From 0b44a0315b47dd8eced9f3b7f31580cf14bbfc01 Mon Sep 17 00:00:00 2001
From: Rich Felker <dalias@aerifal.cx>
Date: Sat, 12 Feb 2011 00:22:29 -0500
Subject: initial check-in, version 0.5.0

---
 src/stdlib/strtoumax.c | 123 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 123 insertions(+)
 create mode 100644 src/stdlib/strtoumax.c

(limited to 'src/stdlib/strtoumax.c')

diff --git a/src/stdlib/strtoumax.c b/src/stdlib/strtoumax.c
new file mode 100644
index 00000000..a529f6e8
--- /dev/null
+++ b/src/stdlib/strtoumax.c
@@ -0,0 +1,123 @@
+#include <inttypes.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <ctype.h>
+#include <stdio.h>
+
+/* Lookup table for digit values. -1==255>=36 -> invalid */
+static const unsigned char digits[] = {
+-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,-1,-1,-1,-1,-1,-1,
+-1,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,
+25,26,27,28,29,30,31,32,33,34,35,-1,-1,-1,-1,-1,
+-1,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,
+25,26,27,28,29,30,31,32,33,34,35,-1,-1,-1,-1,-1,
+-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+};
+
+uintmax_t strtoumax(const char *s1, char **p, int base)
+{
+	const unsigned char *s = s1;
+	size_t x1, z1;
+	uintmax_t x, z=0;
+	int sign = 0;
+	int shift;
+
+	if (!p) p = (char **)&s1;
+
+	/* Initial whitespace */
+	for (; isspace(*s); s++);
+
+	/* Optional sign */
+	if (*s == '-') sign = *s++;
+	else if (*s == '+') s++;
+
+	/* Default base 8, 10, or 16 depending on prefix */
+	if (base == 0) {
+		if (s[0] == '0') {
+			if ((s[1]|32) == 'x') base = 16;
+			else base = 8;
+		} else {
+			base = 10;
+		}
+	}
+
+	if ((unsigned)base-2 > 36-2 || digits[*s]>=base) {
+		*p = (char *)s1;
+		errno = EINVAL;
+		return 0;
+	}
+
+	/* Main loops. Only use big types if we have to. */
+	if (base == 10) {
+		for (x1=0; isdigit(*s) && x1<=SIZE_MAX/10-10; s++)
+			x1 = 10*x1 + *s-'0';
+		for (x=x1; isdigit(*s) && x<=UINTMAX_MAX/10-10; s++)
+			x = 10*x + *s-'0';
+		if (isdigit(*s)) {
+			if (isdigit(s[1]) || 10*x>UINTMAX_MAX-(*s-'0'))
+				goto overflow;
+			x = 10*x + *s-'0';
+		}
+	} else if (!(base & base/2)) {
+		if (base == 16) {
+			if (s[0]=='0' && (s[1]|32)=='x' && digits[s[2]]<16)
+				s+=2;
+			shift=4;
+			z1 = SIZE_MAX/16;
+			z = UINTMAX_MAX/16;
+		} else if (base == 8) {
+			shift=3;
+			z1 = SIZE_MAX/8;
+			z = UINTMAX_MAX/8;
+		} else if (base == 2) {
+			shift=1;
+			z1 = SIZE_MAX/2;
+			z = UINTMAX_MAX/2;
+		} else if (base == 4) {
+			shift=2;
+			z1 = SIZE_MAX/4;
+			z = UINTMAX_MAX/4;
+		} else /* if (base == 32) */ {
+			shift=5;
+			z1 = SIZE_MAX/32;
+			z = UINTMAX_MAX/32;
+		}
+		for (x1=0; digits[*s]<base && x1<=z1; s++)
+			x1 = (x1<<shift) + digits[*s];
+		for (x=x1; digits[*s]<base && x<=z; s++)
+			x = (x<<shift) + digits[*s];
+		if (digits[*s] < base) goto overflow;
+	} else {
+		z1 = SIZE_MAX/base-base;
+		for (x1=0; digits[*s]<base && x1<=z1; s++)
+			x1 = x1*base + digits[*s];
+		if (digits[*s]<base)
+			z = UINTMAX_MAX/base-base;
+		for (x=x1; digits[*s]<base && x<=z; s++)
+			x = x*base + digits[*s];
+		if (digits[*s] < base) {
+			if (digits[s[1]]<base || x*base>UINTMAX_MAX-digits[*s])
+				goto overflow;
+			x = x*base + digits[*s];
+		}
+	}
+
+	*p = (char *)s;
+	return sign ? -x : x;
+
+overflow:
+	for (; digits[*s] < base; s++);
+	*p = (char *)s;
+	errno = ERANGE;
+	return UINTMAX_MAX;
+}
-- 
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