feat: Expand ByteBuffer (#7316)

Co-authored-by: clydebarrow <2366188+clydebarrow@users.noreply.github.com>
Co-authored-by: Jesse Hills <3060199+jesserockz@users.noreply.github.com>

esphome/core/bytebuffer.cpp

@@ -1,19 +1,64 @@
 #include "bytebuffer.h"
 #include <cassert>
+#include <cstring>
 
 namespace esphome {
 
-ByteBuffer ByteBuffer::create(size_t capacity) {
-  std::vector<uint8_t> data(capacity);
-  return {data};
-}
-
-ByteBuffer ByteBuffer::wrap(uint8_t *ptr, size_t len) {
+ByteBuffer ByteBuffer::wrap(const uint8_t *ptr, size_t len, Endian endianness) {
+  // there is a double copy happening here, could be optimized but at cost of clarity.
   std::vector<uint8_t> data(ptr, ptr + len);
-  return {data};
+  ByteBuffer buffer = {data};
+  buffer.endianness_ = endianness;
+  return buffer;
 }
 
-ByteBuffer ByteBuffer::wrap(std::vector<uint8_t> data) { return {std::move(data)}; }
+ByteBuffer ByteBuffer::wrap(std::vector<uint8_t> const &data, Endian endianness) {
+  ByteBuffer buffer = {data};
+  buffer.endianness_ = endianness;
+  return buffer;
+}
+
+ByteBuffer ByteBuffer::wrap(uint8_t value) {
+  ByteBuffer buffer = ByteBuffer(1);
+  buffer.put_uint8(value);
+  buffer.flip();
+  return buffer;
+}
+
+ByteBuffer ByteBuffer::wrap(uint16_t value, Endian endianness) {
+  ByteBuffer buffer = ByteBuffer(2, endianness);
+  buffer.put_uint16(value);
+  buffer.flip();
+  return buffer;
+}
+
+ByteBuffer ByteBuffer::wrap(uint32_t value, Endian endianness) {
+  ByteBuffer buffer = ByteBuffer(4, endianness);
+  buffer.put_uint32(value);
+  buffer.flip();
+  return buffer;
+}
+
+ByteBuffer ByteBuffer::wrap(uint64_t value, Endian endianness) {
+  ByteBuffer buffer = ByteBuffer(8, endianness);
+  buffer.put_uint64(value);
+  buffer.flip();
+  return buffer;
+}
+
+ByteBuffer ByteBuffer::wrap(float value, Endian endianness) {
+  ByteBuffer buffer = ByteBuffer(sizeof(float), endianness);
+  buffer.put_float(value);
+  buffer.flip();
+  return buffer;
+}
+
+ByteBuffer ByteBuffer::wrap(double value, Endian endianness) {
+  ByteBuffer buffer = ByteBuffer(sizeof(double), endianness);
+  buffer.put_double(value);
+  buffer.flip();
+  return buffer;
+}
 
 void ByteBuffer::set_limit(size_t limit) {
   assert(limit <= this->get_capacity());
@@ -27,108 +72,102 @@ void ByteBuffer::clear() {
   this->limit_ = this->get_capacity();
   this->position_ = 0;
 }
-uint16_t ByteBuffer::get_uint16() {
-  assert(this->get_remaining() >= 2);
-  uint16_t value;
-  if (endianness_ == LITTLE) {
-    value = this->data_[this->position_++];
-    value |= this->data_[this->position_++] << 8;
-  } else {
-    value = this->data_[this->position_++] << 8;
-    value |= this->data_[this->position_++];
-  }
-  return value;
+void ByteBuffer::flip() {
+  this->limit_ = this->position_;
+  this->position_ = 0;
 }
 
