// SPDX-License-Identifier: GPL-2.0-only /* * Sparse bit array * * Copyright (C) 2018, Google LLC. * Copyright (C) 2018, Red Hat, Inc. (code style cleanup and fuzzing driver) * * This library provides functions to support a memory efficient bit array, * with an index size of 2^64. A sparsebit array is allocated through * the use sparsebit_alloc() and free'd via sparsebit_free(), * such as in the following: * * struct sparsebit *s; * s = sparsebit_alloc(); * sparsebit_free(&s); * * The struct sparsebit type resolves down to a struct sparsebit. * Note that, sparsebit_free() takes a pointer to the sparsebit * structure. This is so that sparsebit_free() is able to poison * the pointer (e.g. set it to NULL) to the struct sparsebit before * returning to the caller. * * Between the return of sparsebit_alloc() and the call of * sparsebit_free(), there are multiple query and modifying operations * that can be performed on the allocated sparsebit array. All of * these operations take as a parameter the value returned from * sparsebit_alloc() and most also take a bit index. Frequently * used routines include: * * ---- Query Operations * sparsebit_is_set(s, idx) * sparsebit_is_clear(s, idx) * sparsebit_any_set(s) * sparsebit_first_set(s) * sparsebit_next_set(s, prev_idx) * * ---- Modifying Operations * sparsebit_set(s, idx) * sparsebit_clear(s, idx) * sparsebit_set_num(s, idx, num); * sparsebit_clear_num(s, idx, num); * * A common operation, is to itterate over all the bits set in a test * sparsebit array. This can be done via code with the following structure: * * sparsebit_idx_t idx; * if (sparsebit_any_set(s)) { * idx = sparsebit_first_set(s); * do { * ... * idx = sparsebit_next_set(s, idx); * } while (idx != 0); * } * * The index of the first bit set needs to be obtained via * sparsebit_first_set(), because sparsebit_next_set(), needs * the index of the previously set. The sparsebit_idx_t type is * unsigned, so there is no previous index before 0 that is available. * Also, the call to sparsebit_first_set() is not made unless there * is at least 1 bit in the array set. This is because sparsebit_first_set() * aborts if sparsebit_first_set() is called with no bits set. * It is the callers responsibility to assure that the * sparsebit array has at least a single bit set before calling * sparsebit_first_set(). * * ==== Implementation Overview ==== * For the most part the internal implementation of sparsebit is * opaque to the caller. One important implementation detail that the * caller may need to be aware of is the spatial complexity of the * implementation. This implementation of a sparsebit array is not * only sparse, in that it uses memory proportional to the number of bits * set. It is also efficient in memory usage when most of the bits are * set. * * At a high-level the state of the bit settings are maintained through * the use of a binary-search tree, where each node contains at least * the following members: * * typedef uint64_t sparsebit_idx_t; * typedef uint64_t sparsebit_num_t; * * sparsebit_idx_t idx; * uint32_t mask; * sparsebit_num_t num_after; * * The idx member contains the bit index of the first bit described by this * node, while the mask member stores the setting of the first 32-bits. * The setting of the bit at idx + n, where 0 <= n < 32, is located in the * mask member at 1 << n. * * Nodes are sorted by idx and the bits described by two nodes will never * overlap. The idx member is always aligned to the mask size, i.e. a * multiple of 32. * * Beyond a typical implementation, the nodes in this implementation also * contains a member named num_after. The num_after member holds the * number of bits immediately after the mask bits that are contiguously set. * The use of the num_after member allows this implementation to efficiently * represent cases where most bits are set. For example, the case of all * but the last two bits set, is represented by the following two nodes: * * node 0 - idx: 0x0 mask: 0xffffffff num_after: 0xffffffffffffffc0 * node 1 - idx: 0xffffffffffffffe0 mask: 0x3fffffff num_after: 0 * * ==== Invariants ==== * This implementation usses the following invariants: * * + Node are only used to represent bits that are set. * Nodes with a mask of 0 and num_after of 0 are not allowed. * * + Sum of bits set in all the nodes is equal to the value of * the struct sparsebit_pvt num_set member. * * + The setting of at least one bit is always described in a nodes * mask (mask >= 1). * * + A node with all mask bits set only occurs when the