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Ring buffer: Use memcpy when reallocating trivially copyable types

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This commit is contained in:
Jonathan G Rennison
2024-06-18 18:01:25 +01:00
parent 09a70f6216
commit 9fbdfaffa2
1 changed files with 60 additions and 19 deletions
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79
src/core/ring_buffer.hpp
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@@ -264,10 +264,14 @@ public:
}
this->head = 0;
this->count = other.count;
uint8_t *ptr = this->data.get();
for (const T &item : other) {
new (ptr) T(item);
ptr += sizeof(T);
if constexpr (std::is_trivially_copyable_v<T>) {
other.memcpy_to(this->data.get());
} else {
uint8_t *ptr = this->data.get();
for (const T &item : other) {
new (ptr) T(item);
ptr += sizeof(T);
}
}
}
}
@@ -338,15 +342,47 @@ public:
}
private:
uint8_t *memcpy_to(uint8_t *target, uint32_t start_pos, uint32_t end_pos) const
{
if (start_pos == end_pos) return target;
const uint8_t *start_ptr = static_cast<const uint8_t *>(this->raw_ptr_at_pos(start_pos));
const uint8_t *end_ptr = static_cast<const uint8_t *>(this->raw_ptr_at_pos(end_pos));
if (end_ptr <= start_ptr) {
/* Copy in two chunks due to wrap */
const uint8_t *buffer_end = this->data.get() + (this->capacity() * sizeof(T));
memcpy(target, start_ptr, buffer_end - start_ptr);
target += buffer_end - start_ptr;
memcpy(target, this->data.get(), end_ptr - this->data.get());
target += end_ptr - this->data.get();
} else {
/* Copy in one chunk */
memcpy(target, start_ptr, end_ptr - start_ptr);
target += end_ptr - start_ptr;
}
return target;
}
uint8_t *memcpy_to(uint8_t *target) const
{
return this->memcpy_to(target, this->head, this->head + this->count);
}
void reallocate(uint32_t new_cap)
{
const uint32_t cap = round_up_size(new_cap);
uint8_t *new_buf = MallocT<uint8_t>(cap * sizeof(T));
uint8_t *pos = new_buf;
for (T &item : *this) {
new (pos) T(std::move(item));
item.~T();
pos += sizeof(T);
if constexpr (std::is_trivially_copyable_v<T>) {
this->memcpy_to(new_buf);
} else {
uint8_t *pos = new_buf;
for (T &item : *this) {
new (pos) T(std::move(item));
item.~T();
pos += sizeof(T);
}
}
this->mask = cap - 1;
this->head = 0;
@@ -523,17 +559,22 @@ private:
/* grow container */
const uint32_t cap = round_up_size(this->count + num);
uint8_t *new_buf = MallocT<uint8_t>(cap * sizeof(T));
uint8_t *write_to = new_buf;
const uint32_t end = this->head + this->count;
for (uint32_t idx = this->head; idx != end; idx++) {
if (idx == pos) {
/* gap for inserted items */
write_to += num * sizeof(T);
if constexpr (std::is_trivially_copyable_v<T>) {
uint8_t *insert_gap = this->memcpy_to(new_buf, this->head, pos);
this->memcpy_to(insert_gap + (num * sizeof(T)), pos, this->head + this->count);
} else {
uint8_t *write_to = new_buf;
const uint32_t end = this->head + this->count;
for (uint32_t idx = this->head; idx != end; idx++) {
if (idx == pos) {
/* gap for inserted items */
write_to += num * sizeof(T);
}
T &item = *this->ptr_at_pos(idx);
new (write_to) T(std::move(item));
item.~T();
write_to += sizeof(T);
}
T &item = *this->ptr_at_pos(idx);
new (write_to) T(std::move(item));
item.~T();
write_to += sizeof(T);
}
uint32_t res = pos - this->head;
this->mask = cap - 1;