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Diffstat (limited to 'compat/strtoul.c')
| -rw-r--r-- | compat/strtoul.c | 183 |
1 files changed, 183 insertions, 0 deletions
diff --git a/compat/strtoul.c b/compat/strtoul.c new file mode 100644 index 0000000..37fe490 --- /dev/null +++ b/compat/strtoul.c @@ -0,0 +1,183 @@ +/* + * strtoul.c -- + * + * Source code for the "strtoul" library procedure. + * + * Copyright (c) 1988 The Regents of the University of California. + * Copyright (c) 1994 Sun Microsystems, Inc. + * + * See the file "license.terms" for information on usage and redistribution + * of this file, and for a DISCLAIMER OF ALL WARRANTIES. + * + * SCCS: @(#) strtoul.c 1.5 96/02/15 12:08:24 + */ + +#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; +} |