101 lines
2.4 KiB
C
101 lines
2.4 KiB
C
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#ifndef _ROSE_COMPRESSION_RLE_H__
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#define _ROSE_COMPRESSION_RLE_H__
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// Copyright 2007 Google Inc. All Rights Reserved.
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// Author: sears@google.com (Rusty Sears)
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#include <limits.h>
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#include <ctype.h>
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#include "pstar.h"
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namespace rose {
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template <class TYPE>
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class Rle {
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public:
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typedef uint32_t block_index_t;
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typedef uint16_t copy_count_t;
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static const copy_count_t MAX_COPY_COUNT = USHRT_MAX;
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struct triple_t {
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slot_index_t index;
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copy_count_t copies;
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//byte foo[100]; // <-- Uncomment to test boundaries
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TYPE data;
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};
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static const int PLUGIN_ID = 1;
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inline void offset(TYPE off) { nth_block_ptr(0)->data = off; };
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inline size_t max_overrun() { return sizeof(triple_t); }
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/** @see For::append */
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inline slot_index_t append(int xid, const TYPE dat,
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byte_off_t* except, byte * exceptions,
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int * free_bytes);
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/** @see For::recordRead */
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inline TYPE *recordRead(int xid, slot_index_t slot, byte *exceptions,
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TYPE *scratch);
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/**
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This constructor initializes a new Rle region.
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@param xid the transaction that created the new region.
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*/
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Rle(int xid, void * mem): mem_(mem), last_(0) {
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*block_count_ptr() = 1;
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triple_t * n = last_block_ptr();
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n->index = 0;
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n->copies = 0;
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n->data = 0;
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}
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/**
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This constructor is called when existing RLE data is read from
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disk.
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*/
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Rle(void * mem): mem_(mem), last_(0) { }
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Rle() : mem_(0), last_(0) {}
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/**
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@see For::bytes_used();
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*/
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inline byte_off_t bytes_used() {
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return ((intptr_t)(last_block_ptr()+1))-(intptr_t)mem_;
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}
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inline void init_mem(void * mem) {
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mem_=mem;
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last_=0;
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*block_count_ptr() = 1;
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triple_t * n = nth_block_ptr(0);
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n->index = 0;
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n->copies = 0;
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n->data = 0;
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}
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inline void mem(void * mem) {
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mem_=mem;
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last_=0;
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}
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private:
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inline TYPE offset() { return nth_block_ptr(0)->dat; }
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inline block_index_t* block_count_ptr() {
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return reinterpret_cast<block_index_t*>(mem_);
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}
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inline triple_t* nth_block_ptr(block_index_t n) {
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return reinterpret_cast<triple_t*>(block_count_ptr()+1) + n;
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}
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inline triple_t* last_block_ptr() {
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return nth_block_ptr(*block_count_ptr()-1);
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}
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inline triple_t* new_block_ptr() {
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return nth_block_ptr(*block_count_ptr());
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}
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void * mem_;
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block_index_t last_;
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};
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} // namespace rose
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#endif // _ROSE_COMPRESSION_RLE_H__
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