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/* Modified (m) 2017 Thomas Wolff: revise Unicode and locale/wchar handling */
#include <_ansi.h>
#include <wctype.h>
#include <stdint.h>
//#include <errno.h>
#include "local.h"
/*
struct caseconv_entry describes the case conversion behaviour
of a range of Unicode characters.
It was designed to be compact for a minimal table size.
The range is first...first + diff.
Conversion behaviour for a character c in the respective range:
mode == TOLO towlower (c) = c + delta
mode == TOUP towupper (c) = c + delta
mode == TOBOTH (titling case characters)
towlower (c) = c + 1
towupper (c) = c - 1
mode == TO1 capital/small letters are alternating
delta == EVENCAP even codes are capital
delta == ODDCAP odd codes are capital
(this correlates with an even/odd first range value
as of Unicode 10.0 but we do not rely on this)
As of Unicode 10.0, the following field lengths are sufficient
first: 17 bits
diff: 8 bits
delta: 17 bits
mode: 2 bits
The reserve of 4 bits (to limit the struct to 6 bytes)
is currently added to the 'first' field;
should a future Unicode version make it necessary to expand the others,
the 'first' field could be reduced as needed, or larger ranges could
be split up (reduce limit max=255 e.g. to max=127 or max=63 in
script mkcaseconv, check increasing table size).
*/
enum {TO1, TOLO, TOUP, TOBOTH};
enum {EVENCAP, ODDCAP};
static struct caseconv_entry {
uint_least32_t first: 21;
uint_least32_t diff: 8;
uint_least32_t mode: 2;
int_least32_t delta: 17;
} __attribute__ ((packed))
caseconv_table [] = {
#include "caseconv.t"
};
#define first(ce) ce.first
#define last(ce) (ce.first + ce.diff)
/* auxiliary function for binary search in interval properties table */
static const struct caseconv_entry *
bisearch (wint_t ucs, const struct caseconv_entry *table, int max)
{
int min = 0;
int mid;
if (ucs < first(table[0]) || ucs > last(table[max]))
return 0;
while (max >= min)
{
mid = (min + max) / 2;
if (ucs > last(table[mid]))
min = mid + 1;
else if (ucs < first(table[mid]))
max = mid - 1;
else
return &table[mid];
}
return 0;
}
static wint_t
toulower (wint_t c)
{
const struct caseconv_entry * cce =
bisearch(c, caseconv_table,
sizeof(caseconv_table) / sizeof(*caseconv_table) - 1);
if (cce)
switch (cce->mode)
{
case TOLO:
return c + cce->delta;
case TOBOTH:
return c + 1;
case TO1:
switch (cce->delta)
{
case EVENCAP:
if (!(c & 1))
return c + 1;
break;
case ODDCAP:
if (c & 1)
return c + 1;
break;
default:
break;
}
default:
break;
}
return c;
}
static wint_t
touupper (wint_t c)
{
const struct caseconv_entry * cce =
bisearch(c, caseconv_table,
sizeof(caseconv_table) / sizeof(*caseconv_table) - 1);
if (cce)
switch (cce->mode)
{
case TOUP:
return c + cce->delta;
case TOBOTH:
return c - 1;
case TO1:
switch (cce->delta)
{
case EVENCAP:
if (c & 1)
return c - 1;
break;
case ODDCAP:
if (!(c & 1))
return c - 1;
break;
default:
break;
}
default:
break;
}
return c;
}
wint_t
towctrans_l (wint_t c, wctrans_t w, struct __locale_t *locale)
{
wint_t u = _jp2uc_l (c, locale);
wint_t res;
if (w == WCT_TOLOWER)
res = toulower (u);
else if (w == WCT_TOUPPER)
res = touupper (u);
else
{
// skipping the errno setting that was previously involved
// by delegating to towctrans; it was causing trouble (cygwin crash)
// and there is no errno specified for towctrans
return c;
}
if (res != u)
return _uc2jp_l (res, locale);
else
return c;
}
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