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postgresql/contrib/seg/seg.c
Alvaro Herrera c9d2977519 Clean up newlines following left parentheses 
We used to strategically place newlines after some function call left
parentheses to make pgindent move the argument list a few chars to the
left, so that the whole line would fit under 80 chars.  However,
pgindent no longer does that, so the newlines just made the code
vertically longer for no reason.  Remove those newlines, and reflow some
of those lines for some extra naturality.

Reviewed-by: Michael Paquier, Tom Lane
Discussion: https://postgr.es/m/20200129200401.GA6303@alvherre.pgsql
2020-01-30 13:42:14 -03:00

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/*
* contrib/seg/seg.c
*
******************************************************************************
This file contains routines that can be bound to a Postgres backend and
called by the backend in the process of processing queries. The calling
format for these routines is dictated by Postgres architecture.
******************************************************************************/
#include "postgres.h"
#include <float.h>
#include "access/gist.h"
#include "access/stratnum.h"
#include "fmgr.h"
#include "segdata.h"
#define DatumGetSegP(X) ((SEG *) DatumGetPointer(X))
#define PG_GETARG_SEG_P(n) DatumGetSegP(PG_GETARG_DATUM(n))
/*
#define GIST_DEBUG
#define GIST_QUERY_DEBUG
*/
PG_MODULE_MAGIC;
/*
* 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);
/*
** GiST support methods
*/
PG_FUNCTION_INFO_V1(gseg_consistent);
PG_FUNCTION_INFO_V1(gseg_compress);
PG_FUNCTION_INFO_V1(gseg_decompress);
PG_FUNCTION_INFO_V1(gseg_picksplit);
PG_FUNCTION_INFO_V1(gseg_penalty);
PG_FUNCTION_INFO_V1(gseg_union);
PG_FUNCTION_INFO_V1(gseg_same);
static Datum gseg_leaf_consistent(Datum key, Datum query, StrategyNumber strategy);
static Datum gseg_internal_consistent(Datum key, Datum query, StrategyNumber strategy);
static Datum gseg_binary_union(Datum r1, Datum r2, int *sizep);
/*
** R-tree support functions
*/
PG_FUNCTION_INFO_V1(seg_same);
PG_FUNCTION_INFO_V1(seg_contains);
PG_FUNCTION_INFO_V1(seg_contained);
PG_FUNCTION_INFO_V1(seg_overlap);
PG_FUNCTION_INFO_V1(seg_left);
PG_FUNCTION_INFO_V1(seg_over_left);
PG_FUNCTION_INFO_V1(seg_right);
PG_FUNCTION_INFO_V1(seg_over_right);
PG_FUNCTION_INFO_V1(seg_union);
PG_FUNCTION_INFO_V1(seg_inter);
static void rt_seg_size(SEG *a, float *size);
/*
** Various operators
*/
PG_FUNCTION_INFO_V1(seg_cmp);
PG_FUNCTION_INFO_V1(seg_lt);
PG_FUNCTION_INFO_V1(seg_le);
PG_FUNCTION_INFO_V1(seg_gt);
PG_FUNCTION_INFO_V1(seg_ge);
PG_FUNCTION_INFO_V1(seg_different);
/*
** Auxiliary functions
*/
static int restore(char *s, float val, int n);
/*****************************************************************************
* Input/Output functions
*****************************************************************************/
Datum
seg_in(PG_FUNCTION_ARGS)
{
char *str = PG_GETARG_CSTRING(0);
SEG *result = palloc(sizeof(SEG));
seg_scanner_init(str);
if (seg_yyparse(result) != 0)
seg_yyerror(result, "bogus input");
seg_scanner_finish();
PG_RETURN_POINTER(result);
}
Datum
seg_out(PG_FUNCTION_ARGS)
{
SEG *seg = PG_GETARG_SEG_P(0);
char *result;
char *p;
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 = PG_GETARG_SEG_P(0);
PG_RETURN_FLOAT4(((float) seg->lower + (float) seg->upper) / 2.0);
}
Datum
seg_lower(PG_FUNCTION_ARGS)
{
SEG *seg = PG_GETARG_SEG_P(0);
PG_RETURN_FLOAT4(seg->lower);
}
Datum
seg_upper(PG_FUNCTION_ARGS)
{
SEG *seg = PG_GETARG_SEG_P(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.