last bit * described by the previous node is not equal to this nodes * starting index - 1. All such occurrences of this condition are * avoided by moving the setting of the nodes mask bits into * the previous nodes num_after setting. * * + Node starting index is evenly divisible by the number of bits * within a nodes mask member. * * + Nodes never represent a range of bits that wrap around the * highest supported index. * * (idx + MASK_BITS + num_after - 1) <= ((sparsebit_idx_t) 0) - 1) * * As a consequence of the above, the num_after member of a node * will always be <=: * * maximum_index - nodes_starting_index - number_of_mask_bits * * + Nodes within the binary search tree are sorted based on each * nodes starting index. * * + The range of bits described by any two nodes do not overlap. The * range of bits described by a single node is: * * start: node->idx * end (inclusive): node->idx + MASK_BITS + node->num_after - 1; * * Note, at times these invariants are temporarily violated for a * specific portion of the code. For example, when setting a mask * bit, there is a small delay between when the mask bit is set and the * value in the struct sparsebit_pvt num_set member is updated. Other * temporary violations occur when node_split() is called with a specified * index and assures that a node where its mask represents the bit * at the specified index exists. At times to do this node_split() * must split an existing node into two nodes or create a node that * has no bits set. Such temporary violations must be corrected before * returning to the caller. These corrections are typically performed * by the local function node_reduce(). */ #include "test_util.h" #include "sparsebit.h" #include <limits.h> #include <assert.h> #define DUMP_LINE_MAX 100 /* Does not include indent amount */ typedef uint32_t mask_t; #define MASK_BITS (sizeof(mask_t) * CHAR_BIT) struct node { struct node *parent; struct node *left; struct node *right; sparsebit_idx_t idx; /* index of least-significant bit in mask */ sparsebit_num_t num_after; /* num contiguously set after mask */ mask_t mask; }; struct sparsebit { /* * Points to root node of the binary search * tree. Equal to NULL when no bits are set in * the entire sparsebit array. */ struct node *root; /* * A redundant count of the total number of bits set. Used for * diagnostic purposes and to change the time complexity of * sparsebit_num_set() from O(n) to O(1). * Note: Due to overflow, a value of 0 means none or all set. */ sparsebit_num_t num_set; }; /* Returns the number of set bits described by the settings * of the node pointed to by nodep. */ static sparsebit_num_t node_num_set(struct node *nodep) { return nodep->num_after + __builtin_popcount(nodep->mask); } /* Returns a pointer to the node that describes the * lowest bit index. */ static struct node *node_first(const struct sparsebit *s) { struct node *nodep; for (nodep = s->root; nodep && nodep->left; nodep = nodep->left) ; return nodep; } /* Returns a pointer to the node that describes the * lowest bit index > the index of the node pointed to by np. * Returns NULL if no node with a higher index exists. */ static struct node *node_next(const struct sparsebit *s, struct node *np) { struct node *nodep = np; /* * If current node has a right child, next node is the left-most * of the right child. */ if (nodep->right) { for (nodep = nodep->right; nodep->left; nodep = nodep->left) ; return nodep; } /* * No right child. Go up until node is left child of a parent. * That parent is then the next node. */ while (nodep->parent && nodep == nodep->parent->right) nodep = nodep->parent; return nodep->parent; } /* Searches for and returns a pointer to the node that describes the * highest index < the index of the node pointed to by np. * Returns NULL if no node with a lower index exists. */ static struct node *node_prev(const struct sparsebit *s, struct node *np) { struct node *nodep = np; /* * If current node has a left child, next node is the right-most * of the left child. */ if (nodep->left) { for (nodep = nodep->left; nodep->right; nodep = nodep->right) ; return (struct node *) nodep; } /* * No left child. Go up until node is right child of a parent. * That parent is then the next node. */ while (nodep->parent && nodep == nodep->parent->left) nodep = nodep->parent; return (struct node *) nodep->parent; } /* Allocates space to hold a copy of the node sub-tree pointed to by * subtree and duplicates the bit settings to the newly allocated nodes. * Returns the newly allocated copy of