142115Sbostic /*- 242115Sbostic * Copyright (c) 1990 The Regents of the University of California. 335278Sbostic * All rights reserved. 435278Sbostic * 542115Sbostic * %sccs.include.redist.c% 635278Sbostic */ 735278Sbostic 835278Sbostic #if defined(LIBC_SCCS) && !defined(lint) 9*58776Storek static char sccsid[] = "@(#)strtol.c 5.5 (Berkeley) 03/23/93"; 1035278Sbostic #endif /* LIBC_SCCS and not lint */ 1135278Sbostic 1242115Sbostic #include <limits.h> 1335278Sbostic #include <ctype.h> 1442115Sbostic #include <errno.h> 1542179Sbostic #include <stdlib.h> 1635278Sbostic 1742179Sbostic 1842115Sbostic /* 1942115Sbostic * Convert a string to a long integer. 2042115Sbostic * 2142115Sbostic * Ignores `locale' stuff. Assumes that the upper and lower case 2242115Sbostic * alphabets and digits are each contiguous. 2342115Sbostic */ 2435278Sbostic long 2542115Sbostic strtol(nptr, endptr, base) 2646599Sdonn const char *nptr; 2746599Sdonn char **endptr; 2835278Sbostic register int base; 2935278Sbostic { 3046599Sdonn register const char *s = nptr; 3142115Sbostic register unsigned long acc; 3235278Sbostic register int c; 3342115Sbostic register unsigned long cutoff; 3442115Sbostic register int neg = 0, any, cutlim; 3535278Sbostic 3642115Sbostic /* 3742115Sbostic * Skip white space and pick up leading +/- sign if any. 3842115Sbostic * If base is 0, allow 0x for hex and 0 for octal, else 3942115Sbostic * assume decimal; if base is already 16, allow 0x. 4042115Sbostic */ 4142115Sbostic do { 4242115Sbostic c = *s++; 4342115Sbostic } while (isspace(c)); 4442115Sbostic if (c == '-') { 4542115Sbostic neg = 1; 4642115Sbostic c = *s++; 4742115Sbostic } else if (c == '+') 4842115Sbostic c = *s++; 4942115Sbostic if ((base == 0 || base == 16) && 5042115Sbostic c == '0' && (*s == 'x' || *s == 'X')) { 5142115Sbostic c = s[1]; 5242115Sbostic s += 2; 5342115Sbostic base = 16; 5435278Sbostic } 5542115Sbostic if (base == 0) 5642115Sbostic base = c == '0' ? 8 : 10; 5735278Sbostic 5835278Sbostic /* 5942115Sbostic * Compute the cutoff value between legal numbers and illegal 6042115Sbostic * numbers. That is the largest legal value, divided by the 6142115Sbostic * base. An input number that is greater than this value, if 6242115Sbostic * followed by a legal input character, is too big. One that 6342115Sbostic * is equal to this value may be valid or not; the limit 6442115Sbostic * between valid and invalid numbers is then based on the last 6542115Sbostic * digit. For instance, if the range for longs is 6642115Sbostic * [-2147483648..2147483647] and the input base is 10, 6742115Sbostic * cutoff will be set to 214748364 and cutlim to either 6842115Sbostic * 7 (neg==0) or 8 (neg==1), meaning that if we have accumulated 6942115Sbostic * a value > 214748364, or equal but the next digit is > 7 (or 8), 7042115Sbostic * the number is too big, and we will return a range error. 7142115Sbostic * 7242115Sbostic * Set any if any `digits' consumed; make it negative to indicate 7342115Sbostic * overflow. 7435278Sbostic */ 7542115Sbostic cutoff = neg ? -(unsigned long)LONG_MIN : LONG_MAX; 7642115Sbostic cutlim = cutoff % (unsigned long)base; 7742115Sbostic cutoff /= (unsigned long)base; 7842115Sbostic for (acc = 0, any = 0;; c = *s++) { 7935278Sbostic if (isdigit(c)) 8035278Sbostic c -= '0'; 8142115Sbostic else if (isalpha(c)) 8242115Sbostic c -= isupper(c) ? 'A' - 10 : 'a' - 10; 8342115Sbostic else 8442115Sbostic break; 8542115Sbostic if (c >= base) 8642115Sbostic break; 8742115Sbostic if (any < 0 || acc > cutoff || acc == cutoff && c > cutlim) 8842115Sbostic any = -1; 8935278Sbostic else { 9042115Sbostic any = 1; 9142115Sbostic acc *= base; 9242115Sbostic acc += c; 9335278Sbostic } 9435278Sbostic } 9542115Sbostic if (any < 0) { 9642115Sbostic acc = neg ? LONG_MIN : LONG_MAX; 9742115Sbostic errno = ERANGE; 9842115Sbostic } else if (neg) 9942115Sbostic acc = -acc; 10042115Sbostic if (endptr != 0) 101*58776Storek *endptr = (char *)(any ? s - 1 : nptr); 10242115Sbostic return (acc); 10335278Sbostic } 104