From fac10ea799fe9b6158d74f66d6ad46536d38a545 Mon Sep 17 00:00:00 2001
From: Patrick McHardy <kaber@trash.net>
Date: Wed, 18 Mar 2009 04:55:00 +0100
Subject: Initial commit

---
 src/segtree.c | 541 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 541 insertions(+)
 create mode 100644 src/segtree.c

(limited to 'src/segtree.c')

diff --git a/src/segtree.c b/src/segtree.c
new file mode 100644
index 00000000..9e59bb6e
--- /dev/null
+++ b/src/segtree.c
@@ -0,0 +1,541 @@
+/*
+ * Copyright (c) 2008 Patrick McHardy <kaber@trash.net>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * Development of this code funded by Astaro AG (http://www.astaro.com/)
+ */
+
+#include <stdlib.h>
+#include <inttypes.h>
+#include <arpa/inet.h>
+
+#include <expression.h>
+#include <gmputil.h>
+#include <utils.h>
+#include <rbtree.h>
+
+/**
+ * struct seg_tree - segment tree
+ *
+ * @root:	the rbtree's root
+ * @type:	the datatype of the dimension
+ * @dwidth:	width of the dimension
+ * @byteorder:	byteorder of elements
+ */
+struct seg_tree {
+	struct rb_root			root;
+	const struct datatype		*type;
+	unsigned int			dwidth;
+	enum byteorder			byteorder;
+};
+
+enum elementary_interval_flags {
+	EI_F_INTERVAL_END	= 0x1,
+};
+
+/**
+ * struct elementary_interval - elementary interval [left, right]
+ *
+ * @rb_node:	seg_tree rb node
+ * @list:	list node for linearized tree
+ * @left:	left endpoint
+ * @right:	right endpoint
+ * @size:	interval size (right - left)
+ * @flags:	flags
+ * @expr:	associated expression
+ */
+struct elementary_interval {
+	union {
+		struct rb_node		rb_node;
+		struct list_head	list;
+	};
+
+	mpz_t				left;
+	mpz_t				right;
+	mpz_t				size;
+
+	enum elementary_interval_flags	flags;
+	struct expr			*expr;
+};
+
+static void seg_tree_init(struct seg_tree *tree, const struct expr *set)
+{
+	struct expr *first;
+
+	first = list_entry(set->expressions.next, struct expr, list);
+	tree->root	= RB_ROOT;
+	tree->dwidth	= set->len;
+	tree->type	= set->dtype;
+	tree->byteorder	= first->byteorder;
+}
+
+static struct elementary_interval *ei_alloc(const mpz_t left, const mpz_t right,
+					    struct expr *expr,
+					    enum elementary_interval_flags flags)
+{
+	struct elementary_interval *ei;
+
+	ei = xzalloc(sizeof(*ei));
+	mpz_init_set(ei->left, left);
+	mpz_init_set(ei->right, right);
+	mpz_init(ei->size);
+	mpz_sub(ei->size, right, left);
+	if (expr != NULL)
+		ei->expr = expr_get(expr);
+	ei->flags = flags;
+	return ei;
+}
+
+static void ei_destroy(struct elementary_interval *ei)
+{
+	mpz_clear(ei->left);
+	mpz_clear(ei->right);
+	mpz_clear(ei->size);
+	if (ei->expr != NULL)
+		expr_free(ei->expr);
+	xfree(ei);
+}
+
+/**
+ * ei_lookup - find elementary interval containing point p
+ *
+ * @tree:	segment tree
+ * @p:		the point
+ */
+static struct elementary_interval *ei_lookup(struct seg_tree *tree, const mpz_t p)
+{
+	struct rb_node *n = tree->root.rb_node;
+	struct elementary_interval *ei;
+
+	while (n != NULL) {
+		ei = rb_entry(n, struct elementary_interval, rb_node);
+
+		if (mpz_cmp(p, ei->left) >= 0 &&
+		    mpz_cmp(p, ei->right) <= 0)
+			return ei;
+		else if (mpz_cmp(p, ei->left) <= 0)
+			n = n->rb_left;
+		else if (mpz_cmp(p, ei->right) > 0)
+			n = n->rb_right;
+	}
+	return NULL;
+}
+
+static void ei_remove(struct seg_tree *tree, struct elementary_interval *ei)
+{
+	rb_erase(&ei->rb_node, &tree->root);
+}
+
+static void __ei_insert(struct seg_tree *tree, struct elementary_interval *new)
+{
+	struct rb_node **p = &tree->root.rb_node;
+	struct rb_node *parent = NULL;
+	struct elementary_interval *ei;
+
+	while (*p != NULL) {
+		parent = *p;
+		ei = rb_entry(parent, struct elementary_interval, rb_node);
+
+		if (mpz_cmp(new->left, ei->left) >= 0 &&
+		    mpz_cmp(new->left, ei->right) <= 0)
+			break;
+		else if (mpz_cmp(new->left, ei->left) <= 0)
+			p = &(*p)->rb_left;
+		else if (mpz_cmp(new->left, ei->left) > 0)
+			p = &(*p)->rb_right;
+	}
+
+	rb_link_node(&new->rb_node, parent, p);
+	rb_insert_color(&new->rb_node, &tree->root);
+}
+
+/**
+ * ei_insert - insert an elementary interval into the tree
+ *
+ * @tree:	the seg_tree
+ * @new:	the elementary interval
+ *
+ * New entries take precedence over existing ones. Insertions are assumed to
+ * be ordered by descending interval size, meaning the new interval never
+ * extends over more than two existing intervals.
