tabs and tab overview

vt.h

@@ -0,0 +1,28 @@
+#pragma once
+
+#include <limits.h>
+#include <stdint.h>
+#include <stddef.h>
+
+#include "terminal.h"
+
+void vt_from_slave(struct terminal *term, const uint8_t *data, size_t len);
+
+static inline int
+vt_param_get(const struct terminal *term, size_t idx, int default_value)
+{
+    /*
+     * We zero excess bits in parsed param values. In most cases this will
+     * effectively be a no-op; but it prevents negative returns for edge
+     * cases involving unusually large values.
+     */
+    static_assert(INT_MAX >= 0x7fffffff, "POSIX requires INT_MAX >= 0x7fffffff");
+    const unsigned value_mask = 0x7fffffff;
+
+    if (term->vt.params.idx > idx) {
+        unsigned value = term->vt.params.v[idx].value & value_mask;
+        return value != 0 ? (int)value : default_value;
+    }
+
+    return default_value;
+}