upscheme/c/bitvector-ops.c

558 lines
19 KiB
C

#include <sys/types.h>
#include <assert.h>
#include <math.h>
#include <setjmp.h>
#include <stdarg.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#ifdef _WIN32
#include <malloc.h>
#endif
#include "scheme.h"
#ifdef __INTEL_COMPILER
#define count_bits(b) _popcnt32(b)
#else
static uint32_t count_bits(uint32_t b)
{
b = b - ((b >> 1) & 0x55555555);
b = ((b >> 2) & 0x33333333) + (b & 0x33333333);
b = ((b >> 4) + b) & 0x0f0f0f0f;
b += (b >> 8);
b += (b >> 16);
return b & 0x3f;
// here is the non-optimized version, for clarity:
/*
b = ((b>> 1)&0x55555555) + (b&0x55555555);
b = ((b>> 2)&0x33333333) + (b&0x33333333);
b = ((b>> 4)&0x0f0f0f0f) + (b&0x0f0f0f0f);
b = ((b>> 8)&0x00ff00ff) + (b&0x00ff00ff);
b = ((b>>16)&0x0000ffff) + (b&0x0000ffff);
return b & 0x3f;
*/
}
#endif
uint32_t bitreverse(uint32_t x)
{
uint32_t m;
#ifdef __INTEL_COMPILER
x = _bswap(x);
#else
x = (x >> 16) | (x << 16);
m = 0xff00ff00;
x = ((x & m) >> 8) | ((x & ~m) << 8);
#endif
m = 0xf0f0f0f0;
x = ((x & m) >> 4) | ((x & ~m) << 4);
m = 0xcccccccc;
x = ((x & m) >> 2) | ((x & ~m) << 2);
m = 0xaaaaaaaa;
x = ((x & m) >> 1) | ((x & ~m) << 1);
return x;
}
// shift all bits in a long bit vector
// n is # of int32s to consider, s is shift distance
// lowest bit-index is bit 0 of word 0
// TODO: handle boundary case of shift distance >= data size?
void bitvector_shr(uint32_t *b, size_t n, uint32_t s)
{
uint32_t i;
if (s == 0 || n == 0)
return;
i = (s >> 5);
if (i) {
n -= i;
memmove(b, &b[i], n * 4);
memset(&b[n], 0, i * 4);
s &= 31;
}
for (i = 0; i < n - 1; i++) {
b[i] = (b[i] >> s) | (b[i + 1] << (32 - s));
}
b[i] >>= s;
}
// out-of-place version, good for re-aligning a strided submatrix to
// linear representation when a copy is needed
// assumes that dest has the same amount of space as source, even if it
// wouldn't have been necessary to hold the shifted bits
void bitvector_shr_to(uint32_t *dest, uint32_t *b, size_t n, uint32_t s)
{
uint32_t i, j;
if (n == 0)
return;
if (s == 0) {
memcpy(dest, b, n * 4);
return;
}
j = (s >> 5);
if (j) {
n -= j;
memset(&dest[n], 0, j * 4);
s &= 31;
b = &b[j];
}
for (i = 0; i < n - 1; i++) {
dest[i] = (b[i] >> s) | (b[i + 1] << (32 - s));
}
dest[i] = b[i] >> s;
}
void bitvector_shl(uint32_t *b, size_t n, uint32_t s)
{
uint32_t i, scrap = 0, temp;
if (s == 0 || n == 0)
return;
i = (s >> 5);
if (i) {
n -= i;
memmove(&b[i], b, n * 4);
memset(b, 0, i * 4);
s &= 31;
b = &b[i];
}
for (i = 0; i < n; i++) {
temp = (b[i] << s) | scrap;
scrap = b[i] >> (32 - s);
b[i] = temp;
}
}
// if dest has more space than source, set scrap to true to keep the
// top bits that would otherwise be shifted out
void bitvector_shl_to(uint32_t *dest, uint32_t *b, size_t n, uint32_t s,
int scrap)
