summaryrefslogtreecommitdiff
path: root/src/stdlib/strtoumax.c
diff options
context:
space:
mode:
Diffstat (limited to 'src/stdlib/strtoumax.c')
-rw-r--r--src/stdlib/strtoumax.c123
1 files changed, 123 insertions, 0 deletions
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;
+}