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openGauss-server/contrib/seg/seg.cpp

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/*
* contrib/seg/seg.c
*
******************************************************************************
This file contains routines that can be bound to a openGauss backend and
called by the backend in the process of processing queries. The calling
format for these routines is dictated by openGauss architecture.
******************************************************************************/
#include "postgres.h"
#include "knl/knl_variable.h"
#include <float.h>
#include "access/gist.h"
#include "access/skey.h"
#include "segdata.h"
PG_MODULE_MAGIC;
extern int seg_yyparse(void* result);
extern void seg_yyerror(const char* message);
extern void seg_scanner_init(const char* str);
extern void seg_scanner_finish(void);
/*
* Auxiliary data structure for picksplit method.
*/
typedef struct {
float center;
OffsetNumber index;
SEG* data;
} gseg_picksplit_item;
/*
** Input/Output routines
*/
PG_FUNCTION_INFO_V1(seg_in);
PG_FUNCTION_INFO_V1(seg_out);
PG_FUNCTION_INFO_V1(seg_size);
PG_FUNCTION_INFO_V1(seg_lower);
PG_FUNCTION_INFO_V1(seg_upper);
PG_FUNCTION_INFO_V1(seg_center);
extern "C" Datum seg_in(PG_FUNCTION_ARGS);
extern "C" Datum seg_out(PG_FUNCTION_ARGS);
extern "C" Datum seg_size(PG_FUNCTION_ARGS);
extern "C" Datum seg_lower(PG_FUNCTION_ARGS);
extern "C" Datum seg_upper(PG_FUNCTION_ARGS);
extern "C" Datum seg_center(PG_FUNCTION_ARGS);
/*
** GiST support methods
*/
extern "C" bool gseg_consistent(GISTENTRY* entry, SEG* query, StrategyNumber strategy, Oid subtype, bool* recheck);
extern "C" GISTENTRY* gseg_compress(GISTENTRY* entry);
extern "C" GISTENTRY* gseg_decompress(GISTENTRY* entry);
extern "C" float* gseg_penalty(GISTENTRY* origentry, GISTENTRY* newentry, float* result);
extern "C" GIST_SPLITVEC* gseg_picksplit(GistEntryVector* entryvec, GIST_SPLITVEC* v);
extern "C" bool gseg_leaf_consistent(SEG* key, SEG* query, StrategyNumber strategy);
extern "C" bool gseg_internal_consistent(SEG* key, SEG* query, StrategyNumber strategy);
extern "C" SEG* gseg_union(GistEntryVector* entryvec, int* sizep);
extern "C" SEG* gseg_binary_union(SEG* r1, SEG* r2, int* sizep);
extern "C" bool* gseg_same(SEG* b1, SEG* b2, bool* result);
/*
** R-tree support functions
*/
extern "C" bool seg_same(SEG* a, SEG* b);
extern "C" bool seg_contains_int(SEG* a, int* b);
extern "C" bool seg_contains_float4(SEG* a, float4* b);
extern "C" bool seg_contains_float8(SEG* a, float8* b);
extern "C" bool seg_contains(SEG* a, SEG* b);
extern "C" bool seg_contained(SEG* a, SEG* b);
extern "C" bool seg_overlap(SEG* a, SEG* b);
extern "C" bool seg_left(SEG* a, SEG* b);
extern "C" bool seg_over_left(SEG* a, SEG* b);
extern "C" bool seg_right(SEG* a, SEG* b);
extern "C" bool seg_over_right(SEG* a, SEG* b);
extern "C" SEG* seg_union(SEG* a, SEG* b);
extern "C" SEG* seg_inter(SEG* a, SEG* b);
extern "C" void rt_seg_size(SEG* a, float* sz);
/*
** Various operators
*/
extern "C" int32 seg_cmp(SEG* a, SEG* b);
extern "C" bool seg_lt(SEG* a, SEG* b);
extern "C" bool seg_le(SEG* a, SEG* b);
extern "C" bool seg_gt(SEG* a, SEG* b);
extern "C" bool seg_ge(SEG* a, SEG* b);
extern "C" bool seg_different(SEG* a, SEG* b);
/*
** Auxiliary funxtions
*/
static int restore(char* s, float val, int n);
int significant_digits(char* s);
/*****************************************************************************
* Input/Output functions
*****************************************************************************/
Datum seg_in(PG_FUNCTION_ARGS)
{
char* str = PG_GETARG_CSTRING(0);
