3 * Helper functions for bitmap.h.
5 * This source code is licensed under the GNU General Public License,
6 * Version 2. See the file COPYING for more details.
8 #include <linux/module.h>
9 #include <linux/ctype.h>
10 #include <linux/errno.h>
11 #include <linux/bitmap.h>
12 #include <linux/bitops.h>
13 #include <asm/uaccess.h>
16 * bitmaps provide an array of bits, implemented using an an
17 * array of unsigned longs. The number of valid bits in a
18 * given bitmap does _not_ need to be an exact multiple of
21 * The possible unused bits in the last, partially used word
22 * of a bitmap are 'don't care'. The implementation makes
23 * no particular effort to keep them zero. It ensures that
24 * their value will not affect the results of any operation.
25 * The bitmap operations that return Boolean (bitmap_empty,
26 * for example) or scalar (bitmap_weight, for example) results
27 * carefully filter out these unused bits from impacting their
30 * These operations actually hold to a slightly stronger rule:
31 * if you don't input any bitmaps to these ops that have some
32 * unused bits set, then they won't output any set unused bits
35 * The byte ordering of bitmaps is more natural on little
36 * endian architectures. See the big-endian headers
37 * include/asm-ppc64/bitops.h and include/asm-s390/bitops.h
38 * for the best explanations of this ordering.
41 int __bitmap_empty(const unsigned long *bitmap, int bits)
43 int k, lim = bits/BITS_PER_LONG;
44 for (k = 0; k < lim; ++k)
48 if (bits % BITS_PER_LONG)
49 if (bitmap[k] & BITMAP_LAST_WORD_MASK(bits))
54 EXPORT_SYMBOL(__bitmap_empty);
56 int __bitmap_full(const unsigned long *bitmap, int bits)
58 int k, lim = bits/BITS_PER_LONG;
59 for (k = 0; k < lim; ++k)
63 if (bits % BITS_PER_LONG)
64 if (~bitmap[k] & BITMAP_LAST_WORD_MASK(bits))
69 EXPORT_SYMBOL(__bitmap_full);
71 int __bitmap_equal(const unsigned long *bitmap1,
72 const unsigned long *bitmap2, int bits)
74 int k, lim = bits/BITS_PER_LONG;
75 for (k = 0; k < lim; ++k)
76 if (bitmap1[k] != bitmap2[k])
79 if (bits % BITS_PER_LONG)
80 if ((bitmap1[k] ^ bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
85 EXPORT_SYMBOL(__bitmap_equal);
87 void __bitmap_complement(unsigned long *dst, const unsigned long *src, int bits)
89 int k, lim = bits/BITS_PER_LONG;
90 for (k = 0; k < lim; ++k)
93 if (bits % BITS_PER_LONG)
94 dst[k] = ~src[k] & BITMAP_LAST_WORD_MASK(bits);
96 EXPORT_SYMBOL(__bitmap_complement);
99 * __bitmap_shift_right - logical right shift of the bits in a bitmap
100 * @dst - destination bitmap
101 * @src - source bitmap
102 * @nbits - shift by this many bits
103 * @bits - bitmap size, in bits
105 * Shifting right (dividing) means moving bits in the MS -> LS bit
106 * direction. Zeros are fed into the vacated MS positions and the
107 * LS bits shifted off the bottom are lost.
109 void __bitmap_shift_right(unsigned long *dst,
110 const unsigned long *src, int shift, int bits)
112 int k, lim = BITS_TO_LONGS(bits), left = bits % BITS_PER_LONG;
113 int off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;
114 unsigned long mask = (1UL << left) - 1;
115 for (k = 0; off + k < lim; ++k) {
116 unsigned long upper, lower;
119 * If shift is not word aligned, take lower rem bits of
120 * word above and make them the top rem bits of result.
122 if (!rem || off + k + 1 >= lim)
125 upper = src[off + k + 1];
126 if (off + k + 1 == lim - 1 && left)
129 lower = src[off + k];
130 if (left && off + k == lim - 1)
132 dst[k] = upper << (BITS_PER_LONG - rem) | lower >> rem;
133 if (left && k == lim - 1)
137 memset(&dst[lim - off], 0, off*sizeof(unsigned long));
139 EXPORT_SYMBOL(__bitmap_shift_right);
143 * __bitmap_shift_left - logical left shift of the bits in a bitmap
144 * @dst - destination bitmap
145 * @src - source bitmap
146 * @nbits - shift by this many bits
147 * @bits - bitmap size, in bits
149 * Shifting left (multiplying) means moving bits in the LS -> MS
150 * direction. Zeros are fed into the vacated LS bit positions
151 * and those MS bits shifted off the top are lost.
