From 99c775d8cbad9afe3be4ae6c9a446dde34c1f3cd Mon Sep 17 00:00:00 2001
From: Oxan van Leeuwen <oxan@oxanvanleeuwen.nl>
Date: Wed, 10 Nov 2021 19:44:01 +0100
Subject: [PATCH] Introduce encode_value/decode_value() template functions
 (#2662)

---
 esphome/components/ccs811/ccs811.cpp |  2 +-
 esphome/core/helpers.cpp             | 11 --------
 esphome/core/helpers.h               | 42 +++++++++++++++++++++++-----
 3 files changed, 36 insertions(+), 19 deletions(-)

diff --git a/esphome/components/ccs811/ccs811.cpp b/esphome/components/ccs811/ccs811.cpp
index 11a66f5100..f8cee79c55 100644
--- a/esphome/components/ccs811/ccs811.cpp
+++ b/esphome/components/ccs811/ccs811.cpp
@@ -52,7 +52,7 @@ void CCS811Component::setup() {
 
   if (this->baseline_.has_value()) {
     // baseline available, write to sensor
-    this->write_bytes(0x11, decode_uint16(*this->baseline_));
+    this->write_bytes(0x11, decode_value(*this->baseline_));
   }
 
   auto hardware_version_data = this->read_bytes<1>(0x21);
diff --git a/esphome/core/helpers.cpp b/esphome/core/helpers.cpp
index edd2f74c12..daca3ffd32 100644
--- a/esphome/core/helpers.cpp
+++ b/esphome/core/helpers.cpp
@@ -350,17 +350,6 @@ std::string str_sprintf(const char *fmt, ...) {
   return str;
 }
 
-uint16_t encode_uint16(uint8_t msb, uint8_t lsb) { return (uint16_t(msb) << 8) | uint16_t(lsb); }
-std::array<uint8_t, 2> decode_uint16(uint16_t value) {
-  uint8_t msb = (value >> 8) & 0xFF;
-  uint8_t lsb = (value >> 0) & 0xFF;
-  return {msb, lsb};
-}
-
-uint32_t encode_uint32(uint8_t msb, uint8_t byte2, uint8_t byte3, uint8_t lsb) {
-  return (uint32_t(msb) << 24) | (uint32_t(byte2) << 16) | (uint32_t(byte3) << 8) | uint32_t(lsb);
-}
-
 std::string hexencode(const uint8_t *data, uint32_t len) {
   char buf[20];
   std::string res;
diff --git a/esphome/core/helpers.h b/esphome/core/helpers.h
index 9a60d036e4..c67ad8eea3 100644
--- a/esphome/core/helpers.h
+++ b/esphome/core/helpers.h
@@ -138,13 +138,6 @@ uint8_t reverse_bits_8(uint8_t x);
 uint16_t reverse_bits_16(uint16_t x);
 uint32_t reverse_bits_32(uint32_t x);
 
-/// Encode a 16-bit unsigned integer given a most and least-significant byte.
-uint16_t encode_uint16(uint8_t msb, uint8_t lsb);
-/// Decode a 16-bit unsigned integer into an array of two values: most significant byte, least significant byte.
-std::array<uint8_t, 2> decode_uint16(uint16_t value);
-/// Encode a 32-bit unsigned integer given four bytes in MSB -> LSB order
-uint32_t encode_uint32(uint8_t msb, uint8_t byte2, uint8_t byte3, uint8_t lsb);
-
 /// Convert RGB floats (0-1) to hue (0-360) & saturation/value percentage (0-1)
 void rgb_to_hsv(float red, float green, float blue, int &hue, float &saturation, float &value);
 /// Convert hue (0-360) & saturation/value percentage (0-1) to RGB floats (0-1)
@@ -306,6 +299,41 @@ constexpr uint64_t byteswap(uint64_t n) { return __builtin_bswap64(n); }
 /// @name Bit manipulation
 ///@{
 
+/// Encode a 16-bit value given the most and least significant byte.
+constexpr uint16_t encode_uint16(uint8_t msb, uint8_t lsb) {
+  return (static_cast<uint16_t>(msb) << 8) | (static_cast<uint16_t>(lsb));
+}
+/// Encode a 32-bit value given four bytes in most to least significant byte order.
+constexpr uint32_t encode_uint32(uint8_t byte1, uint8_t byte2, uint8_t byte3, uint8_t byte4) {
+  return (static_cast<uint32_t>(byte1) << 24) | (static_cast<uint32_t>(byte2) << 16) |
+         (static_cast<uint32_t>(byte3) << 8) | (static_cast<uint32_t>(byte4));
+}
+
+/// Encode a value from its constituent bytes (from most to least significant) in an array with length sizeof(T).
+template<typename T, enable_if_t<std::is_unsigned<T>::value, int> = 0> inline T encode_value(const uint8_t *bytes) {
+  T val = 0;
+  for (size_t i = 0; i < sizeof(T); i++) {
+    val <<= 8;
+    val |= bytes[i];
+  }
+  return val;
+}
+/// Encode a value from its constituent bytes (from most to least significant) in an std::array with length sizeof(T).
+template<typename T, enable_if_t<std::is_unsigned<T>::value, int> = 0>
+inline T encode_value(const std::array<uint8_t, sizeof(T)> bytes) {
+  return encode_value<T>(bytes.data());
+}
+/// Decode a value into its constituent bytes (from most to least significant).
+template<typename T, enable_if_t<std::is_unsigned<T>::value, int> = 0>
+inline std::array<uint8_t, sizeof(T)> decode_value(T val) {
+  std::array<uint8_t, sizeof(T)> ret{};
+  for (size_t i = sizeof(T); i > 0; i--) {
+    ret[i - 1] = val & 0xFF;
+    val >>= 8;
+  }
+  return ret;
+}
+
 /// Convert a value between host byte order and big endian (most significant byte first) order.
 template<typename T, enable_if_t<std::is_unsigned<T>::value, int> = 0> constexpr T convert_big_endian(T val) {
 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__