cosmopolitan/libc/fmt/unbing.c
2021-03-01 00:18:23 -08:00

82 lines
3.8 KiB
C
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/alg/alg.h"
#include "libc/macros.internal.h"
#include "libc/nexgen32e/nexgen32e.h"
#include "libc/str/str.h"
static const int kCp437iMultimappings[] = {
u'\n' << 8 | '\n', // NEWLINE
u'\r' << 8 | '\r', // CARRIAGE RETURN
u'?' << 8 | '?', // TRIGRAPH
u'\'' << 8 | '\'', // CHARACTER LITERAL
u'\"' << 8 | '\"', // STRING LITERAL
u'\\' << 8 | '\\', // ESCAPE LITERAL
u'' << 8 | '\0', // EMPTY SET
u'' << 8 | '\0', // SYMBOL FOR NULL [sic]
0x20A7 << 8 | 0x9E, // PESETA SIGN
u'Π' << 8 | 0xE3, // GREEK CAPITAL LETTER PI
u'' << 8 | 0xE3, // N-ARY PRODUCT
u'' << 8 | 0xE4, // N-ARY SUMMATION
u'µ' << 8 | 0xE6, // MICRO SIGN
u'' << 8 | 0xEA, // OHM SIGN
u'' << 8 | 0xEB, // PARTIAL DIFFERENTIAL
u'ϕ' << 8 | 0xED, // PHI SMALL (CLOSED FORM)
u'ε' << 8 | 0xEE, // LATIN SMALL LETTER EPSILON
u'' << 8 | 0xEE, // SMALL ELEMENT OF
u'' << 8 | 0xEE, // ELEMENT-OF SIGN
u'β' << 8 | 0xE1, // GREEK SMALL BETA
u'ſ' << 8 | 0xF4, // LATIN SMALL LETTER LONG S
u'·' << 8 | 0xFA // MIDDLE DOT
};
static int g_cp437i[256 + ARRAYLEN(kCp437iMultimappings)];
/**
* Turns CP437 unicode glyph into its binary representation.
*
* @param c is a unicode character
* @return byte representation, or -1 if ch wasn't ibm cp437
* @see bing()
*/
int unbing(int c) {
int m, l, r;
l = 0;
r = ARRAYLEN(g_cp437i) - 1;
while (l <= r) {
m = (l + r) >> 1;
if ((g_cp437i[m] >> 8) < c) {
l = m + 1;
} else if ((g_cp437i[m] >> 8) > c) {
r = m - 1;
} else {
return g_cp437i[m] & 0xff;
}
}
return -1;
}
static textstartup void g_cp437i_init() {
unsigned i;
for (i = 0; i < 256; ++i) g_cp437i[i] = kCp437[i] << 8 | i;
memcpy(g_cp437i + 256, kCp437iMultimappings, sizeof(kCp437iMultimappings));
djbsort(g_cp437i, ARRAYLEN(g_cp437i));
}
const void *const g_cp437i_ctor[] initarray = {g_cp437i_init};