Rework floating point conversions. (#98)
This commit is contained in:
Arnold Robbins
GitHub
parent
e508d2861c
commit
cc9e9b68d1
53
awk.1
53
awk.1
@ -577,3 +577,56 @@ The scope rules for variables in functions are a botch;
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the syntax is worse.
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.PP
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Only eight-bit characters sets are handled correctly.
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.SH UNUSUAL FLOATING-POINT VALUES
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.I Awk
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was designed before IEEE 754 arithmetic defined Not-A-Number (NaN)
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and Infinity values, which are supported by all modern floating-point
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hardware.
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.PP
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Because
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.I awk
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uses
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.IR strtod (3)
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and
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.IR atof (3)
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to convert string values to double-precision floating-point values,
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modern C libraries also convert strings starting with
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.B inf
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and
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.B nan
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into infinity and NaN values respectively. This led to strange results,
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with something like this:
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.PP
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.EX
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.nf
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echo nancy | awk '{ print $1 + 0 }'
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.fi
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.EE
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.PP
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printing
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.B nan
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instead of zero.
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.PP
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.I Awk
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now follows GNU AWK, and prefilters string values before attempting
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to convert them to numbers, as follows:
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.TP
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.I "Hexadecimal values"
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Hexadecimal values (allowed since C99) convert to zero, as they did
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prior to C99.
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.TP
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.I "NaN values"
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The two strings
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.B +nan
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and
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.B \-nan
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(case independent) convert to NaN. No others do.
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(NaNs can have signs.)
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.TP
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.I "Infinity values"
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The two strings
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.B +inf
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and
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.B \-inf
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(case independent) convert to positive and negative infinity, respectively.
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No others do.
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7
lex.c
7
lex.c
@ -191,7 +191,12 @@ int yylex(void)
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return word(buf);
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if (isdigit(c)) {
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char *cp = tostring(buf);
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yylval.cp = setsymtab(buf, cp, atof(buf), CON|NUM, symtab);
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double result;
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if (is_number(cp, & result))
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yylval.cp = setsymtab(buf, cp, result, CON|NUM, symtab);
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else
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yylval.cp = setsymtab(buf, cp, 0.0, STR, symtab);
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free(cp);
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/* should this also have STR set? */
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RET(NUMBER);
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79
lib.c
79
lib.c
@ -30,6 +30,7 @@ THIS SOFTWARE.
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#include <stdlib.h>
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#include <stdarg.h>
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#include <limits.h>
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#include <math.h>
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#include "awk.h"
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char EMPTY[] = { '\0' };
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@ -181,12 +182,14 @@ int getrec(char **pbuf, int *pbufsize, bool isrecord) /* get next input record *
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innew = false;
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if (c != 0 || buf[0] != '\0') { /* normal record */
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if (isrecord) {
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double result;
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if (freeable(fldtab[0]))
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xfree(fldtab[0]->sval);
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fldtab[0]->sval = buf; /* buf == record */
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fldtab[0]->tval = REC | STR | DONTFREE;
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if (is_number(fldtab[0]->sval)) {
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fldtab[0]->fval = atof(fldtab[0]->sval);
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if (is_number(fldtab[0]->sval, & result)) {
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fldtab[0]->fval = result;
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fldtab[0]->tval |= NUM;
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}
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}
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@ -293,6 +296,7 @@ void setclvar(char *s) /* set var=value from s */
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{
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char *p;
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Cell *q;
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double result;
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for (p=s; *p != '='; p++)
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;
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@ -300,8 +304,8 @@ void setclvar(char *s) /* set var=value from s */
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p = qstring(p, '\0');
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q = setsymtab(s, p, 0.0, STR, symtab);
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setsval(q, p);
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if (is_number(q->sval)) {
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q->fval = atof(q->sval);
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if (is_number(q->sval, & result)) {
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q->fval = result;
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q->tval |= NUM;
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}
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DPRINTF("command line set %s to |%s|\n", s, p);
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@ -402,9 +406,11 @@ void fldbld(void) /* create fields from current record */
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lastfld = i;
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donefld = true;
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for (j = 1; j <= lastfld; j++) {
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double result;
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p = fldtab[j];
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if(is_number(p->sval)) {
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p->fval = atof(p->sval);
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if(is_number(p->sval, & result)) {
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p->fval = result;
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p->tval |= NUM;
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}
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}
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@ -756,24 +762,67 @@ int isclvar(const char *s) /* is s of form var=something ? */
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/* strtod is supposed to be a proper test of what's a valid number */
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/* appears to be broken in gcc on linux: thinks 0x123 is a valid FP number */
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/* wrong: violates 4.10.1.4 of ansi C standard */
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/* well, not quite. As of C99, hex floating point is allowed. so this is
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* a bit of a mess.
