root/lib/cmdline.c

DEFINITIONS

1. get_range
2. get_option
3. get_options
4. memparse

/*
 * linux/lib/cmdline.c
 * Helper functions generally used for parsing kernel command line
 * and module options.
 *
 * Code and copyrights come from init/main.c and arch/i386/kernel/setup.c.
 *
 * This source code is licensed under the GNU General Public License,
 * Version 2.  See the file COPYING for more details.
 *
 * GNU Indent formatting options for this file: -kr -i8 -npsl -pcs
 *
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/string.h>

/*
 *      If a hyphen was found in get_option, this will handle the
 *      range of numbers, M-N.  This will expand the range and insert
 *      the values[M, M+1, ..., N] into the ints array in get_options.
 */

static int get_range(char **str, int *pint)
{
        int x, inc_counter, upper_range;

        (*str)++;
        upper_range = simple_strtol((*str), NULL, 0);
        inc_counter = upper_range - *pint;
        for (x = *pint; x < upper_range; x++)
                *pint++ = x;
        return inc_counter;
}

/**
 *      get_option - Parse integer from an option string
 *      @str: option string
 *      @pint: (output) integer value parsed from @str
 *
 *      Read an int from an option string; if available accept a subsequent
 *      comma as well.
 *
 *      Return values:
 *      0 - no int in string
 *      1 - int found, no subsequent comma
 *      2 - int found including a subsequent comma
 *      3 - hyphen found to denote a range
 */

int get_option (char **str, int *pint)
{
        char *cur = *str;

        if (!cur || !(*cur))
                return 0;
        *pint = simple_strtol (cur, str, 0);
        if (cur == *str)
                return 0;
        if (**str == ',') {
                (*str)++;
                return 2;
        }
        if (**str == '-')
                return 3;

        return 1;
}

/**
 *      get_options - Parse a string into a list of integers
 *      @str: String to be parsed
 *      @nints: size of integer array
 *      @ints: integer array
 *
 *      This function parses a string containing a comma-separated
 *      list of integers, a hyphen-separated range of _positive_ integers,
 *      or a combination of both.  The parse halts when the array is
 *      full, or when no more numbers can be retrieved from the
 *      string.
 *
 *      Return value is the character in the string which caused
 *      the parse to end (typically a null terminator, if @str is
 *      completely parseable).
 */
 
char *get_options(const char *str, int nints, int *ints)
{
        int res, i = 1;

        while (i < nints) {
                res = get_option ((char **)&str, ints + i);
                if (res == 0)
                        break;
                if (res == 3) {
                        int range_nums;
                        range_nums = get_range((char **)&str, ints + i);
                        if (range_nums < 0)
                                break;
                        /*
                         * Decrement the result by one to leave out the
                         * last number in the range.  The next iteration
                         * will handle the upper number in the range
                         */
                        i += (range_nums - 1);
                }
                i++;
                if (res == 1)
                        break;
        }
        ints[0] = i - 1;
        return (char *)str;
}

/**
 *      memparse - parse a string with mem suffixes into a number
 *      @ptr: Where parse begins
 *      @retptr: (output) Optional pointer to next char after parse completes
 *
 *      Parses a string into a number.  The number stored at @ptr is
 *      potentially suffixed with %K (for kilobytes, or 1024 bytes),
 *      %M (for megabytes, or 1048576 bytes), or %G (for gigabytes, or
 *      1073741824).  If the number is suffixed with K, M, or G, then
 *      the return value is the number multiplied by one kilobyte, one
 *      megabyte, or one gigabyte, respectively.
 */

unsigned long long memparse(const char *ptr, char **retptr)
{
        char *endptr;   /* local pointer to end of parsed string */

        unsigned long long ret = simple_strtoull(ptr, &endptr, 0);

        switch (*endptr) {
        case 'G':
        case 'g':
                ret <<= 10;
        case 'M':
        case 'm':
                ret <<= 10;
        case 'K':
        case 'k':
                ret <<= 10;
                endptr++;
        default:
                break;
        }

        if (retptr)
                *retptr = endptr;

        return ret;
}


EXPORT_SYMBOL(memparse);
EXPORT_SYMBOL(get_option);
EXPORT_SYMBOL(get_options);