/* * 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. * * RCS: @(#) $Id: strtoul.c,v 1.1.1.1 2007/07/10 15:04:23 duncan Exp $ */ #include "tclInt.h" #include "tclPort.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) CONST 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 CONST char *p; register unsigned long int result = 0; register unsigned digit; int anyDigits = 0; int negative=0; int overflow=0; /* * Skip any leading blanks. */ p = string; while (isspace(UCHAR(*p))) { p += 1; } if (*p == '-') { negative = 1; p += 1; } else { if (*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 == '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[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) { unsigned long maxres = ULONG_MAX >> 3; for ( ; ; p += 1) { digit = *p - '0'; if (digit > 7) { break; } if (result > maxres) { overflow = 1; } result = (result << 3); if (digit > (ULONG_MAX - result)) { overflow = 1; } result += digit; anyDigits = 1; } } else if (base == 10) { unsigned long maxres = ULONG_MAX / 10; for ( ; ; p += 1) { digit = *p - '0'; if (digit > 9) { break; } if (result > maxres) { overflow = 1; } result *= 10; if (digit > (ULONG_MAX - result)) { overflow = 1; } result += digit; anyDigits = 1; } } else if (base == 16) { unsigned long maxres = ULONG_MAX >> 4; for ( ; ; p += 1) { digit = *p - '0'; if (digit > ('z' - '0')) { break; } digit = cvtIn[digit]; if (digit > 15) { break; } if (result > maxres) { overflow = 1; } result = (result << 4); if (digit > (ULONG_MAX - result)) { overflow = 1; } result += digit; anyDigits = 1; } } else if ( base >= 2 && base <= 36 ) { unsigned long maxres = ULONG_MAX / base; for ( ; ; p += 1) { digit = *p - '0'; if (digit > ('z' - '0')) { break; } digit = cvtIn[digit]; if (digit >= ( (unsigned) base )) { break; } if (result > maxres) { overflow = 1; } result *= base; if (digit > (ULONG_MAX - result)) { overflow = 1; } result += digit; anyDigits = 1; } } /* * See if there were any digits at all. */ if (!anyDigits) { p = string; } if (endPtr != 0) { /* unsafe, but required by the strtoul prototype */ *endPtr = (char *) p; } if (overflow) { errno = ERANGE; return ULONG_MAX; } if (negative) { return -result; } return result; }