SEG* result = (SEG*)palloc(sizeof(SEG));
seg_scanner_init(str);
if (seg_yyparse(result) != 0)
seg_yyerror("bogus input");
seg_scanner_finish();
PG_RETURN_POINTER(result);
}
Datum seg_out(PG_FUNCTION_ARGS)
{
SEG* seg = (SEG*)PG_GETARG_POINTER(0);
char* result = NULL;
char* p = NULL;
p = result = (char*)palloc(40);
if (seg->l_ext == '>' || seg->l_ext == '<' || seg->l_ext == '~')
p += sprintf(p, "%c", seg->l_ext);
if (seg->lower == seg->upper && seg->l_ext == seg->u_ext) {
/*
* indicates that this interval was built by seg_in off a single point
*/
p += restore(p, seg->lower, seg->l_sigd);
} else {
if (seg->l_ext != '-') {
/* print the lower boundary if exists */
p += restore(p, seg->lower, seg->l_sigd);
p += sprintf(p, " ");
}
p += sprintf(p, "..");
if (seg->u_ext != '-') {
/* print the upper boundary if exists */
p += sprintf(p, " ");
if (seg->u_ext == '>' || seg->u_ext == '<' || seg->l_ext == '~')
p += sprintf(p, "%c", seg->u_ext);
p += restore(p, seg->upper, seg->u_sigd);
}
}
PG_RETURN_CSTRING(result);
}
Datum seg_center(PG_FUNCTION_ARGS)
{
SEG* seg = (SEG*)PG_GETARG_POINTER(0);
PG_RETURN_FLOAT4(((float)seg->lower + (float)seg->upper) / 2.0);
}
Datum seg_lower(PG_FUNCTION_ARGS)
{
SEG* seg = (SEG*)PG_GETARG_POINTER(0);
PG_RETURN_FLOAT4(seg->lower);
}
Datum seg_upper(PG_FUNCTION_ARGS)
{
SEG* seg = (SEG*)PG_GETARG_POINTER(0);
PG_RETURN_FLOAT4(seg->upper);
}
/*****************************************************************************
* GiST functions
*****************************************************************************/
/*
** The GiST Consistent method for segments
** Should return false if for all data items x below entry,
** the predicate x op query == FALSE, where op is the oper
** corresponding to strategy in the pg_amop table.
*/
bool gseg_consistent(GISTENTRY* entry, SEG* query, StrategyNumber strategy, Oid subtype, bool* recheck)
{
/* All cases served by this function are exact */
*recheck = false;
/*
* if entry is not leaf, use gseg_internal_consistent, else use
* gseg_leaf_consistent
*/
if (GIST_LEAF(entry))
return (gseg_leaf_consistent((SEG*)DatumGetPointer(entry->key), query, strategy));
else
return (gseg_internal_consistent((SEG*)DatumGetPointer(entry->key), query, strategy));
}
/*
** The GiST Union method for segments
** returns the minimal bounding seg that encloses all the entries in entryvec
*/
SEG* gseg_union(GistEntryVector* entryvec, int* sizep)
{
int numranges, i;
SEG* out = (SEG*)NULL;
SEG* tmp = NULL;
#ifdef GIST_DEBUG
fprintf(stderr, "union\n");
#endif
numranges = entryvec->n;
tmp = (SEG*)DatumGetPointer(entryvec->vector[0].key);
*sizep = sizeof(SEG);
for (i = 1; i < numranges; i++) {
out = gseg_binary_union(tmp, (SEG*)DatumGetPointer(entryvec->vector[i].key), sizep);
tmp = out;
}
return (out);
}
/*
** GiST Compress and Decompress methods for segments
** do not do anything.
*/
GISTENTRY* gseg_compress(GISTENTRY* entry)
{
return (entry);
}
GISTENTRY* gseg_decompress(GISTENTRY* entry)
{
return (entry);
}
/*
** The GiST Penalty method for segments
** As in the R-tree paper, we use change in area as our penalty metric
*/
float* gseg_penalty(GISTENTRY* origentry, GISTENTRY* newentry, float* result)
{
SEG* ud = NULL;
float tmp1, tmp2;
ud = seg_union((SEG*)DatumGetPointer(origentry->key), (SEG*)DatumGetPointer(newentry->key));
rt_seg_size(ud, &tmp1);
rt_seg_size((SEG*)DatumGetPointer(origentry->key), &tmp2);
*result = tmp1 - tmp2;
#ifdef GIST_DEBUG
fprintf(stderr, "penalty\n");
fprintf(stderr, "\t%g\n", *result);
#endif
return (result);
}
/*
* Compare function for gseg_picksplit_item: sort by center.
