1#!/usr/bin/env php
2<?php
3
4if ($argc < 2) {
5    echo "Usage: php gen_rare_cp_bitvec.php ./common_codepoints.txt\n";
6    return;
7}
8
9$bitvec = array_fill(0, (0xFFFF / 32) + 1, 0xFFFFFFFF);
10
11$input = file_get_contents($argv[1]);
12foreach (explode("\n", $input) as $line) {
13    if (false !== $hashPos = strpos($line, '#')) {
14        $line = substr($line, 0, $hashPos);
15    }
16
17    $line = trim($line);
18    if ($line === '') {
19        continue;
20    }
21
22    $range = explode("\t", $line);
23    $start = hexdec($range[0]);
24    $end   = hexdec($range[1]);
25
26    for ($i = $start; $i <= $end; $i++) {
27        $bitvec[$i >> 5] &= ~(1 << ($i & 0x1F));
28    }
29}
30
31$result = <<<'HEADER'
32/* Machine-generated file; do not edit! See gen_rare_cp_bitvec.php.
33 *
34 * The below array has one bit for each Unicode codepoint from U+0000 to U+FFFF.
35 * The bit is 1 if the codepoint is considered 'rare' for the purpose of
36 * guessing the text encoding of a string.
37 *
38 * Each 'rare' codepoint which appears in a string when it is interpreted
39 * using a candidate encoding causes the candidate encoding to be treated
40 * as less likely to be the correct one.
41 */
42
43static const uint32_t rare_codepoint_bitvec[] = {
44HEADER;
45
46for ($i = 0; $i < 0xFFFF / 32; $i++) {
47    if ($i % 8 === 0) {
48        $result .= "\n";
49    } else {
50        $result .= " ";
51    }
52
53    $result .= "0x" . str_pad(dechex($bitvec[$i]), 8, '0', STR_PAD_LEFT) . ",";
54}
55
56$result .= "\n};\n";
57
58file_put_contents(__DIR__ . '/rare_cp_bitvec.h', $result);
59
60echo "Done.\n";
61?>
62