*/
Datum
gseg_consistent(PG_FUNCTION_ARGS)
{
GISTENTRY *entry = (GISTENTRY *) PG_GETARG_POINTER(0);
Datum query = PG_GETARG_DATUM(1);
StrategyNumber strategy = (StrategyNumber) PG_GETARG_UINT16(2);
/* Oid subtype = PG_GETARG_OID(3); */
bool *recheck = (bool *) PG_GETARG_POINTER(4);
/* 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(entry->key, query, strategy);
else
return gseg_internal_consistent(entry->key, query, strategy);
}
/*
** The GiST Union method for segments
** returns the minimal bounding seg that encloses all the entries in entryvec
*/
Datum
gseg_union(PG_FUNCTION_ARGS)
{
GistEntryVector *entryvec = (GistEntryVector *) PG_GETARG_POINTER(0);
int *sizep = (int *) PG_GETARG_POINTER(1);
int numranges,
i;
Datum out = 0;
Datum tmp;
#ifdef GIST_DEBUG
fprintf(stderr, "union\n");
#endif
numranges = entryvec->n;
tmp = entryvec->vector[0].key;
*sizep = sizeof(SEG);
for (i = 1; i < numranges; i++)
{
out = gseg_binary_union(tmp, entryvec->vector[i].key, sizep);
tmp = out;
}
PG_RETURN_DATUM(out);
}
/*
** GiST Compress and Decompress methods for segments
** do not do anything.
*/
Datum
gseg_compress(PG_FUNCTION_ARGS)
{
PG_RETURN_POINTER(PG_GETARG_POINTER(0));
}
Datum
gseg_decompress(PG_FUNCTION_ARGS)
{
PG_RETURN_POINTER(PG_GETARG_POINTER(0));
}
/*
** The GiST Penalty method for segments
** As in the R-tree paper, we use change in area as our penalty metric
*/
Datum
gseg_penalty(PG_FUNCTION_ARGS)
{
GISTENTRY *origentry = (GISTENTRY *) PG_GETARG_POINTER(0);
GISTENTRY *newentry = (GISTENTRY *) PG_GETARG_POINTER(1);
float *result = (float *) PG_GETARG_POINTER(2);
SEG *ud;
float tmp1,
tmp2;
ud = DatumGetSegP(DirectFunctionCall2(seg_union,
origentry->key,
newentry->key));
rt_seg_size(ud, &tmp1);
rt_seg_size(DatumGetSegP(origentry->key), &tmp2);
*result = tmp1 - tmp2;
#ifdef GIST_DEBUG
fprintf(stderr, "penalty\n");
fprintf(stderr, "\t%g\n", *result);
#endif
PG_RETURN_POINTER(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.
*/
Datum
gseg_picksplit(PG_FUNCTION_ARGS)
{
GistEntryVector *entryvec = (GistEntryVector *) PG_GETARG_POINTER(0);
GIST_SPLITVEC *v = (GIST_SPLITVEC *) PG_GETARG_POINTER(1);
int i;
SEG *seg,
*seg_l,
*seg_r;
gseg_picksplit_item *sort_items;
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 = DatumGetSegP(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.
*/
seg_l = (SEG *) palloc(sizeof(SEG));
memcpy(seg_l, sort_items[0].data, sizeof(SEG));
*left++ = sort_items[0].index;
v->spl_nleft++;
for (i = 1; i < firstright; i++)
{
Datum sortitem = PointerGetDatum(sort_items[i].data);
seg_l = DatumGetSegP(DirectFunctionCall2(seg_union,
PointerGetDatum(seg_l),
sortitem));
*left++ = sort_items[i].index;
v->spl_nleft++;
}
/*
* Likewise for the right page.
