summaryrefslogtreecommitdiffstats
path: root/tcl8.6/compat/strtoul.c
blob: 15587f1da1a150d4a0223766c5383adffb78ddab (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
/*
 * 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.
 */

#include "tclInt.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 const 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(
    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;
}