Rework floating point conversions. (#98)

master
Arnold Robbins 2 years ago committed by GitHub
parent e508d2861c
commit cc9e9b68d1
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  1. 53
      awk.1
  2. 7
      lex.c
  3. 79
      lib.c
  4. 4
      proto.h
  5. 32
      run.c
  6. 24
      tran.c

53
awk.1

@ -577,3 +577,56 @@ The scope rules for variables in functions are a botch;
the syntax is worse.
.PP
Only eight-bit characters sets are handled correctly.
.SH UNUSUAL FLOATING-POINT VALUES
.I Awk
was designed before IEEE 754 arithmetic defined Not-A-Number (NaN)
and Infinity values, which are supported by all modern floating-point
hardware.
.PP
Because
.I awk
uses
.IR strtod (3)
and
.IR atof (3)
to convert string values to double-precision floating-point values,
modern C libraries also convert strings starting with
.B inf
and
.B nan
into infinity and NaN values respectively. This led to strange results,
with something like this:
.PP
.EX
.nf
echo nancy | awk '{ print $1 + 0 }'
.fi
.EE
.PP
printing
.B nan
instead of zero.
.PP
.I Awk
now follows GNU AWK, and prefilters string values before attempting
to convert them to numbers, as follows:
.TP
.I "Hexadecimal values"
Hexadecimal values (allowed since C99) convert to zero, as they did
prior to C99.
.TP
.I "NaN values"
The two strings
.B +nan
and
.B \-nan
(case independent) convert to NaN. No others do.
(NaNs can have signs.)
.TP
.I "Infinity values"
The two strings
.B +inf
and
.B \-inf
(case independent) convert to positive and negative infinity, respectively.
No others do.

@ -191,7 +191,12 @@ int yylex(void)
return word(buf);
if (isdigit(c)) {
char *cp = tostring(buf);
yylval.cp = setsymtab(buf, cp, atof(buf), CON|NUM, symtab);
double result;
if (is_number(cp, & result))
yylval.cp = setsymtab(buf, cp, result, CON|NUM, symtab);
else
yylval.cp = setsymtab(buf, cp, 0.0, STR, symtab);
free(cp);
/* should this also have STR set? */
RET(NUMBER);

79
lib.c

@ -30,6 +30,7 @@ THIS SOFTWARE.
#include <stdlib.h>
#include <stdarg.h>
#include <limits.h>
#include <math.h>
#include "awk.h"
char EMPTY[] = { '\0' };
@ -181,12 +182,14 @@ int getrec(char **pbuf, int *pbufsize, bool isrecord) /* get next input record *
innew = false;
if (c != 0 || buf[0] != '\0') { /* normal record */
if (isrecord) {
double result;
if (freeable(fldtab[0]))
xfree(fldtab[0]->sval);
fldtab[0]->sval = buf; /* buf == record */
fldtab[0]->tval = REC | STR | DONTFREE;
if (is_number(fldtab[0]->sval)) {
fldtab[0]->fval = atof(fldtab[0]->sval);
if (is_number(fldtab[0]->sval, & result)) {
fldtab[0]->fval = result;
fldtab[0]->tval |= NUM;
}
}
@ -293,6 +296,7 @@ void setclvar(char *s) /* set var=value from s */
{
char *p;
Cell *q;
double result;
for (p=s; *p != '='; p++)
;
@ -300,8 +304,8 @@ void setclvar(char *s) /* set var=value from s */
p = qstring(p, '\0');
q = setsymtab(s, p, 0.0, STR, symtab);
setsval(q, p);
if (is_number(q->sval)) {
q->fval = atof(q->sval);
if (is_number(q->sval, & result)) {
q->fval = result;
q->tval |= NUM;
}
DPRINTF("command line set %s to |%s|\n", s, p);
@ -402,9 +406,11 @@ void fldbld(void) /* create fields from current record */
lastfld = i;
donefld = true;
for (j = 1; j <= lastfld; j++) {
double result;
p = fldtab[j];
if(is_number(p->sval)) {
p->fval = atof(p->sval);
if(is_number(p->sval, & result)) {
p->fval = result;
p->tval |= NUM;
}
}
@ -756,24 +762,67 @@ int isclvar(const char *s) /* is s of form var=something ? */
/* strtod is supposed to be a proper test of what's a valid number */
/* appears to be broken in gcc on linux: thinks 0x123 is a valid FP number */
/* wrong: violates 4.10.1.4 of ansi C standard */
/* well, not quite. As of C99, hex floating point is allowed. so this is
* a bit of a mess.
* a bit of a mess. We work around the mess by checking for a hexadecimal
* value and disallowing it. Similarly, we now follow gawk and allow only
* +nan, -nan, +inf, and -inf for NaN and infinity values.
*/
#include <math.h>
int is_number(const char *s)
/*
* This routine now has a more complicated interface, the main point
* being to avoid the double conversion of a string to double, and
* also to convey out, if requested, the information that the numeric
* value was a leading string or is all of the string. The latter bit
* is used in getfval().
*/
bool is_valid_number(const char *s, bool trailing_stuff_ok,
bool *no_trailing, double *result)
{
double r;
char *ep;
bool retval = false;
if (no_trailing)
*no_trailing = false;
while (*s == ' ' || *s == '\t' || *s == '\n' || *s == '\r')
s++;
if (s[0] == '0' && tolower(s[1]) == 'x') // no hex floating point, sorry
return false;
// allow +nan, -nan, +inf, -inf, any other letter, no
if (s[0] == '+' || s[0] == '-') {
if (strcasecmp(s+1, "nan") == 0 || strcasecmp(s+1, "inf") == 0)
return true;
else if (! isdigit(s[1]) && s[1] != '.')
return false;
}
else if (! isdigit(s[0]) && s[0] != '.')
return false;
errno = 0;
r = strtod(s, &ep);
if (ep == s || r == HUGE_VAL || errno == ERANGE)
return 0;
/* allow \r as well. windows files aren't going to go away. */
return false;
if (result != NULL)
*result = r;
/*
* check for trailing stuff
* allow \r as well. windows files aren't going to go away.
*/
while (*ep == ' ' || *ep == '\t' || *ep == '\n' || *ep == '\r')
ep++;
if (*ep == '\0')
return 1;
else
return 0;
if (no_trailing)
*no_trailing = (*ep == '\0');
// return true if found the end, or trailing stuff is allowed
retval = (*ep == '\0') || trailing_stuff_ok;
return retval;
}

