lua/lctype.h
Roberto Ierusalimschy 8496112a18 Better documentation for 'lctype.h'
The old documentation said that 'ltolower' only works for alphabetic
characters. However, 'l_str2d' uses it (correctly) also on dots ('.').
2020-09-03 09:52:43 -03:00

102 lines
2.1 KiB
C

/*
** $Id: lctype.h $
** 'ctype' functions for Lua
** See Copyright Notice in lua.h
*/
#ifndef lctype_h
#define lctype_h
#include "lua.h"
/*
** WARNING: the functions defined here do not necessarily correspond
** to the similar functions in the standard C ctype.h. They are
** optimized for the specific needs of Lua.
*/
#if !defined(LUA_USE_CTYPE)
#if 'A' == 65 && '0' == 48
/* ASCII case: can use its own tables; faster and fixed */
#define LUA_USE_CTYPE 0
#else
/* must use standard C ctype */
#define LUA_USE_CTYPE 1
#endif
#endif
#if !LUA_USE_CTYPE /* { */
#include <limits.h>
#include "llimits.h"
#define ALPHABIT 0
#define DIGITBIT 1
#define PRINTBIT 2
#define SPACEBIT 3
#define XDIGITBIT 4
#define MASK(B) (1 << (B))
/*
** add 1 to char to allow index -1 (EOZ)
*/
#define testprop(c,p) (luai_ctype_[(c)+1] & (p))
/*
** 'lalpha' (Lua alphabetic) and 'lalnum' (Lua alphanumeric) both include '_'
*/
#define lislalpha(c) testprop(c, MASK(ALPHABIT))
#define lislalnum(c) testprop(c, (MASK(ALPHABIT) | MASK(DIGITBIT)))
#define lisdigit(c) testprop(c, MASK(DIGITBIT))
#define lisspace(c) testprop(c, MASK(SPACEBIT))
#define lisprint(c) testprop(c, MASK(PRINTBIT))
#define lisxdigit(c) testprop(c, MASK(XDIGITBIT))
/*
** In ASCII, this 'ltolower' is correct for alphabetic characters and
** for '.'. That is enough for Lua needs. ('check_exp' ensures that
** the character either is an upper-case letter or is unchanged by
** the transformation, which holds for lower-case letters and '.'.)
*/
#define ltolower(c) \
check_exp(('A' <= (c) && (c) <= 'Z') || (c) == ((c) | ('A' ^ 'a')), \
(c) | ('A' ^ 'a'))
/* one entry for each character and for -1 (EOZ) */
LUAI_DDEC(const lu_byte luai_ctype_[UCHAR_MAX + 2];)
#else /* }{ */
/*
** use standard C ctypes
*/
#include <ctype.h>
#define lislalpha(c) (isalpha(c) || (c) == '_')
#define lislalnum(c) (isalnum(c) || (c) == '_')
#define lisdigit(c) (isdigit(c))
#define lisspace(c) (isspace(c))
#define lisprint(c) (isprint(c))
#define lisxdigit(c) (isxdigit(c))
#define ltolower(c) (tolower(c))
#endif /* } */
#endif