*/
static int gseg_picksplit_item_cmp(const void* a, const void* b)
{
const gseg_picksplit_item* i1 = (const gseg_picksplit_item*)a;
const gseg_picksplit_item* i2 = (const gseg_picksplit_item*)b;
if (i1->center < i2->center)
return -1;
else if (i1->center == i2->center)
return 0;
else
return 1;
}
/*
* The GiST PickSplit method for segments
*
* We used to use Guttman's split algorithm here, but since the data is 1-D
* it's easier and more robust to just sort the segments by center-point and
* split at the middle.
*/
GIST_SPLITVEC* gseg_picksplit(GistEntryVector* entryvec, GIST_SPLITVEC* v)
{
int i;
SEG *datum_l, *datum_r, *seg;
gseg_picksplit_item* sort_items = NULL;
OffsetNumber *left, *right;
OffsetNumber maxoff;
OffsetNumber firstright;
#ifdef GIST_DEBUG
fprintf(stderr, "picksplit\n");
#endif
/* Valid items in entryvec->vector[] are indexed 1..maxoff */
maxoff = entryvec->n - 1;
/*
* Prepare the auxiliary array and sort it.
*/
sort_items = (gseg_picksplit_item*)palloc(maxoff * sizeof(gseg_picksplit_item));
for (i = 1; i <= maxoff; i++) {
seg = (SEG*)DatumGetPointer(entryvec->vector[i].key);
/* center calculation is done this way to avoid possible overflow */
sort_items[i - 1].center = seg->lower * 0.5f + seg->upper * 0.5f;
sort_items[i - 1].index = i;
sort_items[i - 1].data = seg;
}
qsort(sort_items, maxoff, sizeof(gseg_picksplit_item), gseg_picksplit_item_cmp);
/* sort items below "firstright" will go into the left side */
firstright = maxoff / 2;
v->spl_left = (OffsetNumber*)palloc(maxoff * sizeof(OffsetNumber));
v->spl_right = (OffsetNumber*)palloc(maxoff * sizeof(OffsetNumber));
left = v->spl_left;
v->spl_nleft = 0;
right = v->spl_right;
v->spl_nright = 0;
/*
* Emit segments to the left output page, and compute its bounding box.
*/
datum_l = (SEG*)palloc(sizeof(SEG));
memcpy(datum_l, sort_items[0].data, sizeof(SEG));
*left++ = sort_items[0].index;
v->spl_nleft++;
for (i = 1; i < firstright; i++) {
datum_l = seg_union(datum_l, sort_items[i].data);
*left++ = sort_items[i].index;
v->spl_nleft++;
}
/*
* Likewise for the right page.
*/
datum_r = (SEG*)palloc(sizeof(SEG));
memcpy(datum_r, sort_items[firstright].data, sizeof(SEG));
*right++ = sort_items[firstright].index;
v->spl_nright++;
for (i = firstright + 1; i < maxoff; i++) {
datum_r = seg_union(datum_r, sort_items[i].data);
*right++ = sort_items[i].index;
v->spl_nright++;
}
v->spl_ldatum = PointerGetDatum(datum_l);
v->spl_rdatum = PointerGetDatum(datum_r);
return v;
}
/*
** Equality methods
*/
bool* gseg_same(SEG* b1, SEG* b2, bool* result)
{
if (seg_same(b1, b2))
*result = TRUE;
else
*result = FALSE;
#ifdef GIST_DEBUG
fprintf(stderr, "same: %s\n", (*result ? "TRUE" : "FALSE"));
#endif
return (result);
}
/*
** SUPPORT ROUTINES
*/
bool gseg_leaf_consistent(SEG* key, SEG* query, StrategyNumber strategy)
{
bool retval = false;
#ifdef GIST_QUERY_DEBUG
fprintf(stderr, "leaf_consistent, %d\n", strategy);
#endif
switch (strategy) {
case RTLeftStrategyNumber:
retval = (bool)seg_left(key, query);
break;
case RTOverLeftStrategyNumber:
retval = (bool)seg_over_left(key, query);
break;
case RTOverlapStrategyNumber:
retval = (bool)seg_overlap(key, query);
break;
case RTOverRightStrategyNumber:
retval = (bool)seg_over_right(key, query);
break;
case RTRightStrategyNumber:
retval = (bool)seg_right(key, query);
break;
case RTSameStrategyNumber:
retval = (bool)seg_same(key, query);
break;
case RTContainsStrategyNumber:
case RTOldContainsStrategyNumber:
retval = (bool)seg_contains(key, query);
break;
case RTContainedByStrategyNumber:
case RTOldContainedByStrategyNumber:
retval = (bool)seg_contained(key, query);
break;
default:
retval = FALSE;
}
return (retval);
}
bool gseg_internal_consistent(SEG* key, SEG* query, StrategyNumber strategy)
{
bool retval = false;
