cleanup tracker class and move helper functions

src/app/core/common.cc

@@ -58,6 +58,73 @@ bool StringReplace(std::string &str, const std::string &from,
   return true;
 }
 
+void stle(uint8_t *const p_arr, size_t const p_index, unsigned const p_val) {
+  uint8_t v = (p_val >> (8 * p_index)) & 0xff;
+
+  p_arr[p_index] = v;
+}
+
+void stle0(uint8_t *const p_arr, unsigned const p_val) {
+  stle(p_arr, 0, p_val);
+}
+
+void stle1(uint8_t *const p_arr, unsigned const p_val) {
+  stle(p_arr, 1, p_val);
+}
+
+void stle2(uint8_t *const p_arr, unsigned const p_val) {
+  stle(p_arr, 2, p_val);
+}
+
+void stle3(uint8_t *const p_arr, unsigned const p_val) {
+  stle(p_arr, 3, p_val);
+}
+void stle16b(uint8_t *const p_arr, uint16_t const p_val) {
+  stle0(p_arr, p_val);
+  stle1(p_arr, p_val);
+}
+// "Store little endian 16-bit value using a byte pointer, offset by an
+// index before dereferencing"
+void stle16b_i(uint8_t *const p_arr, size_t const p_index,
+               uint16_t const p_val) {
+  stle16b(p_arr + (p_index * 2), p_val);
+}
+// "load little endian value at the given byte offset and shift to get its
+// value relative to the base offset (powers of 256, essentially)"
+unsigned ldle(uint8_t const *const p_arr, unsigned const p_index) {
+  uint32_t v = p_arr[p_index];
+
+  v <<= (8 * p_index);
+
+  return v;
+}
+
+// Helper function to get the first byte in a little endian number
+uint32_t ldle0(uint8_t const *const p_arr) { return ldle(p_arr, 0); }
+
+// Helper function to get the second byte in a little endian number
+uint32_t ldle1(uint8_t const *const p_arr) { return ldle(p_arr, 1); }
+
+// Helper function to get the third byte in a little endian number
+uint32_t ldle2(uint8_t const *const p_arr) { return ldle(p_arr, 2); }
+
+// Helper function to get the third byte in a little endian number
+uint32_t ldle3(uint8_t const *const p_arr) { return ldle(p_arr, 3); }
+// Load little endian halfword (16-bit) dereferenced from
+uint16_t ldle16b(uint8_t const *const p_arr) {
+  uint16_t v = 0;
+
+  v |= (ldle0(p_arr) | ldle1(p_arr));
+
+  return v;
+}
+// Load little endian halfword (16-bit) dereferenced from an arrays of bytes.
+// This version provides an index that will be multiplied by 2 and added to the
+// base address.
+uint16_t ldle16b_i(uint8_t const *const p_arr, size_t const p_index) {
+  return ldle16b(p_arr + (2 * p_index));
+}
+
 }  // namespace core
 }  // namespace app
 }  // namespace yaze