i have a proposal for charstod that should allow it
to recognize numbers without trailing non number
characters.
int xcharstod(int(*f)(void*), void *vp, double *g)
returning -1 on failure to parse a number, and 0
otherwise. in addition, g is set to 0. on failure, not
NaN in keeping with strtod.
the two uses in /sys/src are:
sys/src//cmd/units.y:272: yylval.val = charstod(gdigit, 0);
/sys/src//libbio/bgetd.c:31: d = charstod(Bgetdf, &b);
it would seem easy enough to update them to match.
eof tracking in Bgetd could just be dleted.
also, this orphan function should likely be retired:
/sys/src/ape/lib/fmt/charstod.c:28: fmtcharstod(int(*f)(void*), void *vp)
/sys/src/cmd/unix/drawterm/libc/charstod.c:13: fmtcharstod(int(*f)(void*), void
*vp)
/sys/include/ape/fmt.h:106: extern double fmtcharstod(int(*)(void*),
void*);
- erik
-----
#include <u.h>
#include <libc.h>
/*
* Reads a floating-point number by interpreting successive characters
* returned by (*f)(vp). The last call it makes to f terminates the
* scan, so is not a character in the number. It may therefore be
* necessary to back up the input stream up one byte after calling charstod.
*/
#define ADVANCE *s++ = c; if(s>=e) return -1; c = (*f)(vp)
int
xcharstod(int(*f)(void*), void *vp, double *g)
{
char str[400], *s, *e, *start;
int c;
*g = 0.;
s = str;
e = str + sizeof str - 1;
c = (*f)(vp);
while(c == ' ' || c == '\t')
c = (*f)(vp);
if(c == '-' || c == '+'){
ADVANCE;
}
start = s;
while(c >= '0' && c <= '9'){
ADVANCE;
}
if(c == '.'){
ADVANCE;
while(c >= '0' && c <= '9'){
ADVANCE;
}
}
if(s > start && (c == 'e' || c == 'E')){
ADVANCE;
if(c == '-' || c == '+'){
ADVANCE;
}
while(c >= '0' && c <= '9'){
ADVANCE;
}
}else if(s == start && (c == 'i' || c == 'I')){
ADVANCE;
if(c != 'n' && c != 'N')
return -1;
ADVANCE;
if(c != 'f' && c != 'F')
return -1;
ADVANCE;
if(c != 'i' && c != 'I')
goto accept;
ADVANCE;
if(c != 'n' && c != 'N')
return -1;
ADVANCE;
if(c != 'i' && c != 'I')
return -1;
ADVANCE;
if(c != 't' && c != 'T')
return -1;
ADVANCE;
if(c != 'y' && c != 'Y')
return -1;
ADVANCE; /* so caller can back up uniformly */
USED(c);
}else if(s == str && (c == 'n' || c == 'N')){
ADVANCE;
if(c != 'a' && c != 'A')
return -1;
ADVANCE;
if(c != 'n' && c != 'N')
return -1;
ADVANCE; /* so caller can back up uniformly */
USED(c);
}
accept:
*s = 0;
*g = strtod(str, &s);
if(s > str)
return 0;
return -1;
}
