vrefbuffer.hpp
Go to the documentation of this file.
//
// MessagePack for C++ zero-copy buffer implementation
//
// Copyright (C) 2008-2017 FURUHASHI Sadayuki and KONDO Takatoshi
//
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
//
#ifndef MSGPACK_V1_VREFBUFFER_HPP
#define MSGPACK_V1_VREFBUFFER_HPP
#include "msgpack/v1/vrefbuffer_decl.hpp"
#include <stdexcept>
#include <algorithm>
#if defined(_MSC_VER)
// avoiding confliction std::max, std::min, and macro in windows.h
#ifndef NOMINMAX
#define NOMINMAX
#endif
#endif // defined(_MSC_VER)
#if defined(unix) || defined(__unix) || defined(__APPLE__) || defined(__OpenBSD__)
#include <sys/uio.h>
#else
struct iovec {
void *iov_base;
size_t iov_len;
};
#endif
namespace msgpack {
MSGPACK_API_VERSION_NAMESPACE(v1) {
namespace detail {
// int64, uint64, double
std::size_t const packer_max_buffer_size = 9;
} // detail
class vrefbuffer {
private:
struct chunk {
chunk* next;
};
struct inner_buffer {
size_t free;
char* ptr;
chunk* head;
};
public:
vrefbuffer(size_t ref_size = MSGPACK_VREFBUFFER_REF_SIZE,
size_t chunk_size = MSGPACK_VREFBUFFER_CHUNK_SIZE)
:m_ref_size(std::max(ref_size, detail::packer_max_buffer_size + 1)),
m_chunk_size(chunk_size)
{
size_t nfirst = (sizeof(iovec) < 72/2) ?
72 / sizeof(iovec) : 8;
iovec* array = static_cast<iovec*>(::malloc(
sizeof(iovec) * nfirst));
if(!array) {
throw std::bad_alloc();
}
m_tail = array;
m_end = array + nfirst;
m_array = array;
chunk* c = static_cast<chunk*>(::malloc(sizeof(chunk) + chunk_size));
if(!c) {
::free(array);
throw std::bad_alloc();
}
inner_buffer* const ib = &m_inner_buffer;
ib->free = chunk_size;
ib->ptr = reinterpret_cast<char*>(c) + sizeof(chunk);
ib->head = c;
c->next = MSGPACK_NULLPTR;
}
~vrefbuffer()
{
chunk* c = m_inner_buffer.head;
while(true) {
chunk* n = c->next;
::free(c);
if(n != NULL) {
c = n;
} else {
break;
}
}
::free(m_array);
}
public:
void write(const char* buf, size_t len)
{
if(len < m_ref_size) {
append_copy(buf, len);
} else {
append_ref(buf, len);
}
}
void append_ref(const char* buf, size_t len)
{
if(m_tail == m_end) {
const size_t nused = m_tail - m_array;
const size_t nnext = nused * 2;
iovec* nvec = static_cast<iovec*>(::realloc(
m_array, sizeof(iovec)*nnext));
if(!nvec) {
throw std::bad_alloc();
}
m_array = nvec;
m_end = nvec + nnext;
m_tail = nvec + nused;
}
m_tail->iov_base = const_cast<char*>(buf);
m_tail->iov_len = len;
++m_tail;
}
void append_copy(const char* buf, size_t len)
{
inner_buffer* const ib = &m_inner_buffer;
if(ib->free < len) {
size_t sz = m_chunk_size;
if(sz < len) {
sz = len;
}
chunk* c = static_cast<chunk*>(::malloc(sizeof(chunk) + sz));
if(!c) {
throw std::bad_alloc();
}
c->next = ib->head;
ib->head = c;
ib->free = sz;
ib->ptr = reinterpret_cast<char*>(c) + sizeof(chunk);
}
char* m = ib->ptr;
std::memcpy(m, buf, len);
ib->free -= len;
ib->ptr += len;
if(m_tail != m_array && m ==
static_cast<const char*>(
const_cast<const void *>((m_tail - 1)->iov_base)
) + (m_tail - 1)->iov_len) {
(m_tail - 1)->iov_len += len;
return;
} else {
append_ref( m, len);
}
}
const struct iovec* vector() const
{
return m_array;
}
size_t vector_size() const
{
return m_tail - m_array;
}
void migrate(vrefbuffer* to)
{
size_t sz = m_chunk_size;
chunk* empty = static_cast<chunk*>(::malloc(sizeof(chunk) + sz));
if(!empty) {
throw std::bad_alloc();
}
empty->next = MSGPACK_NULLPTR;
const size_t nused = m_tail - m_array;