*/
seg_r = (SEG *) palloc(sizeof(SEG));
memcpy(seg_r, sort_items[firstright].data, sizeof(SEG));
*right++ = sort_items[firstright].index;
v->spl_nright++;
for (i = firstright + 1; i < maxoff; i++)
{
Datum sortitem = PointerGetDatum(sort_items[i].data);
seg_r = DatumGetSegP(DirectFunctionCall2(seg_union,
PointerGetDatum(seg_r),
sortitem));
*right++ = sort_items[i].index;
v->spl_nright++;
}
v->spl_ldatum = PointerGetDatum(seg_l);
v->spl_rdatum = PointerGetDatum(seg_r);
PG_RETURN_POINTER(v);
}
/*
** Equality methods
*/
Datum
gseg_same(PG_FUNCTION_ARGS)
{
bool *result = (bool *) PG_GETARG_POINTER(2);
if (DirectFunctionCall2(seg_same, PG_GETARG_DATUM(0), PG_GETARG_DATUM(1)))
*result = true;
else
*result = false;
#ifdef GIST_DEBUG
fprintf(stderr, "same: %s\n", (*result ? "TRUE" : "FALSE"));
#endif
PG_RETURN_POINTER(result);
}
/*
** SUPPORT ROUTINES
*/
static Datum
gseg_leaf_consistent(Datum key, Datum query, StrategyNumber strategy)
{
Datum retval;
#ifdef GIST_QUERY_DEBUG
fprintf(stderr, "leaf_consistent, %d\n", strategy);
#endif
switch (strategy)
{
case RTLeftStrategyNumber:
retval = DirectFunctionCall2(seg_left, key, query);
break;
case RTOverLeftStrategyNumber:
retval = DirectFunctionCall2(seg_over_left, key, query);
break;
case RTOverlapStrategyNumber:
retval = DirectFunctionCall2(seg_overlap, key, query);
break;
case RTOverRightStrategyNumber:
retval = DirectFunctionCall2(seg_over_right, key, query);
break;
case RTRightStrategyNumber:
retval = DirectFunctionCall2(seg_right, key, query);
break;
case RTSameStrategyNumber:
retval = DirectFunctionCall2(seg_same, key, query);
break;
case RTContainsStrategyNumber:
case RTOldContainsStrategyNumber:
retval = DirectFunctionCall2(seg_contains, key, query);
break;
case RTContainedByStrategyNumber:
case RTOldContainedByStrategyNumber:
retval = DirectFunctionCall2(seg_contained, key, query);
break;
default:
retval = false;
}
PG_RETURN_DATUM(retval);
}
static Datum
gseg_internal_consistent(Datum key, Datum query, StrategyNumber strategy)
{
bool retval;
#ifdef GIST_QUERY_DEBUG
fprintf(stderr, "internal_consistent, %d\n", strategy);
#endif
switch (strategy)
{
case RTLeftStrategyNumber:
retval =
!DatumGetBool(DirectFunctionCall2(seg_over_right, key, query));
break;
case RTOverLeftStrategyNumber:
retval =
!DatumGetBool(DirectFunctionCall2(seg_right, key, query));
break;
case RTOverlapStrategyNumber:
retval =
DatumGetBool(DirectFunctionCall2(seg_overlap, key, query));
break;
case RTOverRightStrategyNumber:
retval =
!DatumGetBool(DirectFunctionCall2(seg_left, key, query));
break;
case RTRightStrategyNumber:
retval =
!DatumGetBool(DirectFunctionCall2(seg_over_left, key, query));
break;
case RTSameStrategyNumber:
case RTContainsStrategyNumber:
case RTOldContainsStrategyNumber:
retval =
DatumGetBool(DirectFunctionCall2(seg_contains, key, query));
break;
case RTContainedByStrategyNumber:
case RTOldContainedByStrategyNumber:
retval =
DatumGetBool(DirectFunctionCall2(seg_overlap, key, query));
break;
default:
retval = false;
}
PG_RETURN_BOOL(retval);
}
static Datum
gseg_binary_union(Datum r1, Datum r2, int *sizep)
{
Datum retval;
retval = DirectFunctionCall2(seg_union, r1, r2);
*sizep = sizeof(SEG);
return retval;
}
Datum
seg_contains(PG_FUNCTION_ARGS)
{
SEG *a = PG_GETARG_SEG_P(0);
SEG *b = PG_GETARG_SEG_P(1);
PG_RETURN_BOOL((a->lower <= b->lower) && (a->upper >= b->upper));
}
Datum
seg_contained(PG_FUNCTION_ARGS)
{
Datum a = PG_GETARG_DATUM(0);
Datum b = PG_GETARG_DATUM(1);
PG_RETURN_DATUM(DirectFunctionCall2(seg_contains, b, a));
}
/*****************************************************************************
* Operator class for R-tree indexing
*****************************************************************************/
Datum
seg_same(PG_FUNCTION_ARGS)
{
int cmp = DatumGetInt32(DirectFunctionCall2(seg_cmp,
PG_GETARG_DATUM(0),
PG_GETARG_DATUM(1)));
PG_RETURN_BOOL(cmp == 0);
}
/* seg_overlap -- does a overlap b?
