source: trip-planner-front/node_modules/@webassemblyjs/utf8/src/decoder.js@ fa375fe

Last change on this file since fa375fe was 6a3a178, checked in by Ema <ema_spirova@…>, 3 years ago

initial commit

  • Property mode set to 100644
File size: 1.4 KB
Line 
1function con(b) {
2 if ((b & 0xc0) === 0x80) {
3 return b & 0x3f;
4 } else {
5 throw new Error("invalid UTF-8 encoding");
6 }
7}
8
9function code(min, n) {
10 if (n < min || (0xd800 <= n && n < 0xe000) || n >= 0x10000) {
11 throw new Error("invalid UTF-8 encoding");
12 } else {
13 return n;
14 }
15}
16
17export function decode(bytes) {
18 return _decode(bytes)
19 .map(x => String.fromCharCode(x))
20 .join("");
21}
22
23function _decode(bytes) {
24 if (bytes.length === 0) {
25 return [];
26 }
27
28 /**
29 * 1 byte
30 */
31 {
32 const [b1, ...bs] = bytes;
33
34 if (b1 < 0x80) {
35 return [code(0x0, b1), ..._decode(bs)];
36 }
37
38 if (b1 < 0xc0) {
39 throw new Error("invalid UTF-8 encoding");
40 }
41 }
42
43 /**
44 * 2 bytes
45 */
46 {
47 const [b1, b2, ...bs] = bytes;
48
49 if (b1 < 0xe0) {
50 return [code(0x80, ((b1 & 0x1f) << 6) + con(b2)), ..._decode(bs)];
51 }
52 }
53
54 /**
55 * 3 bytes
56 */
57 {
58 const [b1, b2, b3, ...bs] = bytes;
59
60 if (b1 < 0xf0) {
61 return [
62 code(0x800, ((b1 & 0x0f) << 12) + (con(b2) << 6) + con(b3)),
63 ..._decode(bs)
64 ];
65 }
66 }
67
68 /**
69 * 4 bytes
70 */
71 {
72 const [b1, b2, b3, b4, ...bs] = bytes;
73
74 if (b1 < 0xf8) {
75 return [
76 code(
77 0x10000,
78 ((((b1 & 0x07) << 18) + con(b2)) << 12) + (con(b3) << 6) + con(b4)
79 ),
80 ..._decode(bs)
81 ];
82 }
83 }
84
85 throw new Error("invalid UTF-8 encoding");
86}
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