[set] Implement iteration using bitop intrinsics

This commit is contained in:
Behdad Esfahbod 2018-02-16 18:14:41 -08:00
parent 6a91a2eb04
commit f18b9fbf65
1 changed files with 19 additions and 36 deletions

View File

@ -109,21 +109,16 @@ struct hb_set_t
unsigned int i = m / ELT_BITS;
unsigned int j = m & ELT_MASK;
for (; j < ELT_BITS; j++)
if (v[i] & (elt_t (1) << j))
goto found;
for (i++; i < len (); i++)
if (v[i])
for (j = 0; j < ELT_BITS; j++)
if (v[i] & (elt_t (1) << j))
goto found;
const elt_t vv = v[i] & ~((elt_t (1) << j) - 1);
for (const elt_t *p = &vv; i < len (); p = &v[++i])
if (*p)
{
*codepoint = i * ELT_BITS + elt_get_min (*p);
return true;
}
*codepoint = INVALID;
return false;
found:
*codepoint = i * ELT_BITS + j;
return true;
}
inline bool previous (hb_codepoint_t *codepoint) const
{
@ -136,44 +131,29 @@ struct hb_set_t
unsigned int i = m / ELT_BITS;
unsigned int j = m & ELT_MASK;
for (; (int) j >= 0; j--)
if (v[i] & (elt_t (1) << j))
goto found;
for (i--; (int) i >= 0; i--)
if (v[i])
for (j = ELT_BITS - 1; (int) j >= 0; j--)
if (v[i] & (elt_t (1) << j))
goto found;
const elt_t vv = v[i] & ((elt_t (1) << (j + 1)) - 1);
for (const elt_t *p = &vv; (int) i >= 0; p = &v[--i])
if (*p)
{
*codepoint = i * ELT_BITS + elt_get_max (*p);
return true;
}
*codepoint = INVALID;
return false;
found:
*codepoint = i * ELT_BITS + j;
return true;
}
inline hb_codepoint_t get_min (void) const
{
for (unsigned int i = 0; i < len (); i++)
if (v[i])
{
elt_t e = v[i];
for (unsigned int j = 0; j < ELT_BITS; j++)
if (e & (elt_t (1) << j))
return i * ELT_BITS + j;
}
return i * ELT_BITS + elt_get_min (v[i]);
return INVALID;
}
inline hb_codepoint_t get_max (void) const
{
for (int i = len () - 1; i >= 0; i--)
if (v[i])
{
elt_t e = v[i];
for (int j = ELT_BITS - 1; j >= 0; j--)
if (e & (elt_t (1) << j))
return i * ELT_BITS + j;
}
return i * ELT_BITS + elt_get_max (v[i]);
return 0;
}
@ -181,6 +161,9 @@ struct hb_set_t
static const unsigned int PAGE_BITS = 1024;
static_assert ((PAGE_BITS & ((PAGE_BITS) - 1)) == 0, "");
static inline unsigned int elt_get_min (const elt_t &elt) { return _hb_ctz (elt); }
static inline unsigned int elt_get_max (const elt_t &elt) { return _hb_bit_storage (elt) - 1; }
#if 0 && HAVE_VECTOR_SIZE
/* The vectorized version does not work with clang as non-const
* elt() errs "non-const reference cannot bind to vector element". */