From 144b0094c31b0a3604e5bd2686a7df15c0fd324d Mon Sep 17 00:00:00 2001 From: Pieter Noordhuis Date: Thu, 3 Jun 2010 16:06:18 +0200 Subject: [PATCH] initial implementation for the intset --- intset.c | 379 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ intset.h | 16 +++ 2 files changed, 395 insertions(+) create mode 100644 intset.c create mode 100644 intset.h diff --git a/intset.c b/intset.c new file mode 100644 index 00000000..8ffaef25 --- /dev/null +++ b/intset.c @@ -0,0 +1,379 @@ +#include +#include +#include +#include +#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; + int64_t cur; + + /* The value can never be found when the set is empty */ + if (is->length == 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 { + if (is->length == 0) { + pos = 0; + } else { + /* Check for the case where we know the insert position */ + if (value > INTSET_GET(is,is->length-1)) { + pos = is->length; + } else if (value < INTSET_GET(is,0)) { + pos = 0; + } else { + /* Abort if the value is already present in the set */ + 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 *intsetDelete(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); +} + +#ifdef INTSET_TEST_MAIN +#include + +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< 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<