@ -146,7 +146,9 @@ extern void eprint(void);
extern void bclass(int);
extern double errcheck(double, const char *);
extern int isclvar(const char *);
extern int is_number(const char *);
extern bool is_valid_number(const char *s, bool trailing_stuff_ok,
bool *no_trailing, double *result);
#define is_number(s, val) is_valid_number(s, false, NULL, val)
extern int adjbuf(char **pb, int *sz, int min, int q, char **pbp, const char *what);
extern void run(Node *);

32
run.c

@ -407,6 +407,7 @@ Cell *awkgetline(Node **a, int n) /* get next line from specific input */
int bufsize = recsize;
int mode;
bool newflag;
double result;
if ((buf = (char *) malloc(bufsize)) == NULL)
FATAL("out of memory in getline");
@ -429,15 +430,15 @@ Cell *awkgetline(Node **a, int n) /* get next line from specific input */
} else if (a[0] != NULL) { /* getline var <file */
x = execute(a[0]);
setsval(x, buf);
if (is_number(x->sval)) {
x->fval = atof(x->sval);
if (is_number(x->sval, & result)) {
x->fval = result;
x->tval |= NUM;
}
tempfree(x);
} else { /* getline <file */
setsval(fldtab[0], buf);
if (is_number(fldtab[0]->sval)) {
fldtab[0]->fval = atof(fldtab[0]->sval);
if (is_number(fldtab[0]->sval, & result)) {
fldtab[0]->fval = result;
fldtab[0]->tval |= NUM;
}
}
@ -448,8 +449,8 @@ Cell *awkgetline(Node **a, int n) /* get next line from specific input */
n = getrec(&buf, &bufsize, false);
x = execute(a[0]);
setsval(x, buf);
if (is_number(x->sval)) {
x->fval = atof(x->sval);
if (is_number(x->sval, & result)) {
x->fval = result;
x->tval |= NUM;
}
tempfree(x);
@ -726,7 +727,7 @@ Cell *indirect(Node **a, int n) /* $( a[0] ) */
if ((Awkfloat)INT_MAX < val)
FATAL("trying to access out of range field %s", x->nval);
m = (int) val;
if (m == 0 && !is_number(s = getsval(x))) /* suspicion! */
if (m == 0 && !is_number(s = getsval(x), NULL)) /* suspicion! */
FATAL("illegal field $(%s), name \"%s\"", s, x->nval);
/* BUG: can x->nval ever be null??? */
tempfree(x);
@ -1259,6 +1260,7 @@ Cell *split(Node **a, int nnn) /* split(a[0], a[1], a[2]); a[3] is type */
int sep;
char temp, num[50];
int n, tempstat, arg3type;
double result;
y = execute(a[0]); /* source string */
origs = s = strdup(getsval(y));
@ -1303,8 +1305,8 @@ Cell *split(Node **a, int nnn) /* split(a[0], a[1], a[2]); a[3] is type */
snprintf(num, sizeof(num), "%d", n);
temp = *patbeg;
setptr(patbeg, '\0');
if (is_number(s))
setsymtab(num, s, atof(s), STR|NUM, (Array *) ap->sval);
if (is_number(s, & result))
setsymtab(num, s, result, STR|NUM, (Array *) ap->sval);
else
setsymtab(num, s, 0.0, STR, (Array *) ap->sval);
setptr(patbeg, temp);
@ -1322,8 +1324,8 @@ Cell *split(Node **a, int nnn) /* split(a[0], a[1], a[2]); a[3] is type */