+ */
+static void ei_insert(struct seg_tree *tree, struct elementary_interval *new)
+{
+	struct elementary_interval *lei, *rei;
+	mpz_t p;
+
+	mpz_init2(p, tree->dwidth);
+
+	/*
+	 * Lookup the intervals containing the left and right endpoints.
+	 */
+	lei = ei_lookup(tree, new->left);
+	rei = ei_lookup(tree, new->right);
+
+	pr_debug("insert: [%Zx %Zx]\n", new->left, new->right);
+
+	if (lei != NULL && rei != NULL && lei == rei) {
+		/*
+		 * The new interval is entirely contained in the same interval,
+		 * split it into two parts:
+		 *
+		 * [lei_left, new_left) and (new_right, rei_right]
+		 */
+		pr_debug("split [%Zx %Zx]\n", lei->left, lei->right);
+
+		ei_remove(tree, lei);
+
+		mpz_sub_ui(p, new->left, 1);
+		if (mpz_cmp(lei->left, p) <= 0)
+			__ei_insert(tree, ei_alloc(lei->left, p, lei->expr, 0));
+
+		mpz_add_ui(p, new->right, 1);
+		if (mpz_cmp(p, rei->right) < 0)
+			__ei_insert(tree, ei_alloc(p, rei->right, lei->expr, 0));
+		ei_destroy(lei);
+	} else {
+		if (lei != NULL) {
+			/*
+			 * Left endpoint is within lei, adjust it so we have:
+			 *
+			 * [lei_left, new_left)[new_left, new_right]
+			 */
+			pr_debug("adjust left [%Zx %Zx]\n", lei->left, lei->right);
+
+			mpz_sub_ui(lei->right, new->left, 1);
+			mpz_sub(lei->size, lei->right, lei->left);
+			if (mpz_sgn(lei->size) < 0) {
+				ei_remove(tree, lei);
+				ei_destroy(lei);
+			}
+		}
+		if (rei != NULL) {
+			/*
+			 * Right endpoint is within rei, adjust it so we have:
+			 *
+			 * [new_left, new_right](new_right, rei_right]
+			 */
+			pr_debug("adjust right [%Zx %Zx]\n", rei->left, rei->right);
+
+			mpz_add_ui(rei->left, new->right, 1);
+			mpz_sub(rei->size, rei->right, rei->left);
+			if (mpz_sgn(rei->size) < 0) {
+				ei_remove(tree, rei);
+				ei_destroy(rei);
+			}
+		}
+	}
+
+	__ei_insert(tree, new);
+
+	mpz_clear(p);
+}
+
+static void range_low(mpz_t rop, struct expr *expr)
+{
+	switch (expr->ops->type) {
+	case EXPR_VALUE:
+		return mpz_set(rop, expr->value);
+	case EXPR_PREFIX:
+		return range_low(rop, expr->expr);
+	case EXPR_RANGE:
+		return range_low(rop, expr->left);
+	case EXPR_MAPPING:
+		return range_low(rop, expr->left);
+	default:
+		BUG();
+	}
+}
+
+static void range_high(mpz_t rop, const struct expr *expr)
+{
+	mpz_t tmp;
+
+	switch (expr->ops->type) {
+	case EXPR_VALUE:
+		return mpz_set(rop, expr->value);
+	case EXPR_PREFIX:
+		range_low(rop, expr->expr);
+		mpz_init_bitmask(tmp, expr->len - expr->prefix_len);
+		mpz_add(rop, rop, tmp);
+		mpz_clear(tmp);
+		return;
+	case EXPR_RANGE:
+		return range_high(rop, expr->right);
+	case EXPR_MAPPING:
+		return range_high(rop, expr->left);
+	default:
+		BUG();
+	}
+}
+
+/*
+ * Sort intervals according to their priority, which is defined inversely to
+ * their size.
