Initial import

1 files changed, 507 insertions, 0 deletions

diff --git a/lib/string_helpers.c b/lib/string_helpers.c
new file mode 100644
index 000000000..c98ae818e
--- /dev/null
+++ b/lib/string_helpers.c
@@ -0,0 +1,507 @@
+/*
+ * Helpers for formatting and printing strings
+ *
+ * Copyright 31 August 2008 James Bottomley
+ * Copyright (C) 2013, Intel Corporation
+ */
+#include <linux/bug.h>
+#include <linux/kernel.h>
+#include <linux/math64.h>
+#include <linux/export.h>
+#include <linux/ctype.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <linux/string_helpers.h>
+
+/**
+ * string_get_size - get the size in the specified units
+ * @size:	The size to be converted in blocks
+ * @blk_size:	Size of the block (use 1 for size in bytes)
+ * @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.  @buf should have room for
+ * at least 9 bytes and will always be zero terminated.
+ *
+ */
+void string_get_size(u64 size, u64 blk_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"
+	};
+	static const char *const units_2[] = {
+		"B", "KiB", "MiB", "GiB", "TiB", "PiB", "EiB", "ZiB", "YiB"
+	};
+	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;
+	u32 remainder = 0, sf_cap, exp;
+	char tmp[8];
+	const char *unit;
+
+	tmp[0] = '\0';
+	i = 0;
+	if (!size)
+		goto out;
+
+	while (blk_size >= divisor[units]) {
+		remainder = do_div(blk_size, divisor[units]);
+		i++;
+	}
+
+	exp = divisor[units] / (u32)blk_size;
+	if (size >= exp) {
+		remainder = do_div(size, divisor[units]);
+		remainder *= blk_size;
+		i++;
+	} else {
+		remainder *= size;
+	}
+
+	size *= blk_size;
+	size += remainder / divisor[units];
+	remainder %= divisor[units];
+
+	while (size >= divisor[units]) {
+		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;
+		remainder /= divisor[units];
+		snprintf(tmp, sizeof(tmp), ".%03u", remainder);
+		tmp[j+1] = '\0';
+	}
+
+ out:
+	if (i >= ARRAY_SIZE(units_2))
+		unit = "UNK";
+	else
+		unit = units_str[units][i];
+
+	snprintf(buf, len, "%u%s %s", (u32)size,
+		 tmp, unit);
+}
+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;
+}
+
+/**
+ * string_unescape - unquote characters in the given string
+ * @src:	source buffer (escaped)
+ * @dst:	destination buffer (unescaped)
+ * @size:	size of the destination buffer (0 to unlimit)
+ * @flags:	combination of the flags (bitwise OR):
+ *	%UNESCAPE_SPACE:
+ *		'\f' - form feed
+ *		'\n' - new line
+ *		'\r' - carriage return
+ *		'\t' - horizontal tab
+ *		'\v' - vertical tab
+ *	%UNESCAPE_OCTAL:
+ *		'\NNN' - byte with octal value NNN (1 to 3 digits)
+ *	%UNESCAPE_HEX:
+ *		'\xHH' - byte with hexadecimal value HH (1 to 2 digits)
+ *	%UNESCAPE_SPECIAL:
+ *		'\"' - double quote
+ *		'\\' - backslash
+ *		'\a' - alert (BEL)
+ *		'\e' - escape
+ *	%UNESCAPE_ANY:
+ *		all previous together
+ *
+ * Description:
+ * The function unquotes characters in the given string.
+ *
+ * Because the size of the output will be the same as or less than the size of
+ * the input, the transformation may be performed in place.
+ *
+ * Caller must provide valid source and destination pointers. Be aware that
+ * destination buffer will always be NULL-terminated. Source string must be
+ * NULL-terminated as well.
+ *
+ * Return:
+ * The amount of the characters processed to the destination buffer excluding
+ * trailing '\0' is returned.