}
n++;
snprintf(num, sizeof(num), "%d", n);
if (is_number(s))
setsymtab(num, s, atof(s), STR|NUM, (Array *) ap->sval);
if (is_number(s, & result))
setsymtab(num, s, result, STR|NUM, (Array *) ap->sval);
else
setsymtab(num, s, 0.0, STR, (Array *) ap->sval);
spdone:
@ -1343,8 +1345,8 @@ Cell *split(Node **a, int nnn) /* split(a[0], a[1], a[2]); a[3] is type */
temp = *s;
setptr(s, '\0');
snprintf(num, sizeof(num), "%d", n);
if (is_number(t))
setsymtab(num, t, atof(t), STR|NUM, (Array *) ap->sval);
if (is_number(t, & result))
setsymtab(num, t, result, STR|NUM, (Array *) ap->sval);
else
setsymtab(num, t, 0.0, STR, (Array *) ap->sval);
setptr(s, temp);
@ -1372,8 +1374,8 @@ Cell *split(Node **a, int nnn) /* split(a[0], a[1], a[2]); a[3] is type */
temp = *s;
setptr(s, '\0');
snprintf(num, sizeof(num), "%d", n);
if (is_number(t))
setsymtab(num, t, atof(t), STR|NUM, (Array *) ap->sval);
if (is_number(t, & result))
setsymtab(num, t, result, STR|NUM, (Array *) ap->sval);
else
setsymtab(num, t, 0.0, STR, (Array *) ap->sval);
setptr(s, temp);

@ -129,9 +129,11 @@ void arginit(int ac, char **av) /* set up ARGV and ARGC */
free(cp->sval);
cp->sval = (char *) ARGVtab;
for (i = 0; i < ac; i++) {
double result;
sprintf(temp, "%d", i);
if (is_number(*av))
setsymtab(temp, *av, atof(*av), STR|NUM, ARGVtab);
if (is_number(*av, & result))
setsymtab(temp, *av, result, STR|NUM, ARGVtab);
else
setsymtab(temp, *av, 0.0, STR, ARGVtab);
av++;
@ -148,13 +150,15 @@ void envinit(char **envp) /* set up ENVIRON variable */
free(cp->sval);
cp->sval = (char *) ENVtab;
for ( ; *envp; envp++) {
double result;
if ((p = strchr(*envp, '=')) == NULL)
continue;
if( p == *envp ) /* no left hand side name in env string */
continue;
*p++ = 0; /* split into two strings at = */
if (is_number(p))
setsymtab(*envp, p, atof(p), STR|NUM, ENVtab);
if (is_number(p, & result))
setsymtab(*envp, p, result, STR|NUM, ENVtab);
else
setsymtab(*envp, p, 0.0, STR, ENVtab);
p[-1] = '='; /* restore in case env is passed down to a shell */
@ -399,9 +403,15 @@ Awkfloat getfval(Cell *vp) /* get float val of a Cell */
else if (isrec(vp) && !donerec)
recbld();
if (!isnum(vp)) { /* not a number */
vp->fval = atof(vp->sval); /* best guess */
if (is_number(vp->sval) && !(vp->tval&CON))
vp->tval |= NUM; /* make NUM only sparingly */
double fval;
bool no_trailing;
if (is_valid_number(vp->sval, true, & no_trailing, & fval)) {
vp->fval = fval;
if (no_trailing && !(vp->tval&CON))
vp->tval |= NUM; /* make NUM only sparingly */
} else
vp->fval = 0.0;
}
DPRINTF("getfval %p: %s = %g, t=%o\n",
(void*)vp, NN(vp->nval), vp->fval, vp->tval);

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