t pos);
  94 SCM_API void scm_c_string_set_x (SCM str, size_t pos, SCM chr);
  95 SCM_API SCM scm_c_substring (SCM str, size_t start, size_t end);
  96 SCM_API SCM scm_c_substring_shared (SCM str, size_t start, size_t end);
  97 SCM_API SCM scm_c_substring_copy (SCM str, size_t start, size_t end);
  98
  99 SCM_API int scm_is_string (SCM x);
 100 SCM_API SCM scm_from_locale_string (const char *str);
 101 SCM_API SCM scm_from_locale_stringn (const char *str, size_t len);
 102 SCM_API SCM scm_take_locale_string (char *str);
 103 SCM_API SCM scm_take_locale_stringn (char *str, size_t len);
 104 SCM_API char *scm_to_locale_string (SCM str);
 105 SCM_API char *scm_to_locale_stringn (SCM str, size_t *lenp);
 106 SCM_API size_t scm_to_locale_stringbuf (SCM str, char *buf, size_t max_len);
 107
 108 SCM_API SCM scm_makfromstrs (int argc, char **argv);
 109
 110 /* internal accessor functions.  Arguments must be valid. */
 111
 112 SCM_API SCM scm_i_make_string (size_t len, char **datap);
 113 SCM_API SCM scm_i_substring (SCM str, size_t start, size_t end);
 114 SCM_API SCM scm_i_substring_shared (SCM str, size_t start, size_t end);
 115 SCM_API SCM scm_i_substring_copy (SCM str, size_t start, size_t end);
 116 SCM_API size_t scm_i_string_length (SCM str);
 117 SCM_API const char *scm_i_string_chars (SCM str);
 118 SCM_API char *scm_i_string_writable_chars (SCM str);
 119 SCM_API void scm_i_string_stop_writing (void);
 120
 121 /* internal functions related to symbols. */
 122
 123 SCM_API SCM scm_i_make_symbol (SCM name, unsigned long hash, SCM props);
 124 SCM_API const char *scm_i_symbol_chars (SCM sym);
 125 SCM_API size_t scm_i_symbol_length (SCM sym);
 126 SCM_API SCM scm_i_symbol_substring (SCM sym, size_t start, size_t end);
 127
 128 /* internal GC functions. */
 129
 130 SCM_API SCM scm_i_string_mark (SCM str);
 131 SCM_API SCM scm_i_stringbuf_mark (SCM buf);
 132 SCM_API SCM scm_i_symbol_mark (SCM buf);
 133 SCM_API void scm_i_string_free (SCM str);
 134 SCM_API void scm_i_stringbuf_free (SCM buf);
 135 SCM_API void scm_i_symbol_free (SCM sym);
 136
 137 /* internal utility functions. */
 138
 139 SCM_API char **scm_i_allocate_string_pointers (SCM list);
 140 SCM_API void scm_i_free_string_pointers (char **pointers);
 141 SCM_API void scm_i_get_substring_spec (size_t len,
 142                                        SCM start, size_t *cstart,
 143                                        SCM end, size_t *cend);
 144
 145 /* deprecated stuff */
 146
 147 #if SCM_ENABLE_DEPRECATED
 148
 149 SCM_API int SCM_STRINGP (SCM obj);
 150 SCM_API char *SCM_STRING_CHARS (SCM str);
 151 SCM_API size_t SCM_STRING_LENGTH (SCM str);
 152 #define SCM_STRING_UCHARS ((unsigned char *)SCM_STRING_CHARS (str))
 153
 154 #endif
 155
 156 SCM_API void scm_init_strings (void);
 157
 158 #endif  /* SCM_STRINGS_H */
 159
 160 /*
 161   Local Variables:
 162   c-file-style: "gnu"
 163   End:
 164 */