*/
Datum
seg_overlap(PG_FUNCTION_ARGS)
{
SEG *a = PG_GETARG_SEG_P(0);
SEG *b = PG_GETARG_SEG_P(1);
PG_RETURN_BOOL(((a->upper >= b->upper) && (a->lower <= b->upper)) ||
((b->upper >= a->upper) && (b->lower <= a->upper)));
}
/* seg_over_left -- is the right edge of (a) located at or left of the right edge of (b)?
*/
Datum
seg_over_left(PG_FUNCTION_ARGS)
{
SEG *a = PG_GETARG_SEG_P(0);
SEG *b = PG_GETARG_SEG_P(1);
PG_RETURN_BOOL(a->upper <= b->upper);
}
/* seg_left -- is (a) entirely on the left of (b)?
*/
Datum
seg_left(PG_FUNCTION_ARGS)
{
SEG *a = PG_GETARG_SEG_P(0);
SEG *b = PG_GETARG_SEG_P(1);
PG_RETURN_BOOL(a->upper < b->lower);
}
/* seg_right -- is (a) entirely on the right of (b)?
*/
Datum
seg_right(PG_FUNCTION_ARGS)
{
SEG *a = PG_GETARG_SEG_P(0);
SEG *b = PG_GETARG_SEG_P(1);
PG_RETURN_BOOL(a->lower > b->upper);
}
/* seg_over_right -- is the left edge of (a) located at or right of the left edge of (b)?
*/
Datum
seg_over_right(PG_FUNCTION_ARGS)
{
SEG *a = PG_GETARG_SEG_P(0);
SEG *b = PG_GETARG_SEG_P(1);
PG_RETURN_BOOL(a->lower >= b->lower);
}
Datum
seg_union(PG_FUNCTION_ARGS)
{
SEG *a = PG_GETARG_SEG_P(0);
SEG *b = PG_GETARG_SEG_P(1);
SEG *n;
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;
}
PG_RETURN_POINTER(n);
}
Datum
seg_inter(PG_FUNCTION_ARGS)
{
SEG *a = PG_GETARG_SEG_P(0);
SEG *b = PG_GETARG_SEG_P(1);
SEG *n;
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;
}
PG_RETURN_POINTER(n);
}
static 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);
}
Datum
seg_size(PG_FUNCTION_ARGS)
{
SEG *seg = PG_GETARG_SEG_P(0);
PG_RETURN_FLOAT4((float) Abs(seg->upper - seg->lower));
}
/*****************************************************************************
* Miscellaneous operators
*****************************************************************************/
Datum
seg_cmp(PG_FUNCTION_ARGS)
{
SEG *a = PG_GETARG_SEG_P(0);
SEG *b = PG_GETARG_SEG_P(1);
/*
* First compare on lower boundary position
*/
if (a->lower < b->lower)
PG_RETURN_INT32(-1);
if (a->lower > b->lower)
PG_RETURN_INT32(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 == '-')
PG_RETURN_INT32(-1);
if (b->l_ext == '-')
PG_RETURN_INT32(1);
if (a->l_ext == '<')
PG_RETURN_INT32(-1);
if (b->l_ext == '<')
PG_RETURN_INT32(1);
if (a->l_ext == '>')
PG_RETURN_INT32(1);
if (b->l_ext == '>')
PG_RETURN_INT32(-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) */
PG_RETURN_INT32(-1);
if (a->l_sigd > b->l_sigd) /* (a) is less blurred and is likely to be
* included in (b) */
PG_RETURN_INT32(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 */
PG_RETURN_INT32(-1);
if (b->l_ext == '~')
PG_RETURN_INT32(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)
PG_RETURN_INT32(-1);
if (a->upper > b->upper)
PG_RETURN_INT32(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 == '-')
PG_RETURN_INT32(1);
if (b->u_ext == '-')
PG_RETURN_INT32(-1);
if (a->u_ext == '<')
PG_RETURN_INT32(-1);
