| 1 | // Copyright 2017-2022 @polkadot/util authors & contributors
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| 2 | // SPDX-License-Identifier: Apache-2.0
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| 3 | // Adapted from https://github.com/JulienPalard/is_utf8/blob/master/is_utf8.c
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| 4 | import { u8aToU8a } from "../u8a/toU8a.js";
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| 5 | import { isString } from "./string.js";
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| 6 | /**
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| 7 | * @name isUtf8
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| 8 | * @summary Tests if the input is valid Utf8
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| 9 | * @description
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| 10 | * Checks to see if the input string or Uint8Array is valid Utf8
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| 11 | */
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| 12 |
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| 13 | export function isUtf8(value) {
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| 14 | if (!value) {
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| 15 | return isString(value);
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| 16 | }
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| 17 |
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| 18 | const u8a = u8aToU8a(value);
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| 19 | const len = u8a.length;
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| 20 | let i = 0;
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| 21 |
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| 22 | while (i < len) {
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| 23 | if (u8a[i] <= 0x7F)
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| 24 | /* 00..7F */
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| 25 | {
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| 26 | i += 1;
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| 27 | } else if (u8a[i] >= 0xC2 && u8a[i] <= 0xDF)
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| 28 | /* C2..DF 80..BF */
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| 29 | {
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| 30 | if (i + 1 < len)
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| 31 | /* Expect a 2nd byte */
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| 32 | {
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| 33 | if (u8a[i + 1] < 0x80 || u8a[i + 1] > 0xBF) {
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| 34 | // *message = "After a first byte between C2 and DF, expecting a 2nd byte between 80 and BF";
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| 35 | // *faulty_bytes = 2;
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| 36 | return false;
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| 37 | }
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| 38 | } else {
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| 39 | // *message = "After a first byte between C2 and DF, expecting a 2nd byte.";
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| 40 | // *faulty_bytes = 1;
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| 41 | return false;
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| 42 | }
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| 43 |
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| 44 | i += 2;
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| 45 | } else if (u8a[i] === 0xE0)
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| 46 | /* E0 A0..BF 80..BF */
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| 47 | {
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| 48 | if (i + 2 < len)
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| 49 | /* Expect a 2nd and 3rd byte */
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| 50 | {
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| 51 | if (u8a[i + 1] < 0xA0 || u8a[i + 1] > 0xBF) {
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| 52 | // *message = "After a first byte of E0, expecting a 2nd byte between A0 and BF.";
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| 53 | // *faulty_bytes = 2;
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| 54 | return false;
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| 55 | }
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| 56 |
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| 57 | if (u8a[i + 2] < 0x80 || u8a[i + 2] > 0xBF) {
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| 58 | // *message = "After a first byte of E0, expecting a 3nd byte between 80 and BF.";
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| 59 | // *faulty_bytes = 3;
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| 60 | return false;
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| 61 | }
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| 62 | } else {
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| 63 | // *message = "After a first byte of E0, expecting two following bytes.";
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| 64 | // *faulty_bytes = 1;
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| 65 | return false;
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| 66 | }
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| 67 |
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| 68 | i += 3;
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| 69 | } else if (u8a[i] >= 0xE1 && u8a[i] <= 0xEC)
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| 70 | /* E1..EC 80..BF 80..BF */
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| 71 | {
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| 72 | if (i + 2 < len)
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| 73 | /* Expect a 2nd and 3rd byte */
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| 74 | {
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| 75 | if (u8a[i + 1] < 0x80 || u8a[i + 1] > 0xBF) {
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| 76 | // *message = "After a first byte between E1 and EC, expecting the 2nd byte between 80 and BF.";
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| 77 | // *faulty_bytes = 2;
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| 78 | return false;
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| 79 | }
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| 80 |
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| 81 | if (u8a[i + 2] < 0x80 || u8a[i + 2] > 0xBF) {
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| 82 | // *message = "After a first byte between E1 and EC, expecting the 3rd byte between 80 and BF.";
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| 83 | // *faulty_bytes = 3;
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| 84 | return false;
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| 85 | }
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| 86 | } else {
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| 87 | // *message = "After a first byte between E1 and EC, expecting two following bytes.";
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| 88 | // *faulty_bytes = 1;
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| 89 | return false;
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| 90 | }
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| 91 |
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| 92 | i += 3;
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| 93 | } else if (u8a[i] === 0xED)
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| 94 | /* ED 80..9F 80..BF */
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| 95 | {
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| 96 | if (i + 2 < len)
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| 97 | /* Expect a 2nd and 3rd byte */
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| 98 | {
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| 99 | if (u8a[i + 1] < 0x80 || u8a[i + 1] > 0x9F) {
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| 100 | // *message = "After a first byte of ED, expecting 2nd byte between 80 and 9F.";
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| 101 | // *faulty_bytes = 2;
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| 102 | return false;
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| 103 | }
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| 104 |
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| 105 | if (u8a[i + 2] < 0x80 || u8a[i + 2] > 0xBF) {
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| 106 | // *message = "After a first byte of ED, expecting 3rd byte between 80 and BF.";
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| 107 | // *faulty_bytes = 3;
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| 108 | return false;
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| 109 | }
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| 110 | } else {
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| 111 | // *message = "After a first byte of ED, expecting two following bytes.";
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| 112 | // *faulty_bytes = 1;
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| 113 | return false;
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| 114 | }
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| 115 |
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| 116 | i += 3;
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| 117 | } else if (u8a[i] >= 0xEE && u8a[i] <= 0xEF)
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| 118 | /* EE..EF 80..BF 80..BF */
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| 119 | {
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| 120 | if (i + 2 < len)
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| 121 | /* Expect a 2nd and 3rd byte */
