File size: 2,495 Bytes
78d0c37 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 | export type ArtifactBase64Payload = {
data?: string;
sizeBytes: number;
};
export function mimeFromDataUrl(value: string): string | undefined {
const match = /^data:([^;,]+)(?:;[^,]*)?,/i.exec(value.trim());
return match?.[1]?.toLowerCase();
}
export function base64FromDataUrl(value: string): string | undefined {
const trimmed = value.trim();
const commaIndex = trimmed.indexOf(",");
if (commaIndex < 0 || trimmed.slice(0, 5).toLowerCase() !== "data:") {
return undefined;
}
const metadata = trimmed.slice(0, commaIndex).toLowerCase();
if (!metadata.includes(";base64")) {
return undefined;
}
return trimmed.slice(commaIndex + 1);
}
function isBase64Whitespace(value: string): boolean {
return value === " " || value === "\n" || value === "\r" || value === "\t";
}
function isArtifactBase64DataChar(value: string): boolean {
const code = value.charCodeAt(0);
return (
(code >= 0x41 && code <= 0x5a) ||
(code >= 0x61 && code <= 0x7a) ||
(code >= 0x30 && code <= 0x39) ||
value === "+" ||
value === "/" ||
value === "-" ||
value === "_"
);
}
function normalizeArtifactBase64Char(value: string): string {
if (value === "-") {
return "+";
}
if (value === "_") {
return "/";
}
return value;
}
export function readArtifactBase64Payload(
value: string | undefined,
opts: { includeData: boolean },
): ArtifactBase64Payload | undefined {
if (value === undefined) {
return undefined;
}
let encodedLength = 0;
let padding = 0;
let sawPadding = false;
let data = opts.includeData ? "" : undefined;
for (const char of value) {
if (isBase64Whitespace(char)) {
continue;
}
if (char === "=") {
padding += 1;
if (padding > 2) {
return undefined;
}
sawPadding = true;
encodedLength += 1;
if (data !== undefined) {
data += char;
}
continue;
}
if (sawPadding || !isArtifactBase64DataChar(char)) {
return undefined;
}
encodedLength += 1;
if (data !== undefined) {
data += normalizeArtifactBase64Char(char);
}
}
const remainder = encodedLength % 4;
if ((padding > 0 && remainder !== 0) || remainder === 1) {
return undefined;
}
if (data !== undefined && padding === 0 && remainder > 0) {
data += "=".repeat(4 - remainder);
}
return {
...(data !== undefined ? { data } : {}),
sizeBytes: Math.max(0, Math.floor((encodedLength * 3) / 4) - padding),
};
}
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