/*

This file is taken from the Linux kernel and minimally adapted for use in userspace

*/

/*

 * lib/bitmap.c

 * Helper functions for bitmap.h.

 *

 * This source code is licensed under the GNU General Public License,

 * Version 2.  See the file COPYING for more details.

 */

#include "config.h"

#include <unistd.h>

#include <errno.h>

#include <stdio.h>

#include <stdlib.h>

#include <ctype.h>

#include "bitmap.h"

#include "non-atomic.h"

/*

 * bitmaps provide an array of bits, implemented using an an

 * array of unsigned longs.  The number of valid bits in a

 * given bitmap does _not_ need to be an exact multiple of

 * BITS_PER_LONG.

 *

 * The possible unused bits in the last, partially used word

 * of a bitmap are 'don't care'.  The implementation makes

 * no particular effort to keep them zero.  It ensures that

 * their value will not affect the results of any operation.

 * The bitmap operations that return Boolean (bitmap_empty,

 * for example) or scalar (bitmap_weight, for example) results

 * carefully filter out these unused bits from impacting their

 * results.

 *

 * These operations actually hold to a slightly stronger rule:

 * if you don't input any bitmaps to these ops that have some

 * unused bits set, then they won't output any set unused bits

 * in output bitmaps.

 *

 * The byte ordering of bitmaps is more natural on little

 * endian architectures.  See the big-endian headers

 * include/asm-ppc64/bitops.h and include/asm-s390/bitops.h

 * for the best explanations of this ordering.

 */

int __bitmap_empty(const unsigned long *bitmap, int bits)

{

	int k, lim = bits/BITS_PER_LONG;

	for (k = 0; k < lim; ++k)

		if (bitmap[k])

			return 0;

	if (bits % BITS_PER_LONG)

		if (bitmap[k] & BITMAP_LAST_WORD_MASK(bits))

			return 0;

	return 1;

}

int __bitmap_full(const unsigned long *bitmap, int bits)

{

	int k, lim = bits/BITS_PER_LONG;

	for (k = 0; k < lim; ++k)

		if (~bitmap[k])

			return 0;

	if (bits % BITS_PER_LONG)

		if (~bitmap[k] & BITMAP_LAST_WORD_MASK(bits))

			return 0;

	return 1;

}

int __bitmap_weight(const unsigned long *bitmap, int bits)

{

	int k, w = 0, lim = bits/BITS_PER_LONG;

	for (k = 0; k < lim; k++)

		w += hweight_long(bitmap[k]);

	if (bits % BITS_PER_LONG)

		w += hweight_long(bitmap[k] & BITMAP_LAST_WORD_MASK(bits));

	return w;

}

int __bitmap_equal(const unsigned long *bitmap1,

		const unsigned long *bitmap2, int bits)

{

	int k, lim = bits/BITS_PER_LONG;

	for (k = 0; k < lim; ++k)

		if (bitmap1[k] != bitmap2[k])

			return 0;

	if (bits % BITS_PER_LONG)

		if ((bitmap1[k] ^ bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))

			return 0;

	return 1;

}

void __bitmap_complement(unsigned long *dst, const unsigned long *src, int bits)

{

	int k, lim = bits/BITS_PER_LONG;

	for (k = 0; k < lim; ++k)

		dst[k] = ~src[k];

	if (bits % BITS_PER_LONG)

		dst[k] = ~src[k] & BITMAP_LAST_WORD_MASK(bits);

}

/*

 * __bitmap_shift_right - logical right shift of the bits in a bitmap

 *   @dst - destination bitmap

 *   @src - source bitmap

 *   @nbits - shift by this many bits

 *   @bits - bitmap size, in bits

 *

 * Shifting right (dividing) means moving bits in the MS -> LS bit

 * direction.  Zeros are fed into the vacated MS positions and the

 * LS bits shifted off the bottom are lost.

 */

void __bitmap_shift_right(unsigned long *dst,

			const unsigned long *src, int shift, int bits)

{

	int k, lim = BITS_TO_LONGS(bits), left = bits % BITS_PER_LONG;

	int off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;

	unsigned long mask = (1UL << left) - 1;

	for (k = 0; off + k < lim; ++k) {

		unsigned long upper, lower;

		/*

		 * If shift is not word aligned, take lower rem bits of

		 * word above and make them the top rem bits of result.

		 */

		if (!rem || off + k + 1 >= lim)

			upper = 0;

		else {

			upper = src[off + k + 1];

			if (off + k + 1 == lim - 1 && left)

				upper &= mask;

		}

		lower = src[off + k];

		if (left && off + k == lim - 1)

			lower &= mask;

		dst[k] = upper << (BITS_PER_LONG - rem) | lower >> rem;

		if (left && k == lim - 1)

			dst[k] &= mask;

	}

	if (off)

		memset(&dst[lim - off], 0, off*sizeof(unsigned long));

}

/*

 * __bitmap_shift_left - logical left shift of the bits in a bitmap

 *   @dst - destination bitmap

 *   @src - source bitmap

 *   @nbits - shift by this many bits

 *   @bits - bitmap size, in bits

 *

 * Shifting left (multiplying) means moving bits in the LS -> MS

 * direction.  Zeros are fed into the vacated LS bit positions

 * and those MS bits shifted off the top are lost.

