Adding upstream version 9.1.upstream/9.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 276 insertions, 0 deletions

diff --git a/lib/bitfield.h b/lib/bitfield.h
new file mode 100644
index 0000000..cc8c311
--- /dev/null
+++ b/lib/bitfield.h
@@ -0,0 +1,276 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* Bitfields
+ * Copyright (C) 2016 Cumulus Networks, Inc.
+ */
+/**
+ * A simple bit array implementation to allocate and free IDs. An example
+ * of its usage is in allocating link state IDs for OSPFv3 as OSPFv3 has
+ * removed all address semantics from LS ID. Another usage can be in
+ * allocating IDs for BGP neighbors (and dynamic update groups) for
+ * efficient storage of adj-rib-out.
+ *
+ * An example:
+ * #include "bitfield.h"
+ *
+ * bitfield_t bitfield;
+ *
+ * bf_init(bitfield, 32);
+ * ...
+ * bf_assign_index(bitfield, id1);
+ * bf_assign_index(bitfield, id2);
+ * ...
+ * bf_release_index(bitfield, id1);
+ */
+
+#ifndef _BITFIELD_H
+#define _BITFIELD_H
+
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef unsigned int word_t;
+#define WORD_MAX 0xFFFFFFFF
+#define WORD_SIZE (sizeof(word_t) * 8)
+
+/**
+ * The bitfield structure.
+ * @data: the bits to manage.
+ * @n: The current word number that is being used.
+ * @m: total number of words in 'data'
+ */
+typedef struct {word_t *data; size_t n, m; } bitfield_t;
+
+DECLARE_MTYPE(BITFIELD);
+
+/**
+ * Initialize the bits.
+ * @v: an instance of bitfield_t struct.
+ * @N: number of bits to start with, which equates to how many
+ *     IDs can be allocated.
+ */
+#define bf_init(v, N)                                                          \
+	do {                                                                   \
+		(v).n = 0;                                                     \
+		(v).m = ((N) / WORD_SIZE + 1);                                 \
+		(v).data = (word_t *)XCALLOC(MTYPE_BITFIELD,                   \
+					     ((v).m * sizeof(word_t)));        \
+	} while (0)
+
+/**
+ * allocate and assign an id from bitfield v.
+ */
+#define bf_assign_index(v, id)                                                 \
+	do {                                                                   \
+		bf_find_bit(v, id);                                            \
+		bf_set_bit(v, id);                                             \
+	} while (0)
+
+/*
+ * allocate and assign 0th bit in the bitfiled.
+ */
+#define bf_assign_zero_index(v)                                                \
+	do {                                                                   \
+		int id = 0;                                                    \
+		bf_assign_index(v, id);                                        \
+	} while (0)
+
+/*
+ * return an id to bitfield v
+ */
+#define bf_release_index(v, id)                                                \
+	(v).data[bf_index(id)] &= ~(1 << (bf_offset(id)))
+
+/* check if an id is in use */
+#define bf_test_index(v, id)                                                \
+	((v).data[bf_index(id)] & (1 << (bf_offset(id))))
+
+/* check if the bit field has been setup */
+#define bf_is_inited(v) ((v).data)
+
+/* compare two bitmaps of the same length */
+#define bf_cmp(v1, v2) (memcmp((v1).data, (v2).data, ((v1).m * sizeof(word_t))))
+
+/*
+ * return 0th index back to bitfield
+ */
+#define bf_release_zero_index(v) bf_release_index(v, 0)
+
+#define bf_index(b) ((b) / WORD_SIZE)
+#define bf_offset(b) ((b) % WORD_SIZE)
+
+/**
+ * Set a bit in the array. If it fills up that word and we are
+ * out of words, extend it by one more word.
+ */
+#define bf_set_bit(v, b)                                                       \
+	do {                                                                   \
+		size_t w = bf_index(b);                                        \
+		(v).data[w] |= 1 << (bf_offset(b));                            \
+		(v).n += ((v).data[w] == WORD_MAX);                            \
+		if ((v).n == (v).m) {                                          \
+			(v).m = (v).m + 1;                                     \
+			(v).data = XREALLOC(MTYPE_BITFIELD, (v).data,          \
+					    (v).m * sizeof(word_t));           \
+		}                                                              \
+	} while (0)
+
+/* Find a clear bit in v and assign it to b. */
+#define bf_find_bit(v, b)                                                      \
+	do {                                                                   \
+		word_t word = 0;                                               \
+		unsigned int w, sh;                                            \
+		for (w = 0; w <= (v).n; w++) {                                 \
+			if ((word = (v).data[w]) != WORD_MAX)                  \
+				break;                                         \
+		}                                                              \
+		(b) = ((word & 0xFFFF) == 0xFFFF) << 4;                        \
+		word >>= (b);                                                  \
+		sh = ((word & 0xFF) == 0xFF) << 3;                             \
+		word >>= sh;                                                   \
+		(b) |= sh;                                                     \
+		sh = ((word & 0xF) == 0xF) << 2;                               \
+		word >>= sh;                                                   \
+		(b) |= sh;                                                     \
+		sh = ((word & 0x3) == 0x3) << 1;                               \
+		word >>= sh;                                                   \
+		(b) |= sh;                                                     \
+		sh = ((word & 0x1) == 0x1) << 0;                               \
+		word >>= sh;                                                   \
+		(b) |= sh;                                                     \
+		(b) += (w * WORD_SIZE);                                        \
+	} while (0)
+
+/*
+ * Find a clear bit in v and return it
+ * Start looking in the word containing bit position start_index.
