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1.1 root 1: /*
2: * strtoul.c --
3: *
4: * Source code for the "strtoul" library procedure.
5: *
6: * Copyright 1988 Regents of the University of California
7: * Permission to use, copy, modify, and distribute this
8: * software and its documentation for any purpose and without
9: * fee is hereby granted, provided that the above copyright
10: * notice appear in all copies. The University of California
11: * makes no representations about the suitability of this
12: * software for any purpose. It is provided "as is" without
13: * express or implied warranty.
14: */
15:
16: #ifndef lint
17: static char rcsid[] = "$Header: /sprite/src/lib/tcl/compat/RCS/strtoul.c,v 1.2 91/09/22 14:04:43 ouster Exp $ SPRITE (Berkeley)";
18: #endif /* not lint */
19:
20: #include <ctype.h>
21:
22: /*
23: * The table below is used to convert from ASCII digits to a
24: * numerical equivalent. It maps from '0' through 'z' to integers
25: * (100 for non-digit characters).
26: */
27:
28: static char cvtIn[] = {
29: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, /* '0' - '9' */
30: 100, 100, 100, 100, 100, 100, 100, /* punctuation */
31: 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, /* 'A' - 'Z' */
32: 20, 21, 22, 23, 24, 25, 26, 27, 28, 29,
33: 30, 31, 32, 33, 34, 35,
34: 100, 100, 100, 100, 100, 100, /* punctuation */
35: 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, /* 'a' - 'z' */
36: 20, 21, 22, 23, 24, 25, 26, 27, 28, 29,
37: 30, 31, 32, 33, 34, 35};
38:
39: /*
40: *----------------------------------------------------------------------
41: *
42: * strtoul --
43: *
44: * Convert an ASCII string into an integer.
45: *
46: * Results:
47: * The return value is the integer equivalent of string. If endPtr
48: * is non-NULL, then *endPtr is filled in with the character
49: * after the last one that was part of the integer. If string
50: * doesn't contain a valid integer value, then zero is returned
51: * and *endPtr is set to string.
52: *
53: * Side effects:
54: * None.
55: *
56: *----------------------------------------------------------------------
57: */
58:
59: unsigned long int
60: strtoul(string, endPtr, base)
61: char *string; /* String of ASCII digits, possibly
62: * preceded by white space. For bases
63: * greater than 10, either lower- or
64: * upper-case digits may be used.
65: */
66: char **endPtr; /* Where to store address of terminating
67: * character, or NULL. */
68: int base; /* Base for conversion. Must be less
69: * than 37. If 0, then the base is chosen
70: * from the leading characters of string:
71: * "0x" means hex, "0" means octal, anything
72: * else means decimal.
73: */
74: {
75: register char *p;
76: register unsigned long int result = 0;
77: register unsigned digit;
78: int anyDigits = 0;
79:
80: /*
81: * Skip any leading blanks.
82: */
83:
84: p = string;
85: while (isspace(*p)) {
86: p += 1;
87: }
88:
89: /*
90: * If no base was provided, pick one from the leading characters
91: * of the string.
92: */
93:
94: if (base == 0)
95: {
96: if (*p == '0') {
97: p += 1;
98: if (*p == 'x') {
99: p += 1;
100: base = 16;
101: } else {
102:
103: /*
104: * Must set anyDigits here, otherwise "0" produces a
105: * "no digits" error.
106: */
107:
108: anyDigits = 1;
109: base = 8;
110: }
111: }
112: else base = 10;
113: } else if (base == 16) {
114:
115: /*
116: * Skip a leading "0x" from hex numbers.
117: */
118:
119: if ((p[0] == '0') && (p[1] == 'x')) {
120: p += 2;
121: }
122: }
123:
124: /*
125: * Sorry this code is so messy, but speed seems important. Do
126: * different things for base 8, 10, 16, and other.
127: */
128:
129: if (base == 8) {
130: for ( ; ; p += 1) {
131: digit = *p - '0';
132: if (digit > 7) {
133: break;
134: }
135: result = (result << 3) + digit;
136: anyDigits = 1;
137: }
138: } else if (base == 10) {
139: for ( ; ; p += 1) {
140: digit = *p - '0';
141: if (digit > 9) {
142: break;
143: }
144: result = (10*result) + digit;
145: anyDigits = 1;
146: }
147: } else if (base == 16) {
148: for ( ; ; p += 1) {
149: digit = *p - '0';
150: if (digit > ('z' - '0')) {
151: break;
152: }
153: digit = cvtIn[digit];
154: if (digit > 15) {
155: break;
156: }
157: result = (result << 4) + digit;
158: anyDigits = 1;
159: }
160: } else {
161: for ( ; ; p += 1) {
162: digit = *p - '0';
163: if (digit > ('z' - '0')) {
164: break;
165: }
166: digit = cvtIn[digit];
167: if (digit >= base) {
168: break;
169: }
170: result = result*base + digit;
171: anyDigits = 1;
172: }
173: }
174:
175: /*
176: * See if there were any digits at all.
177: */
178:
179: if (!anyDigits) {
180: p = string;
181: }
182:
183: if (endPtr != 0) {
184: *endPtr = p;
185: }
186:
187: return result;
188: }
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