154 void __bitmap_shift_left(unsigned long *dst,
155 const unsigned long *src, int shift, int bits)
157 int k, lim = BITS_TO_LONGS(bits), left = bits % BITS_PER_LONG;
158 int off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;
159 for (k = lim - off - 1; k >= 0; --k) {
160 unsigned long upper, lower;
163 * If shift is not word aligned, take upper rem bits of
164 * word below and make them the bottom rem bits of result.
171 if (left && k == lim - 1)
172 upper &= (1UL << left) - 1;
173 dst[k + off] = lower >> (BITS_PER_LONG - rem) | upper << rem;
174 if (left && k + off == lim - 1)
175 dst[k + off] &= (1UL << left) - 1;
178 memset(dst, 0, off*sizeof(unsigned long));
180 EXPORT_SYMBOL(__bitmap_shift_left);
182 void __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
183 const unsigned long *bitmap2, int bits)
186 int nr = BITS_TO_LONGS(bits);
188 for (k = 0; k < nr; k++)
189 dst[k] = bitmap1[k] & bitmap2[k];
191 EXPORT_SYMBOL(__bitmap_and);
193 void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
194 const unsigned long *bitmap2, int bits)
197 int nr = BITS_TO_LONGS(bits);
199 for (k = 0; k < nr; k++)
200 dst[k] = bitmap1[k] | bitmap2[k];
202 EXPORT_SYMBOL(__bitmap_or);
204 void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,
205 const unsigned long *bitmap2, int bits)
208 int nr = BITS_TO_LONGS(bits);
210 for (k = 0; k < nr; k++)
211 dst[k] = bitmap1[k] ^ bitmap2[k];
213 EXPORT_SYMBOL(__bitmap_xor);
215 void __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
216 const unsigned long *bitmap2, int bits)
219 int nr = BITS_TO_LONGS(bits);
221 for (k = 0; k < nr; k++)
222 dst[k] = bitmap1[k] & ~bitmap2[k];
224 EXPORT_SYMBOL(__bitmap_andnot);
226 int __bitmap_intersects(const unsigned long *bitmap1,
227 const unsigned long *bitmap2, int bits)
229 int k, lim = bits/BITS_PER_LONG;
230 for (k = 0; k < lim; ++k)
231 if (bitmap1[k] & bitmap2[k])
234 if (bits % BITS_PER_LONG)
235 if ((bitmap1[k] & bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
239 EXPORT_SYMBOL(__bitmap_intersects);
241 int __bitmap_subset(const unsigned long *bitmap1,
242 const unsigned long *bitmap2, int bits)
244 int k, lim = bits/BITS_PER_LONG;
245 for (k = 0; k < lim; ++k)
246 if (bitmap1[k] & ~bitmap2[k])
249 if (bits % BITS_PER_LONG)
250 if ((bitmap1[k] & ~bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
254 EXPORT_SYMBOL(__bitmap_subset);
256 #if BITS_PER_LONG == 32
257 int __bitmap_weight(const unsigned long *bitmap, int bits)
259 int k, w = 0, lim = bits/BITS_PER_LONG;
261 for (k = 0; k < lim; k++)
262 w += hweight32(bitmap[k]);
264 if (bits % BITS_PER_LONG)
265 w += hweight32(bitmap[k] & BITMAP_LAST_WORD_MASK(bits));
270 int __bitmap_weight(const unsigned long *bitmap, int bits)
272 int k, w = 0, lim = bits/BITS_PER_LONG;
274 for (k = 0; k < lim; k++)
275 w += hweight64(bitmap[k]);
277 if (bits % BITS_PER_LONG)
278 w += hweight64(bitmap[k] & BITMAP_LAST_WORD_MASK(bits));
283 EXPORT_SYMBOL(__bitmap_weight);
286 * Bitmap printing & parsing functions: first version by Bill Irwin,
287 * second version by Paul Jackson, third by Joe Korty.
291 #define nbits_to_hold_value(val) fls(val)
292 #define unhex(c) (isdigit(c) ? (c - '0') : (toupper(c) - 'A' + 10))
293 #define BASEDEC 10 /* fancier cpuset lists input in decimal */
296 * bitmap_scnprintf - convert bitmap to an ASCII hex string.
