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redict/intset.c

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12 KiB
C
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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "intset.h"
#include "zmalloc.h"
/* Note that these encodings are ordered, so:
* INTSET_ENC_INT16 < INTSET_ENC_INT32 < INTSET_ENC_INT64. */
#define INTSET_ENC_INT16 (sizeof(int16_t))
#define INTSET_ENC_INT32 (sizeof(int32_t))
#define INTSET_ENC_INT64 (sizeof(int64_t))
/* Accessors for each type of encoding */
#define INTSET_VALUE_ENCODING(__val) (((__val) < INT32_MIN || (__val) > INT32_MAX) ? \
INTSET_ENC_INT64 : (((__val) < INT16_MIN || (__val) > INT16_MAX) ? \
INTSET_ENC_INT32 : INTSET_ENC_INT16))
#define INTSET_GET_ENCODED(__is,__pos,__enc) ((__enc == INTSET_ENC_INT64) ? \
((int64_t*)(__is)->contents)[__pos] : ((__enc == INTSET_ENC_INT32) ? \
((int32_t*)(__is)->contents)[__pos] : ((int16_t*)(__is)->contents)[__pos]))
#define INTSET_GET(__is,__pos) (INTSET_GET_ENCODED(__is,__pos,(__is)->encoding))
#define INTSET_SET(__is,__pos,__val) { \
if ((__is)->encoding == INTSET_ENC_INT64) \
((int64_t*)(__is)->contents)[__pos] = (__val); \
else if ((__is)->encoding == INTSET_ENC_INT32) \
((int32_t*)(__is)->contents)[__pos] = (__val); \
else \
((int16_t*)(__is)->contents)[__pos] = (__val); }
/* Create an empty intset. */
intset *intsetNew(void) {
intset *is = zmalloc(sizeof(intset));
is->encoding = INTSET_ENC_INT16;
is->length = 0;
return is;
}
/* Resize the intset */
static intset *intsetResize(intset *is, uint32_t len) {
uint32_t size = len*is->encoding;
is = zrealloc(is,sizeof(intset)+size);
return is;
}
static intset *intsetUpgrade(intset *is, uint8_t newenc, uint8_t extra, uint8_t offset) {
uint8_t curenc = is->encoding;
int length = is->length;
/* First set new encoding and resize */
is->encoding = newenc;
is = intsetResize(is,is->length+extra);
/* Upgrade back-to-front so we don't overwrite values */
while(length--)
INTSET_SET(is,length+offset,INTSET_GET_ENCODED(is,length,curenc));
return is;
}
/* Search for the position of "value". Return 1 when the value was found and
* sets "pos" to the position of the value within the intset. Return 0 when
* the value is not present in the intset and sets "pos" to the position
* where "value" can be inserted. */
static uint8_t intsetSearch(intset *is, int64_t value, uint32_t *pos) {
int min = 0, max = is->length-1, mid = -1;
int64_t cur = -1;
/* The value can never be found when the set is empty */
if (is->length == 0) {
if (pos) *pos = 0;
return 0;
} else {
/* Check for the case where we know we cannot find the value,
* but do know the insert position. */
if (value > INTSET_GET(is,is->length-1)) {
if (pos) *pos = is->length;
return 0;
} else if (value < INTSET_GET(is,0)) {
if (pos) *pos = 0;
return 0;
}
}
while(max >= min) {
mid = (min+max)/2;
cur = INTSET_GET(is,mid);
if (value > cur) {
min = mid+1;
} else if (value < cur) {
max = mid-1;
} else {
break;
}
}
if (value == cur) {
if (pos) *pos = mid;
return 1;
} else {
if (pos) *pos = min;
return 0;
}
}
static void intsetMoveTail(intset *is, uint32_t from, uint32_t to) {
void *src, *dst;
uint32_t bytes = is->length-from;
if (is->encoding == INTSET_ENC_INT64) {
src = (int64_t*)is->contents+from;
dst = (int64_t*)is->contents+to;
bytes *= sizeof(int64_t);
} else if (is->encoding == INTSET_ENC_INT32) {
src = (int32_t*)is->contents+from;
dst = (int32_t*)is->contents+to;
bytes *= sizeof(int32_t);
} else {
src = (int16_t*)is->contents+from;
dst = (int16_t*)is->contents+to;
bytes *= sizeof(int16_t);
}
memmove(dst,src,bytes);
}
/* Insert an integer in the intset */
intset *intsetAdd(intset *is, int64_t value, uint8_t *success) {
uint8_t valenc = INTSET_VALUE_ENCODING(value);
uint32_t pos, offset;
if (success) *success = 1;
/* Upgrade encoding if necessary. If we need to upgrade, we know that
* this value should be either appended (if > 0) or prepended (if < 0),
* because it lies outside the range of existing values. */
if (valenc > is->encoding) {
offset = value < 0 ? 1 : 0;
is = intsetUpgrade(is,valenc,1,offset);
pos = (value < 0) ? 0 : is->length;
} else {
/* Abort if the value is already present in the set.