+ * If necessary, wrap around after bit position max_index.
+ */
+static inline unsigned int
+bf_find_next_clear_bit_wrap(bitfield_t *v, word_t start_index, word_t max_index)
+{
+	int start_bit;
+	unsigned long i, offset, scanbits, wordcount_max, index_max;
+
+	if (start_index > max_index)
+		start_index = 0;
+
+	start_bit = start_index & (WORD_SIZE - 1);
+	wordcount_max = bf_index(max_index) + 1;
+
+	scanbits = WORD_SIZE;
+	for (i = bf_index(start_index); i < v->m; ++i) {
+		if (v->data[i] == WORD_MAX) {
+			/* if the whole word is full move to the next */
+			start_bit = 0;
+			continue;
+		}
+		/* scan one word for clear bits */
+		if ((i == v->m - 1) && (v->m >= wordcount_max))
+			/* max index could be only part of word */
+			scanbits = (max_index % WORD_SIZE) + 1;
+		for (offset = start_bit; offset < scanbits; ++offset) {
+			if (!((v->data[i] >> offset) & 1))
+				return ((i * WORD_SIZE) + offset);
+		}
+		/* move to the next word */
+		start_bit = 0;
+	}
+
+	if (v->m < wordcount_max) {
+		/*
+		 * We can expand bitfield, so no need to wrap.
+		 * Return the index of the first bit of the next word.
+		 * Assumption is that caller will call bf_set_bit which
+		 * will allocate additional space.
+		 */
+		v->m += 1;
+		v->data = (word_t *)XREALLOC(MTYPE_BITFIELD, v->data,
+					     v->m * sizeof(word_t));
+		v->data[v->m - 1] = 0;
+		return v->m * WORD_SIZE;
+	}
+
+	/*
+	 * start looking for a clear bit at the start of the bitfield and
+	 * stop when we reach start_index
+	 */
+	scanbits = WORD_SIZE;
+	index_max = bf_index(start_index - 1);
+	for (i = 0; i <= index_max; ++i) {
+		if (i == index_max)
+			scanbits = ((start_index - 1) % WORD_SIZE) + 1;
+		for (offset = start_bit; offset < scanbits; ++offset) {
+			if (!((v->data[i] >> offset) & 1))
+				return ((i * WORD_SIZE) + offset);
+		}
+		/* move to the next word */
+		start_bit = 0;
+	}
+
+	return WORD_MAX;
+}
+
+static inline unsigned int bf_find_next_set_bit(bitfield_t v,
+		word_t start_index)
+{
+	int start_bit;
+	unsigned long i, offset;
+
+	start_bit = start_index & (WORD_SIZE - 1);
+
+	for (i = bf_index(start_index); i < v.m; ++i) {
+		if (v.data[i] == 0) {
+			/* if the whole word is empty move to the next */
+			start_bit = 0;
+			continue;
+		}
+		/* scan one word for set bits */
+		for (offset = start_bit; offset < WORD_SIZE; ++offset) {
+			if ((v.data[i] >> offset) & 1)
+				return ((i * WORD_SIZE) + offset);
+		}
+		/* move to the next word */
+		start_bit = 0;
+	}
+	return WORD_MAX;
+}
+
+/* iterate through all the set bits */
+#define bf_for_each_set_bit(v, b, max)                 \
+	for ((b) = bf_find_next_set_bit((v), 0);           \
+			(b) < max;                                 \
+			(b) = bf_find_next_set_bit((v), (b) + 1))
+
+/*
+ * Free the allocated memory for data
+ * @v: an instance of bitfield_t struct.
+ */
+#define bf_free(v)                                                             \
+	do {                                                                   \
+		XFREE(MTYPE_BITFIELD, (v).data);                               \
+		(v).data = NULL;                                               \
+	} while (0)
+
+static inline bitfield_t bf_copy(bitfield_t src)
+{
+	bitfield_t dst;
+
+	assert(bf_is_inited(src));
+	bf_init(dst, WORD_SIZE * (src.m - 1));
+	for (size_t i = 0; i < src.m; i++)
+		dst.data[i] = src.data[i];
+	dst.n = src.n;
+	return dst;
+}
+
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif