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RingBuffer<> is now templated with size, buffer is now static.

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This commit is contained in:
Adam Ierymenko 2019-03-22 14:39:52 -07:00
parent af3ec000a0
commit d530356055
6 changed files with 95 additions and 247 deletions
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122
node/RingBuffer.hpp
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@ -47,40 +47,28 @@ namespace ZeroTier {
* to reduce the complexity of code needed to interact with this type of buffer.
*/
template <class T>
template <class T,size_t S>
class RingBuffer
{
private:
T * buf;
size_t size;
T buf[S];
size_t begin;
size_t end;
bool wrap;
public:
/**
* create a RingBuffer with space for up to size elements.
*/
explicit RingBuffer(size_t size)
: size(size),
RingBuffer() :
begin(0),
end(0),
wrap(false)
{
buf = new T[size];
memset(buf, 0, sizeof(T) * size);
}
~RingBuffer()
{
delete [] buf;
memset(buf,0,sizeof(T)*S);
}
/**
* @return A pointer to the underlying buffer
*/
T* get_buf()
inline T *get_buf()
{
return buf + begin;
}
@ -90,17 +78,17 @@ public:
* @param n Number of elements to copy in
* @return Number of elements we copied in
*/
size_t produce(size_t n)
inline size_t produce(size_t n)
{
n = std::min(n, getFree());
if (n == 0) {
return n;
}
const size_t first_chunk = std::min(n, size - end);
end = (end + first_chunk) % size;
const size_t first_chunk = std::min(n, S - end);
end = (end + first_chunk) % S;
if (first_chunk < n) {
const size_t second_chunk = n - first_chunk;
end = (end + second_chunk) % size;
end = (end + second_chunk) % S;
}
if (begin == end) {
wrap = true;
@ -112,17 +100,14 @@ public:
* Fast erase, O(1).
* Merely reset the buffer pointer, doesn't erase contents
*/
void reset()
{
consume(count());
}
inline void reset() { consume(count()); }
/**
* adjust buffer index pointer as if we copied data out
* @param n Number of elements we copied from the buffer
* @return Number of elements actually available from the buffer
*/
size_t consume(size_t n)
inline size_t consume(size_t n)
{
n = std::min(n, count());
if (n == 0) {
@ -131,11 +116,11 @@ public:
if (wrap) {
wrap = false;
}
const size_t first_chunk = std::min(n, size - begin);
begin = (begin + first_chunk) % size;
const size_t first_chunk = std::min(n, S - begin);
begin = (begin + first_chunk) % S;
if (first_chunk < n) {
const size_t second_chunk = n - first_chunk;
begin = (begin + second_chunk) % size;
begin = (begin + second_chunk) % S;
}
return n;
}
@ -144,19 +129,19 @@ public:
* @param data Buffer that is to be written to the ring
* @param n Number of elements to write to the buffer
*/
size_t write(const T * data, size_t n)
inline size_t write(const T * data, size_t n)
{
n = std::min(n, getFree());
if (n == 0) {
return n;
}
const size_t first_chunk = std::min(n, size - end);
const size_t first_chunk = std::min(n, S - end);
memcpy(buf + end, data, first_chunk * sizeof(T));
end = (end + first_chunk) % size;
end = (end + first_chunk) % S;
if (first_chunk < n) {
const size_t second_chunk = n - first_chunk;
memcpy(buf + end, data + first_chunk, second_chunk * sizeof(T));
end = (end + second_chunk) % size;
end = (end + second_chunk) % S;
}
if (begin == end) {
wrap = true;
@ -169,14 +154,14 @@ public:
*
* @param value A single value to be placed in the buffer
*/
void push(const T value)
inline void push(const T value)
{
if (count() == size) {
if (count() == S) {
consume(1);
}
const size_t first_chunk = std::min((size_t)1, size - end);
const size_t first_chunk = std::min((size_t)1, S - end);
*(buf + end) = value;
end = (end + first_chunk) % size;
end = (end + first_chunk) % S;
if (begin == end) {
wrap = true;
}
@ -185,14 +170,14 @@ public:
/**
* @return The most recently pushed element on the buffer
*/
T get_most_recent() { return *(buf + end); }
inline T get_most_recent() { return *(buf + end); }
/**
* @param dest Destination buffer
* @param n Size (in terms of number of elements) of the destination buffer
* @return Number of elements read from the buffer
*/