{
uint32_t i, j, sc = 0;
if (n == 0)
return;
if (s == 0) {
memcpy(dest, b, n * 4);
return;
}
j = (s >> 5);
if (j) {
n -= j;
memset(dest, 0, j * 4);
s &= 31;
dest = &dest[j];
}
for (i = 0; i < n; i++) {
dest[i] = (b[i] << s) | sc;
sc = b[i] >> (32 - s);
}
if (scrap)
dest[i] = sc;
}
// set nbits to c, starting at given bit offset
// assumes offs < 32
void bitvector_fill(uint32_t *b, uint32_t offs, uint32_t c, uint32_t nbits)
{
uintptr_t i;
uint32_t nw, tail;
uint32_t mask;
if (nbits == 0)
return;
nw = (offs + nbits + 31) >> 5;
if (nw == 1) {
mask = (lomask(nbits) << offs);
if (c)
b[0] |= mask;
else
b[0] &= (~mask);
return;
}
mask = lomask(offs);
if (c)
b[0] |= (~mask);
else
b[0] &= mask;
if (c)
mask = ONES32;
else
mask = 0;
for (i = 1; i < nw - 1; i++)
b[i] = mask;
tail = (offs + nbits) & 31;
if (tail == 0) {
b[i] = mask;
} else {
mask = lomask(tail);
if (c)
b[i] |= mask;
else
b[i] &= (~mask);
}
}
void bitvector_not(uint32_t *b, uint32_t offs, uint32_t nbits)
{
uintptr_t i;
uint32_t nw, tail;
uint32_t mask;
if (nbits == 0)
return;
nw = (offs + nbits + 31) >> 5;
if (nw == 1) {
mask = (lomask(nbits) << offs);
b[0] ^= mask;
return;
}
mask = ~lomask(offs);
b[0] ^= mask;
for (i = 1; i < nw - 1; i++)
b[i] = ~b[i];
tail = (offs + nbits) & 31;
if (tail == 0) {
b[i] = ~b[i];
} else {
mask = lomask(tail);
b[i] ^= mask;
}
}
// constant-space bit vector copy in a single pass, with arbitrary
// offsets and lengths. to get this right, there are 16 cases to handle!
#define BITVECTOR_COPY_OP(name, OP) \
void bitvector_##name(uint32_t *dest, uint32_t doffs, uint32_t *src, \
uint32_t soffs, uint32_t nbits) \
{ \
uintptr_t i; \
uint32_t s, nw, tail, snw; \
uint32_t mask, scrap; \
\
if (nbits == 0) \
return; \
nw = (doffs + nbits + 31) >> 5; \
\
if (soffs == doffs) { \
if (nw == 1) { \
mask = (lomask(nbits) << doffs); \
dest[0] = (dest[0] & ~mask) | (OP(src[0]) & mask); \
return; \
} \
mask = ~lomask(doffs); \
dest[0] = (dest[0] & ~mask) | (OP(src[0]) & mask); \
for (i = 1; i < nw - 1; i++) \
dest[i] = OP(src[i]); \
tail = (doffs + nbits) & 31; \
if (tail == 0) { \
dest[i] = src[i]; \
} else { \
mask = lomask(tail); \
dest[i] = (dest[i] & ~mask) | (OP(src[i]) & mask); \
} \
return; \
} \
snw = (soffs + nbits + 31) >> 5; \
if (soffs < doffs) { \
s = doffs - soffs; \
if (nw == 1) { \
mask = (lomask(nbits) << doffs); \
dest[0] = (dest[0] & ~mask) | ((OP(src[0]) << s) & mask); \
return; \
} \
mask = ~lomask(doffs); \
dest[0] = (dest[0] & ~mask) | ((OP(src[0]) << s) & mask); \
scrap = OP(src[0]) >> (32 - s); \
for (i = 1; i < snw - 1; i++) { \
dest[i] = (OP(src[i]) << s) | scrap; \
scrap = OP(src[i]) >> (32 - s); \
} \
tail = (doffs + nbits) & 31; \
if (tail == 0) { \
mask = ONES32; \
} else { \
mask = lomask(tail); \
} \
