libinput Generic way of gathering user commandline input

libinput/in_gb.h

@@ -0,0 +1,38 @@
+#ifndef _LIBINPUT_INPUT_GAPBUFFER_H
+#define _LIBINPUT_INPUT_GAPBUFFER_H
+
+#include <stddef.h>
+
+struct in_gb {
+  char* buffer;
+  size_t size;
+  size_t gap_start;
+  size_t gap_end;
+};
+
+typedef void* (*in_gb_malloc_func_t) (void*, size_t);
+
+typedef void* (*in_gb_realloc_func_t) (void*, void*, size_t, size_t);
+
+typedef void (*in_gb_free_func_t) (void*, void*);
+
+void in_gb_init (in_gb_malloc_func_t mallocfn, void* ctx, struct in_gb* gb, size_t capacity);
+
+void in_gb_fini (in_gb_free_func_t freefn, void* ctx, struct in_gb* gb);
+
+void in_gb_move (struct in_gb* gb, size_t pos);
+
+void in_gb_insert (in_gb_realloc_func_t reallocfn, void* ctx, struct in_gb* gb, char c);
+
+void in_gb_backspace (struct in_gb* gb);
+
+void in_gb_grow (in_gb_realloc_func_t reallocfn, void* ctx, struct in_gb* gb);
+
+size_t in_gb_length (struct in_gb* gb);
+
+char* in_gb_string_at (in_gb_malloc_func_t mallocfn, void* ctx, struct in_gb* gb, size_t pos);
+
+void in_gb_concat (in_gb_realloc_func_t reallocfn, void* ctx, struct in_gb* dest,
+                   struct in_gb* src);
+
+#endif // _LIBINPUT_INPUT_GAPBUFFER_H