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Diffstat (limited to 'Cytore.hpp')
-rw-r--r-- | Cytore.hpp | 205 |
1 files changed, 205 insertions, 0 deletions
diff --git a/Cytore.hpp b/Cytore.hpp new file mode 100644 index 0000000..62e956c --- /dev/null +++ b/Cytore.hpp @@ -0,0 +1,205 @@ +// Copyright Notice (GNU Affero GPL) {{{ +/* Cyndir - (Awesome) Memory Mapped Dictionary + * Copyright (C) 2010 Jay Freeman (saurik) +*/ + +/* + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU Affero General Public License as + * published by the Free Software Foundation, either version 3 of the + * License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU Affero General Public License for more details. + * + * You should have received a copy of the GNU Affero General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. +*/ +// }}} + +#ifndef CYTORE_HPP +#define CYTORE_HPP + +#include <fcntl.h> + +#include <sys/mman.h> +#include <sys/stat.h> + +#include <cstdio> +#include <cstdlib> + +#include <errno.h> +#include <stdint.h> +#include <unistd.h> + +#define _assert(test) do \ + if (!(test)) { \ + fprintf(stderr, "_assert(%d:%s)@%s:%u[%s]\n", errno, #test, __FILE__, __LINE__, __FUNCTION__); \ + exit(-1); \ + } \ +while (false) + +namespace Cytore { + +static const uint32_t Magic = 'cynd'; + +struct Header { + uint32_t magic_; + uint32_t version_; + uint32_t size_; + uint32_t reserved_; +}; + +struct Block { +}; + +template <typename Target_> +class Offset { + private: + uint32_t offset_; + + public: + Offset() : + offset_(0) + { + } + + Offset(uint32_t offset) : + offset_(offset) + { + } + + Offset &operator =(uint32_t offset) { + offset_ = offset; + return *this; + } + + uint32_t GetOffset() const { + return offset_; + } + + bool IsNull() const { + return offset_ == 0; + } +}; + +template <typename Type_> +static _finline Type_ Round(Type_ value, Type_ size) { + Type_ mask(size - 1); + return value + mask & ~mask; +} + +template <typename Base_> +class File { + private: + static const unsigned Shift_ = 17; + static const size_t Block_ = 1 << Shift_; + static const size_t Mask_ = Block_ - 1; + + private: + int file_; + std::vector<uint8_t *> blocks_; + + Header &Header_() { + return *reinterpret_cast<Header *>(blocks_[0]); + } + + uint32_t &Size_() { + return Header_().size_; + } + + void Map_(size_t size) { + size_t before(blocks_.size() * Block_); + size_t extend(size - before); + + void *data(mmap(NULL, extend, PROT_READ | PROT_WRITE, MAP_FILE | MAP_SHARED, file_, before)); + for (size_t i(0); i != extend >> Shift_; ++i) + blocks_.push_back(reinterpret_cast<uint8_t *>(data) + Block_ * i); + } + + void Truncate_(size_t capacity) { + capacity = Round(capacity, Block_); + ftruncate(file_, capacity); + Map_(capacity); + } + + public: + File() : + file_(-1) + { + } + + File(const char *path) : + file_(-1) + { + Open(path); + } + + ~File() { + // XXX: this object is never deconstructed. if it were, this should unmap the memory + close(file_); + } + + size_t Capacity() const { + return blocks_.size() * Block_; + } + + void Open(const char *path) { + _assert(file_ == -1); + file_ = open(path, O_RDWR | O_CREAT | O_EXLOCK, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH); + + struct stat stat; + fstat(file_, &stat); + + size_t core(sizeof(Header) + sizeof(Base_)); + + size_t size(stat.st_size); + if (size == 0) { + Truncate_(core); + Header_().magic_ = Magic; + Size_() = core; + } else { + _assert(size >= core); + Truncate_(size); + _assert(Header_().magic_ == Magic); + _assert(Header_().version_ == 0); + } + } + + void Reserve(size_t capacity) { + if (capacity <= Capacity()) + return; + blocks_.pop_back(); + Truncate_(capacity); + } + + template <typename Target_> + Target_ &Get(uint32_t offset) { + return *reinterpret_cast<Target_ *>(blocks_[offset >> Shift_] + (offset & Mask_)); + } + + template <typename Target_> + Target_ &Get(Offset<Target_> &ref) { + return Get<Target_>(ref.GetOffset()); + } + + Base_ *operator ->() { + return &Get<Base_>(sizeof(Header)); + } + + template <typename Target_> + Offset<Target_> New(size_t extra = 0) { + size_t size(sizeof(Target_) + extra); + size = Round(size, sizeof(uintptr_t)); + Reserve(Size_() + size); + uint32_t offset(Size_()); + Size_() += size; + return Offset<Target_>(offset); + } +}; + +} + +#endif//CYTORE_HPP |