system for looking up static symbols

 * symbols are extracted from C header files by a TECO macro
 * macro is executed using a "minimal" version of SciTECO that does not include symbols (uses gcc's weak symbols)
 * the generated C++ code contains the symbol-name-to-define mapping as a constant sorted array and initializes the appropriate SymbolList object
 * a symbol lookup is super fast using a simple binary search in the symbol lists
 * except for object initialization, no there's no overhead for keeping the symbol lists!
 * build process is complicated by introduction of bootstrapping via sciteco-minimal

1 files changed, 47 insertions, 0 deletions

diff --git a/symbols.cpp b/symbols.cpp
new file mode 100644
index 0000000..c123ebc
--- /dev/null
+++ b/symbols.cpp
@@ -0,0 +1,47 @@
+#include <glib.h>
+
+#include "symbols.h"
+
+/*
+ * defaults for sciteco-minimal
+ */
+namespace Symbols {
+	SymbolList __attribute__((weak)) scintilla;
+}
+
+/*
+ * Since symbol lists are presorted constant arrays we can do a simple
+ * binary search.
+ */
+gint
+SymbolList::lookup(const gchar *name)
+{
+	gint left = 0;
+	gint right = size - 1;
+
+	while (left <= right) {
+		gint cur = left + (right-left)/2;
+		gint cmp = g_strcmp0(entries[cur].name, name);
+
+		if (!cmp)
+			return entries[cur].value;
+
+		if (cmp > 0)
+			right = cur-1;
+		else /* cmp < 0 */
+			left = cur+1;
+	}
+
+	return -1;
+}
+
+GList *
+SymbolList::get_glist(void)
+{
+	GList *list = NULL;
+
+	while (size--)
+		list = g_list_prepend(list, (gchar *)entries[size].name);
+
+	return list;
+}