+ */
+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);
+
+static bool escape_passthrough(unsigned char c, char **dst, char *end)
+{
+	char *out = *dst;
+
+	if (out < end)
+		*out = c;
+	*dst = out + 1;
+	return true;
+}
+
+static bool escape_space(unsigned char c, char **dst, char *end)
+{
+	char *out = *dst;
+	unsigned char to;
+
+	switch (c) {
+	case '\n':
+		to = 'n';
+		break;
+	case '\r':
+		to = 'r';
+		break;
+	case '\t':
+		to = 't';
+		break;
+	case '\v':
+		to = 'v';
+		break;
+	case '\f':
+		to = 'f';
+		break;
+	default:
+		return false;
+	}
+
+	if (out < end)
+		*out = '\\';
+	++out;
+	if (out < end)
+		*out = to;
+	++out;
+
+	*dst = out;
+	return true;
+}
+
+static bool escape_special(unsigned char c, char **dst, char *end)
+{
+	char *out = *dst;
+	unsigned char to;
+
+	switch (c) {
+	case '\\':
+		to = '\\';
+		break;
+	case '\a':
+		to = 'a';
+		break;
+	case '\e':
+		to = 'e';
+		break;
+	default:
+		return false;
+	}
+
+	if (out < end)
+		*out = '\\';
+	++out;
+	if (out < end)
+		*out = to;
+	++out;
+
+	*dst = out;
+	return true;
+}
+
+static bool escape_null(unsigned char c, char **dst, char *end)
+{
+	char *out = *dst;
+
+	if (c)
+		return false;
+
+	if (out < end)
+		*out = '\\';
+	++out;
+	if (out < end)
+		*out = '0';
+	++out;
+
+	*dst = out;
+	return true;
+}
+
+static bool escape_octal(unsigned char c, char **dst, char *end)
+{
+	char *out = *dst;
+
+	if (out < end)
+		*out = '\\';
+	++out;
+	if (out < end)
+		*out = ((c >> 6) & 0x07) + '0';
+	++out;
+	if (out < end)
+		*out = ((c >> 3) & 0x07) + '0';
+	++out;
+	if (out < end)
+		*out = ((c >> 0) & 0x07) + '0';
+	++out;
+
+	*dst = out;
+	return true;
+}
+
+static bool escape_hex(unsigned char c, char **dst, char *end)
+{
+	char *out = *dst;
+
+	if (out < end)
+		*out = '\\';
+	++out;
+	if (out < end)
+		*out = 'x';
+	++out;
+	if (out < end)
+		*out = hex_asc_hi(c);
+	++out;
+	if (out < end)
+		*out = hex_asc_lo(c);
+	++out;
+
+	*dst = out;
+	return true;
+}
+
+/**
+ * string_escape_mem - quote characters in the given memory buffer
+ * @src:	source buffer (unescaped)
+ * @isz:	source buffer size
+ * @dst:	destination buffer (escaped)
+ * @osz:	destination buffer size
+ * @flags:	combination of the flags (bitwise OR):
+ *	%ESCAPE_SPACE:
+ *		'\f' - form feed
+ *		'\n' - new line
+ *		'\r' - carriage return
+ *		'\t' - horizontal tab
+ *		'\v' - vertical tab
+ *	%ESCAPE_SPECIAL:
+ *		'\\' - backslash
+ *		'\a' - alert (BEL)
+ *		'\e' - escape
+ *	%ESCAPE_NULL:
+ *		'\0' - null
+ *	%ESCAPE_OCTAL:
+ *		'\NNN' - byte with octal value NNN (3 digits)
+ *	%ESCAPE_ANY:
+ *		all previous together
+ *	%ESCAPE_NP:
+ *		escape only non-printable characters (checked by isprint)
+ *	%ESCAPE_ANY_NP:
+ *		all previous together
+ *	%ESCAPE_HEX:
+ *		'\xHH' - byte with hexadecimal value HH (2 digits)
+ * @esc:	NULL-terminated string of characters any of which, if found in
+ *		the source, has to be escaped
+ *
+ * Description:
+ * The process of escaping byte buffer includes several parts. They are applied
+ * in the following sequence.
+ *	1. The character is matched to the printable class, if asked, and in
+ *	   case of match it passes through to the output.
+ *	2. The character is not matched to the one from @esc string and thus
+ *	   must go as is to the output.
+ *	3. The character is checked if it falls into the class given by @flags.
+ *	   %ESCAPE_OCTAL and %ESCAPE_HEX are going last since they cover any
+ *	   character. Note that they actually can't go together, otherwise
+ *	   %ESCAPE_HEX will be ignored.
+ *
+ * Caller must provide valid source and destination pointers. Be aware that
+ * destination buffer will not be NULL-terminated, thus caller have to append
+ * it if needs.
+ *
+ * Return:
+ * The total size of the escaped output that would be generated for
+ * the given input and flags. To check whether the output was
+ * truncated, compare the return value to osz. There is room left in
+ * dst for a '\0' terminator if and only if ret < osz.
+ */
+int string_escape_mem(const char *src, size_t isz, char *dst, size_t osz,
+		      unsigned int flags, const char *esc)
+{
+	char *p = dst;
+	char *end = p + osz;
+	bool is_dict = esc && *esc;
+
+	while (isz--) {
+		unsigned char c = *src++;
+
+		/*
+		 * Apply rules in the following sequence:
+		 *	- the character is printable, when @flags has
+		 *	  %ESCAPE_NP bit set
+		 *	- the @esc string is supplied and does not contain a
+		 *	  character under question
+		 *	- the character doesn't fall into a class of symbols
+		 *	  defined by given @flags
+		 * In these cases we just pass through a character to the
+		 * output buffer.
+		 */
+		if ((flags & ESCAPE_NP && isprint(c)) ||
+		    (is_dict && !strchr(esc, c))) {
+			/* do nothing */
+		} else {
+			if (flags & ESCAPE_SPACE && escape_space(c, &p, end))
+				continue;
+
+			if (flags & ESCAPE_SPECIAL && escape_special(c, &p, end))
+				continue;
+
+			if (flags & ESCAPE_NULL && escape_null(c, &p, end))
+				continue;
+
+			/* ESCAPE_OCTAL and ESCAPE_HEX always go last */
+			if (flags & ESCAPE_OCTAL && escape_octal(c, &p, end))
+				continue;
+
+			if (flags & ESCAPE_HEX && escape_hex(c, &p, end))
+				continue;
+		}
+
+		escape_passthrough(c, &p, end);
+	}
+
+	return p - dst;
+}
+EXPORT_SYMBOL(string_escape_mem);