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76afb429ee
Previously they were unaligned, unlike their parent strings, and so could end up with the wrong pointer tag. Observed on i686-linux-gnu, where they ended up tagged as immediates (SCM_IMP()), causing failures in TYP7 related checks. * libguile/strings.h (SCM_IMMUTABLE_STRINGBUF): align resulting buffer via SCM_ALIGNED(8).
308 lines
12 KiB
C
308 lines
12 KiB
C
#ifndef SCM_STRINGS_H
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#define SCM_STRINGS_H
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/* Copyright 1995-1998,2000-2001,2004-2006,2008-2011,2013,2015-2019,2022
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Free Software Foundation, Inc.
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This file is part of Guile.
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Guile is free software: you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published
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by the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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Guile is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
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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 Guile. If not, see
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<https://www.gnu.org/licenses/>. */
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#include <libguile/gc.h>
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#include <libguile/error.h>
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#include "libguile/inline.h"
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#include <libguile/snarf.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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efficient.
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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_is_narrow_string to determine is the string is narrow or
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wide.
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- Use scm_i_string_chars or scm_i_string_wide_chars to get a
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pointer to the byte or scm_t_wchar array of a string for reading.
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Use scm_i_string_length to get the number of characters in that
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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_start_writing to get a version of the string
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ready for reading and writing. This is a potentially costly
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operation since it implements the copy-on-write behavior. When
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done with the writing, call scm_i_string_stop_writing. You must
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do this before the next SCM_TICK. (This means, before calling
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almost any other scm_ function and you can't allow throws, of
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course.)
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- New strings can be created with scm_i_make_string or
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scm_i_make_wide_string. This gives access to a writable pointer
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that remains valid as long as nobody else makes a copy-on-write
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substring of the string. Do not call scm_i_string_stop_writing
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for this pointer.
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- Alternately, scm_i_string_ref and scm_i_string_set_x can be used
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to read and write strings without worrying about whether the
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string is narrow or wide. scm_i_string_set_x still needs to be
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bracketed by scm_i_string_start_writing and
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scm_i_string_stop_writing.
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Legacy interface
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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 strings that are not null-terminated. There is
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no wide version of this interface.
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*/
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/* A type indicating what strategy to take when string locale
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conversion is unsuccessful. */
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typedef enum
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{
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SCM_FAILED_CONVERSION_ERROR = SCM_ICONVEH_ERROR,
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SCM_FAILED_CONVERSION_QUESTION_MARK = SCM_ICONVEH_QUESTION_MARK,
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SCM_FAILED_CONVERSION_ESCAPE_SEQUENCE = SCM_ICONVEH_ESCAPE_SEQUENCE
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} scm_t_string_failed_conversion_handler;
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SCM_INTERNAL SCM scm_nullstr;
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SCM_INTERNAL scm_t_string_failed_conversion_handler
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scm_i_default_string_failed_conversion_handler (void);
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SCM_INLINE int scm_is_string (SCM x);
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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_utf8_length (SCM str);
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SCM_API SCM scm_string_bytes_per_char (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_from_stringn (const char *str, size_t len, const char *encoding,
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scm_t_string_failed_conversion_handler handler);
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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 size_t scm_c_string_utf8_length (SCM str);
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SCM_API size_t scm_c_symbol_length (SCM sym);
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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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/* Use locale encoding for user input, user output, or interacting with
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the C library. Use latin1 for ASCII, and for literals in source
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code. Use utf8 for interaction with modern libraries which deal in
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UTF-8. Otherwise use scm_to_stringn or scm_from_stringn with a
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specific encoding. */
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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 SCM scm_from_latin1_string (const char *str);
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SCM_API SCM scm_from_latin1_stringn (const char *str, size_t len);
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SCM_API char *scm_to_latin1_string (SCM str);
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SCM_API char *scm_to_latin1_stringn (SCM str, size_t *lenp);
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SCM_API char *scm_to_utf8_string (SCM str);
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SCM_API char *scm_to_utf8_stringn (SCM str, size_t *lenp);
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SCM_API SCM scm_from_utf8_string (const char *str);
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SCM_API SCM scm_from_utf8_stringn (const char *str, size_t len);
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SCM_API scm_t_wchar *scm_to_utf32_string (SCM str);
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SCM_API scm_t_wchar *scm_to_utf32_stringn (SCM str, size_t *lenp);
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SCM_API SCM scm_from_utf32_string (const scm_t_wchar *str);
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SCM_API SCM scm_from_utf32_stringn (const scm_t_wchar *str, size_t len);
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SCM_API char *scm_to_port_string (SCM str, SCM port);
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SCM_API char *scm_to_port_stringn (SCM str, size_t *lenp, SCM port);
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SCM_API SCM scm_from_port_string (const char *str, SCM port);
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SCM_API SCM scm_from_port_stringn (const char *str, size_t len, SCM port);
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SCM_API char *scm_to_stringn (SCM str, size_t *lenp, const char *encoding,
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scm_t_string_failed_conversion_handler handler);
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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_string_normalize_nfd (SCM str);
