Add option to change Header layout

HeaderLayout.h

@@ -0,0 +1,54 @@
+#ifndef HEADER_HeaderLayout
+#define HEADER_HeaderLayout
+/*
+htop - HeaderLayout.h
+(C) 2021 htop dev team
+Released under the GNU GPLv2, see the COPYING file
+in the source distribution for its full text.
+*/
+
+#include <assert.h>
+#include <stddef.h>
+#include <stdint.h>
+
+#include "Macros.h"
+
+
+typedef enum HeaderLayout_ {
+   HF_TWO_50_50,
+   HF_TWO_33_67,
+   HF_TWO_67_33,
+   HF_THREE_33_34_33,
+   HF_THREE_25_25_50,
+   HF_THREE_25_50_25,
+   HF_THREE_50_25_25,
+   HF_THREE_40_20_40,
+   HF_FOUR_25_25_25_25,
+   LAST_HEADER_LAYOUT
+} HeaderLayout;
+
+static const struct {
+   uint8_t columns;
+   const uint8_t widths[4];
+   const char* description;
+} HeaderLayout_layouts[LAST_HEADER_LAYOUT] = {
+   [HF_TWO_50_50]        = { 2, { 50, 50,  0,  0 }, "2 columns - 50/50 (default)", },
+   [HF_TWO_33_67]        = { 2, { 33, 67,  0,  0 }, "2 columns - 33/67", },
+   [HF_TWO_67_33]        = { 2, { 67, 33,  0,  0 }, "2 columns - 67/33", },
+   [HF_THREE_33_34_33]   = { 3, { 33, 34, 33,  0 }, "3 columns - 33/34/33", },
+   [HF_THREE_25_25_50]   = { 3, { 25, 25, 50,  0 }, "3 columns - 25/25/50", },
+   [HF_THREE_25_50_25]   = { 3, { 25, 50, 25,  0 }, "3 columns - 25/50/25", },
+   [HF_THREE_50_25_25]   = { 3, { 50, 25, 25,  0 }, "3 columns - 50/25/25", },
+   [HF_THREE_40_20_40]   = { 3, { 40, 20, 40,  0 }, "3 columns - 40/20/40", },
+   [HF_FOUR_25_25_25_25] = { 4, { 25, 25, 25, 25 }, "4 columns - 25/25/25/25", },
+};
+
+static inline size_t HeaderLayout_getColumns(HeaderLayout hLayout) {
+   /* assert the layout is initialized */
+   assert(0 <= hLayout);
+   assert(hLayout < LAST_HEADER_LAYOUT);
+   assert(HeaderLayout_layouts[hLayout].description[0]);
+   return HeaderLayout_layouts[hLayout].columns;
+}
+
+#endif /* HEADER_HeaderLayout */