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Encapsulate unsigned char within new type bitset_limb

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Patrick Pelissier committed 2017-03-04 18:49:49 +01:00
1 parent 43ce32ab69
commit dd6f52e3a1
1 file changed
+44 -40
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m-bitset.h
+44 -40
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@@ -34,10 +34,14 @@
#include "m-core.h"
#include "m-string.h" // Only for bitset_get_str function
// Define a limb of a bitset
typedef unsigned char bitset_limb;
#define BITSET_LIMB_BIT (sizeof(bitset_limb) * CHAR_BIT)
typedef struct bitset_s {
size_t size; // Size is the number of bits
size_t alloc; // Alloc is the number of allocated bytes
unsigned char *ptr;
bitset_limb *ptr;
} bitset_t[1];
typedef struct bitset_it_s {
@@ -48,8 +52,8 @@ typedef struct bitset_it_s {
// Compute alloc from size.
#define BITSETI_INC_ALLOC_SIZE(n) ((n) < 8 ? 16 : (n) * 2)
#define BITSETI_TO_ALLOC(n) (((n) + CHAR_BIT - 1) / CHAR_BIT)
#define BITSETI_FROM_ALLOC(n) ((n) * CHAR_BIT)
#define BITSETI_TO_ALLOC(n) (((n) + BITSET_LIMB_BIT - 1) / BITSET_LIMB_BIT)
#define BITSETI_FROM_ALLOC(n) ((n) * BITSET_LIMB_BIT)
#define BITSETI_CONTRACT(t) \
assert (t != NULL); \
@@ -60,7 +64,7 @@ static inline void
bitset_init(bitset_t t)
{
assert (t != NULL);
assert (M_POWEROF2_P(CHAR_BIT));
assert (M_POWEROF2_P(BITSET_LIMB_BIT));
t->size = t->alloc = 0;
t->ptr = NULL;
}
@@ -89,7 +93,7 @@ bitset_set(bitset_t d, const bitset_t s)
if (d == s) return;
const size_t needAlloc = BITSETI_TO_ALLOC (s->size);
if (s->size > BITSETI_FROM_ALLOC (d->alloc)) {
unsigned char *ptr = M_MEMORY_REALLOC (unsigned char, d->ptr, needAlloc);
bitset_limb *ptr = M_MEMORY_REALLOC (bitset_limb, d->ptr, needAlloc);
if (ptr == NULL) {
M_MEMORY_FULL(needAlloc);
return ;
@@ -134,8 +138,8 @@ bitset_set_at(bitset_t v, size_t i, bool x)
{
BITSETI_CONTRACT(v);
assert (i < v->size && v->ptr != NULL);
size_t offset = i / CHAR_BIT;
size_t index = i % CHAR_BIT;
size_t offset = i / BITSET_LIMB_BIT;
size_t index = i % BITSET_LIMB_BIT;
if (x == true){
v->ptr[offset] |= 1<<index;
} else {
@@ -150,7 +154,7 @@ bitset_push_back (bitset_t v, bool x)
BITSETI_CONTRACT (v);
if (v->size >= BITSETI_FROM_ALLOC (v->alloc)) {
const size_t needAlloc = BITSETI_INC_ALLOC_SIZE(v->alloc);
unsigned char *ptr = M_MEMORY_REALLOC (unsigned char, v->ptr, needAlloc);
bitset_limb *ptr = M_MEMORY_REALLOC (bitset_limb, v->ptr, needAlloc);
if (ptr == NULL) {
M_MEMORY_FULL(needAlloc);
return;
@@ -170,7 +174,7 @@ bitset_resize (bitset_t v, size_t size)
size_t oldbytes = BITSETI_TO_ALLOC (v->size);
size_t newbytes = BITSETI_TO_ALLOC (size);
if (oldbytes != newbytes) {
unsigned char *ptr = M_MEMORY_REALLOC (unsigned char, v->ptr, newbytes);
bitset_limb *ptr = M_MEMORY_REALLOC (bitset_limb, v->ptr, newbytes);
if (ptr == NULL) {
M_MEMORY_FULL(newbytes);
return;
@@ -188,8 +192,8 @@ bitset_get(const bitset_t v, size_t i)
{
BITSETI_CONTRACT(v);
assert (v->ptr != NULL && i < v->size);
size_t offset = i / CHAR_BIT;
size_t index = i % CHAR_BIT;
size_t offset = i / BITSET_LIMB_BIT;
size_t index = i % BITSET_LIMB_BIT;
return ( v->ptr[offset] & (1 << index) ) != 0;
}
#define bitset_cget bitset_get
@@ -246,25 +250,25 @@ bitset_swap (bitset_t v, size_t i, size_t j)
BITSETI_CONTRACT (v);
}
static inline unsigned char
bitseti_lshift(unsigned char ptr[], size_t n, unsigned char carry)
static inline bitset_limb
bitseti_lshift(bitset_limb ptr[], size_t n, bitset_limb carry)
{
for(size_t i = 0; i < n; i++)
{
unsigned char v = ptr[i];
bitset_limb v = ptr[i];
ptr[i] = (v << 1) | carry;
carry = (v >> (CHAR_BIT-1) );
carry = (v >> (BITSET_LIMB_BIT-1) );
}
return carry;
}
static inline unsigned char
bitseti_rshift(unsigned char ptr[], size_t n, unsigned char carry)
static inline bitset_limb