+ *
+ * The beginning of the interval is used as secondary sorting criterion. This
+ * makes sure that overlapping ranges with equal priority are next to each
+ * other, allowing to easily detect unsolvable conflicts during insertion.
+ *
+ * Note: unsolvable conflicts can only occur when using ranges or two identical
+ * prefix specifications.
+ */
+static int interval_cmp(const void *p1, const void *p2)
+{
+	const struct elementary_interval *e1 = *(void * const *)p1;
+	const struct elementary_interval *e2 = *(void * const *)p2;
+	mpz_t d;
+	int ret;
+
+	mpz_init(d);
+
+	mpz_sub(d, e2->size, e1->size);
+	if (mpz_cmp_ui(d, 0))
+		ret = mpz_sgn(d);
+	else
+		ret = mpz_cmp(e1->left, e2->left);
+
+	mpz_clear(d);
+	return ret;
+}
+
+static bool interval_conflict(const struct elementary_interval *e1,
+			      const struct elementary_interval *e2)
+{
+	if (mpz_cmp(e1->left, e2->left) <= 0 &&
+	    mpz_cmp(e1->right, e2->left) >= 0 &&
+	    mpz_cmp(e1->size, e2->size) == 0)
+		return true;
+	else
+		return false;
+}
+
+static void set_to_segtree(struct expr *set, struct seg_tree *tree)
+{
+	struct elementary_interval *intervals[set->size];
+	struct elementary_interval *ei;
+	struct expr *i, *next;
+	unsigned int n;
+	mpz_t low, high;
+
+	mpz_init2(low, tree->dwidth);
+	mpz_init2(high, tree->dwidth);
+
+	/*
+	 * Convert elements to intervals and sort by priority.
+	 */
+	n = 0;
+	list_for_each_entry_safe(i, next, &set->expressions, list) {
+		range_low(low, i);
+		range_high(high, i);
+		ei = ei_alloc(low, high, i, 0);
+		intervals[n++] = ei;
+
+		list_del(&i->list);
+		expr_free(i);
+	}
+	qsort(intervals, n, sizeof(intervals[0]), interval_cmp);
+
+	/*
+	 * Insert elements into tree
+	 */
+	for (n = 0; n < set->size; n++) {
+		if (n < set->size - 1 &&
+		    interval_conflict(intervals[n], intervals[n+1]))
+			printf("conflict\n");
+		ei_insert(tree, intervals[n]);
+	}
+
+	mpz_clear(high);
+	mpz_clear(low);
+}
+
+static void segtree_linearize(struct list_head *list, struct seg_tree *tree)
+{
+	struct rb_node *node, *next;
+	struct elementary_interval *ei, *nei, *prev = NULL;
+	mpz_t p, q;
+
+	mpz_init2(p, tree->dwidth);
+	mpz_init2(q, tree->dwidth);
+
+	/*
+	 * Convert the tree of open intervals to half-closed map expressions.
+	 */
+	rb_for_each_entry_safe(ei, node, next, &tree->root, rb_node) {
+		pr_debug("iter: [%Zx %Zx]\n", ei->left, ei->right);
+
+		if (prev == NULL) {
+			/*
+			 * If the first segment doesn't begin at zero, insert a
+			 * non-matching segment to cover [0, first_left).
+			 */
+			if (mpz_cmp_ui(ei->left, 0)) {
+				mpz_set_ui(p, 0);
+				mpz_sub_ui(q, ei->left, 1);
+				nei = ei_alloc(p, q, NULL, EI_F_INTERVAL_END);
+				list_add_tail(&nei->list, list);
+			}
+		} else {
+			/*
+			 * If the previous segment doesn't end directly left to
+			 * this one, insert a non-matching segment to cover
+			 * (prev_right, ei_left).
+			 */
+			mpz_add_ui(p, prev->right, 1);
+			if (mpz_cmp(p, ei->left) < 0) {
+				mpz_sub_ui(q, ei->left, 1);
+				nei = ei_alloc(p, q, NULL, EI_F_INTERVAL_END);
+				list_add_tail(&nei->list, list);
+			} else if (ei->expr->ops->type != EXPR_MAPPING) {
+				mpz_set(prev->right, ei->right);
+				ei_remove(tree, ei);
+				ei_destroy(ei);
+				continue;
+			}
+		}
+
+		ei_remove(tree, ei);
+		list_add_tail(&ei->list, list);
+
+		prev = ei;
+	}
+
+	/*
+	 * If the last segment doesn't end at the right side of the dimension,
+	 * insert a non-matching segment to cover (last_right, end].
