1/*
2 * Copyright (C) 2008 The Android Open Source Project
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *  * Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 *  * Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in
12 *    the documentation and/or other materials provided with the
13 *    distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28#include <stddef.h>
29#include <stdint.h>
30#include <ctype.h>
31
32static inline int digitval(int ch)
33{
34    unsigned  d;
35
36    d = (unsigned)(ch - '0');
37    if (d < 10) return (int)d;
38
39    d = (unsigned)(ch - 'a');
40    if (d < 6) return (int)(d+10);
41
42    d = (unsigned)(ch - 'A');
43    if (d < 6) return (int)(d+10);
44
45    return -1;
46}
47
48uintmax_t
49strntoumax(const char *nptr, char **endptr, int base, size_t n)
50{
51    const unsigned char*  p   = (const unsigned char *)nptr;
52    const unsigned char*  end = p + n;
53    int                   minus = 0;
54    uintmax_t             v = 0;
55    int                   d;
56
57    /* skip leading space */
58    while (p < end && isspace(*p))
59        p++;
60
61    /* Single optional + or - */
62    if (p < end) {
63        char c = p[0];
64        if ( c == '-' || c == '+' ) {
65            minus = (c == '-');
66            p++;
67        }
68    }
69
70    if ( base == 0 ) {
71        if ( p+2 < end && p[0] == '0' && (p[1] == 'x' || p[1] == 'X') ) {
72            p += 2;
73            base = 16;
74        } else if ( p+1 < end && p[0] == '0' ) {
75            p   += 1;
76            base = 8;
77        } else {
78            base = 10;
79        }
80    } else if ( base == 16 ) {
81        if ( p+2 < end && p[0] == '0' && (p[1] == 'x' || p[1] == 'X') ) {
82            p += 2;
83        }
84    }
85
86    while ( p < end && (d = digitval(*p)) >= 0 && d < base ) {
87        v = v*base + d;
88        p += 1;
89    }
90
91    if ( endptr )
92        *endptr = (char *)p;
93
94    return minus ? -v : v;
95}
96