bionic/libc/stdlib/strntoumax.c
2009-03-03 19:28:35 -08:00

96 lines
2.8 KiB
C

/*
* Copyright (C) 2008 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <stddef.h>
#include <stdint.h>
#include <ctype.h>
static inline int digitval(int ch)
{
unsigned d;
d = (unsigned)(ch - '0');
if (d < 10) return (int)d;
d = (unsigned)(ch - 'a');
if (d < 6) return (int)(d+10);
d = (unsigned)(ch - 'A');
if (d < 6) return (int)(d+10);
return -1;
}
uintmax_t
strntoumax(const char *nptr, char **endptr, int base, size_t n)
{
const unsigned char* p = nptr;
const unsigned char* end = p + n;
int minus = 0;
uintmax_t v = 0;
int d;
/* skip leading space */
while (p < end && isspace(*p))
p++;
/* Single optional + or - */
if (p < end) {
char c = p[0];
if ( c == '-' || c == '+' ) {
minus = (c == '-');
p++;
}
}
if ( base == 0 ) {
if ( p+2 < end && p[0] == '0' && (p[1] == 'x' || p[1] == 'X') ) {
p += 2;
base = 16;
} else if ( p+1 < end && p[0] == '0' ) {
p += 1;
base = 8;
} else {
base = 10;
}
} else if ( base == 16 ) {
if ( p+2 < end && p[0] == '0' && (p[1] == 'x' || p[1] == 'X') ) {
p += 2;
}
}
while ( p < end && (d = digitval(*p)) >= 0 && d < base ) {
v = v*base + d;
p += 1;
}
if ( endptr )
*endptr = (char *)p;
return minus ? -v : v;
}