Commit 21a28ca8 authored by Alexandre Duret-Lutz's avatar Alexandre Duret-Lutz
Browse files

* src/misc/intvcomp.cc: Low-level fine-tuning.

parent 445a785e
2011-04-15 Alexandre Duret-Lutz <adl@lrde.epita.fr>
* src/misc/intvcomp.cc: Low-level fine-tuning.
2011-04-13 Alexandre Duret-Lutz <adl@lrde.epita.fr>
Fix compression of large repetitions
......
......@@ -22,6 +22,15 @@
#include <cassert>
#include "intvcomp.hh"
#if __GNUC__ >= 3
# define likely(expr) __builtin_expect(!!(expr), 1)
# define unlikely(expr) __builtin_expect(!!(expr), 0)
#else
# define likely(expr) (expr)
# define unlikely(expr) (expr)
#endif
namespace spot
{
......@@ -90,7 +99,7 @@ namespace spot
{
unsigned int last_val = 0;
while (self().have_data())
while (likely(self().have_data()))
{
unsigned int val = self().next_data();
// Repeated value? Try to find more.
......@@ -135,7 +144,7 @@ namespace spot
{
cur_ <<= n;
cur_ |= (bits & mask);
if (bits_left_ -= n)
if (likely(bits_left_ -= n))
return;
self().push_data(cur_);
......@@ -146,7 +155,7 @@ namespace spot
void
push_bits(unsigned int bits, unsigned int n, unsigned int mask)
{
if (n <= bits_left_)
if (likely(n <= bits_left_))
{
push_bits_unchecked(bits, n, mask);
return;
......@@ -215,7 +224,7 @@ namespace spot
bool skip_if(unsigned int val)
{
if (!have_data())
if (unlikely(!have_data()))
return false;
if (static_cast<unsigned int>(array_[pos_]) != val)
......@@ -259,7 +268,7 @@ namespace spot
bool skip_if(unsigned int val)
{
if (!have_data())
if (unlikely(!have_data()))
return false;
if (static_cast<unsigned int>(*pos_) != val)
......@@ -307,7 +316,7 @@ namespace spot
bool skip_if(unsigned int val)
{
if (!have_data())
if (unlikely(!have_data()))
return false;
if (static_cast<unsigned int>(array_[pos_]) != val)
......@@ -364,91 +373,105 @@ namespace spot
public:
void refill()
{
oncemore:
unsigned int fill_size = max_bits - look_bits_;
if (fill_size > buffer_bits_)
fill_size = buffer_bits_;
look_ <<= fill_size;
look_ |= (buffer_ >> (buffer_bits_ - fill_size));
buffer_bits_ -= fill_size;
buffer_mask_ >>= fill_size;
buffer_ &= buffer_mask_;
look_bits_ += fill_size;
if (buffer_bits_ == 0)
if (unlikely(look_bits_ == 0))
{
if (self().have_comp_data())
look_bits_ = max_bits;
look_ = buffer_;
if (likely(self().have_comp_data()))
buffer_ = self().next_comp_data();
buffer_bits_ = max_bits;
buffer_mask_ = -1U;
if (look_bits_ != max_bits)
goto oncemore;
}
// Do not fold these two cases, because we cannot write
// "x<<max_bits" safely. (Intel "shl" instruction considers
// only the first 5 bits, in other words "shl 32" is similar to
// "shl 0": it has no effect.)
if (look_bits_ == max_bits)
{
look_mask_ = -1U;
if (likely(buffer_bits_ != max_bits))
{
unsigned int fill_size = max_bits - buffer_bits_;
look_ <<= fill_size;
look_ |= buffer_ >> buffer_bits_;
}
}
else
{
look_mask_ = (1U << look_bits_) - 1U;
unsigned int fill_size = max_bits - look_bits_;
if (fill_size > buffer_bits_)
fill_size = buffer_bits_;
look_ <<= fill_size;
buffer_bits_ -= fill_size;
look_ |= (buffer_ >> buffer_bits_) & ((1 << fill_size) - 1);
look_bits_ += fill_size;
if (buffer_bits_ == 0)
{
if (likely(self().have_comp_data()))
buffer_ = self().next_comp_data();
unsigned int left = max_bits - look_bits_;
if (left != 0)
{
look_ <<= left;
look_ |= buffer_ >> look_bits_;
buffer_bits_ = look_bits_;
look_bits_ = max_bits;
}
else
{
buffer_bits_ = max_bits;
}
}
}
}
unsigned int look_n_bits(unsigned int n)
{
if (look_bits_ < n)
if (unlikely(look_bits_ < n))
refill();
assert(n <= look_bits_);
return look_ >> (look_bits_ - n);
return (look_ >> (look_bits_ - n)) & ((1 << n) - 1);
}
void skip_n_bits(unsigned int n)
{
assert (n <= look_bits_);
look_bits_ -= n;
look_mask_ >>= n;
look_ &= look_mask_;
}
unsigned int get_n_bits(unsigned int n)
{
if (look_bits_ < n)
if (unlikely(look_bits_ < n))
refill();
look_bits_ -= n;
unsigned int val = look_ >> look_bits_;
look_mask_ >>= n;
look_ &= look_mask_;
return (look_ >> look_bits_) & ((1 << n) - 1);
}
unsigned int get_32_bits()
{
// std::cerr << "get_32" << std::endl;
if (likely(look_bits_ < 32))
refill();
unsigned int val = look_;
look_bits_ = 0;
refill();
return val;
}
void run()
{
if (!self().have_comp_data())
if (unlikely(!self().have_comp_data()))
return;
look_ = self().next_comp_data();
look_bits_ = max_bits;
look_mask_ = -1U;
if (self().have_comp_data())
if (likely(self().have_comp_data()))
{
buffer_ = self().next_comp_data();
buffer_bits_ = max_bits;
buffer_mask_ = -1U;
}
else
{
buffer_ = 0;
buffer_bits_ = 0;
buffer_mask_ = 0;
}
while (!self().complete())
while (likely(!self().complete()))
{
unsigned int token = look_n_bits(3);
switch (token)
......@@ -480,7 +503,7 @@ namespace spot
break;
case 0x7: // 111
skip_n_bits(3);
self().push_data(get_n_bits(32));
self().push_data(get_32_bits());
break;
default:
assert(0);
......@@ -502,10 +525,8 @@ namespace spot
unsigned int look_;
unsigned int look_bits_;
unsigned int look_mask_;
unsigned int buffer_;
unsigned int buffer_bits_;
unsigned int buffer_mask_;
};
class int_vector_vector_decompression:
......
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