up

electron/range.ts

@@ -0,0 +1,20 @@
+export function parseRange(
+  header: string | null,
+  size: number,
+): { start: number; end: number } | null {
+  if (!Number.isSafeInteger(size) || size <= 0) return null
+  if (header === null) return { start: 0, end: size - 1 }
+  const match = /^bytes=(\d*)-(\d*)$/.exec(header)
+  if (!match || (!match[1] && !match[2])) return null
+  const start = match[1] ? Number(match[1]) : Math.max(0, size - Number(match[2]))
+  const end = match[1] && match[2] ? Math.min(Number(match[2]), size - 1) : size - 1
+  if (
+    !Number.isSafeInteger(start) ||
+    !Number.isSafeInteger(end) ||
+    start > end ||
+    start >= size ||
+    end < 0
+  )
+    return null
+  return { start, end }
+}