js/src/jit/BitSet.cpp

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
   2  * vim: set ts=8 sts=2 et sw=2 tw=80:
   3  * This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "jit/BitSet.h"
   8
   9 #include <string.h>
  10
  11 #include "jit/JitAllocPolicy.h"
  12
  13 using namespace js;
  14 using namespace js::jit;
  15
  16 bool BitSet::init(TempAllocator& alloc) {
  17   size_t sizeRequired = numWords() * sizeof(*bits_);
  18
  19   bits_ = (uint32_t*)alloc.allocate(sizeRequired);
  20   if (!bits_) {
  21     return false;
  22   }
  23
  24   memset(bits_, 0, sizeRequired);
  25
  26   return true;
  27 }
  28
  29 bool BitSet::empty() const {
  30   MOZ_ASSERT(bits_);
  31   const uint32_t* bits = bits_;
  32   for (unsigned int i = 0, e = numWords(); i < e; i++) {
  33     if (bits[i]) {
  34       return false;
  35     }
  36   }
  37   return true;
  38 }
  39
  40 void BitSet::insertAll(const BitSet& other) {
  41   MOZ_ASSERT(bits_);
  42   MOZ_ASSERT(other.numBits_ == numBits_);
  43   MOZ_ASSERT(other.bits_);
  44
  45   uint32_t* bits = bits_;
  46   const uint32_t* otherBits = other.bits_;
  47   for (unsigned int i = 0, e = numWords(); i < e; i++) {
  48     bits[i] |= otherBits[i];
  49   }
  50 }
  51
  52 void BitSet::removeAll(const BitSet& other) {
  53   MOZ_ASSERT(bits_);
  54   MOZ_ASSERT(other.numBits_ == numBits_);
  55   MOZ_ASSERT(other.bits_);
  56
  57   uint32_t* bits = bits_;
  58   const uint32_t* otherBits = other.bits_;
  59   for (unsigned int i = 0, e = numWords(); i < e; i++) {
  60     bits[i] &= ~otherBits[i];
  61   }
  62 }
  63
  64 void BitSet::intersect(const BitSet& other) {
  65   MOZ_ASSERT(bits_);
  66   MOZ_ASSERT(other.numBits_ == numBits_);
  67   MOZ_ASSERT(other.bits_);
  68
  69   uint32_t* bits = bits_;
  70   const uint32_t* otherBits = other.bits_;
  71   for (unsigned int i = 0, e = numWords(); i < e; i++) {
  72     bits[i] &= otherBits[i];
  73   }
  74 }
  75
  76 // returns true if the intersection caused the contents of the set to change.
  77 bool BitSet::fixedPointIntersect(const BitSet& other) {
  78   MOZ_ASSERT(bits_);
  79   MOZ_ASSERT(other.numBits_ == numBits_);
  80   MOZ_ASSERT(other.bits_);
  81
  82   bool changed = false;
  83
  84   uint32_t* bits = bits_;
  85   const uint32_t* otherBits = other.bits_;
  86   for (unsigned int i = 0, e = numWords(); i < e; i++) {
  87     uint32_t old = bits[i];
  88     bits[i] &= otherBits[i];
  89
  90     if (!changed && old != bits[i]) {
  91       changed = true;
  92     }
  93   }
  94   return changed;
  95 }
  96
  97 void BitSet::complement() {
  98   MOZ_ASSERT(bits_);
  99   uint32_t* bits = bits_;
 100   for (unsigned int i = 0, e = numWords(); i < e; i++) {
 101     bits[i] = ~bits[i];
 102   }
 103 }
 104
 105 void BitSet::clear() {
 106   MOZ_ASSERT(bits_);
 107   uint32_t* bits = bits_;
 108   for (unsigned int i = 0, e = numWords(); i < e; i++) {
 109     bits[i] = 0;
 110   }
 111 }