research: preserve adopted legacy memory fixture

research/legacy-memory-gold/index.js

@@ -0,0 +1,54 @@
+/**
+ * index.js — Riverbraid Memory-Gold
+ * Invariant: MEMORY_SIGNAL_RATIO | Ring: 1
+ *
+ * Deterministic meaning-centric persistence logic.
+ */
+export const INVARIANT = "MEMORY_SIGNAL_RATIO";
+export const PETAL = "Memory-Gold";
+export const RING = 1;
+
+const MEANING_FLOOR = 0.35;
+const REDUNDANCY_CEILING = 0.40;
+const RING_BUFFER_SIZE = 32;
+const _ringBuffer = [];
+
+export function verify(input) {
+  if (typeof input?.text !== "string" || input.text.trim().length === 0) {
+    return { pass: false, signal: "memory:INVALID", reason: "input.text must be a non-empty string" };
+  }
+  if (typeof input?.tokens !== "number" || !isFinite(input.tokens) || input.tokens <= 0) {
+    return { pass: false, signal: "memory:INVALID", reason: "input.tokens must be a positive finite number" };
+  }
+  if (input.reset_buffer === true) { _ringBuffer.length = 0; }
+
+  const tokens = Math.floor(input.tokens);
+  const words = input.text.trim().split(/\s+/);
+  const uniqueWords = new Set(words);
+  const ratio = uniqueWords.size / tokens;
+
+  if (ratio < MEANING_FLOOR) {
+    return { pass: false, signal: `memory:LOW_DENSITY:ratio=${ratio.toFixed(4)}`, reason: "Density floor failure", ratio };
+  }
+
+  const freq = {};
+  for (const word of words) { freq[word] = (freq[word] ?? 0) + 1; }
+  const maxFreq = Math.max(...Object.values(freq));
+  const redundancy = maxFreq / tokens;
+
+  if (redundancy > REDUNDANCY_CEILING) {
+    return { pass: false, signal: "memory:REDUNDANT", reason: "Redundancy ceiling failure", ratio };
+  }
+
+  const normalized = input.text.trim().toLowerCase();
+  if (_ringBuffer.includes(normalized)) {
+    return { pass: false, signal: "memory:DUPLICATE", reason: "Duplicate rejection", ratio };
+  }
+
+  _ringBuffer.push(normalized);
+  if (_ringBuffer.length > RING_BUFFER_SIZE) { _ringBuffer.shift(); }
+
+  return { pass: true, signal: `memory:COMMITTED:ratio=${ratio.toFixed(4)}`, reason: "Signal meets floor", ratio };
+}
+
+export function getBufferDepth() { return _ringBuffer.length; }