#ifdef GIST_QUERY_DEBUG
fprintf(stderr, "internal_consistent, %d\n", strategy);
#endif
switch (strategy) {
case RTLeftStrategyNumber:
retval = (bool)!seg_over_right(key, query);
break;
case RTOverLeftStrategyNumber:
retval = (bool)!seg_right(key, query);
break;
case RTOverlapStrategyNumber:
retval = (bool)seg_overlap(key, query);
break;
case RTOverRightStrategyNumber:
retval = (bool)!seg_left(key, query);
break;
case RTRightStrategyNumber:
retval = (bool)!seg_over_left(key, query);
break;
case RTSameStrategyNumber:
case RTContainsStrategyNumber:
case RTOldContainsStrategyNumber:
retval = (bool)seg_contains(key, query);
break;
case RTContainedByStrategyNumber:
case RTOldContainedByStrategyNumber:
retval = (bool)seg_overlap(key, query);
break;
default:
retval = FALSE;
}
return (retval);
}
SEG* gseg_binary_union(SEG* r1, SEG* r2, int* sizep)
{
SEG* retval = NULL;
retval = seg_union(r1, r2);
*sizep = sizeof(SEG);
return (retval);
}
bool seg_contains(SEG* a, SEG* b)
{
return ((a->lower <= b->lower) && (a->upper >= b->upper));
}
bool seg_contained(SEG* a, SEG* b)
{
return (seg_contains(b, a));
}
/*****************************************************************************
* Operator class for R-tree indexing
*****************************************************************************/
bool seg_same(SEG* a, SEG* b)
{
return seg_cmp(a, b) == 0;
}
/* seg_overlap -- does a overlap b?
*/
bool seg_overlap(SEG* a, SEG* b)
{
return (((a->upper >= b->upper) && (a->lower <= b->upper)) || ((b->upper >= a->upper) && (b->lower <= a->upper)));
}
/* seg_overleft -- is the right edge of (a) located at or left of the right edge of (b)?
*/
bool seg_over_left(SEG* a, SEG* b)
{
return (a->upper <= b->upper);
}
/* seg_left -- is (a) entirely on the left of (b)?
*/
bool seg_left(SEG* a, SEG* b)
{
return (a->upper < b->lower);
}
/* seg_right -- is (a) entirely on the right of (b)?
*/
bool seg_right(SEG* a, SEG* b)
{
return (a->lower > b->upper);
}
/* seg_overright -- is the left edge of (a) located at or right of the left edge of (b)?
*/
bool seg_over_right(SEG* a, SEG* b)
{
return (a->lower >= b->lower);
}
SEG* seg_union(SEG* a, SEG* b)
{
SEG* n = NULL;
n = (SEG*)palloc(sizeof(*n));
/* take max of upper endpoints */
if (a->upper > b->upper) {
n->upper = a->upper;
n->u_sigd = a->u_sigd;
n->u_ext = a->u_ext;
} else {
n->upper = b->upper;
n->u_sigd = b->u_sigd;
n->u_ext = b->u_ext;
}
/* take min of lower endpoints */
if (a->lower < b->lower) {
n->lower = a->lower;
n->l_sigd = a->l_sigd;
n->l_ext = a->l_ext;
} else {
n->lower = b->lower;
n->l_sigd = b->l_sigd;
n->l_ext = b->l_ext;
}
return (n);
}
SEG* seg_inter(SEG* a, SEG* b)
{
SEG* n = NULL;
n = (SEG*)palloc(sizeof(*n));
/* take min of upper endpoints */
if (a->upper < b->upper) {
n->upper = a->upper;
n->u_sigd = a->u_sigd;
n->u_ext = a->u_ext;
} else {
n->upper = b->upper;
n->u_sigd = b->u_sigd;
n->u_ext = b->u_ext;
}
/* take max of lower endpoints */
if (a->lower > b->lower) {
n->lower = a->lower;
n->l_sigd = a->l_sigd;
n->l_ext = a->l_ext;
} else {
n->lower = b->lower;
n->l_sigd = b->l_sigd;
n->l_ext = b->l_ext;
}
return (n);
}
void rt_seg_size(SEG* a, float* size)
{
if (a == (SEG*)NULL || a->upper <= a->lower)
*size = 0.0;
else
*size = (float)Abs(a->upper - a->lower);
return;
}
Datum seg_size(PG_FUNCTION_ARGS)
{
SEG* seg = (SEG*)PG_GETARG_POINTER(0);
PG_RETURN_FLOAT4((float)Abs(seg->upper - seg->lower));
}
/*****************************************************************************
* Miscellaneous operators
*****************************************************************************/
int32 seg_cmp(SEG* a, SEG* b)
{
/*
* First compare on lower boundary position
*/
if (a->lower < b->lower)
return -1;
if (a->lower > b->lower)
return 1;
/*
* a->lower == b->lower, so consider type of boundary.