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* a bit of a mess. We work around the mess by checking for a hexadecimal
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* value and disallowing it. Similarly, we now follow gawk and allow only
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* +nan, -nan, +inf, and -inf for NaN and infinity values.
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*/
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#include <math.h>
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int is_number(const char *s)
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/*
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* This routine now has a more complicated interface, the main point
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* being to avoid the double conversion of a string to double, and
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* also to convey out, if requested, the information that the numeric
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* value was a leading string or is all of the string. The latter bit
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* is used in getfval().
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*/
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bool is_valid_number(const char *s, bool trailing_stuff_ok,
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bool *no_trailing, double *result)
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{
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double r;
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char *ep;
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bool retval = false;
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if (no_trailing)
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*no_trailing = false;
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while (*s == ' ' || *s == '\t' || *s == '\n' || *s == '\r')
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s++;
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if (s[0] == '0' && tolower(s[1]) == 'x') // no hex floating point, sorry
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return false;
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// allow +nan, -nan, +inf, -inf, any other letter, no
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if (s[0] == '+' || s[0] == '-') {
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if (strcasecmp(s+1, "nan") == 0 || strcasecmp(s+1, "inf") == 0)
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return true;
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else if (! isdigit(s[1]) && s[1] != '.')
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return false;
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}
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else if (! isdigit(s[0]) && s[0] != '.')
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return false;
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errno = 0;
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r = strtod(s, &ep);
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if (ep == s || r == HUGE_VAL || errno == ERANGE)
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return 0;
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/* allow \r as well. windows files aren't going to go away. */
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return false;
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if (result != NULL)
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*result = r;
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/*
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* check for trailing stuff
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* allow \r as well. windows files aren't going to go away.
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*/
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while (*ep == ' ' || *ep == '\t' || *ep == '\n' || *ep == '\r')
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ep++;
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if (*ep == '\0')
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return 1;
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else
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return 0;
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if (no_trailing)
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*no_trailing = (*ep == '\0');
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// return true if found the end, or trailing stuff is allowed
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retval = (*ep == '\0') || trailing_stuff_ok;
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return retval;
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}
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4
proto.h
4
proto.h
@ -146,7 +146,9 @@ extern void eprint(void);
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extern void bclass(int);
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extern double errcheck(double, const char *);
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extern int isclvar(const char *);
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extern int is_number(const char *);
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extern bool is_valid_number(const char *s, bool trailing_stuff_ok,
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bool *no_trailing, double *result);
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#define is_number(s, val) is_valid_number(s, false, NULL, val)
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extern int adjbuf(char **pb, int *sz, int min, int q, char **pbp, const char *what);
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extern void run(Node *);
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32
run.c
32
run.c
@ -407,6 +407,7 @@ Cell *awkgetline(Node **a, int n) /* get next line from specific input */
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int bufsize = recsize;
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int mode;
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bool newflag;
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double result;
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if ((buf = (char *) malloc(bufsize)) == NULL)
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FATAL("out of memory in getline");
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@ -429,15 +430,15 @@ Cell *awkgetline(Node **a, int n) /* get next line from specific input */
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} else if (a[0] != NULL) { /* getline var <file */
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x = execute(a[0]);
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setsval(x, buf);
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if (is_number(x->sval)) {
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x->fval = atof(x->sval);
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if (is_number(x->sval, & result)) {
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x->fval = result;
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x->tval |= NUM;
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}
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tempfree(x);
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} else { /* getline <file */
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setsval(fldtab[0], buf);
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if (is_number(fldtab[0]->sval)) {
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fldtab[0]->fval = atof(fldtab[0]->sval);
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if (is_number(fldtab[0]->sval, & result)) {
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fldtab[0]->fval = result;
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fldtab[0]->tval |= NUM;
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}
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}
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@ -448,8 +449,8 @@ Cell *awkgetline(Node **a, int n) /* get next line from specific input */
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n = getrec(&buf, &bufsize, false);
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x = execute(a[0]);
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setsval(x, buf);
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if (is_number(x->sval)) {
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x->fval = atof(x->sval);
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if (is_number(x->sval, & result)) {
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x->fval = result;
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x->tval |= NUM;
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}
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tempfree(x);
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@ -726,7 +727,7 @@ Cell *indirect(Node **a, int n) /* $( a[0] ) */
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if ((Awkfloat)INT_MAX < val)
