diff options
Diffstat (limited to 'libc/misc/strtol.c')
-rw-r--r-- | libc/misc/strtol.c | 106 |
1 files changed, 106 insertions, 0 deletions
diff --git a/libc/misc/strtol.c b/libc/misc/strtol.c new file mode 100644 index 0000000..bcd3334 --- /dev/null +++ b/libc/misc/strtol.c @@ -0,0 +1,106 @@ +/* + * strtol.c - This file is part of the libc-8086 package for ELKS, + * Copyright (C) 1995, 1996 Nat Friedman <ndf@linux.mit.edu>. + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Library General Public + * License as published by the Free Software Foundation; either + * version 2 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Library General Public License for more details. + * + * You should have received a copy of the GNU Library General Public + * License along with this library; if not, write to the Free + * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + * + */ + +#include <ctype.h> +#include <stdlib.h> + +long int +strtol(const char *nptr, char **endptr, int base) +{ + const char * ptr; + unsigned short negative; + long int number; + + ptr=nptr; + + while (isspace(*ptr)) + ptr++; + + negative=0; + if (*ptr=='-') + negative=1; + + number=(long int)strtoul(nptr, endptr, base); + + return (negative ? -number:number); +} + +unsigned long int +strtoul(const char *nptr, char **endptr, int base) +{ + unsigned long int number; + + /* Sanity check the arguments */ + if (base==1 || base>36 || base<0) + base=0; + + /* advance beyond any leading whitespace */ + while (isspace(*nptr)) + nptr++; + + /* check for optional '+' or '-' */ + if (*nptr=='-') + nptr++; + else + if (*nptr=='+') + nptr++; + + /* If base==0 and the string begins with "0x" then we're supposed + to assume that it's hexadecimal (base 16). */ + else + if (base==0 && *nptr=='0') + if (toupper(*(nptr+1))=='X') + { + base=16; + nptr+=2; + } + /* If base==0 and the string begins with "0" but not "0x", + then we're supposed to assume that it's octal (base 8). */ + else + { + base=8; + nptr++; + } + + + /* If base is still 0 (it was 0 to begin with and the string didn't begin + with "0"), then we are supposed to assume that it's base 10 */ + if (base==0) + base=10; + + number=0; + while (isalnum(*nptr)) + { + number= (number*base)+((isalpha(*nptr) ? toupper(*nptr) : *nptr) + - (isdigit(*nptr) ? '0' : 'A' + 9)); + nptr++; + if (*nptr>'0'+base) + break; + } + + /* Some code is simply _impossible_ to write with -Wcast-qual .. :-\ */ + if (endptr!=NULL) + *endptr=(char *)nptr; + + /* All done */ + return number; +} + + |