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SCM_API SCM scm_string_normalize_nfkd (SCM str);
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SCM_API SCM scm_string_normalize_nfc (SCM str);
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SCM_API SCM scm_string_normalize_nfkc (SCM str);
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SCM_API SCM scm_makfromstrs (int argc, char **argv);
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/* Snarfing support. See snarf.h. */
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#ifdef SCM_SUPPORT_STATIC_ALLOCATION
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#define SCM_IMMUTABLE_STRINGBUF(c_name, contents) \
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static SCM_UNUSED SCM_ALIGNED(8) const \
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struct \
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{ \
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scm_t_bits word_0; \
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scm_t_bits word_1; \
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const char buffer[sizeof (contents)]; \
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} \
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c_name = \
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{ \
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scm_tc7_stringbuf, \
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sizeof (contents) - 1, \
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contents \
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}
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#define SCM_IMMUTABLE_STRING(c_name, contents) \
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SCM_IMMUTABLE_STRINGBUF (scm_i_paste (c_name, _stringbuf), contents); \
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SCM_IMMUTABLE_DOUBLE_CELL (c_name, \
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scm_tc7_ro_string, \
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(scm_t_bits) &scm_i_paste (c_name, \
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_stringbuf), \
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(scm_t_bits) 0, \
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(scm_t_bits) (sizeof (contents) - 1))
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#endif /* SCM_SUPPORT_STATIC_ALLOCATION */
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/* internal constants */
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/* Type tag for read-only strings. */
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#define scm_tc7_ro_string (scm_tc7_string + 0x200)
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/* Flags for shared and wide strings. */
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#define SCM_I_STRINGBUF_F_WIDE 0x400
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#define SCM_I_STRINGBUF_F_MUTABLE 0x800
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SCM_INTERNAL void scm_i_print_stringbuf (SCM exp, SCM port,
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scm_print_state *pstate);
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/* internal accessor functions. Arguments must be valid. */
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SCM_INTERNAL SCM scm_i_make_string (size_t len, char **datap,
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int read_only_p);
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SCM_INTERNAL SCM scm_i_make_wide_string (size_t len, scm_t_wchar **datap,
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int read_only_p);
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SCM_INTERNAL SCM scm_i_substring (SCM str, size_t start, size_t end);
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SCM_INTERNAL SCM scm_i_substring_read_only (SCM str, size_t start, size_t end);
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SCM_INTERNAL SCM scm_i_substring_shared (SCM str, size_t start, size_t end);
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SCM_INTERNAL SCM scm_i_substring_copy (SCM str, size_t start, size_t end);
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SCM_INTERNAL size_t scm_i_string_length (SCM str);
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SCM_INTERNAL int scm_i_string_is_mutable (SCM str);
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SCM_API /* FIXME: not internal */ const char *scm_i_string_chars (SCM str);
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SCM_API /* FIXME: not internal */ char *scm_i_string_writable_chars (SCM str);
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SCM_INTERNAL const scm_t_wchar *scm_i_string_wide_chars (SCM str);
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SCM_INTERNAL const void *scm_i_string_data (SCM str);
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SCM_INTERNAL SCM scm_i_string_start_writing (SCM str);
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SCM_INTERNAL void scm_i_string_stop_writing (void);
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SCM_INTERNAL int scm_i_is_narrow_string (SCM str);
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SCM_INTERNAL scm_t_wchar scm_i_string_ref (SCM str, size_t x);
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SCM_INTERNAL int scm_i_string_contains_char (SCM str, char c);
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SCM_INTERNAL int scm_i_string_strcmp (SCM sstr, size_t start_x, const char *cstr);
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SCM_INTERNAL void scm_i_string_set_x (SCM str, size_t p, scm_t_wchar chr);
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/* internal functions related to symbols. */
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SCM_INTERNAL SCM scm_i_make_symbol (SCM name, scm_t_bits flags,
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unsigned long hash);
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SCM_INTERNAL const char *scm_i_symbol_chars (SCM sym);
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SCM_INTERNAL const scm_t_wchar *scm_i_symbol_wide_chars (SCM sym);
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SCM_INTERNAL size_t scm_i_symbol_length (SCM sym);
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SCM_INTERNAL int scm_i_is_narrow_symbol (SCM str);
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SCM_INTERNAL int scm_i_try_narrow_string (SCM str);
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SCM_INTERNAL SCM scm_i_symbol_substring (SCM sym, size_t start, size_t end);
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SCM_INTERNAL scm_t_wchar scm_i_symbol_ref (SCM sym, size_t x);
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SCM_INTERNAL void scm_encoding_error (const char *subr, int err,
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const char *message, SCM port, SCM chr);
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SCM_INTERNAL void scm_decoding_error (const char *subr, int err,
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const char *message, SCM port);
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/* internal utility functions. */
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SCM_INTERNAL char **scm_i_allocate_string_pointers (SCM list);
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SCM_INTERNAL 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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/* Debugging functions */
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SCM_API SCM scm_sys_string_dump (SCM);
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SCM_API SCM scm_sys_symbol_dump (SCM);
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#ifdef SCM_STRING_LENGTH_HISTOGRAM
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SCM_API SCM scm_sys_stringbuf_hist (void);
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#endif
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#if SCM_CAN_INLINE || defined SCM_INLINE_C_IMPLEMENTING_INLINES
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/* Either inlining, or being included from inline.c. */
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SCM_INLINE_IMPLEMENTATION int
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scm_is_string (SCM x)
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{
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return SCM_HAS_TYP7 (x, scm_tc7_string);
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}
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#endif
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#define SCM_VALIDATE_STRING(pos, str) \
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do { \
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SCM_ASSERT_TYPE (scm_is_string (str), str, pos, FUNC_NAME, "string"); \
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} while (0)
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SCM_INTERNAL void scm_init_strings (void);
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#endif /* SCM_STRINGS_H */
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