bitseti_rshift(bitset_limb ptr[], size_t n, bitset_limb carry)
{
for(size_t i = n - 1; i < n; i--)
{
unsigned char v = ptr[i];
v = (v >> 1) | (carry << (CHAR_BIT-1) );
bitset_limb v = ptr[i];
v = (v >> 1) | (carry << (BITSET_LIMB_BIT-1) );
carry = v & 1;
}
return carry;
@@ -278,17 +282,17 @@ bitset_push_at(bitset_t set, size_t key, bool value)
bitset_push_back(set, true);
assert (set->ptr != NULL && key < set->size);
// Then shift it
size_t offset = key / CHAR_BIT;
size_t index = key % CHAR_BIT;
size_t offset = key / BITSET_LIMB_BIT;
size_t index = key % BITSET_LIMB_BIT;
// BEFORE: 76543210 FEDBCA98
// if key=5 ==>
// AFTER: 65X43210 EDBCA987 000000F
unsigned char v = set->ptr[offset];
unsigned char mask = (1<<index)-1;
unsigned char carry = (v >> (CHAR_BIT-1) );
bitset_limb v = set->ptr[offset];
bitset_limb mask = (1<<index)-1;
bitset_limb carry = (v >> (BITSET_LIMB_BIT-1) );
v = (v & mask) | (value << index) | ((v & ~mask) << 1);
set->ptr[offset] = v;
size_t size = (set->size + CHAR_BIT - 1) / CHAR_BIT;
size_t size = (set->size + BITSET_LIMB_BIT - 1) / BITSET_LIMB_BIT;
v = bitseti_lshift(&set->ptr[offset+1], size - offset - 1, carry);
BITSETI_CONTRACT (set);
}
@@ -302,17 +306,17 @@ bitset_pop_at(bool *dest, bitset_t set, size_t key)
*dest = bitset_get (set, key);
}
// Shift it
size_t offset = key / CHAR_BIT;
size_t index = key % CHAR_BIT;
size_t offset = key / BITSET_LIMB_BIT;
size_t index = key % BITSET_LIMB_BIT;
// BEFORE: 76543210 FEDBCA98
// if key=5 ==>
// AFTER: 8643210 XFEDBCA9
size_t size = (set->size + CHAR_BIT - 1) / CHAR_BIT;
unsigned char v, mask, carry;
size_t size = (set->size + BITSET_LIMB_BIT - 1) / BITSET_LIMB_BIT;
bitset_limb v, mask, carry;
carry = bitseti_rshift(&set->ptr[offset+1], size - offset - 1, false);
v = set->ptr[offset];
mask = (1<<index)-1;
v = (v & mask) | ((v>>1) & ~mask) | (carry << (CHAR_BIT-1)) ;
v = (v & mask) | ((v>>1) & ~mask) | (carry << (BITSET_LIMB_BIT-1)) ;
set->ptr[offset] = v;
// Decrease size
set->size --;
@@ -328,12 +332,12 @@ bitset_equal_p (const bitset_t set1, const bitset_t set2)
return false;
/* We won't parse each bit individualy, but instead compare
them per byte */
size_t size = (set1->size) / CHAR_BIT;
size_t size = (set1->size) / BITSET_LIMB_BIT;
for(size_t i = 0 ; i < size;i++)
if (set1->ptr[i] != set2->ptr[i])
return false;
/* Compare last byte if needed */
size_t index = set1->size % CHAR_BIT;
size_t index = set1->size % BITSET_LIMB_BIT;
if (index > 0) {
size_t mask = (1 << index) - 1;
if ((set1->ptr[size] & mask) != (set2->ptr[size] & mask))
@@ -473,8 +477,8 @@ bitset_and(bitset_t dest, const bitset_t src)
BITSETI_CONTRACT(dest);
BITSETI_CONTRACT(src);
size_t s = M_MIN(dest->size, src->size);
size_t n = s / CHAR_BIT;
size_t m = s % CHAR_BIT;
size_t n = s / BITSET_LIMB_BIT;
size_t m = s % BITSET_LIMB_BIT;
for(size_t i = 0 ; i < n; i++)
dest->ptr[i] &= src->ptr[i];
if (m) {
@@ -491,8 +495,8 @@ bitset_or(bitset_t dest, const bitset_t src)
BITSETI_CONTRACT(dest);
BITSETI_CONTRACT(src);
size_t s = M_MIN(dest->size, src->size);
size_t n = s / CHAR_BIT;
size_t m = s % CHAR_BIT;
size_t n = s / BITSET_LIMB_BIT;
size_t m = s % BITSET_LIMB_BIT;
for(size_t i = 0 ; i < n; i++)
dest->ptr[i] |= src->ptr[i];
if (m) {
@@ -509,8 +513,8 @@ bitset_xor(bitset_t dest, const bitset_t src)
BITSETI_CONTRACT(dest);
BITSETI_CONTRACT(src);
size_t s = M_MIN(dest->size, src->size);
size_t n = s / CHAR_BIT;
size_t m = s % CHAR_BIT;
size_t n = s / BITSET_LIMB_BIT;
size_t m = s % BITSET_LIMB_BIT;
for(size_t i = 0 ; i < n; i++)
dest->ptr[i] ^= src->ptr[i];
if (m) {
@@ -526,8 +530,8 @@ bitset_not(bitset_t dest)
{
BITSETI_CONTRACT(dest);
size_t s = dest->size;
size_t n = s / CHAR_BIT;
size_t m = s % CHAR_BIT;
size_t n = s / BITSET_LIMB_BIT;
size_t m = s % BITSET_LIMB_BIT;
for(size_t i = 0 ; i < n; i++)
dest->ptr[i] = ~ (dest->ptr[i]);
if (m) {