if(to->m_tail + nused < m_end) {
const size_t tosize = to->m_tail - to->m_array;
const size_t reqsize = nused + tosize;
size_t nnext = (to->m_end - to->m_array) * 2;
while(nnext < reqsize) {
size_t tmp_nnext = nnext * 2;
if (tmp_nnext <= nnext) {
nnext = reqsize;
break;
}
nnext = tmp_nnext;
}
iovec* nvec = static_cast<iovec*>(::realloc(
to->m_array, sizeof(iovec)*nnext));
if(!nvec) {
::free(empty);
throw std::bad_alloc();
}
to->m_array = nvec;
to->m_end = nvec + nnext;
to->m_tail = nvec + tosize;
}
std::memcpy(to->m_tail, m_array, sizeof(iovec)*nused);
to->m_tail += nused;
m_tail = m_array;
inner_buffer* const ib = &m_inner_buffer;
inner_buffer* const toib = &to->m_inner_buffer;
chunk* last = ib->head;
while(last->next) {
last = last->next;
}
last->next = toib->head;
toib->head = ib->head;
if(toib->free < ib->free) {
toib->free = ib->free;
toib->ptr = ib->ptr;
}
ib->head = empty;
ib->free = sz;
ib->ptr = reinterpret_cast<char*>(empty) + sizeof(chunk);
}
void clear()
{
chunk* c = m_inner_buffer.head->next;
chunk* n;
while(c) {
n = c->next;
::free(c);
c = n;
}
inner_buffer* const ib = &m_inner_buffer;
c = ib->head;
c->next = MSGPACK_NULLPTR;
ib->free = m_chunk_size;
ib->ptr = reinterpret_cast<char*>(c) + sizeof(chunk);
m_tail = m_array;
}
#if defined(MSGPACK_USE_CPP03)
private:
vrefbuffer(const vrefbuffer&);
vrefbuffer& operator=(const vrefbuffer&);
#else // defined(MSGPACK_USE_CPP03)
vrefbuffer(const vrefbuffer&) = delete;
vrefbuffer& operator=(const vrefbuffer&) = delete;
#endif // defined(MSGPACK_USE_CPP03)
private:
iovec* m_tail;
iovec* m_end;
iovec* m_array;
size_t m_ref_size;
size_t m_chunk_size;
inner_buffer m_inner_buffer;
};
} // MSGPACK_API_VERSION_NAMESPACE(v1)
} // namespace msgpack
#endif // MSGPACK_V1_VREFBUFFER_HPP
iovec::iov_len
size_t iov_len
Definition: vrefbuffer.hpp:30
iovec::iov_base
void * iov_base
Definition: vrefbuffer.hpp:29
msgpack::vrefbuffer::vector_size
size_t vector_size() const
Definition: vrefbuffer.hpp:177
msgpack::vrefbuffer::append_ref
void append_ref(const char *buf, size_t len)
Definition: vrefbuffer.hpp:113
MSGPACK_VREFBUFFER_REF_SIZE
#define MSGPACK_VREFBUFFER_REF_SIZE
Definition: vrefbuffer_decl.hpp:18
msgpack::vrefbuffer::~vrefbuffer
~vrefbuffer()
Definition: vrefbuffer.hpp:88
msgpack::vrefbuffer::vector
const struct iovec * vector() const
Definition: vrefbuffer.hpp:172
msgpack
Definition: adaptor_base.hpp:15
msgpack::detail::packer_max_buffer_size
std::size_t const packer_max_buffer_size
Definition: vrefbuffer.hpp:42
MSGPACK_VREFBUFFER_CHUNK_SIZE
#define MSGPACK_VREFBUFFER_CHUNK_SIZE
Definition: vrefbuffer_decl.hpp:22
vrefbuffer_decl.hpp
msgpack::vrefbuffer::append_copy
void append_copy(const char *buf, size_t len)
Definition: vrefbuffer.hpp:135
iovec
Definition: vrefbuffer.hpp:28
MSGPACK_API_VERSION_NAMESPACE
#define MSGPACK_API_VERSION_NAMESPACE(ns)
Definition: versioning.hpp:58
msgpack::vrefbuffer::write
void write(const char *buf, size_t len)
Definition: vrefbuffer.hpp:104
msgpack::vrefbuffer::migrate
void migrate(vrefbuffer *to)
Definition: vrefbuffer.hpp:182
MSGPACK_NULLPTR
#define MSGPACK_NULLPTR
Definition: cpp_config_decl.hpp:35
msgpack::vrefbuffer::vrefbuffer
vrefbuffer(size_t ref_size=MSGPACK_VREFBUFFER_REF_SIZE, size_t chunk_size=MSGPACK_VREFBUFFER_CHUNK_SIZE)
Definition: vrefbuffer.hpp:56
msgpack::vrefbuffer
Definition: vrefbuffer.hpp:45
msgpack::vrefbuffer::clear
void clear()
Definition: vrefbuffer.hpp:246