1/* 2 * Copyright (c) 2001-2005 The Regents of The University of Michigan 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions are 7 * met: redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer; --- 23 unchanged lines hidden (view full) --- 32#define __BASE__CHUNK_GENERATOR_HH__ 33 34/** 35 * @file 36 * Declaration and inline definition of ChunkGenerator object. 37 */ 38 39#include <algorithm> |
40 |
41#include "base/intmath.hh" |
42#include "base/types.hh" |
43 44/** 45 * This class takes an arbitrary memory region (address/length pair) 46 * and generates a series of appropriately (e.g. block- or page-) 47 * aligned chunks covering the same region. 48 * 49 * Example usage: 50 --- 6 unchanged lines hidden (view full) --- 57class ChunkGenerator 58{ 59 private: 60 /** The starting address of the current chunk. */ 61 Addr curAddr; 62 /** The starting address of the next chunk (after the current one). */ 63 Addr nextAddr; 64 /** The size of the current chunk (in bytes). */ |
65 unsigned curSize; |
66 /** The number of bytes remaining in the region after the current chunk. */ |
67 unsigned sizeLeft; |
68 /** The start address so we can calculate offset in writing block. */ 69 const Addr startAddr; 70 /** The maximum chunk size, e.g., the cache block size or page size. */ |
71 const unsigned chunkSize; |
72 73 public: 74 /** 75 * Constructor. 76 * @param _startAddr The starting address of the region. 77 * @param totalSize The total size of the region. 78 * @param _chunkSize The size/alignment of chunks into which 79 * the region should be decomposed. 80 */ |
81 ChunkGenerator(Addr _startAddr, unsigned totalSize, unsigned _chunkSize) |
82 : startAddr(_startAddr), chunkSize(_chunkSize) 83 { 84 // chunkSize must be a power of two 85 assert(chunkSize == 0 || isPowerOf2(chunkSize)); 86 assert(totalSize >= 0); 87 88 // set up initial chunk. 89 curAddr = startAddr; --- 8 unchanged lines hidden (view full) --- 98 nextAddr = roundUp(startAddr, chunkSize); 99 if (curAddr == nextAddr) { 100 // ... even if startAddr is already chunk-aligned 101 nextAddr += chunkSize; 102 } 103 } 104 105 // how many bytes are left between curAddr and the end of this chunk? |
106 unsigned left_in_chunk = nextAddr - curAddr; |
107 curSize = std::min(totalSize, left_in_chunk); 108 sizeLeft = totalSize - curSize; 109 } 110 111 /** Return starting address of current chunk. */ |
112 Addr addr() const { return curAddr; } |
113 /** Return size in bytes of current chunk. */ |
114 unsigned size() const { return curSize; } |
115 116 /** Number of bytes we have already chunked up. */ |
117 unsigned complete() const { return curAddr - startAddr; } 118 |
119 /** 120 * Are we done? That is, did the last call to next() advance 121 * past the end of the region? 122 * @return True if yes, false if more to go. 123 */ |
124 bool done() const { return (curSize == 0); } |
125 126 /** 127 * Advance generator to next chunk. 128 * @return True if successful, false if unsuccessful 129 * (because we were at the last chunk). 130 */ |
131 bool 132 next() |
133 { 134 if (sizeLeft == 0) { 135 curSize = 0; 136 return false; 137 } 138 139 curAddr = nextAddr; 140 curSize = std::min(sizeLeft, chunkSize); 141 sizeLeft -= curSize; 142 nextAddr += curSize; 143 return true; 144 } 145}; 146 147#endif // __BASE__CHUNK_GENERATOR_HH__ |