* This call will populate "pos" with the right position to insert
* the value when it cannot be found. */
if (intsetSearch(is,value,&pos)) {
if (success) *success = 0;
return is;
}
is = intsetResize(is,is->length+1);
if (pos < is->length) intsetMoveTail(is,pos,pos+1);
}
INTSET_SET(is,pos,value);
is->length++;
return is;
}
/* Delete integer from intset */
intset *intsetRemove(intset *is, int64_t value, uint8_t *success) {
uint8_t valenc = INTSET_VALUE_ENCODING(value);
uint32_t pos;
if (success) *success = 0;
if (valenc <= is->encoding && intsetSearch(is,value,&pos)) {
/* We know we can delete */
if (success) *success = 1;
/* Overwrite value with tail and update length */
if (pos < (is->length-1)) intsetMoveTail(is,pos+1,pos);
is = intsetResize(is,is->length-1);
is->length--;
}
return is;
}
/* Determine whether a value belongs to this set */
uint8_t intsetFind(intset *is, int64_t value) {
uint8_t valenc = INTSET_VALUE_ENCODING(value);
return valenc <= is->encoding && intsetSearch(is,value,NULL);
}
/* Return random member */
int64_t intsetRandom(intset *is) {
return INTSET_GET(is,rand()%is->length);
}
/* Sets the value to the value at the given position. When this position is
* out of range the function returns 0, when in range it returns 1. */
uint8_t intsetGet(intset *is, uint32_t pos, int64_t *value) {
if (pos < is->length) {
*value = INTSET_GET(is,pos);
return 1;
}
return 0;
}
/* Return intset length */
uint32_t intsetLen(intset *is) {
return is->length;
}
#ifdef INTSET_TEST_MAIN
#include <sys/time.h>
void intsetRepr(intset *is) {
int i;
for (i = 0; i < is->length; i++) {
printf("%lld\n", (uint64_t)INTSET_GET(is,i));
}
printf("\n");
}
void error(char *err) {
printf("%s\n", err);
exit(1);
}
void ok(void) {
printf("OK\n");
}
long long usec(void) {
struct timeval tv;
gettimeofday(&tv,NULL);
return (((long long)tv.tv_sec)*1000000)+tv.tv_usec;
}
#define assert(_e) ((_e)?(void)0:(_assert(#_e,__FILE__,__LINE__),exit(1)))
void _assert(char *estr, char *file, int line) {
printf("\n\n=== ASSERTION FAILED ===\n");
printf("==> %s:%d '%s' is not true\n",file,line,estr);
}
intset *createSet(int bits, int size) {
uint64_t mask = (1<<bits)-1;
uint64_t i, value;
intset *is = intsetNew();
for (i = 0; i < size; i++) {
if (bits > 32) {
value = (rand()*rand()) & mask;
} else {
value = rand() & mask;
}
is = intsetAdd(is,value,NULL);
}
return is;
}
void checkConsistency(intset *is) {
int i;
for (i = 0; i < (is->length-1); i++) {
if (is->encoding == INTSET_ENC_INT16) {
int16_t *i16 = (int16_t*)is->contents;
assert(i16[i] < i16[i+1]);
} else if (is->encoding == INTSET_ENC_INT32) {
int32_t *i32 = (int32_t*)is->contents;
assert(i32[i] < i32[i+1]);
} else {
int64_t *i64 = (int64_t*)is->contents;
assert(i64[i] < i64[i+1]);
}
}
}
int main(int argc, char **argv) {
uint8_t success;
int i;
intset *is;
sranddev();
printf("Value encodings: "); {
assert(INTSET_VALUE_ENCODING(-32768) == INTSET_ENC_INT16);
assert(INTSET_VALUE_ENCODING(+32767) == INTSET_ENC_INT16);
assert(INTSET_VALUE_ENCODING(-32769) == INTSET_ENC_INT32);
assert(INTSET_VALUE_ENCODING(+32768) == INTSET_ENC_INT32);
assert(INTSET_VALUE_ENCODING(-2147483648) == INTSET_ENC_INT32);
