1 /* SPDX-License-Identifier: GPL-2.0-only */
3 -*- linux-c -*-
7    Copyright (C) 2001-2008, LINBIT Information Technologies GmbH.
8    Copyright (C) 1999-2008, Philipp Reisner <philipp.reisner@linbit.com>.
9    Copyright (C) 2002-2008, Lars Ellenberg <lars.ellenberg@linbit.com>.
19  * and possibly small-bandwidth replication,
55  *  * simple byte-based
69  * __little endian__ bitstream, least significant bit first (left most)
108 -+-----------------------------------------------------------------------
140 		if ((in & ((1 << b) -1)) == v) {	\  in vli_decode_bits()
141 			*out = ((in & ((~0ULL) >> (64-t))) >> b) + adj;	\  in vli_decode_bits()
144 		adj += 1ULL << (t - b);			\  in vli_decode_bits()
162 		return -EINVAL;  in __vli_encode_bits()
165 		max += 1ULL << (t - b);	\  in __vli_encode_bits()
168 				*out = ((in - adj) << b) | v;	\  in __vli_encode_bits()
176 	return -EOVERFLOW;  in __vli_encode_bits()
186  * This encodes arbitrary bit length, not whole bytes: we have a bit-stream,
201 	cur->b = s;  in bitstream_cursor_reset()
202 	cur->bit = 0;  in bitstream_cursor_reset()
209 	bits += cur->bit;  in bitstream_cursor_advance()
210 	cur->b = cur->b + (bits >> 3);  in bitstream_cursor_advance()
211 	cur->bit = bits & 7;  in bitstream_cursor_advance()
222 	 * total number of valid bits in stream: buf_len * 8 - pad_bits */
228 	bs->buf = s;  in bitstream_init()
229 	bs->buf_len = len;  in bitstream_init()
230 	bs->pad_bits = pad_bits;  in bitstream_init()
231 	bitstream_cursor_reset(&bs->cur, bs->buf);  in bitstream_init()
236 	bitstream_cursor_reset(&bs->cur, bs->buf);  in bitstream_rewind()
237 	memset(bs->buf, 0, bs->buf_len);  in bitstream_rewind()
240 /* Put (at most 64) least significant bits of val into bitstream, and advance cursor.
245  * If there is not enough room left in bitstream,
246  * leaves bitstream unchanged and returns -ENOBUFS.
250 	unsigned char *b = bs->cur.b;  in bitstream_put_bits()
256 	if ((bs->cur.b + ((bs->cur.bit + bits -1) >> 3)) - bs->buf >= bs->buf_len)  in bitstream_put_bits()
257 		return -ENOBUFS;  in bitstream_put_bits()
261 		val &= ~0ULL >> (64 - bits);  in bitstream_put_bits()
263 	*b++ |= (val & 0xff) << bs->cur.bit;  in bitstream_put_bits()
265 	for (tmp = 8 - bs->cur.bit; tmp < bits; tmp += 8)  in bitstream_put_bits()
268 	bitstream_cursor_advance(&bs->cur, bits);  in bitstream_put_bits()
272 /* Fetch (at most 64) bits from bitstream into *out, and advance cursor.
274  * If more than 64 bits are requested, returns -EINVAL and leave *out unchanged.
276  * If there are less than the requested number of valid bits left in the
287 		return -EINVAL;  in bitstream_get_bits()
289 	if (bs->cur.b + ((bs->cur.bit + bs->pad_bits + bits -1) >> 3) - bs->buf >= bs->buf_len)  in bitstream_get_bits()
290 		bits = ((bs->buf_len - (bs->cur.b - bs->buf)) << 3)  in bitstream_get_bits()
291 			- bs->cur.bit - bs->pad_bits;  in bitstream_get_bits()
300 	n = (bs->cur.bit + bits + 7) >> 3;  in bitstream_get_bits()
301 	/* n may be at most 9, if cur.bit + bits > 64 */  in bitstream_get_bits()
302 	/* which means this copies at most 8 byte */  in bitstream_get_bits()
304 		memcpy(&val, bs->cur.b+1, n - 1);  in bitstream_get_bits()
305 		val = le64_to_cpu(val) << (8 - bs->cur.bit);  in bitstream_get_bits()
309 	val |= bs->cur.b[0] >> bs->cur.bit;  in bitstream_get_bits()
312 	val &= ~0ULL >> (64 - bits);  in bitstream_get_bits()
314 	bitstream_cursor_advance(&bs->cur, bits);  in bitstream_get_bits()
324  * -ENOBUFS @bs is full
325  * -EINVAL input zero (invalid)
326  * -EOVERFLOW input too large for this vli code (invalid)