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improve profiled performance of C++ BitArray::get(). Closes issue 1101

Browse source 
From evansepdx. Thanks!

git-svn-id: https://zxing.googlecode.com/svn/trunk@2083 59b500cc-1b3d-0410-9834-0bbf25fbcc57
This commit is contained in:
smparkes@smparkes.net 2011-12-12 22:54:51 +00:00
parent 1cd49dbcb1
commit a569f179ff
3 changed files with 18 additions and 38 deletions
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23
cpp/core/src/zxing/common/BitArray.cpp
View file

@ -1,8 +1,5 @@
// -*- mode:c++; tab-width:2; indent-tabs-mode:nil; c-basic-offset:2 -*-
/*
* BitArray.cpp
* zxing
*
* Copyright 2010 ZXing authors. All rights reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
@ -19,32 +16,14 @@
*/
#include <zxing/common/BitArray.h>
#include <iostream>
#include <limits>
using namespace std;
namespace zxing {
static unsigned int logDigits(unsigned digits) {
unsigned log = 0;
unsigned val = 1;
while (val < digits) {
log++;
val <<= 1;
}
return log;
}
const unsigned int BitArray::bitsPerWord_ = numeric_limits<unsigned int>::digits;
const unsigned int BitArray::logBits_ = logDigits(bitsPerWord_);
const unsigned int BitArray::bitsMask_ = (1 << logBits_) - 1;
size_t BitArray::wordsForBits(size_t bits) {
int arraySize = bits >> logBits_;
if (bits - (arraySize << logBits_) != 0) {
arraySize++;
}
int arraySize = (bits + bitsPerWord_ - 1) >> logBits_;
return arraySize;
}

20
cpp/core/src/zxing/common/BitArray.h
View file

@ -3,9 +3,6 @@
#define __BIT_ARRAY_H__
/*
* BitArray.h
* zxing
*
* Copyright 2010 ZXing authors. All rights reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
@ -24,17 +21,26 @@
#include <zxing/common/Counted.h>
#include <zxing/common/IllegalArgumentException.h>
#include <vector>
#include <iostream>
#include <limits>
namespace zxing {
#define ZX_LOG_DIGITS(digits) \
((digits == 8) ? 3 : \
((digits == 16) ? 4 : \
((digits == 32) ? 5 : \
((digits == 64) ? 6 : \
((digits == 128) ? 7 : \
(-1))))))
class BitArray : public Counted {
private:
size_t size_;
std::vector<unsigned int> bits_;
static const unsigned int bitsPerWord_;
static const unsigned int logBits_;
static const unsigned int bitsMask_;
static const unsigned int bitsPerWord_ =
std::numeric_limits<unsigned int>::digits;
static const unsigned int logBits_ = ZX_LOG_DIGITS(bitsPerWord_);
static const unsigned int bitsMask_ = (1 << logBits_) - 1;
static size_t wordsForBits(size_t bits);
explicit BitArray();

13
cpp/core/src/zxing/common/BitMatrix.cpp
View file

@ -1,8 +1,5 @@
// -*- mode:c++; tab-width:2; indent-tabs-mode:nil; c-basic-offset:2 -*-
/*
* BitMatrix.cpp
* zxing
*
* Copyright 2010 ZXing authors. All rights reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
@ -35,26 +32,24 @@ using zxing::Ref;
namespace {
size_t wordsForSize(size_t width,
size_t height,
unsigned int bitsPerWord,
unsigned int logBits) {
size_t bits = width * height;
int arraySize = bits >> logBits;
if (bits - (arraySize << logBits) != 0) {
arraySize++;
}
int arraySize = (bits + bitsPerWord - 1) >> logBits;
return arraySize;
}
}
BitMatrix::BitMatrix(size_t dimension) :
width_(dimension), height_(dimension), words_(0), bits_(NULL) {
words_ = wordsForSize(width_, height_, logBits);
words_ = wordsForSize(width_, height_, bitsPerWord, logBits);
bits_ = new unsigned int[words_];
clear();
}
BitMatrix::BitMatrix(size_t width, size_t height) :
width_(width), height_(height), words_(0), bits_(NULL) {
words_ = wordsForSize(width_, height_, logBits);
words_ = wordsForSize(width_, height_, bitsPerWord, logBits);
bits_ = new unsigned int[words_];
clear();
}