FreeBSD/Linux Kernel Cross Reference
sys/lib/cmdline.c

     /*
      * 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/export.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);

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