cmdline.c

嵌入式系统设计与实例开发实验教材二源码 多线程应用程序设计 串行端口程序设计 AD接口实验 CAN总线通信实验 GPS通信实验 Linux内核移植与编译实验 IC卡读写实验 SD驱动使

/*
 * 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>


/**
 *	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
 */

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;
	}

	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.  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 (char *str, int nints, int *ints)
{
	int res, i = 1;

	while (i < nints) {
		res = get_option (&str, ints + i);
		if (res == 0)
			break;
		i++;
		if (res == 1)
			break;
	}
	ints[0] = i - 1;
	return (str);
}

/**
 *	memparse - parse a string with mem suffixes into a number
 *	@ptr: Where parse begins
 *	@retptr: (output) 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 (char *ptr, char **retptr)
{
	unsigned long long ret = simple_strtoull (ptr, retptr, 0);

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


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