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femtolisp/llt/bitvector.c

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import of llt library source
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/*
bit vector primitives
todo:
* reverse
* nreverse
(- rotate left/right)
* shl_to
* not
- shr_row, shl_row
These routines are the back end supporting bit matrices. Many operations
on bit matrices are slow (such as accessing or setting a single element!)
but certain operations are privileged and lend themselves to extremely
efficient implementation due to the bit-vector nature of machine integers.
These are:
done:
& | $ ~ copy reverse fill sum prod
todo:
shift trans rowswap
would be nice:
channel interleave
Important note:
Out-of-place functions always assume dest and source have the same amount
of space available.
shr_to, shl_to, not_to, and reverse_to assume source and dest don't overlap
and_to, or_to, and xor_to allow overlap.
*/
#include <stdlib.h>
#include <assert.h>
#include <string.h>
#include "dtypes.h"
#include "bitvector.h"
#ifdef WIN32
#include <malloc.h>
#define alloca _alloca
#endif
// greater than this # of words we use malloc instead of alloca
#define MALLOC_CUTOFF 2000
updating bitvector functions to use int64s in more places, since after all that's the whole point of bitvectors some prettyprinting tweaks more uniform way to handle forwarding pointers. fix forwarding of gensyms :keyword symbols
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u_int32_t *bitvector_resize(u_int32_t *b, u_int64_t n, int initzero)
import of llt library source
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{
u_int32_t *p;
size_t sz = ((n+31)>>5) * 4;
p = realloc(b, sz);
if (p == NULL) return NULL;
if (initzero) memset(p, 0, sz);
return p;
}
updating bitvector functions to use int64s in more places, since after all that's the whole point of bitvectors some prettyprinting tweaks more uniform way to handle forwarding pointers. fix forwarding of gensyms :keyword symbols
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u_int32_t *bitvector_new(u_int64_t n, int initzero)
import of llt library source
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{
return bitvector_resize(NULL, n, initzero);
}
updating bitvector functions to use int64s in more places, since after all that's the whole point of bitvectors some prettyprinting tweaks more uniform way to handle forwarding pointers. fix forwarding of gensyms :keyword symbols
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size_t bitvector_nwords(u_int64_t nbits)
{
return ((nbits+31)>>5) * 4;
}
void bitvector_set(u_int32_t *b, u_int64_t n, u_int32_t c)
import of llt library source
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{
if (c)
b[n>>5] |= (1<<(n&31));
else
b[n>>5] &= ~(1<<(n&31));
}
updating bitvector functions to use int64s in more places, since after all that's the whole point of bitvectors some prettyprinting tweaks more uniform way to handle forwarding pointers. fix forwarding of gensyms :keyword symbols
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u_int32_t bitvector_get(u_int32_t *b, u_int64_t n)
import of llt library source
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{
return b[n>>5] & (1<<(n&31));
}
u_int32_t bitreverse(u_int32_t x)
{
u_int32_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(u_int32_t *b, size_t n, u_int32_t s)
{
u_int32_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(u_int32_t *dest, u_int32_t *b, size_t n, u_int32_t s)
{
u_int32_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(u_int32_t *b, size_t n, u_int32_t s)
{
u_int32_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(u_int32_t *dest, u_int32_t *b, size_t n, u_int32_t s,
bool_t scrap)
{
u_int32_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(u_int32_t *b, u_int32_t offs, u_int32_t c, u_int32_t nbits)
{
index_t i;
u_int32_t nw, tail;
u_int32_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(u_int32_t *b, u_int32_t offs, u_int32_t nbits)
{
index_t i;
u_int32_t nw, tail;
u_int32_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(u_int32_t *dest, u_int32_t doffs, \
u_int32_t *src, u_int32_t soffs, u_int32_t nbits) \
{ \
index_t i; \
u_int32_t s, nw, tail, snw; \
u_int32_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(u_int32_t *b, u_int32_t offs, size_t nbits, u_int32_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(u_int32_t *dest, u_int32_t *src, u_int32_t soffs,
u_int32_t nbits)
{
index_t i;
u_int32_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(u_int32_t *b, u_int32_t offs, u_int32_t nbits)
{
index_t i;
u_int32_t nw, tail;
u_int32_t *temp;
if (nbits == 0) return;
nw = (offs+nbits+31)>>5;
temp = (nw > MALLOC_CUTOFF) ? malloc(nw*4) : alloca(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);
if (nw > MALLOC_CUTOFF) free(temp);
}
updating bitvector functions to use int64s in more places, since after all that's the whole point of bitvectors some prettyprinting tweaks more uniform way to handle forwarding pointers. fix forwarding of gensyms :keyword symbols
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u_int64_t bitvector_count(u_int32_t *b, u_int32_t offs, u_int64_t nbits)
import of llt library source
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{
updating bitvector functions to use int64s in more places, since after all that's the whole point of bitvectors some prettyprinting tweaks more uniform way to handle forwarding pointers. fix forwarding of gensyms :keyword symbols
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size_t i, nw;
u_int32_t ntail;
u_int64_t ans;
import of llt library source
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if (nbits == 0) return 0;
updating bitvector functions to use int64s in more places, since after all that's the whole point of bitvectors some prettyprinting tweaks more uniform way to handle forwarding pointers. fix forwarding of gensyms :keyword symbols
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nw = ((u_int64_t)offs+nbits+31)>>5;
import of llt library source
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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]);
}
updating bitvector functions to use int64s in more places, since after all that's the whole point of bitvectors some prettyprinting tweaks more uniform way to handle forwarding pointers. fix forwarding of gensyms :keyword symbols
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ntail = (offs+(u_int32_t)nbits)&31;
ans += count_bits(b[i]&(ntail>0?lomask(ntail):ONES32)); // last end cap
import of llt library source
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return ans;
}
u_int32_t bitvector_any0(u_int32_t *b, u_int32_t offs, u_int32_t nbits)
{
index_t i;
u_int32_t nw, tail;
u_int32_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;
}
u_int32_t bitvector_any1(u_int32_t *b, u_int32_t offs, u_int32_t nbits)
{
index_t i;
u_int32_t nw, tail;
u_int32_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(u_int32_t *dest, u_int32_t *src, u_int32_t nw,
u_int32_t soffs, u_int32_t newoffs)
{
if (newoffs > soffs)
bitvector_shl_to(dest, src, nw, newoffs-soffs, true);
else
bitvector_shr_to(dest, src, nw, soffs-newoffs);
}
#define BITVECTOR_BINARY_OP_TO(opname, OP) \
void bitvector_##opname##_to(u_int32_t *dest, u_int32_t doffs, \
u_int32_t *a, u_int32_t aoffs, \
u_int32_t *b, u_int32_t boffs, u_int32_t nbits) \
{ \
u_int32_t nw = (doffs+nbits+31)>>5; \
u_int32_t *temp = nw>MALLOC_CUTOFF ? malloc((nw+1)*4) : alloca((nw+1)*4);\
u_int32_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); \
if (nw>MALLOC_CUTOFF) 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)