Mercurial > cpython-lru_cache-weakref
view Python/atof.c @ 17405:afbb65b60fa2 2.0
Inspired by Tim Peters' 1.14->1.15 checkin to asynchat
Quoting orignal message:
'''
Fix from the Madusa mailing list:
http://groups.yahoo.com/group/medusa/message/333
It's clear that Medusa should not be checking for an empty buffer
via "buf is ''". The patch merely changes "is" to "==". However,
there's a mystery here all the same: Python attempts to store null
strings uniquely, so it's unclear why "buf is ''" ever returned
false when buf actually was empty. *Some* string operations produce
non-unique null strings, e.g.
'''
| author | Moshe Zadka <moshez@math.huji.ac.il> |
|---|---|
| date | Wed, 11 Apr 2001 08:06:02 +0000 |
| parents | 6f6f965c5e2d |
| children | 2dea40e40d9d |
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/* Just in case you haven't got an atof() around... This one doesn't check for bad syntax or overflow, and is slow and inaccurate. But it's good enough for the occasional string literal... */ #include "config.h" #include <ctype.h> double atof(char *s) { double a = 0.0; int e = 0; int c; while ((c = *s++) != '\0' && isdigit(c)) { a = a*10.0 + (c - '0'); } if (c == '.') { while ((c = *s++) != '\0' && isdigit(c)) { a = a*10.0 + (c - '0'); e = e-1; } } if (c == 'e' || c == 'E') { int sign = 1; int i = 0; c = *s++; if (c == '+') c = *s++; else if (c == '-') { c = *s++; sign = -1; } while (isdigit(c)) { i = i*10 + (c - '0'); c = *s++; } e += i*sign; } while (e > 0) { a *= 10.0; e--; } while (e < 0) { a *= 0.1; e++; } return a; }
