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authormatz <matz@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>2006-05-11 10:59:12 +0000
committermatz <matz@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>2006-05-11 10:59:12 +0000
commitb0c7f088aabf933cca10585539b133d589c5412e (patch)
treee9a6c6ca6eca1863fc3f9a74819a4fec0df12665 /util.c
parent5f5405a0865b85dd4d73e52e2bd1dd9cfcb819bf (diff)
* util.c (ruby_strtod): differ addition to minimize error.
[ruby-dev:28619] git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_8@10146 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Diffstat (limited to 'util.c')
-rw-r--r--util.c62
1 files changed, 50 insertions, 12 deletions
diff --git a/util.c b/util.c
index 1b60948..9424fa5 100644
--- a/util.c
+++ b/util.c
@@ -811,12 +811,26 @@ ruby_strtod(string, endPtr)
p = string;
}
else {
- for (; mantSize > 0; mantSize--) {
- c = *p++;
+ double frac1, frac2;
+ frac1 = 0;
+ for ( ; mantSize > 9; mantSize -= 1) {
+ c = *p;
+ p += 1;
if (c == '.') {
- c = *p++;
+ c = *p;
+ p += 1;
}
- fraction = 10*fraction + (c - '0');
+ frac1 = 10*frac1 + (c - '0');
+ }
+ frac2 = 0;
+ for (; mantSize > 0; mantSize -= 1) {
+ c = *p;
+ p += 1;
+ if (c == '.') {
+ c = *p;
+ p += 1;
+ }
+ frac2 = 10*frac2 + (c - '0');
}
/*
@@ -868,6 +882,8 @@ ruby_strtod(string, endPtr)
errno = ERANGE;
return 0.0 * (sign ? -1.0 : 1.0);
}
+ fracExp = exp;
+ exp += 9;
if (exp < 0) {
expSign = Qtrue;
exp = -exp;
@@ -876,23 +892,45 @@ ruby_strtod(string, endPtr)
expSign = Qfalse;
}
dblExp = 10.0;
- while (exp)
- {
- if (exp & 1) {
- if (expSign)
- fraction /= dblExp;
- else
- fraction *= dblExp;
+ while (exp) {
+ if (exp & 01) {
+ if (expSign) {
+ frac1 /= dblExp;
+ }
+ else {
+ frac1 *= dblExp;
+ }
}
exp >>= 1;
dblExp *= dblExp;
}
+ exp = fracExp;
+ if (exp < 0) {
+ expSign = Qtrue;
+ exp = -exp;
+ }
+ else {
+ expSign = Qfalse;
+ }
+ dblExp = 10.0;
+ while (exp) {
+ if (exp & 01) {
+ if (expSign) {
+ frac2 /= dblExp;
+ }
+ else {
+ frac2 *= dblExp;
+ }
+ }
+ exp >>= 1;
+ dblExp *= dblExp;
+ }
+ fraction = frac1 + frac2;
}
if (endPtr != NULL) {
*endPtr = (char *)p;
}
-
if (sign) {
return -fraction;
}