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-rw-r--r--src/stdlib/strtold.c93
1 files changed, 93 insertions, 0 deletions
diff --git a/src/stdlib/strtold.c b/src/stdlib/strtold.c
new file mode 100644
index 00000000..54f80469
--- /dev/null
+++ b/src/stdlib/strtold.c
@@ -0,0 +1,93 @@
+#include <stdlib.h>
+#include <errno.h>
+#include <ctype.h>
+
+long double strtold(const char *s1, char **p)
+{
+ const unsigned char *s = s1;
+ long double x = 0;
+ long double frac;
+ int sign = 0;
+ int nonzero = 0;
+ int radix = '.';
+ long e;
+
+ if (!p) p = (char **)&s1;
+
+ /* Initial whitespace */
+ for (; isspace(*s); s++);
+
+ /* Optional sign */
+ if (*s == '-') sign = *s++;
+ else if (*s == '+') s++;
+
+ /* Handle infinities and NaNs. */
+ if ((s[0]|32)=='i' && (s[1]|32)=='n' && (s[2]|32)=='f') {
+ *p = (char *)s + 3;
+ return sign ? -1.0/0.0 : 1.0/0.0;
+ } else if ((s[0]|32)=='n' && (s[1]|32)=='a' && (s[2]|32)=='n') {
+ *p = (char *)s + 3;
+ return 0.0/0.0;
+ }
+
+ /* Possible hex float */
+ if (s[0]=='0' && (s[1]|32)=='x') {
+ /* Mantissa must be non-degenerate */
+ if (!isxdigit(s[2]) && (s[2]!=radix || !isxdigit(s[3]))) {
+ /* Decimal float 0, 'x' extraneous */
+ *p = (char *)++s;
+ return 0;
+ }
+ /* We have a real hex float */
+ s += 2;
+ for (; isxdigit(*s); s++) {
+ x = 16*x + (isdigit(*s)?*s-'0':(*s|32)-'a');
+ if (*s!='0') nonzero=1;
+ }
+ if (*s == radix) {
+ frac = 1.0/16.0;
+ for (s++; isxdigit(*s); s++) {
+ x += frac * (isdigit(*s)?*s-'0':(*s|32)-'a');
+ frac *= 1.0/16.0;
+ if (*s!='0') nonzero=1;
+ }
+ }
+ if ((*s|32) == 'p') {
+ e = strtol(s+1, (void *)&s, 10);
+ for (; e>0; e--) x *= 2.0;
+ for (; e<0; e++) x *= 0.5;
+ }
+ if ((nonzero && !x) || !(1.0/x))
+ errno = ERANGE;
+ *p = (char *)s;
+ return sign ? -x : x;
+ }
+
+ /* Mantissa must be non-degenerate */
+ if (!isdigit(s[0]) && (s[0]!=radix || !isdigit(s[1]))) {
+ *p = (char *)s1;
+ return 0;
+ }
+
+ for (; isdigit(*s); s++) {
+ x = 10*x + *s-'0';
+ if (*s!='0') nonzero=1;
+ }
+ if (*s == radix) {
+ frac = 10.0;
+ for (s++; isdigit(*s); s++) {
+ x += (*s-'0') / frac;
+ frac *= 10.0;
+ if (*s!='0') nonzero=1;
+ }
+ }
+ if ((*s|32)=='e') {
+ e = strtol(++s, (void *)&s, 10);
+ for (; e>0; e--) x *= 10.0;
+ for (; e<0; e++) x /= 10.0;
+ }
+ if ((nonzero && !x) || !(1.0/x))
+ errno = ERANGE;
+ *p = (char*)s;
+ return sign ? -x : x;
+}