*
* A '-' lower bound is < any other kind (this could only be relevant if
* -HUGE_VAL is used as a regular data value). A '<' lower bound is < any
* other kind except '-'. A '>' lower bound is > any other kind.
*/
if (a->l_ext != b->l_ext) {
if (a->l_ext == '-')
return -1;
if (b->l_ext == '-')
return 1;
if (a->l_ext == '<')
return -1;
if (b->l_ext == '<')
return 1;
if (a->l_ext == '>')
return 1;
if (b->l_ext == '>')
return -1;
}
/*
* For other boundary types, consider # of significant digits first.
*/
if (a->l_sigd < b->l_sigd) /* (a) is blurred and is likely to include (b) */
return -1;
if (a->l_sigd > b->l_sigd) /* (a) is less blurred and is likely to be
* included in (b) */
return 1;
/*
* For same # of digits, an approximate boundary is more blurred than
* exact.
*/
if (a->l_ext != b->l_ext) {
if (a->l_ext == '~') /* (a) is approximate, while (b) is exact */
return -1;
if (b->l_ext == '~')
return 1;
/* can't get here unless data is corrupt */
elog(ERROR, "bogus lower boundary types %d %d", (int)a->l_ext, (int)b->l_ext);
}
/* at this point, the lower boundaries are identical */
/*
* First compare on upper boundary position
*/
if (a->upper < b->upper)
return -1;
if (a->upper > b->upper)
return 1;
/*
* a->upper == b->upper, so consider type of boundary.
*
* A '-' upper bound is > any other kind (this could only be relevant if
* HUGE_VAL is used as a regular data value). A '<' upper bound is < any
* other kind. A '>' upper bound is > any other kind except '-'.
*/
if (a->u_ext != b->u_ext) {
if (a->u_ext == '-')
return 1;
if (b->u_ext == '-')
return -1;
if (a->u_ext == '<')
return -1;
if (b->u_ext == '<')
return 1;
if (a->u_ext == '>')
return 1;
if (b->u_ext == '>')
return -1;
}
/*
* For other boundary types, consider # of significant digits first. Note
* result here is converse of the lower-boundary case.
*/
if (a->u_sigd < b->u_sigd) /* (a) is blurred and is likely to include (b) */
return 1;
if (a->u_sigd > b->u_sigd) /* (a) is less blurred and is likely to be
* included in (b) */
return -1;
/*
* For same # of digits, an approximate boundary is more blurred than
* exact. Again, result is converse of lower-boundary case.