 */

void __bitmap_shift_left(unsigned long *dst,

			const unsigned long *src, int shift, int bits)

{

	int k, lim = BITS_TO_LONGS(bits), left = bits % BITS_PER_LONG;

	int off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;

	for (k = lim - off - 1; k >= 0; --k) {

		unsigned long upper, lower;

		/*

		 * If shift is not word aligned, take upper rem bits of

		 * word below and make them the bottom rem bits of result.

		 */

		if (rem && k > 0)

			lower = src[k - 1];

		else

			lower = 0;

		upper = src[k];

		if (left && k == lim - 1)

			upper &= (1UL << left) - 1;

		dst[k + off] = lower  >> (BITS_PER_LONG - rem) | upper << rem;

		if (left && k + off == lim - 1)

			dst[k + off] &= (1UL << left) - 1;

	}

	if (off)

		memset(dst, 0, off*sizeof(unsigned long));

}

void __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,

				const unsigned long *bitmap2, int bits)

{

	int k;

	int nr = BITS_TO_LONGS(bits);

	for (k = 0; k < nr; k++)

		dst[k] = bitmap1[k] & bitmap2[k];

}

void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1,

				const unsigned long *bitmap2, int bits)

{

	int k;

	int nr = BITS_TO_LONGS(bits);

	for (k = 0; k < nr; k++)

		dst[k] = bitmap1[k] | bitmap2[k];

}

void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,

				const unsigned long *bitmap2, int bits)

{

	int k;

	int nr = BITS_TO_LONGS(bits);

	for (k = 0; k < nr; k++)

		dst[k] = bitmap1[k] ^ bitmap2[k];

}

void __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,

				const unsigned long *bitmap2, int bits)

{

	int k;

	int nr = BITS_TO_LONGS(bits);

	for (k = 0; k < nr; k++)

		dst[k] = bitmap1[k] & ~bitmap2[k];

}

int __bitmap_intersects(const unsigned long *bitmap1,

				const unsigned long *bitmap2, int bits)

{

	int k, lim = bits/BITS_PER_LONG;

	for (k = 0; k < lim; ++k)

		if (bitmap1[k] & bitmap2[k])

			return 1;

	if (bits % BITS_PER_LONG)

		if ((bitmap1[k] & bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))

			return 1;

	return 0;

}

/*

 * Bitmap printing & parsing functions: first version by Bill Irwin,

 * second version by Paul Jackson, third by Joe Korty.

 */

#define CHUNKSZ				32

#define nbits_to_hold_value(val)	fls(val)

#define unhex(c)			(isdigit(c) ? (c - '0') : (toupper(c) - 'A' + 10))

#define BASEDEC 10		/* fancier cpuset lists input in decimal */

/**

 * bitmap_scnprintf - convert bitmap to an ASCII hex string.

 * @buf: byte buffer into which string is placed

 * @buflen: reserved size of @buf, in bytes

 * @maskp: pointer to bitmap to convert

 * @nmaskbits: size of bitmap, in bits

 *

 * Exactly @nmaskbits bits are displayed.  Hex digits are grouped into

 * comma-separated sets of eight digits per set.

 */

int bitmap_scnprintf(char *buf, unsigned int buflen,

	const unsigned long *maskp, int nmaskbits)

{

	int i, word, bit, len = 0;

	unsigned long val;

	const char *sep = "";

	int chunksz;

	uint32_t chunkmask;

	int first = 1;

	chunksz = nmaskbits & (CHUNKSZ - 1);

	if (chunksz == 0)

		chunksz = CHUNKSZ;

	i = ALIGN(nmaskbits, CHUNKSZ) - CHUNKSZ;

	for (; i >= 0; i -= CHUNKSZ) {

		chunkmask = ((1ULL << chunksz) - 1);

		word = i / BITS_PER_LONG;

		bit = i % BITS_PER_LONG;

		val = (maskp[word] >> bit) & chunkmask;

		if (val!=0 || !first || i==0)  {

			len += snprintf(buf+len, buflen-len, "%s%0*lx", sep,

				(chunksz+3)/4, val);

			sep = ",";

			first = 0;

		}

		chunksz = CHUNKSZ;

	}

	return len;

}

/**

 * __bitmap_parse - convert an ASCII hex string into a bitmap.

 * @buf: pointer to buffer containing string.

 * @buflen: buffer size in bytes.  If string is smaller than this

 *    then it must be terminated with a \0.