if (b->u_ext == '<')
PG_RETURN_INT32(1);
if (a->u_ext == '>')
PG_RETURN_INT32(1);
if (b->u_ext == '>')
PG_RETURN_INT32(-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) */
PG_RETURN_INT32(1);
if (a->u_sigd > b->u_sigd) /* (a) is less blurred and is likely to be
* included in (b) */
PG_RETURN_INT32(-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 */
PG_RETURN_INT32(1);
if (b->u_ext == '~')
PG_RETURN_INT32(-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);
}
PG_RETURN_INT32(0);
}
Datum
seg_lt(PG_FUNCTION_ARGS)
{
int cmp = DatumGetInt32(DirectFunctionCall2(seg_cmp,
PG_GETARG_DATUM(0),
PG_GETARG_DATUM(1)));
PG_RETURN_BOOL(cmp < 0);
}
Datum
seg_le(PG_FUNCTION_ARGS)
{
int cmp = DatumGetInt32(DirectFunctionCall2(seg_cmp,
PG_GETARG_DATUM(0),
PG_GETARG_DATUM(1)));
PG_RETURN_BOOL(cmp <= 0);
}
Datum
seg_gt(PG_FUNCTION_ARGS)
{
int cmp = DatumGetInt32(DirectFunctionCall2(seg_cmp,
PG_GETARG_DATUM(0),
PG_GETARG_DATUM(1)));
PG_RETURN_BOOL(cmp > 0);
}
Datum
seg_ge(PG_FUNCTION_ARGS)
{
int cmp = DatumGetInt32(DirectFunctionCall2(seg_cmp,
PG_GETARG_DATUM(0),
PG_GETARG_DATUM(1)));
PG_RETURN_BOOL(cmp >= 0);
}
Datum
seg_different(PG_FUNCTION_ARGS)
{
int cmp = DatumGetInt32(DirectFunctionCall2(seg_cmp,
PG_GETARG_DATUM(0),
PG_GETARG_DATUM(1)));
PG_RETURN_BOOL(cmp != 0);
}
/*****************************************************************************
* Auxiliary functions
*****************************************************************************/
/*
* The purpose of this routine is to print the given floating point
* value with exactly n significant digits. Its behaviour
* is similar to %.ng except it prints 8.00 where %.ng would
* print 8. Returns the length of the string written at "result".
*
* Caller must provide a sufficiently large result buffer; 16 bytes
* should be enough for all known float implementations.
*/
static int
restore(char *result, float val, int n)
{
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;
int exp;
int i,
dp,
sign;
/*
* Put a cap on the number of significant digits to avoid garbage in the
* output and ensure we don't overrun the result buffer.
*/
n = Min(n, FLT_DIG);
/* remember the sign */
sign = (val < 0 ? 1 : 0);
/* print, in %e style to start with */
sprintf(result, "%.*e", n - 1, val);
/* find the exponent */
p = strchr(result, 'e');
/* punt if we have 'inf' or similar */
if (p == NULL)
return strlen(result);
exp = atoi(p + 1);
if (exp == 0)
{
/* just truncate off the 'e+00' */
*p = '\0';
}
else
{
if (Abs(exp) <= 4)
{
/*
* remove the decimal point from the mantissa 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. */
}
return strlen(result);
}
/*
** Miscellany
*/
/* find out the number of significant digits in a string representing
* a floating point number
*/
int
significant_digits(const char *s)
{
const 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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