297 * @buf: byte buffer into which string is placed
298 * @buflen: reserved size of @buf, in bytes
299 * @maskp: pointer to bitmap to convert
300 * @nmaskbits: size of bitmap, in bits
302 * Exactly @nmaskbits bits are displayed. Hex digits are grouped into
303 * comma-separated sets of eight digits per set.
305 int bitmap_scnprintf(char *buf, unsigned int buflen,
306 const unsigned long *maskp, int nmaskbits)
308 int i, word, bit, len = 0;
310 const char *sep = "";
314 chunksz = nmaskbits & (CHUNKSZ - 1);
318 i = ALIGN(nmaskbits, CHUNKSZ) - CHUNKSZ;
319 for (; i >= 0; i -= CHUNKSZ) {
320 chunkmask = ((1ULL << chunksz) - 1);
321 word = i / BITS_PER_LONG;
322 bit = i % BITS_PER_LONG;
323 val = (maskp[word] >> bit) & chunkmask;
324 len += scnprintf(buf+len, buflen-len, "%s%0*lx", sep,
331 EXPORT_SYMBOL(bitmap_scnprintf);
334 * bitmap_parse - convert an ASCII hex string into a bitmap.
335 * @buf: pointer to buffer in user space containing string.
336 * @buflen: buffer size in bytes. If string is smaller than this
337 * then it must be terminated with a \0.
338 * @maskp: pointer to bitmap array that will contain result.
339 * @nmaskbits: size of bitmap, in bits.
341 * Commas group hex digits into chunks. Each chunk defines exactly 32
342 * bits of the resultant bitmask. No chunk may specify a value larger
343 * than 32 bits (-EOVERFLOW), and if a chunk specifies a smaller value
344 * then leading 0-bits are prepended. -EINVAL is returned for illegal
345 * characters and for grouping errors such as "1,,5", ",44", "," and "".
346 * Leading and trailing whitespace accepted, but not embedded whitespace.
348 int bitmap_parse(const char __user *ubuf, unsigned int ubuflen,
349 unsigned long *maskp, int nmaskbits)
351 int c, old_c, totaldigits, ndigits, nchunks, nbits;
354 bitmap_zero(maskp, nmaskbits);
356 nchunks = nbits = totaldigits = c = 0;
360 /* Get the next chunk of the bitmap */
363 if (get_user(c, ubuf++))
370 * If the last character was a space and the current
371 * character isn't '\0', we've got embedded whitespace.
372 * This is a no-no, so throw an error.
374 if (totaldigits && c && isspace(old_c))
377 /* A '\0' or a ',' signal the end of the chunk */
378 if (c == '\0' || c == ',')
385 * Make sure there are at least 4 free bits in 'chunk'.
386 * If not, this hexdigit will overflow 'chunk', so
389 if (chunk & ~((1UL << (CHUNKSZ - 4)) - 1))
392 chunk = (chunk << 4) | unhex(c);
393 ndigits++; totaldigits++;
397 if (nchunks == 0 && chunk == 0)
400 __bitmap_shift_left(maskp, maskp, CHUNKSZ, nmaskbits);
403 nbits += (nchunks == 1) ? nbits_to_hold_value(chunk) : CHUNKSZ;
404 if (nbits > nmaskbits)
406 } while (ubuflen && c == ',');
410 EXPORT_SYMBOL(bitmap_parse);
413 * bscnl_emit(buf, buflen, rbot, rtop, bp)
415 * Helper routine for bitmap_scnlistprintf(). Write decimal number
416 * or range to buf, suppressing output past buf+buflen, with optional
417 * comma-prefix. Return len of what would be written to buf, if it
420 static inline int bscnl_emit(char *buf, int buflen, int rbot, int rtop, int len)
423 len += scnprintf(buf + len, buflen - len, ",");
425 len += scnprintf(buf + len, buflen - len, "%d", rbot);
427 len += scnprintf(buf + len, buflen - len, "%d-%d", rbot, rtop);
432 * bitmap_scnlistprintf - convert bitmap to list format ASCII string
433 * @buf: byte buffer into which string is placed
434 * @buflen: reserved size of @buf, in bytes
435 * @maskp: pointer to bitmap to convert
436 * @nmaskbits: size of bitmap, in bits
438 * Output format is a comma-separated list of decimal numbers and
439 * ranges. Consecutively set bits are shown as two hyphen-separated
440 * decimal numbers, the smallest and largest bit numbers set in
441 * the range. Output format is compatible with the format
442 * accepted as input by bitmap_parselist().