+	 */
+	if (mpz_scan0(prev->right, 0) != tree->dwidth) {
+		mpz_add_ui(p, prev->right, 1);
+		mpz_bitmask(q, tree->dwidth);
+		nei = ei_alloc(p, q, NULL, EI_F_INTERVAL_END);
+		list_add_tail(&nei->list, list);
+	}
+
+	mpz_clear(p);
+	mpz_clear(q);
+}
+
+static void set_insert_interval(struct expr *set, struct seg_tree *tree,
+				const struct elementary_interval *ei)
+{
+	struct expr *expr;
+
+	expr = constant_expr_alloc(&internal_location, tree->type,
+				   tree->byteorder, tree->dwidth, NULL);
+	mpz_set(expr->value, ei->left);
+
+	if (ei->expr != NULL && ei->expr->ops->type == EXPR_MAPPING)
+		expr = mapping_expr_alloc(&ei->expr->location, expr,
+					  expr_get(ei->expr->right));
+
+	if (ei->flags & EI_F_INTERVAL_END)
+		expr->flags |= EXPR_F_INTERVAL_END;
+
+	compound_expr_add(set, expr);
+}
+
+void set_to_intervals(struct expr *set)
+{
+	struct elementary_interval *ei, *next;
+	struct seg_tree tree;
+	LIST_HEAD(list);
+
+	seg_tree_init(&tree, set);
+	set_to_segtree(set, &tree);
+	segtree_linearize(&list, &tree);
+
+	list_for_each_entry_safe(ei, next, &list, list) {
+		pr_debug("list: [%.*Zx %.*Zx]\n",
+			 2 * tree.dwidth / BITS_PER_BYTE, ei->left,
+			 2 * tree.dwidth / BITS_PER_BYTE, ei->right);
+		set_insert_interval(set, &tree, ei);
+		ei_destroy(ei);
+	}
+
+	expr_print(set); printf("\n");
+}
+
+static bool range_is_prefix(const mpz_t range)
+{
+	mpz_t tmp;
+
+	mpz_init_set(tmp, range);
+	mpz_add_ui(tmp, tmp, 1);
+	mpz_and(tmp, range, tmp);
+	return !mpz_cmp_ui(tmp, 0);
+}
+
+// FIXME: does not support maps
+extern void interval_map_decompose(struct expr *set);
+
+void interval_map_decompose(struct expr *set)
+{
+	struct expr *ranges[set->size];
+	struct expr *i, *tmp, *prefix, *low = NULL;
+	unsigned int n, size, prefix_len;
+	mpz_t range, p;
+
+	mpz_init(range);
+	mpz_init(p);
+
+	size = set->size;
+	n = 0;
+	list_for_each_entry_safe_reverse(i, tmp, &set->expressions, list) {
+		compound_expr_remove(set, i);
+		ranges[n++] = i;
+	}
+
+	for (n = 0; n < size; n++) {
+		i = ranges[n];
+
+		if (low == NULL) {
+			if (i->flags & EXPR_F_INTERVAL_END) {
+				/*
+				 * End of interval mark
+				 */
+				expr_free(i);
+				continue;
+			} else {
+				/*
+				 * Start a new interval
+				 */
+				low = i;
+				continue;
+			}
+		} else
+			expr_get(low);
+
+		mpz_sub(range, i->value, low->value);
+		mpz_sub_ui(range, range, 1);
+
+		mpz_and(p, low->value, range);
+
+		if (!mpz_cmp_ui(range, 0))
+			compound_expr_add(set, low);
+		else if (!range_is_prefix(range) || mpz_cmp_ui(p, 0)) {
+			mpz_add(range, range, low->value);
+			tmp = constant_expr_alloc(&low->location, low->dtype,
+						  low->byteorder, low->len,
+						  NULL);
+			mpz_set(tmp->value, range);
+
+			tmp = range_expr_alloc(&low->location, low,tmp);
+			compound_expr_add(set, tmp);
+		} else {
+			prefix_len = i->len - mpz_scan0(range, 0);
+			prefix = prefix_expr_alloc(&low->location, low,
+						   prefix_len);
+			compound_expr_add(set, prefix);
+		}
+
+		if (i->flags & EXPR_F_INTERVAL_END) {
+			expr_free(low);
+			low = NULL;
+		}
+		expr_free(i);
+	}
+}
-- 
cgit v1.2.3