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+/*
+ * strtoul.c --
+ *
+ * Source code for the "strtoul" library procedure.
+ *
+ * Copyright 1988 Regents of the University of California
+ * Permission to use, copy, modify, and distribute this
+ * software and its documentation for any purpose and without
+ * fee is hereby granted, provided that the above copyright
+ * notice appear in all copies. The University of California
+ * makes no representations about the suitability of this
+ * software for any purpose. It is provided "as is" without
+ * express or implied warranty.
+ */
+
+#include <ctype.h>
+
+/*
+ * The table below is used to convert from ASCII digits to a
+ * numerical equivalent. It maps from '0' through 'z' to integers
+ * (100 for non-digit characters).
+ */
+
+static char cvtIn[] = {
+ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, /* '0' - '9' */
+ 100, 100, 100, 100, 100, 100, 100, /* punctuation */
+ 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, /* 'A' - 'Z' */
+ 20, 21, 22, 23, 24, 25, 26, 27, 28, 29,
+ 30, 31, 32, 33, 34, 35,
+ 100, 100, 100, 100, 100, 100, /* punctuation */
+ 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, /* 'a' - 'z' */
+ 20, 21, 22, 23, 24, 25, 26, 27, 28, 29,
+ 30, 31, 32, 33, 34, 35};
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * strtoul --
+ *
+ * Convert an ASCII string into an integer.
+ *
+ * Results:
+ * The return value is the integer equivalent of string. If endPtr
+ * is non-NULL, then *endPtr is filled in with the character
+ * after the last one that was part of the integer. If string
+ * doesn't contain a valid integer value, then zero is returned
+ * and *endPtr is set to string.
+ *
+ * Side effects:
+ * None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+unsigned long int
+strtoul(string, endPtr, base)
+ char *string; /* String of ASCII digits, possibly
+ * preceded by white space. For bases
+ * greater than 10, either lower- or
+ * upper-case digits may be used.
+ */
+ char **endPtr; /* Where to store address of terminating
+ * character, or NULL. */
+ int base; /* Base for conversion. Must be less
+ * than 37. If 0, then the base is chosen
+ * from the leading characters of string:
+ * "0x" means hex, "0" means octal, anything
+ * else means decimal.
+ */
+{
+ register char *p;
+ register unsigned long int result = 0;
+ register unsigned digit;
+ int anyDigits = 0;
+
+ /*
+ * Skip any leading blanks.
+ */
+
+ p = string;
+ while (isspace(*p)) {
+ p += 1;
+ }
+
+ /*
+ * If no base was provided, pick one from the leading characters
+ * of the string.
+ */
+
+ if (base == 0)
+ {
+ if (*p == '0') {
+ p += 1;
+ if (*p == 'x') {
+ p += 1;
+ base = 16;
+ } else {
+
+ /*
+ * Must set anyDigits here, otherwise "0" produces a
+ * "no digits" error.
+ */
+
+ anyDigits = 1;
+ base = 8;
+ }
+ }
+ else base = 10;
+ } else if (base == 16) {
+
+ /*
+ * Skip a leading "0x" from hex numbers.
+ */
+
+ if ((p[0] == '0') && (p[1] == 'x')) {
+ p += 2;
+ }
+ }
+
+ /*
+ * Sorry this code is so messy, but speed seems important. Do
+ * different things for base 8, 10, 16, and other.
+ */
+
+ if (base == 8) {
+ for ( ; ; p += 1) {
+ digit = *p - '0';
+ if (digit > 7) {
+ break;
+ }
+ result = (result << 3) + digit;
+ anyDigits = 1;
+ }
+ } else if (base == 10) {
+ for ( ; ; p += 1) {
+ digit = *p - '0';
+ if (digit > 9) {
+ break;
+ }
+ result = (10*result) + digit;
+ anyDigits = 1;
+ }
+ } else if (base == 16) {
+ for ( ; ; p += 1) {
+ digit = *p - '0';
+ if (digit > ('z' - '0')) {
+ break;
+ }
+ digit = cvtIn[digit];
+ if (digit > 15) {
+ break;
+ }
+ result = (result << 4) + digit;
+ anyDigits = 1;
+ }
+ } else {
+ for ( ; ; p += 1) {
+ digit = *p - '0';
+ if (digit > ('z' - '0')) {
+ break;
+ }
+ digit = cvtIn[digit];
+ if (digit >= base) {
+ break;
+ }
+ result = result*base + digit;
+ anyDigits = 1;
+ }
+ }
+
+ /*
+ * See if there were any digits at all.
+ */
+
+ if (!anyDigits) {
+ p = string;
+ }
+
+ if (endPtr != 0) {
+ *endPtr = p;
+ }
+
+ return result;
+}