assert(INTSET_VALUE_ENCODING(+2147483647) == INTSET_ENC_INT32);
assert(INTSET_VALUE_ENCODING(-2147483649) == INTSET_ENC_INT64);
assert(INTSET_VALUE_ENCODING(+2147483648) == INTSET_ENC_INT64);
assert(INTSET_VALUE_ENCODING(-9223372036854775808ull) == INTSET_ENC_INT64);
assert(INTSET_VALUE_ENCODING(+9223372036854775807ull) == INTSET_ENC_INT64);
ok();
}
printf("Basic adding: "); {
is = intsetNew();
is = intsetAdd(is,5,&success); assert(success);
is = intsetAdd(is,6,&success); assert(success);
is = intsetAdd(is,4,&success); assert(success);
is = intsetAdd(is,4,&success); assert(!success);
ok();
}
printf("Large number of random adds: "); {
int inserts = 0;
is = intsetNew();
for (i = 0; i < 1024; i++) {
is = intsetAdd(is,rand()%0x800,&success);
if (success) inserts++;
}
assert(is->length == inserts);
checkConsistency(is);
ok();
}
printf("Upgrade from int16 to int32: "); {
is = intsetNew();
is = intsetAdd(is,32,NULL);
assert(is->encoding == INTSET_ENC_INT16);
is = intsetAdd(is,65535,NULL);
assert(is->encoding == INTSET_ENC_INT32);
assert(intsetFind(is,32));
assert(intsetFind(is,65535));
checkConsistency(is);
is = intsetNew();
is = intsetAdd(is,32,NULL);
assert(is->encoding == INTSET_ENC_INT16);
is = intsetAdd(is,-65535,NULL);
assert(is->encoding == INTSET_ENC_INT32);
assert(intsetFind(is,32));
assert(intsetFind(is,-65535));
checkConsistency(is);
ok();
}
printf("Upgrade from int16 to int64: "); {
is = intsetNew();
is = intsetAdd(is,32,NULL);
assert(is->encoding == INTSET_ENC_INT16);
is = intsetAdd(is,4294967295,NULL);
assert(is->encoding == INTSET_ENC_INT64);
assert(intsetFind(is,32));
assert(intsetFind(is,4294967295));
checkConsistency(is);
is = intsetNew();
is = intsetAdd(is,32,NULL);
assert(is->encoding == INTSET_ENC_INT16);
is = intsetAdd(is,-4294967295,NULL);
assert(is->encoding == INTSET_ENC_INT64);
assert(intsetFind(is,32));
assert(intsetFind(is,-4294967295));
checkConsistency(is);
ok();
}
printf("Upgrade from int32 to int64: "); {
is = intsetNew();
is = intsetAdd(is,65535,NULL);
assert(is->encoding == INTSET_ENC_INT32);
is = intsetAdd(is,4294967295,NULL);
assert(is->encoding == INTSET_ENC_INT64);
assert(intsetFind(is,65535));
assert(intsetFind(is,4294967295));
checkConsistency(is);
is = intsetNew();
is = intsetAdd(is,65535,NULL);
assert(is->encoding == INTSET_ENC_INT32);
is = intsetAdd(is,-4294967295,NULL);
assert(is->encoding == INTSET_ENC_INT64);
assert(intsetFind(is,65535));
assert(intsetFind(is,-4294967295));
checkConsistency(is);
ok();
}
printf("Stress lookups: "); {
long num = 100000, size = 10000;
int i, bits = 20;
long long start;
is = createSet(bits,size);
checkConsistency(is);
start = usec();
for (i = 0; i < num; i++) intsetSearch(is,rand() % ((1<<bits)-1),NULL);
printf("%ld lookups, %ld element set, %lldusec\n",num,size,usec()-start);
}
printf("Stress add+delete: "); {
int i, v1, v2;
is = intsetNew();
for (i = 0; i < 0xffff; i++) {
v1 = rand() % 0xfff;
is = intsetAdd(is,v1,NULL);
assert(intsetFind(is,v1));
v2 = rand() % 0xfff;
is = intsetRemove(is,v2,NULL);
assert(!intsetFind(is,v2));
}
checkConsistency(is);
ok();
}
}
#endif
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