From 3e56dfb14c86ee1f77dec212538703742c8cb16a Mon Sep 17 00:00:00 2001
From: Phil Howard <phil@gadgetoid.com>
Date: Mon, 17 May 2021 16:05:09 +0100
Subject: [PATCH] Remove unecessary manual conversion to byte arrays

---
 drivers/vl53l1x/vl53l1x.cpp | 55 +++++++++++++++++++------------------
 1 file changed, 28 insertions(+), 27 deletions(-)

diff --git a/drivers/vl53l1x/vl53l1x.cpp b/drivers/vl53l1x/vl53l1x.cpp
index d50be0ac..059b406c 100644
--- a/drivers/vl53l1x/vl53l1x.cpp
+++ b/drivers/vl53l1x/vl53l1x.cpp
@@ -162,61 +162,62 @@ namespace pimoroni {
   // Write an 8-bit register
   void VL53L1X::writeReg(uint16_t reg, uint8_t value)
   {
-    uint8_t buffer[3] = {(reg >> 8) & 0xFF, reg & 0xFF, value};
-    i2c->write_blocking(address, buffer, 3, false);
+    alignas(2) struct u16_u32_buffer {
+      uint16_t reg;
+      uint8_t value;
+    } buffer{reg, value};
+    i2c->write_blocking(address, (uint8_t *)&buffer, 3, false);
   }
 
   // Write a 16-bit register
   void VL53L1X::writeReg16Bit(uint16_t reg, uint16_t value)
   {
-    uint8_t buffer[4] = {(reg >> 8) & 0xFF, reg & 0xFF, (value >> 8) & 0xFF, value & 0xFF};
-    i2c->write_blocking(address, buffer, 4, false);
+    uint16_t buffer[2] = {reg, value};
+    i2c->write_blocking(address, (uint8_t *)buffer, 4, false);
   }
 
   // Write a 32-bit register
   void VL53L1X::writeReg32Bit(uint16_t reg, uint32_t value)
   {
-    uint8_t buffer[6] = {(reg >> 8) & 0xFF, reg & 0xFF,
-      (value >> 24) & 0xFF, (value >> 16) & 0xFF, (value >> 8) & 0xFF, value & 0xFF};
-    i2c->write_blocking(address, buffer, 6, false);
+    alignas(2) struct u16_u32_buffer {
+      uint16_t reg;
+      uint32_t value;
+    } buffer{reg, value};
+    i2c->write_blocking(address, (uint8_t *)&buffer, 6, false);
   }
 
   // Read an 8-bit register
   uint8_t VL53L1X::readReg(regAddr reg)
   {
-    uint8_t regbuf[2] = {((uint8_t)reg >> 8) & 0xFF, (uint8_t)reg & 0xFF};
-    uint8_t buffer[1];
     uint8_t value;
-    i2c->write_blocking(address, regbuf, 2, true);
-    i2c->read_blocking(address, buffer, 1, false);
-    value = buffer[0];
+    // TODO do we need to bswap reg?
+    i2c->write_blocking(address, (uint8_t *)&reg, 2, true);
+    i2c->read_blocking(address, &value, 1, false);
     return value;
   }
 
   // Read a 16-bit register
   uint16_t VL53L1X::readReg16Bit(uint16_t reg)
   {
-    uint8_t regbuf[2] = {(reg >> 8) & 0xFF, reg & 0xFF};
-    uint8_t buffer[2];
     uint16_t value;
-    reg= (reg << 8) + (reg >> 8);
-    i2c->write_blocking(address, regbuf, 2, true);
-    i2c->read_blocking(address, buffer, 2, false);
-    value= (buffer[0] << 8) + buffer[1];
-    return value;
+    // TODO do we need to bswap reg?
+    i2c->write_blocking(address, (uint8_t *)&reg, 2, true);
+    i2c->read_blocking(address, (uint8_t *)&value, 2, false);
+
+    // TODO do we need to bswap this return value?
+    return __bswap16(value);
   }
 
   // Read a 32-bit register
   uint32_t VL53L1X::readReg32Bit(uint16_t reg)
   {
-    uint8_t regbuf[2] = {(reg >> 8) & 0xFF, reg & 0xFF};
-    uint8_t buffer[4];
     uint32_t value;
     reg= (reg << 8) + (reg >> 8);
-    i2c->write_blocking(address, regbuf, 2, true);
-    i2c->read_blocking(address, buffer, 4, false);
-    value= (buffer[0] << 24) + (buffer[1] << 16) + (buffer[2] << 8) + buffer[3];
-    return value;
+    i2c->write_blocking(address, (uint8_t *)&reg, 2, true);
+    i2c->read_blocking(address, (uint8_t *)&value, 4, false);
+
+    // TODO do we need to bswap this return value?
+    return __bswap32(value);
   }
 
   // set distance mode to Short, Medium, or Long
@@ -572,9 +573,9 @@ namespace pimoroni {
   void VL53L1X::readResults()
   {
     uint16_t reg = RESULT__RANGE_STATUS;
-    uint8_t regbuf[2] = {(reg >> 8) & 0xFF, reg & 0xFF};
+    // TODO do we need to bswap reg?
     uint8_t buffer[17];
-    i2c->write_blocking(address, regbuf, 2, true);
+    i2c->write_blocking(address, (uint8_t *)&reg, 2, true);
     i2c->read_blocking(address, buffer, 17, false);
 
     results.range_status = buffer[0];