Initial Commit

packages/foundation/data/mime/src/detection/from-magic-bytes/registry.ts

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+/**
+ * Magic-byte signature registry.
+ *
+ * Signatures are evaluated in descending priority order; the first match wins.
+ * Priority 105 = disambiguation required (container formats with multiple brands).
+ * Priority 100 = default, unambiguous magic bytes.
+ * Priority  90 = slight ambiguity (e.g. WebM / MKV share EBML).
+ * Priority  80 = deep probe (signature requires many bytes, e.g. TAR at offset 257).
+ *
+ * NOTE: registry.ts must NOT import signatures/index.ts directly — that would
+ * create a circular dependency (signatures/index.ts imports registerSignature
+ * from registry.ts). The side-effect import lives in from-magic-bytes.ts instead.
+ *
+ * @module detection/from-magic-bytes/registry
+ */
+
+/** A compiled magic-byte signature entry. */
+export interface Signature {
+    readonly mime: string;
+    readonly priority: number;
+    readonly minBytes: number;
+    readonly match: (bytes: Uint8Array) => boolean;
+}
+
+const SIGS: Signature[] = [];
+let sortedCache: readonly Signature[] | null = null;
+
+/** Register a compiled signature. Clears the sorted cache. */
+export function registerSignature(sig: Signature): void {
+    SIGS.push(sig);
+    sortedCache = null;
+}
+
+/** Returns all registered signatures sorted by descending priority. */
+export function getSignatures(): readonly Signature[] {
+    if (sortedCache === null) {
+        sortedCache = [...SIGS].sort((a, b) => b.priority - a.priority);
+    }
+    return sortedCache;
+}
+
+/**
+ * Reset all registered signatures. Intended for tests only.
+ * @internal
+ */
+export function resetSignatures(): void {
+    SIGS.length = 0;
+    sortedCache = null;
+}