size_t read(T * dest, size_t n)
inline size_t read(T *dest,size_t n)
{
n = std::min(n, count());
if (n == 0) {
@ -201,13 +186,13 @@ public:
if (wrap) {
wrap = false;
}
const size_t first_chunk = std::min(n, size - begin);
const size_t first_chunk = std::min(n, S - begin);
memcpy(dest, buf + begin, first_chunk * sizeof(T));
begin = (begin + first_chunk) % size;
begin = (begin + first_chunk) % S;
if (first_chunk < n) {
const size_t second_chunk = n - first_chunk;
memcpy(dest + first_chunk, buf + begin, second_chunk * sizeof(T));
begin = (begin + second_chunk) % size;
begin = (begin + second_chunk) % S;
}
return n;
}
@ -217,34 +202,34 @@ public:
*
* @return The number of elements in the buffer
*/
size_t count()
inline size_t count()
{
if (end == begin) {
return wrap ? size : 0;
return wrap ? S : 0;
}
else if (end > begin) {
return end - begin;
}
else {
return size + end - begin;
return S + end - begin;
}
}
/**
* @return The number of slots that are unused in the buffer
*/
size_t getFree() { return size - count(); }
inline size_t getFree() { return S - count(); }
/**
* @return The arithmetic mean of the contents of the buffer
*/
float mean()
inline float mean()
{
size_t iterator = begin;
float subtotal = 0;
size_t curr_cnt = count();
for (size_t i=0; i<curr_cnt; i++) {
iterator = (iterator + size - 1) % curr_cnt;
iterator = (iterator + S - 1) % curr_cnt;
subtotal += (float)*(buf + iterator);
}
return curr_cnt ? subtotal / (float)curr_cnt : 0;
@ -253,14 +238,14 @@ public:
/**
* @return The arithmetic mean of the most recent 'n' elements of the buffer
*/
float mean(size_t n)
inline float mean(size_t n)
{
n = n < size ? n : size;
n = n < S ? n : S;
size_t iterator = begin;
float subtotal = 0;
size_t curr_cnt = count();
for (size_t i=0; i<n; i++) {
iterator = (iterator + size - 1) % curr_cnt;
iterator = (iterator + S - 1) % curr_cnt;
subtotal += (float)*(buf + iterator);
}
return curr_cnt ? subtotal / (float)curr_cnt : 0;
@ -269,39 +254,36 @@ public:
/**
* @return The sample standard deviation of element values
*/
float stddev() { return sqrt(variance()); }
inline float stddev() { return sqrt(variance()); }
/**
* @return The variance of element values
*/
float variance()
inline float variance()
{
size_t iterator = begin;
float cached_mean = mean();
size_t curr_cnt = count();
if (size) {
T sum_of_squared_deviations = 0;
for (size_t i=0; i<curr_cnt; i++) {
iterator = (iterator + size - 1) % curr_cnt;
float deviation = (buf[i] - cached_mean);
sum_of_squared_deviations += (deviation*deviation);
}
float variance = (float)sum_of_squared_deviations / (float)(size - 1);
return variance;
T sum_of_squared_deviations = 0;
for (size_t i=0; i<curr_cnt; i++) {
iterator = (iterator + S - 1) % curr_cnt;
float deviation = (buf[i] - cached_mean);
sum_of_squared_deviations += (deviation*deviation);
}
return 0;
float variance = (float)sum_of_squared_deviations / (float)(S - 1);
return variance;
}
/**
* @return The number of elements of zero value
*/
size_t zeroCount()
inline size_t zeroCount()
{
size_t iterator = begin;
size_t zeros = 0;
size_t curr_cnt = count();
for (size_t i=0; i<curr_cnt; i++) {
iterator = (iterator + size - 1) % curr_cnt;
iterator = (iterator + S - 1) % curr_cnt;
if (*(buf + iterator) == 0) {
zeros++;
}
@ -313,13 +295,13 @@ public:
* @param value Value to match against in buffer
* @return The number of values held in the ring buffer which match a given value
*/
size_t countValue(T value)
inline size_t countValue(T value)
{
size_t iterator = begin;
size_t cnt = 0;
size_t curr_cnt = count();
for (size_t i=0; i<curr_cnt; i++) {
iterator = (iterator + size - 1) % curr_cnt;
iterator = (iterator + S - 1) % curr_cnt;
if (*(buf + iterator) == value) {
cnt++;
}
@ -330,11 +312,11 @@ public:
/**
* Print the contents of the buffer
*/
void dump()
inline void dump()
{
size_t iterator = begin;
for (size_t i=0; i<size; i++) {
iterator = (iterator + size - 1) % size;
for (size_t i=0; i<S; i++) {
iterator = (iterator + S - 1) % S;
if (typeid(T) == typeid(int)) {
//DEBUG_INFO("buf[%2zu]=%2d", iterator, (int)*(buf + iterator));
}