444 * The return value is the number of characters which would be
445 * generated for the given input, excluding the trailing '\0', as
448 int bitmap_scnlistprintf(char *buf, unsigned int buflen,
449 const unsigned long *maskp, int nmaskbits)
452 /* current bit is 'cur', most recently seen range is [rbot, rtop] */
455 rbot = cur = find_first_bit(maskp, nmaskbits);
456 while (cur < nmaskbits) {
458 cur = find_next_bit(maskp, nmaskbits, cur+1);
459 if (cur >= nmaskbits || cur > rtop + 1) {
460 len = bscnl_emit(buf, buflen, rbot, rtop, len);
466 EXPORT_SYMBOL(bitmap_scnlistprintf);
469 * bitmap_parselist - convert list format ASCII string to bitmap
470 * @buf: read nul-terminated user string from this buffer
471 * @mask: write resulting mask here
472 * @nmaskbits: number of bits in mask to be written
474 * Input format is a comma-separated list of decimal numbers and
475 * ranges. Consecutively set bits are shown as two hyphen-separated
476 * decimal numbers, the smallest and largest bit numbers set in
479 * Returns 0 on success, -errno on invalid input strings:
480 * -EINVAL: second number in range smaller than first
481 * -EINVAL: invalid character in string
482 * -ERANGE: bit number specified too large for mask
484 int bitmap_parselist(const char *bp, unsigned long *maskp, int nmaskbits)
488 bitmap_zero(maskp, nmaskbits);
492 b = a = simple_strtoul(bp, (char **)&bp, BASEDEC);
497 b = simple_strtoul(bp, (char **)&bp, BASEDEC);
509 } while (*bp != '\0' && *bp != '\n');
512 EXPORT_SYMBOL(bitmap_parselist);
515 * bitmap_find_free_region - find a contiguous aligned mem region
516 * @bitmap: an array of unsigned longs corresponding to the bitmap
517 * @bits: number of bits in the bitmap
518 * @order: region size to find (size is actually 1<<order)
520 * This is used to allocate a memory region from a bitmap. The idea is
521 * that the region has to be 1<<order sized and 1<<order aligned (this
522 * makes the search algorithm much faster).
524 * The region is marked as set bits in the bitmap if a free one is
527 * Returns either beginning of region or negative error
529 int bitmap_find_free_region(unsigned long *bitmap, int bits, int order)
532 int pages = 1 << order;
535 if(pages > BITS_PER_LONG)
538 /* make a mask of the order */
539 mask = (1ul << (pages - 1));
542 /* run up the bitmap pages bits at a time */
543 for (i = 0; i < bits; i += pages) {
544 int index = i/BITS_PER_LONG;
545 int offset = i - (index * BITS_PER_LONG);
546 if((bitmap[index] & (mask << offset)) == 0) {
547 /* set region in bimap */
548 bitmap[index] |= (mask << offset);
554 EXPORT_SYMBOL(bitmap_find_free_region);
557 * bitmap_release_region - release allocated bitmap region
558 * @bitmap: a pointer to the bitmap
559 * @pos: the beginning of the region
560 * @order: the order of the bits to release (number is 1<<order)
562 * This is the complement to __bitmap_find_free_region and releases
563 * the found region (by clearing it in the bitmap).
565 void bitmap_release_region(unsigned long *bitmap, int pos, int order)
567 int pages = 1 << order;
568 unsigned long mask = (1ul << (pages - 1));
569 int index = pos/BITS_PER_LONG;
570 int offset = pos - (index * BITS_PER_LONG);
572 bitmap[index] &= ~(mask << offset);
574 EXPORT_SYMBOL(bitmap_release_region);
576 int bitmap_allocate_region(unsigned long *bitmap, int pos, int order)
578 int pages = 1 << order;
579 unsigned long mask = (1ul << (pages - 1));
580 int index = pos/BITS_PER_LONG;
581 int offset = pos - (index * BITS_PER_LONG);
583 /* We don't do regions of pages > BITS_PER_LONG. The
584 * algorithm would be a simple look for multiple zeros in the
585 * array, but there's no driver today that needs this. If you
586 * trip this BUG(), you get to code it... */
587 BUG_ON(pages > BITS_PER_LONG);
589 if (bitmap[index] & (mask << offset))
591 bitmap[index] |= (mask << offset);
594 EXPORT_SYMBOL(bitmap_allocate_region);