/* * Helpers for formatting and printing strings * * Copyright 31 August 2008 James Bottomley * Copyright (C) 2013, Intel Corporation */#include <linux/kernel.h>#include <linux/math64.h>#include <linux/export.h>#include <linux/ctype.h>#include <linux/string_helpers.h> /** * string_get_size - get the size in the specified units * @size:	The size to be converted * @units:	units to use (powers of 1000 or 1024) * @buf:	buffer to format to * @len:	length of buffer * * This function returns a string formatted to 3 significant figures * giving the size in the required units.  Returns 0 on success or * error on failure.  @buf is always zero terminated. * */int string_get_size(u64 size, const enum string_size_units units,		    char *buf, int len){	static const char *const units_10[] = {		"B", "kB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB", NULL	};	static const char *const units_2[] = {		"B", "KiB", "MiB", "GiB", "TiB", "PiB", "EiB", "ZiB", "YiB",		NULL	};	static const char *const *const units_str[] = {		[STRING_UNITS_10] = units_10,		[STRING_UNITS_2] = units_2,	};	static const unsigned int divisor[] = {		[STRING_UNITS_10] = 1000,		[STRING_UNITS_2] = 1024,	};	int i, j;	u64 remainder = 0, sf_cap;	char tmp[8]; 	tmp[0] = '\0';	i = 0;	if (size >= divisor[units]) {		while (size >= divisor[units] && units_str[units][i]) {			remainder = do_div(size, divisor[units]);			i++;		} 		sf_cap = size;		for (j = 0; sf_cap*10 < 1000; j++)			sf_cap *= 10; 		if (j) {			remainder *= 1000;			do_div(remainder, divisor[units]);			snprintf(tmp, sizeof(tmp), ".%03lld",				 (unsigned long long)remainder);			tmp[j+1] = '\0';		}	} 	snprintf(buf, len, "%lld%s %s", (unsigned long long)size,		 tmp, units_str[units][i]); 	return 0;}EXPORT_SYMBOL(string_get_size); static bool unescape_space(char **src, char **dst){	char *p = *dst, *q = *src; 	switch (*q) {	case 'n':		*p = '\n';		break;	case 'r':		*p = '\r';		break;	case 't':		*p = '\t';		break;	case 'v':		*p = '\v';		break;	case 'f':		*p = '\f';		break;	default:		return false;	}	*dst += 1;	*src += 1;	return true;} static bool unescape_octal(char **src, char **dst){	char *p = *dst, *q = *src;	u8 num; 	if (isodigit(*q) == 0)		return false; 	num = (*q++) & 7;	while (num < 32 && isodigit(*q) && (q - *src < 3)) {		num <<= 3;		num += (*q++) & 7;	}	*p = num;	*dst += 1;	*src = q;	return true;} static bool unescape_hex(char **src, char **dst){	char *p = *dst, *q = *src;	int digit;	u8 num; 	if (*q++ != 'x')		return false; 	num = digit = hex_to_bin(*q++);	if (digit < 0)		return false; 	digit = hex_to_bin(*q);	if (digit >= 0) {		q++;		num = (num << 4) | digit;	}	*p = num;	*dst += 1;	*src = q;	return true;} static bool unescape_special(char **src, char **dst){	char *p = *dst, *q = *src; 	switch (*q) {	case '\"':		*p = '\"';		break;	case '\\':		*p = '\\';		break;	case 'a':		*p = '\a';		break;	case 'e':		*p = '\e';		break;	default:		return false;	}	*dst += 1;	*src += 1;	return true;} int string_unescape(char *src, char *dst, size_t size, unsigned int flags){	char *out = dst; 	while (*src && --size) {		if (src[0] == '\\' && src[1] != '\0' && size > 1) {			src++;			size--; 			if (flags & UNESCAPE_SPACE &&					unescape_space(&src, &out))				continue; 			if (flags & UNESCAPE_OCTAL &&					unescape_octal(&src, &out))				continue; 			if (flags & UNESCAPE_HEX &&					unescape_hex(&src, &out))				continue; 			if (flags & UNESCAPE_SPECIAL &&					unescape_special(&src, &out))				continue; 			*out++ = '\\';		}		*out++ = *src++;	}	*out = '\0'; 	return out - dst;}EXPORT_SYMBOL(string_unescape);