 * @is_user: location of buffer, 0 indicates kernel space

 * @maskp: pointer to bitmap array that will contain result.

 * @nmaskbits: size of bitmap, in bits.

 *

 * Commas group hex digits into chunks.  Each chunk defines exactly 32

 * bits of the resultant bitmask.  No chunk may specify a value larger

 * than 32 bits (%-EOVERFLOW), and if a chunk specifies a smaller value

 * then leading 0-bits are prepended.  %-EINVAL is returned for illegal

 * characters and for grouping errors such as "1,,5", ",44", "," and "".

 * Leading and trailing whitespace accepted, but not embedded whitespace.

 */

int __bitmap_parse(const char *buf, unsigned int buflen,

		int is_user __attribute((unused)), unsigned long *maskp,

		int nmaskbits)

{

	int c, old_c, totaldigits, ndigits, nchunks, nbits;

	uint32_t chunk;

	bitmap_zero(maskp, nmaskbits);

	nchunks = nbits = totaldigits = c = 0;

	do {

		chunk = ndigits = 0;

		/* Get the next chunk of the bitmap */

		while (buflen) {

			old_c = c;

			c = *buf++;

			buflen--;

			if (isspace(c))

				continue;

			/*

			 * If the last character was a space and the current

			 * character isn't '\0', we've got embedded whitespace.

			 * This is a no-no, so throw an error.

			 */

			if (totaldigits && c && isspace(old_c))

				return 0;

			/* A '\0' or a ',' signal the end of the chunk */

			if (c == '\0' || c == ',')

				break;

			if (!isxdigit(c))

				return -EINVAL;

			/*

			 * Make sure there are at least 4 free bits in 'chunk'.

			 * If not, this hexdigit will overflow 'chunk', so

			 * throw an error.

			 */

			if (chunk & ~((1UL << (CHUNKSZ - 4)) - 1))

				return -EOVERFLOW;

			chunk = (chunk << 4) | unhex(c);

			ndigits++; totaldigits++;

		}

		if (ndigits == 0)

			return -EINVAL;

		if (nchunks == 0 && chunk == 0)

			continue;

		__bitmap_shift_left(maskp, maskp, CHUNKSZ, nmaskbits);

		*maskp |= chunk;

		nchunks++;

		nbits += (nchunks == 1) ? nbits_to_hold_value(chunk) : CHUNKSZ;

		if (nbits > nmaskbits)

			return -EOVERFLOW;

	} while (buflen && c == ',');

	return 0;

}

/**

 * __bitmap_parselist - convert list format ASCII string to bitmap

 * @buf: read nul-terminated user string from this buffer

 * @buflen: buffer size in bytes.  If string is smaller than this

 *    then it must be terminated with a \0.

 * @is_user: location of buffer, 0 indicates kernel space

 * @maskp: write resulting mask here

 * @nmaskbits: number of bits in mask to be written

 *

 * Input format is a comma-separated list of decimal numbers and

 * ranges.  Consecutively set bits are shown as two hyphen-separated

 * decimal numbers, the smallest and largest bit numbers set in

 * the range.

 *

 * Returns 0 on success, -errno on invalid input strings.

 * Error values:

 *    %-EINVAL: second number in range smaller than first

 *    %-EINVAL: invalid character in string

 *    %-ERANGE: bit number specified too large for mask

 */

int __bitmap_parselist(const char *buf, unsigned int buflen,

		int is_user __attribute((unused)), unsigned long *maskp,

		int nmaskbits)

{

	int a, b, c, old_c, totaldigits;

	int exp_digit, in_range;

	totaldigits = c = 0;

	bitmap_zero(maskp, nmaskbits);

	do {

		exp_digit = 1;

		in_range = 0;

		a = b = 0;

		/* Get the next cpu# or a range of cpu#'s */

		while (buflen) {

			old_c = c;

			c = *buf++;

			buflen--;

			if (isspace(c))

				continue;

			/*

			 * If the last character was a space and the current

			 * character isn't '\0', we've got embedded whitespace.

			 * This is a no-no, so throw an error.

			 */

			if (totaldigits && c && isspace(old_c))

				return -EINVAL;

			/* A '\0' or a ',' signal the end of a cpu# or range */

			if (c == '\0' || c == ',')

				break;

			if (c == '-') {

				if (exp_digit || in_range)

					return -EINVAL;

				b = 0;

				in_range = 1;

				exp_digit = 1;

				continue;

			}

			if (!isdigit(c))

				return -EINVAL;

			b = b * 10 + (c - '0');

			if (!in_range)

				a = b;

			exp_digit = 0;

			totaldigits++;

		}

		if (!(a <= b))

			return -EINVAL;

		if (b >= nmaskbits)

			return -ERANGE;

		while (a <= b) {

			set_bit(a, maskp);

			a++;

		}

	} while (buflen && c == ',');

	return 0;

}