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|
%{
/* contrib/seg/segparse.y */
#include "postgres.h"
#include <float.h>
#include <math.h>
#include "fmgr.h"
#include "utils/builtins.h"
#include "segdata.h"
/*
* Bison doesn't allocate anything that needs to live across parser calls,
* so we can easily have it use palloc instead of malloc. This prevents
* memory leaks if we error out during parsing. Note this only works with
* bison >= 2.0. However, in bison 1.875 the default is to use alloca()
* if possible, so there's not really much problem anyhow, at least if
* you're building with gcc.
*/
#define YYMALLOC palloc
#define YYFREE pfree
static float seg_atof(const char *value);
static int sig_digits(const char *value);
static char strbuf[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'
};
%}
/* BISON Declarations */
%parse-param {SEG *result}
%expect 0
%name-prefix="seg_yy"
%union
{
struct BND
{
float val;
char ext;
char sigd;
} bnd;
char *text;
}
%token <text> SEGFLOAT
%token <text> RANGE
%token <text> PLUMIN
%token <text> EXTENSION
%type <bnd> boundary
%type <bnd> deviation
%start range
/* Grammar follows */
%%
range: boundary PLUMIN deviation
{
result->lower = $1.val - $3.val;
result->upper = $1.val + $3.val;
sprintf(strbuf, "%g", result->lower);
result->l_sigd = Max(sig_digits(strbuf), Max($1.sigd, $3.sigd));
sprintf(strbuf, "%g", result->upper);
result->u_sigd = Max(sig_digits(strbuf), Max($1.sigd, $3.sigd));
result->l_ext = '\0';
result->u_ext = '\0';
}
| boundary RANGE boundary
{
result->lower = $1.val;
result->upper = $3.val;
if ( result->lower > result->upper ) {
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("swapped boundaries: %g is greater than %g",
result->lower, result->upper)));
YYERROR;
}
result->l_sigd = $1.sigd;
result->u_sigd = $3.sigd;
result->l_ext = ( $1.ext ? $1.ext : '\0' );
result->u_ext = ( $3.ext ? $3.ext : '\0' );
}
| boundary RANGE
{
result->lower = $1.val;
result->upper = HUGE_VAL;
result->l_sigd = $1.sigd;
result->u_sigd = 0;
result->l_ext = ( $1.ext ? $1.ext : '\0' );
result->u_ext = '-';
}
| RANGE boundary
{
result->lower = -HUGE_VAL;
result->upper = $2.val;
result->l_sigd = 0;
result->u_sigd = $2.sigd;
result->l_ext = '-';
result->u_ext = ( $2.ext ? $2.ext : '\0' );
}
| boundary
{
result->lower = result->upper = $1.val;
result->l_sigd = result->u_sigd = $1.sigd;
result->l_ext = result->u_ext = ( $1.ext ? $1.ext : '\0' );
}
;
boundary: SEGFLOAT
{
/* temp variable avoids a gcc 3.3.x bug on Sparc64 */
float val = seg_atof($1);
$$.ext = '\0';
$$.sigd = sig_digits($1);
$$.val = val;
}
| EXTENSION SEGFLOAT
{
/* temp variable avoids a gcc 3.3.x bug on Sparc64 */
float val = seg_atof($2);
$$.ext = $1[0];
$$.sigd = sig_digits($2);
$$.val = val;
}
;
deviation: SEGFLOAT
{
/* temp variable avoids a gcc 3.3.x bug on Sparc64 */
float val = seg_atof($1);
$$.ext = '\0';
$$.sigd = sig_digits($1);
$$.val = val;
}
;
%%
static float
seg_atof(const char *value)
{
Datum datum;
datum = DirectFunctionCall1(float4in, CStringGetDatum(value));
return DatumGetFloat4(datum);
}
static int
sig_digits(const char *value)
{
int n = significant_digits(value);
/* Clamp, to ensure value will fit in sigd fields */
return Min(n, FLT_DIG);
}
#include "segscan.c"
|
