20080611-1520

1 files changed, 96 insertions, 0 deletions

diff --git a/libkern/strtoull.c b/libkern/strtoull.c
new file mode 100644
index 00000000..2f527981
--- /dev/null
+++ b/libkern/strtoull.c
@@ -0,0 +1,96 @@
+#include <lib9.h>
+
+#define UVLONG_MAX	(1LL<<63)
+
+uvlong
+strtoull(char *nptr, char **endptr, int base)
+{
+	char *p;
+	uvlong n, nn, m;
+	int c, ovfl, v, neg, ndig;
+
+	p = nptr;
+	neg = 0;
+	n = 0;
+	ndig = 0;
+	ovfl = 0;
+
+	/*
+	 * White space
+	 */
+	for(;; p++) {
+		switch(*p) {
+		case ' ':
+		case '\t':
+		case '\n':
+		case '\f':
+		case '\r':
+		case '\v':
+			continue;
+		}
+		break;
+	}
+
+	/*
+	 * Sign
+	 */
+	if(*p == '-' || *p == '+')
+		if(*p++ == '-')
+			neg = 1;
+
+	/*
+	 * Base
+	 */
+	if(base == 0) {
+		base = 10;
+		if(*p == '0') {
+			base = 8;
+			if(p[1] == 'x' || p[1] == 'X'){
+				p += 2;
+				base = 16;
+			}
+		}
+	} else
+	if(base == 16 && *p == '0') {
+		if(p[1] == 'x' || p[1] == 'X')
+			p += 2;
+	} else
+	if(base < 0 || 36 < base)
+		goto Return;
+
+	/*
+	 * Non-empty sequence of digits
+	 */
+	m = UVLONG_MAX/base;
+	for(;; p++,ndig++) {
+		c = *p;
+		v = base;
+		if('0' <= c && c <= '9')
+			v = c - '0';
+		else
+		if('a' <= c && c <= 'z')
+			v = c - 'a' + 10;
+		else
+		if('A' <= c && c <= 'Z')
+			v = c - 'A' + 10;
+		if(v >= base)
+			break;
+		if(n > m)
+			ovfl = 1;
+		nn = n*base + v;
+		if(nn < n)
+			ovfl = 1;
+		n = nn;
+	}
+
+Return:
+	if(ndig == 0)
+		p = nptr;
+	if(endptr)
+		*endptr = p;
+	if(ovfl)
+		return UVLONG_MAX;
+	if(neg)
+		return -n;
+	return n;
+}