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| 122 | {
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| 123 | if (u8a[i + 1] < 0x80 || u8a[i + 1] > 0xBF) {
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| 124 | // *message = "After a first byte between EE and EF, expecting 2nd byte between 80 and BF.";
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| 125 | // *faulty_bytes = 2;
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| 126 | return false;
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| 127 | }
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| 128 |
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| 129 | if (u8a[i + 2] < 0x80 || u8a[i + 2] > 0xBF) {
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| 130 | // *message = "After a first byte between EE and EF, expecting 3rd byte between 80 and BF.";
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| 131 | // *faulty_bytes = 3;
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| 132 | return false;
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| 133 | }
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| 134 | } else {
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| 135 | // *message = "After a first byte between EE and EF, two following bytes.";
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| 136 | // *faulty_bytes = 1;
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| 137 | return false;
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| 138 | }
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| 139 |
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| 140 | i += 3;
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| 141 | } else if (u8a[i] === 0xF0)
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| 142 | /* F0 90..BF 80..BF 80..BF */
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| 143 | {
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| 144 | if (i + 3 < len)
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| 145 | /* Expect a 2nd, 3rd 3th byte */
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| 146 | {
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| 147 | if (u8a[i + 1] < 0x90 || u8a[i + 1] > 0xBF) {
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| 148 | // *message = "After a first byte of F0, expecting 2nd byte between 90 and BF.";
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| 149 | // *faulty_bytes = 2;
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| 150 | return false;
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| 151 | }
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| 152 |
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| 153 | if (u8a[i + 2] < 0x80 || u8a[i + 2] > 0xBF) {
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| 154 | // *message = "After a first byte of F0, expecting 3rd byte between 80 and BF.";
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| 155 | // *faulty_bytes = 3;
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| 156 | return false;
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| 157 | }
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| 158 |
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| 159 | if (u8a[i + 3] < 0x80 || u8a[i + 3] > 0xBF) {
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| 160 | // *message = "After a first byte of F0, expecting 4th byte between 80 and BF.";
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| 161 | // *faulty_bytes = 4;
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| 162 | return false;
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| 163 | }
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| 164 | } else {
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| 165 | // *message = "After a first byte of F0, expecting three following bytes.";
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| 166 | // *faulty_bytes = 1;
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| 167 | return false;
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| 168 | }
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| 169 |
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| 170 | i += 4;
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| 171 | } else if (u8a[i] >= 0xF1 && u8a[i] <= 0xF3)
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| 172 | /* F1..F3 80..BF 80..BF 80..BF */
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| 173 | {
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| 174 | if (i + 3 < len)
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| 175 | /* Expect a 2nd, 3rd 3th byte */
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| 176 | {
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| 177 | if (u8a[i + 1] < 0x80 || u8a[i + 1] > 0xBF) {
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| 178 | // *message = "After a first byte of F1, F2, or F3, expecting a 2nd byte between 80 and BF.";
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| 179 | // *faulty_bytes = 2;
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| 180 | return false;
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| 181 | }
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| 182 |
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| 183 | if (u8a[i + 2] < 0x80 || u8a[i + 2] > 0xBF) {
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| 184 | // *message = "After a first byte of F1, F2, or F3, expecting a 3rd byte between 80 and BF.";
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| 185 | // *faulty_bytes = 3;
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| 186 | return false;
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| 187 | }
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| 188 |
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| 189 | if (u8a[i + 3] < 0x80 || u8a[i + 3] > 0xBF) {
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| 190 | // *message = "After a first byte of F1, F2, or F3, expecting a 4th byte between 80 and BF.";
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| 191 | // *faulty_bytes = 4;
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| 192 | return false;
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| 193 | }
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| 194 | } else {
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| 195 | // *message = "After a first byte of F1, F2, or F3, expecting three following bytes.";
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| 196 | // *faulty_bytes = 1;
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| 197 | return false;
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| 198 | }
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| 199 |
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| 200 | i += 4;
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| 201 | } else if (u8a[i] === 0xF4)
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| 202 | /* F4 80..8F 80..BF 80..BF */
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| 203 | {
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| 204 | if (i + 3 < len)
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| 205 | /* Expect a 2nd, 3rd 3th byte */
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| 206 | {
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| 207 | if (u8a[i + 1] < 0x80 || u8a[i + 1] > 0x8F) {
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| 208 | // *message = "After a first byte of F4, expecting 2nd byte between 80 and 8F.";
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| 209 | // *faulty_bytes = 2;
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| 210 | return false;
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| 211 | }
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| 212 |
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| 213 | if (u8a[i + 2] < 0x80 || u8a[i + 2] > 0xBF) {
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| 214 | // *message = "After a first byte of F4, expecting 3rd byte between 80 and BF.";
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| 215 | // *faulty_bytes = 3;
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| 216 | return false;
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| 217 | }
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| 218 |
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| 219 | if (u8a[i + 3] < 0x80 || u8a[i + 3] > 0xBF) {
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| 220 | // *message = "After a first byte of F4, expecting 4th byte between 80 and BF.";
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| 221 | // *faulty_bytes = 4;
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| 222 | return false;
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| 223 | }
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| 224 | } else {
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| 225 | // *message = "After a first byte of F4, expecting three following bytes.";
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| 226 | // *faulty_bytes = 1;
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| 227 | return false;
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| 228 | }
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| 229 |
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| 230 | i += 4;
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| 231 | } else {
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| 232 | // *message = "Expecting bytes in the following ranges: 00..7F C2..F4.";
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| 233 | // *faulty_bytes = 1;
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| 234 | return false;
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| 235 | }
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| 236 | }
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| 237 |
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| 238 | return true;
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| 239 | } |
| \ | No newline at end of file |