-uint32_t ByteBuffer::get_uint32() {
-  assert(this->get_remaining() >= 4);
-  uint32_t value;
-  if (endianness_ == LITTLE) {
-    value = this->data_[this->position_++];
-    value |= this->data_[this->position_++] << 8;
-    value |= this->data_[this->position_++] << 16;
-    value |= this->data_[this->position_++] << 24;
-  } else {
-    value = this->data_[this->position_++] << 24;
-    value |= this->data_[this->position_++] << 16;
-    value |= this->data_[this->position_++] << 8;
-    value |= this->data_[this->position_++];
-  }
-  return value;
-}
-uint32_t ByteBuffer::get_uint24() {
-  assert(this->get_remaining() >= 3);
-  uint32_t value;
-  if (endianness_ == LITTLE) {
-    value = this->data_[this->position_++];
-    value |= this->data_[this->position_++] << 8;
-    value |= this->data_[this->position_++] << 16;
-  } else {
-    value = this->data_[this->position_++] << 16;
-    value |= this->data_[this->position_++] << 8;
-    value |= this->data_[this->position_++];
-  }
-  return value;
-}
-uint32_t ByteBuffer::get_int24() {
-  auto value = this->get_uint24();
-  uint32_t mask = (~(uint32_t) 0) << 23;
-  if ((value & mask) != 0)
-    value |= mask;
-  return value;
-}
+/// Getters
 uint8_t ByteBuffer::get_uint8() {
   assert(this->get_remaining() >= 1);
   return this->data_[this->position_++];
 }
-float ByteBuffer::get_float() {
-  auto value = this->get_uint32();
-  return *(float *) &value;
+uint64_t ByteBuffer::get_uint(size_t length) {
+  assert(this->get_remaining() >= length);
+  uint64_t value = 0;
+  if (this->endianness_ == LITTLE) {
+    this->position_ += length;
+    auto index = this->position_;
+    while (length-- != 0) {
+      value <<= 8;
+      value |= this->data_[--index];
+    }
+  } else {
+    while (length-- != 0) {
+      value <<= 8;
+      value |= this->data_[this->position_++];
+    }
+  }
+  return value;
 }
+
+uint32_t ByteBuffer::get_int24() {
+  auto value = this->get_uint24();
+  uint32_t mask = (~static_cast<uint32_t>(0)) << 23;
+  if ((value & mask) != 0)
+    value |= mask;
+  return value;
+}
+float ByteBuffer::get_float() {
+  assert(this->get_remaining() >= sizeof(float));
+  auto ui_value = this->get_uint32();
+  float value;
+  memcpy(&value, &ui_value, sizeof(float));
+  return value;
+}
+double ByteBuffer::get_double() {
+  assert(this->get_remaining() >= sizeof(double));
+  auto ui_value = this->get_uint64();
+  double value;
+  memcpy(&value, &ui_value, sizeof(double));
+  return value;
+}
+std::vector<uint8_t> ByteBuffer::get_vector(size_t length) {
+  assert(this->get_remaining() >= length);
+  auto start = this->data_.begin() + this->position_;
+  this->position_ += length;
+  return {start, start + length};
+}
+
+/// Putters
 void ByteBuffer::put_uint8(uint8_t value) {
   assert(this->get_remaining() >= 1);
   this->data_[this->position_++] = value;
 }
 
-void ByteBuffer::put_uint16(uint16_t value) {
-  assert(this->get_remaining() >= 2);
+void ByteBuffer::put_uint(uint64_t value, size_t length) {
+  assert(this->get_remaining() >= length);
   if (this->endianness_ == LITTLE) {
-    this->data_[this->position_++] = (uint8_t) value;
-    this->data_[this->position_++] = (uint8_t) (value >> 8);
+    while (length-- != 0) {
+      this->data_[this->position_++] = static_cast<uint8_t>(value);
+      value >>= 8;
+    }
   } else {
-    this->data_[this->position_++] = (uint8_t) (value >> 8);
-    this->data_[this->position_++] = (uint8_t) value;
+    this->position_ += length;
+    auto index = this->position_;
+    while (length-- != 0) {
+      this->data_[--index] = static_cast<uint8_t>(value);
+      value >>= 8;
+    }
   }
 }
-void ByteBuffer::put_uint24(uint32_t value) {
-  assert(this->get_remaining() >= 3);
-  if (this->endianness_ == LITTLE) {
-    this->data_[this->position_++] = (uint8_t) value;
-    this->data_[this->position_++] = (uint8_t) (value >> 8);
-    this->data_[this->position_++] = (uint8_t) (value >> 16);
-  } else {
-    this->data_[this->position_++] = (uint8_t) (value >> 16);
-    this->data_[this->position_++] = (uint8_t) (value >> 8);
-    this->data_[this->position_++] = (uint8_t) value;
-  }
+void ByteBuffer::put_float(float value) {
+  static_assert(sizeof(float) == sizeof(uint32_t), "Float sizes other than 32 bit not supported");
+  assert(this->get_remaining() >= sizeof(float));
+  uint32_t ui_value;
+  memcpy(&ui_value, &value, sizeof(float));  // this work-around required to silence compiler warnings
+  this->put_uint32(ui_value);
 }
-void ByteBuffer::put_uint32(uint32_t value) {
-  assert(this->get_remaining() >= 4);
-  if (this->endianness_ == LITTLE) {
-    this->data_[this->position_++] = (uint8_t) value;
-    this->data_[this->position_++] = (uint8_t) (value >> 8);
-    this->data_[this->position_++] = (uint8_t) (value >> 16);
-    this->data_[this->position_++] = (uint8_t) (value >> 24);
-  } else {
-    this->data_[this->position_++] = (uint8_t) (value >> 24);
-    this->data_[this->position_++] = (uint8_t) (value >> 16);
-    this->data_[this->position_++] = (uint8_t) (value >> 8);
-    this->data_[this->position_++] = (uint8_t) value;
-  }
+void ByteBuffer::put_double(double value) {
+  static_assert(sizeof(double) == sizeof(uint64_t), "Double sizes other than 64 bit not supported");
+  assert(this->get_remaining() >= sizeof(double));
+  uint64_t ui_value;
+  memcpy(&ui_value, &value, sizeof(double));
+  this->put_uint64(ui_value);
 }
-void ByteBuffer::put_float(float value) { this->put_uint32(*(uint32_t *) &value); }
-void ByteBuffer::flip() {
-  this->limit_ = this->position_;
-  this->position_ = 0;
+void ByteBuffer::put_vector(const std::vector<uint8_t> &value) {
+  assert(this->get_remaining() >= value.size());
+  std::copy(value.begin(), value.end(), this->data_.begin() + this->position_);
+  this->position_ += value.size();
 }
 }  // namespace esphome