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FATAL("trying to access out of range field %s", x->nval);
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m = (int) val;
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if (m == 0 && !is_number(s = getsval(x))) /* suspicion! */
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if (m == 0 && !is_number(s = getsval(x), NULL)) /* suspicion! */
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FATAL("illegal field $(%s), name \"%s\"", s, x->nval);
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/* BUG: can x->nval ever be null??? */
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tempfree(x);
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@ -1259,6 +1260,7 @@ Cell *split(Node **a, int nnn) /* split(a[0], a[1], a[2]); a[3] is type */
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int sep;
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char temp, num[50];
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int n, tempstat, arg3type;
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double result;
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y = execute(a[0]); /* source string */
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origs = s = strdup(getsval(y));
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@ -1303,8 +1305,8 @@ Cell *split(Node **a, int nnn) /* split(a[0], a[1], a[2]); a[3] is type */
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snprintf(num, sizeof(num), "%d", n);
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temp = *patbeg;
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setptr(patbeg, '\0');
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if (is_number(s))
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setsymtab(num, s, atof(s), STR|NUM, (Array *) ap->sval);
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if (is_number(s, & result))
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setsymtab(num, s, result, STR|NUM, (Array *) ap->sval);
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else
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setsymtab(num, s, 0.0, STR, (Array *) ap->sval);
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setptr(patbeg, temp);
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@ -1322,8 +1324,8 @@ Cell *split(Node **a, int nnn) /* split(a[0], a[1], a[2]); a[3] is type */
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}
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n++;
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snprintf(num, sizeof(num), "%d", n);
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if (is_number(s))
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setsymtab(num, s, atof(s), STR|NUM, (Array *) ap->sval);
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if (is_number(s, & result))
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setsymtab(num, s, result, STR|NUM, (Array *) ap->sval);
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else
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setsymtab(num, s, 0.0, STR, (Array *) ap->sval);
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spdone:
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@ -1343,8 +1345,8 @@ Cell *split(Node **a, int nnn) /* split(a[0], a[1], a[2]); a[3] is type */
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temp = *s;
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setptr(s, '\0');
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snprintf(num, sizeof(num), "%d", n);
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if (is_number(t))
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setsymtab(num, t, atof(t), STR|NUM, (Array *) ap->sval);
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if (is_number(t, & result))
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setsymtab(num, t, result, STR|NUM, (Array *) ap->sval);
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else
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setsymtab(num, t, 0.0, STR, (Array *) ap->sval);
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setptr(s, temp);
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@ -1372,8 +1374,8 @@ Cell *split(Node **a, int nnn) /* split(a[0], a[1], a[2]); a[3] is type */
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temp = *s;
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setptr(s, '\0');
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snprintf(num, sizeof(num), "%d", n);
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if (is_number(t))
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setsymtab(num, t, atof(t), STR|NUM, (Array *) ap->sval);
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if (is_number(t, & result))
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setsymtab(num, t, result, STR|NUM, (Array *) ap->sval);
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else
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setsymtab(num, t, 0.0, STR, (Array *) ap->sval);
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setptr(s, temp);
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22
tran.c
22
tran.c
@ -129,9 +129,11 @@ void arginit(int ac, char **av) /* set up ARGV and ARGC */
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free(cp->sval);
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cp->sval = (char *) ARGVtab;
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for (i = 0; i < ac; i++) {
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double result;
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sprintf(temp, "%d", i);
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if (is_number(*av))
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setsymtab(temp, *av, atof(*av), STR|NUM, ARGVtab);
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if (is_number(*av, & result))
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setsymtab(temp, *av, result, STR|NUM, ARGVtab);
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else
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setsymtab(temp, *av, 0.0, STR, ARGVtab);
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av++;
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@ -148,13 +150,15 @@ void envinit(char **envp) /* set up ENVIRON variable */
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free(cp->sval);
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cp->sval = (char *) ENVtab;
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for ( ; *envp; envp++) {
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double result;
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if ((p = strchr(*envp, '=')) == NULL)
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continue;
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if( p == *envp ) /* no left hand side name in env string */
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continue;
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*p++ = 0; /* split into two strings at = */
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if (is_number(p))
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setsymtab(*envp, p, atof(p), STR|NUM, ENVtab);
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if (is_number(p, & result))
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setsymtab(*envp, p, result, STR|NUM, ENVtab);
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else
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setsymtab(*envp, p, 0.0, STR, ENVtab);
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p[-1] = '='; /* restore in case env is passed down to a shell */
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@ -399,9 +403,15 @@ Awkfloat getfval(Cell *vp) /* get float val of a Cell */
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else if (isrec(vp) && !donerec)
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recbld();
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if (!isnum(vp)) { /* not a number */
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vp->fval = atof(vp->sval); /* best guess */
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if (is_number(vp->sval) && !(vp->tval&CON))
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double fval;
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bool no_trailing;
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if (is_valid_number(vp->sval, true, & no_trailing, & fval)) {
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vp->fval = fval;
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if (no_trailing && !(vp->tval&CON))
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vp->tval |= NUM; /* make NUM only sparingly */
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} else
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vp->fval = 0.0;
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}
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DPRINTF("getfval %p: %s = %g, t=%o\n",
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(void*)vp, NN(vp->nval), vp->fval, vp->tval);
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