if (snw == nw) { \
dest[i] = \
(dest[i] & ~mask) | (((OP(src[i]) << s) | scrap) & mask); \
} else /* snw < nw */ { \
if (snw == 1) { \
dest[i] = (dest[i] & ~mask) | \
(((OP(src[i]) << s) | scrap) & mask); \
} else { \
dest[i] = (OP(src[i]) << s) | scrap; \
scrap = OP(src[i]) >> (32 - s); \
i++; \
dest[i] = (dest[i] & ~mask) | (scrap & mask); \
} \
} \
} else { \
s = soffs - doffs; \
if (snw == 1) { \
mask = (lomask(nbits) << doffs); \
dest[0] = (dest[0] & ~mask) | ((OP(src[0]) >> s) & mask); \
return; \
} \
if (nw == 1) { \
mask = (lomask(nbits) << doffs); \
dest[0] = \
(dest[0] & ~mask) | \
(((OP(src[0]) >> s) | (OP(src[1]) << (32 - s))) & mask); \
return; \
} \
mask = ~lomask(doffs); \
dest[0] = \
(dest[0] & ~mask) | \
(((OP(src[0]) >> s) | (OP(src[1]) << (32 - s))) & mask); \
for (i = 1; i < nw - 1; i++) { \
dest[i] = (OP(src[i]) >> s) | (OP(src[i + 1]) << (32 - s)); \
} \
tail = (doffs + nbits) & 31; \
if (tail == 0) { \
mask = ONES32; \
} else { \
mask = lomask(tail); \
} \
if (snw == nw) { \
dest[i] = (dest[i] & ~mask) | ((OP(src[i]) >> s) & mask); \
} else /* snw > nw */ { \
dest[i] = \
(dest[i] & ~mask) | \
(((OP(src[i]) >> s) | (OP(src[i + 1]) << (32 - s))) & mask); \
} \
} \
}
#define BV_COPY(a) (a)
#define BV_NOT(a) (~(a))
BITVECTOR_COPY_OP(copy, BV_COPY)
BITVECTOR_COPY_OP(not_to, BV_NOT)
// right-shift the bits in one logical "row" of a long 2d bit vector
/*
void bitvector_shr_row(uint32_t *b, uint32_t offs, size_t nbits, uint32_t
s)
{
}
*/
// copy from source to dest while reversing bit-order
// assumes dest offset == 0
// assumes source and dest don't overlap
// assumes offset < 32
void bitvector_reverse_to(uint32_t *dest, uint32_t *src, uint32_t soffs,
uint32_t nbits)
{
uintptr_t i;
uint32_t nw, tail;
if (nbits == 0)
return;
nw = (soffs + nbits + 31) >> 5;
// first, reverse the words while reversing bit order within each word
for (i = 0; i < nw / 2; i++) {
dest[i] = bitreverse(src[nw - i - 1]);
dest[nw - i - 1] = bitreverse(src[i]);
}
if (nw & 0x1)
dest[i] = bitreverse(src[i]);
tail = (soffs + nbits) & 31;
if (tail)
bitvector_shr(dest, nw, 32 - tail);
}
void bitvector_reverse(uint32_t *b, uint32_t offs, uint32_t nbits)
{
uintptr_t i;
uint32_t nw, tail;
uint32_t *temp;
if (nbits == 0)
return;
nw = (offs + nbits + 31) >> 5;
temp = malloc(nw * 4);
for (i = 0; i < nw / 2; i++) {
temp[i] = bitreverse(b[nw - i - 1]);
temp[nw - i - 1] = bitreverse(b[i]);
}
if (nw & 0x1)
temp[i] = bitreverse(b[i]);
tail = (offs + nbits) & 31;
bitvector_copy(b, offs, temp, (32 - tail) & 31, nbits);
free(temp);
}
uint64_t bitvector_count(uint32_t *b, uint32_t offs, uint64_t nbits)
{
size_t i, nw;
uint32_t ntail;
uint64_t ans;
if (nbits == 0)
return 0;
nw = ((uint64_t)offs + nbits + 31) >> 5;
if (nw == 1) {