*/
if (a->u_ext != b->u_ext) {
if (a->u_ext == '~') /* (a) is approximate, while (b) is exact */
return 1;
if (b->u_ext == '~')
return -1;
/* can't get here unless data is corrupt */
elog(ERROR, "bogus upper boundary types %d %d", (int)a->u_ext, (int)b->u_ext);
}
return 0;
}
bool seg_lt(SEG* a, SEG* b)
{
return seg_cmp(a, b) < 0;
}
bool seg_le(SEG* a, SEG* b)
{
return seg_cmp(a, b) <= 0;
}
bool seg_gt(SEG* a, SEG* b)
{
return seg_cmp(a, b) > 0;
}
bool seg_ge(SEG* a, SEG* b)
{
return seg_cmp(a, b) >= 0;
}
bool seg_different(SEG* a, SEG* b)
{
return seg_cmp(a, b) != 0;
}
/*****************************************************************************
* Auxiliary functions
*****************************************************************************/
/* The purpose of this routine is to print the floating point
* value with exact number of significant digits. Its behaviour
* is similar to %.ng except it prints 8.00 where %.ng would
* print 8
*/
static int restore(char* result, float val, int n)
{
static char efmt[8] = {'%', '-', '1', '5', '.', '#', 'e', 0};
char buf[25] = {'0',
'0',
'0',
'0',
'0',
'0',
'0',
'0',
'0',
'0',
'0',
'0',
'0',
'0',
'0',
'0',
'0',
'0',
'0',
'0',
'0',
'0',
'0',
'0',
'\0'};
char* p = NULL;
int exp;
int i, dp, sign;
/*
* put a cap on the number of siugnificant digits to avoid nonsense in the
* output
*/
n = Min(n, FLT_DIG);
/* remember the sign */
sign = (val < 0 ? 1 : 0);
efmt[5] = '0' + (n - 1) % 10; /* makes %-15.(n-1)e -- this format
* guarantees that the exponent is
* always present */
sprintf(result, efmt, val);
/* trim the spaces left by the %e */
for (p = result; *p != ' '; p++)
;
*p = '\0';
/* get the exponent */
char *tmp = pstrdup(result);
strtok(tmp, "e");
exp = atoi(strtok(NULL, "e"));
if (exp == 0) {
/* use the supplied mantyssa with sign */
strcpy((char*)strchr(result, 'e'), "");
} else {
if (Abs(exp) <= 4) {
/*
* remove the decimal point from the mantyssa and write the digits
* to the buf array
*/
for (p = result + sign, i = 10, dp = 0; *p != 'e'; p++, i++) {
buf[i] = *p;
if (*p == '.') {
dp = i--; /* skip the decimal point */
}
}
if (dp == 0)
dp = i--; /* no decimal point was found in the above
* for() loop */
if (exp > 0) {
if (dp - 10 + exp >= n) {
/*
* the decimal point is behind the last significant digit;
* the digits in between must be converted to the exponent
* and the decimal point placed after the first digit
*/
exp = dp - 10 + exp - n;
buf[10 + n] = '\0';
/* insert the decimal point */
if (n > 1) {
dp = 11;
for (i = 23; i > dp; i--)
buf[i] = buf[i - 1];
buf[dp] = '.';
}
/*
* adjust the exponent by the number of digits after the
* decimal point
*/
if (n > 1)
sprintf(&buf[11 + n], "e%d", exp + n - 1);
else
sprintf(&buf[11], "e%d", exp + n - 1);
if (sign) {
buf[9] = '-';
strcpy(result, &buf[9]);
} else
strcpy(result, &buf[10]);
} else { /* insert the decimal point */
dp += exp;
for (i = 23; i > dp; i--)
buf[i] = buf[i - 1];
buf[11 + n] = '\0';
buf[dp] = '.';
if (sign) {
buf[9] = '-';
strcpy(result, &buf[9]);
} else
strcpy(result, &buf[10]);
}
} else { /* exp <= 0 */
dp += exp - 1;
buf[10 + n] = '\0';
buf[dp] = '.';
if (sign) {
buf[dp - 2] = '-';
strcpy(result, &buf[dp - 2]);
} else
strcpy(result, &buf[dp - 1]);
}
}
/* do nothing for Abs(exp) > 4; %e must be OK */
/* just get rid of zeroes after [eE]- and +zeroes after [Ee]. */
/* ... this is not done yet. */
}
pfree_ext(tmp);
return (strlen(result));
}
/*
** Miscellany
*/
bool seg_contains_int(SEG* a, int* b)
{
return ((a->lower <= *b) && (a->upper >= *b));
}
bool seg_contains_float4(SEG* a, float4* b)
{
return ((a->lower <= *b) && (a->upper >= *b));
}
bool seg_contains_float8(SEG* a, float8* b)
{
return ((a->lower <= *b) && (a->upper >= *b));
}
/* find out the number of significant digits in a string representing
* a floating point number
*/
int significant_digits(char* s)
{
char* p = s;
int n, c, zeroes;
zeroes = 1;
/* skip leading zeroes and sign */
for (c = *p; (c == '0' || c == '+' || c == '-') && c != 0; c = *(++p))
;
/* skip decimal point and following zeroes */
for (c = *p; (c == '0' || c == '.') && c != 0; c = *(++p)) {
if (c != '.')
zeroes++;
}
/* count significant digits (n) */
for (c = *p, n = 0; c != 0; c = *(++p)) {
if (!((c >= '0' && c <= '9') || (c == '.')))
break;
if (c != '.')
n++;
}
if (!n)
return (zeroes);
return (n);
}
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