mirror of
https://github.com/jart/cosmopolitan.git
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80 lines
3.7 KiB
C
80 lines
3.7 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2020 Justine Alexandra Roberts Tunney │
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│ │
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│ This program is free software; you can redistribute it and/or modify │
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│ it under the terms of the GNU General Public License as published by │
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│ the Free Software Foundation; version 2 of the License. │
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│ │
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│ This program is distributed in the hope that it will be useful, but │
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│ WITHOUT ANY WARRANTY; without even the implied warranty of │
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│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU │
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│ General Public License for more details. │
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│ │
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│ You should have received a copy of the GNU General Public License │
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│ along with this program; if not, write to the Free Software │
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│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA │
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│ 02110-1301 USA │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/alg/alg.h"
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#include "libc/macros.h"
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#include "libc/nexgen32e/nexgen32e.h"
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#include "libc/str/str.h"
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static const int kCp437iMultimappings[] = {
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u'\n' << 8 | '\n', // NEWLINE
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u'\r' << 8 | '\r', // CARRIAGE RETURN
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u'?' << 8 | '?', // TRIGRAPH
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u'\'' << 8 | '\'', // CHARACTER LITERAL
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u'\"' << 8 | '\"', // STRING LITERAL
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u'\\' << 8 | '\\', // ESCAPE LITERAL
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u'∅' << 8 | '\0', // EMPTY SET
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u'␀' << 8 | '\0', // SYMBOL FOR NULL [sic]
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0x20A7 << 8 | 0x9E, // PESETA SIGN
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u'Π' << 8 | 0xE3, // GREEK CAPITAL LETTER PI
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u'∏' << 8 | 0xE3, // N-ARY PRODUCT
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u'∑' << 8 | 0xE4, // N-ARY SUMMATION
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u'µ' << 8 | 0xE6, // MICRO SIGN
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u'Ω' << 8 | 0xEA, // OHM SIGN
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u'∂' << 8 | 0xEB, // PARTIAL DIFFERENTIAL
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u'ϕ' << 8 | 0xED, // PHI SMALL (CLOSED FORM)
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u'ε' << 8 | 0xEE, // LATIN SMALL LETTER EPSILON
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u'∊' << 8 | 0xEE, // SMALL ELEMENT OF
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u'∈' << 8 | 0xEE, // ELEMENT-OF SIGN
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u'β' << 8 | 0xE1, // GREEK SMALL BETA
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u'ſ' << 8 | 0xF4, // LATIN SMALL LETTER LONG S
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};
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static int g_cp437i[256 + ARRAYLEN(kCp437iMultimappings)];
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/**
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* Turns CP437 unicode glyph into its binary representation.
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*
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* @param c is a unicode character
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* @return byte representation, or -1 if ch wasn't ibm cp437
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* @see bing()
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*/
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int unbing(int c) {
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int i, m, l, r;
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static bool once;
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if (!once) {
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for (i = 0; i < 256; ++i) g_cp437i[i] = kCp437[i] << 8 | i;
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memcpy(g_cp437i + 256, kCp437iMultimappings, sizeof(kCp437iMultimappings));
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insertionsort(ARRAYLEN(g_cp437i), g_cp437i);
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once = true;
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}
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l = 0;
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r = ARRAYLEN(g_cp437i) - 1;
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while (l <= r) {
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m = (l + r) >> 1;
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if ((g_cp437i[m] >> 8) < c) {
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l = m + 1;
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} else if ((g_cp437i[m] >> 8) > c) {
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r = m - 1;
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} else {
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return g_cp437i[m] & 0xff;
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}
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}
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return -1;
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}
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