return count_bits(b[0] & (lomask(nbits) << offs));
}
ans = count_bits(b[0] >> offs); // first end cap
for (i = 1; i < nw - 1; i++) {
/* popcnt can be computed branch-free, so these special cases
probably don't help much */
/*
v = b[i];
if (v == 0)
continue;
if (v == ONES32)
ans += 32;
else
*/
ans += count_bits(b[i]);
}
ntail = (offs + (uint32_t)nbits) & 31;
ans +=
count_bits(b[i] & (ntail > 0 ? lomask(ntail) : ONES32)); // last end cap
return ans;
}
uint32_t bitvector_any0(uint32_t *b, uint32_t offs, uint32_t nbits)
{
uintptr_t i;
uint32_t nw, tail;
uint32_t mask;
if (nbits == 0)
return 0;
nw = (offs + nbits + 31) >> 5;
if (nw == 1) {
mask = (lomask(nbits) << offs);
if ((b[0] & mask) != mask)
return 1;
return 0;
}
mask = ~lomask(offs);
if ((b[0] & mask) != mask)
return 1;
for (i = 1; i < nw - 1; i++) {
if (b[i] != ONES32)
return 1;
}
tail = (offs + nbits) & 31;
if (tail == 0) {
if (b[i] != ONES32)
return 1;
} else {
mask = lomask(tail);
if ((b[i] & mask) != mask)
return 1;
}
return 0;
}
uint32_t bitvector_any1(uint32_t *b, uint32_t offs, uint32_t nbits)
{
uintptr_t i;
uint32_t nw, tail;
uint32_t mask;
if (nbits == 0)
return 0;
nw = (offs + nbits + 31) >> 5;
if (nw == 1) {
mask = (lomask(nbits) << offs);
if ((b[0] & mask) != 0)
return 1;
return 0;
}
mask = ~lomask(offs);
if ((b[0] & mask) != 0)
return 1;
for (i = 1; i < nw - 1; i++) {
if (b[i] != 0)
return 1;
}
tail = (offs + nbits) & 31;
if (tail == 0) {
if (b[i] != 0)
return 1;
} else {
mask = lomask(tail);
if ((b[i] & mask) != 0)
return 1;
}
return 0;
}
static void adjust_offset_to(uint32_t *dest, uint32_t *src, uint32_t nw,
uint32_t soffs, uint32_t newoffs)
{
if (newoffs > soffs)
bitvector_shl_to(dest, src, nw, newoffs - soffs, 1);
else
bitvector_shr_to(dest, src, nw, soffs - newoffs);
}
#define BITVECTOR_BINARY_OP_TO(opname, OP) \
void bitvector_##opname##_to(uint32_t *dest, uint32_t doffs, \
uint32_t *a, uint32_t aoffs, uint32_t *b, \
uint32_t boffs, uint32_t nbits) \
{ \
uint32_t nw = (doffs + nbits + 31) >> 5; \
uint32_t *temp = malloc((nw + 1) * 4); \
uint32_t i, anw, bnw; \
if (aoffs == boffs) { \
anw = (aoffs + nbits + 31) >> 5; \
} else if (aoffs == doffs) { \
bnw = (boffs + nbits + 31) >> 5; \
adjust_offset_to(temp, b, bnw, boffs, aoffs); \
b = temp; \
anw = nw; \
} else { \
anw = (aoffs + nbits + 31) >> 5; \
bnw = (boffs + nbits + 31) >> 5; \
adjust_offset_to(temp, a, anw, aoffs, boffs); \
a = temp; \
aoffs = boffs; \
anw = bnw; \
} \
for (i = 0; i < anw; i++) \
temp[i] = OP(a[i], b[i]); \
bitvector_copy(dest, doffs, temp, aoffs, nbits); \
free(temp); \
}
#define BV_AND(a, b) ((a) & (b))
#define BV_OR(a, b) ((a) | (b))
#define BV_XOR(a, b) ((a) ^ (b))
BITVECTOR_BINARY_OP_TO(and, BV_AND)
BITVECTOR_BINARY_OP_TO(or, BV_OR)
BITVECTOR_BINARY_OP_TO(xor, BV_XOR)