58 lines
1.1 KiB
C++
58 lines
1.1 KiB
C++
#include "base/rolling_hash.h"
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using namespace base;
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using namespace boost;
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using namespace hash_detail;
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using namespace std;
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//----------------------------------------------------------------
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rolling_hash::rolling_hash(unsigned window_size)
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: a_(MULTIPLIER),
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a_to_k_minus_1_(a_),
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window_size_(window_size),
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buffer_(window_size) {
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for (unsigned i = 1; i < window_size_ - 1; i++)
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a_to_k_minus_1_ *= a_;
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reset();
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}
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void
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rolling_hash::reset()
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{
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// prime with zeroes
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buffer_.clear();
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hash_ = 0;
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for (unsigned i = 0; i < window_size_; i++) {
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hash_ = (hash_ * a_) + SEED;
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buffer_.push_back(0);
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}
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}
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//--------------------------------
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content_based_hash::content_based_hash(unsigned window_size)
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: rhash_(window_size),
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// FIXME: hard coded values
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backup_div_((window_size / 4) - 1),
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div_((window_size / 2) - 1),
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min_len_(window_size / 4),
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max_len_(window_size),
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len_(0)
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{
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}
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void
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content_based_hash::reset()
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{
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len_ = 0;
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backup_break_.reset();
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rhash_.reset();
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}
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//----------------------------------------------------------------
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