1 files changed, 70 insertions, 0 deletions
diff --git a/src/range_cache.cpp b/src/range_cache.cpp
new file mode 100644
index 000000000..9701fb432
--- /dev/null
+++ b/src/range_cache.cpp
@@ -0,0 +1,70 @@
+
+// Integers only
+struct RangeValue {
+	i64 lo;
+	i64 hi;
+};
+
+struct RangeCache {
+	Array<RangeValue> ranges;
+};
+
+
+RangeCache range_cache_make(gbAllocator a) {
+	RangeCache cache = {};
+	array_init(&cache.ranges, a);
+	return cache;
+}
+
+void range_cache_destroy(RangeCache *c) {
+	array_free(&c->ranges);
+}
+
+bool range_cache_add_index(RangeCache *c, i64 index) {
+	for_array(i, c->ranges) {
+		RangeValue v = c->ranges[i];
+		if (v.lo <= index && index <= v.hi) {
+			return false;
+		}
+	}
+	RangeValue v = {index, index};
+	array_add(&c->ranges, v);
+	return true;
+}
+
+
+bool range_cache_add_range(RangeCache *c, i64 lo, i64 hi) {
+	GB_ASSERT(lo <= hi);
+	for_array(i, c->ranges) {
+		RangeValue v = c->ranges[i];
+		if (hi < v.lo) {
+			continue;
+		}
+		if (lo > v.hi) {
+			continue;
+		}
+
+		if (v.hi < hi) {
+			v.hi = hi;
+		}
+		if (lo < v.lo) {
+			v.lo = lo;
+		}
+		c->ranges[i] = v;
+		return false;
+	}
+	RangeValue v = {lo, hi};
+	array_add(&c->ranges, v);
+	return true;
+}
+
+
+bool range_cache_index_exists(RangeCache *c, i64 index) {
+	for_array(i, c->ranges) {
+		RangeValue v = c->ranges[i];
+		if (v.lo <= index && index <= v.hi) {
+			return true;
+		}
+	}
+	return false;
+}