subtree. */ static struct node *node_copy_subtree(const struct node *subtree) { struct node *root; /* Duplicate the node at the root of the subtree */ root = calloc(1, sizeof(*root)); if (!root) { perror("calloc"); abort(); } root->idx = subtree->idx; root->mask = subtree->mask; root->num_after = subtree->num_after; /* As needed, recursively duplicate the left and right subtrees */ if (subtree->left) { root->left = node_copy_subtree(subtree->left); root->left->parent = root; } if (subtree->right) { root->right = node_copy_subtree(subtree->right); root->right->parent = root; } return root; } /* Searches for and returns a pointer to the node that describes the setting * of the bit given by idx. A node describes the setting of a bit if its * index is within the bits described by the mask bits or the number of * contiguous bits set after the mask. Returns NULL if there is no such node. */ static struct node *node_find(const struct sparsebit *s, sparsebit_idx_t idx) { struct node *nodep; /* Find the node that describes the setting of the bit at idx */ for (nodep = s->root; nodep; nodep = nodep->idx > idx ? nodep->left : nodep->right) { if (idx >= nodep->idx && idx <= nodep->idx + MASK_BITS + nodep->num_after - 1) break; } return nodep; } /* Entry Requirements: * + A node that describes the setting of idx is not already present. * * Adds a new node to describe the setting of the bit at the index given * by idx. Returns a pointer to the newly added node. * * TODO(lhuemill): Degenerate cases causes the tree to get unbalanced. */ static struct node *node_add(struct sparsebit *s, sparsebit_idx_t idx) { struct node *nodep, *parentp, *prev; /* Allocate and initialize the new node. */ nodep = calloc(1, sizeof(*nodep)); if (!nodep) { perror("calloc"); abort(); } nodep->idx = idx & -MASK_BITS; /* If no nodes, set it up as the root node. */ if (!s->root) { s->root = nodep; return nodep; } /* * Find the parent where the new node should be attached * and add the node there. */ parentp = s->root; while (true) { if (idx < parentp->idx) { if (!parentp->left) { parentp->left = nodep; nodep->parent = parentp; break; } parentp = parentp->left; } else { assert(idx > parentp->idx + MASK_BITS + parentp->num_after - 1); if (!parentp->right) { parentp->right = nodep; nodep->parent = parentp; break; } parentp = parentp->right; } } /* * Does num_after bits of previous node overlap with the mask * of the new node? If so set the bits in the new nodes mask * and reduce the previous nodes num_after. */ prev = node_prev(s, nodep); while (prev && prev->idx + MASK_BITS + prev->num_after - 1 >= nodep->idx) { unsigned int n1 = (prev->idx + MASK_BITS + prev->num_after - 1) - nodep->idx; assert(prev->num_after > 0); assert(n1 < MASK_BITS); assert(!(nodep->mask & (1 << n1))); nodep->mask |= (1 << n1); prev->num_after--; } return nodep; } /* Returns whether all the bits in the sparsebit array are set. */ bool sparsebit_all_set(const struct sparsebit *s) { /* * If any nodes there must be at least one bit set. Only case * where a bit is set and total num set is 0, is when all bits * are set. */ return s->root && s->num_set == 0; } /* Clears all bits described by the node pointed to by nodep, then * removes the node. */ static void node_rm(struct sparsebit *s, struct node *nodep) { struct node *tmp; sparsebit_num_t num_set; num_set = node_num_set(nodep); assert(s->num_set >= num_set || sparsebit_all_set(s)); s->num_set -= node_num_set(nodep); /* Have both left and right child */ if (nodep->left && nodep->right) { /* * Move left children to the leftmost leaf node * of the right child. */ for (tmp = nodep->right; tmp->left; tmp = tmp->left) ; tmp->left = nodep->left; nodep->left = NULL; tmp->left->parent = tmp; } /* Left only child */ if (nodep->left) { if (!nodep->parent) { s->root = nodep->left; nodep->left->parent = NULL; } else { nodep->left->parent = nodep->parent; if (nodep == nodep->parent->left) nodep->parent->left = nodep->left; else { assert(nodep == nodep->parent->right); nodep->parent->right = nodep->left; } } nodep->parent = nodep->left = nodep->right = NULL; free(nodep); return; } /* Right only child */ if (nodep->right) { if (!nodep->parent) { s->root = nodep->right; nodep->right->parent = NULL; } else { nodep->right->parent = nodep->parent; if (nodep == nodep->parent->left) nodep->parent->left = nodep->right; else { assert(nodep == nodep->parent->right); nodep->parent->right = nodep->right; } } nodep->parent = nodep->left = nodep->right = NULL; free(nodep); return; } /* Leaf Node */ if (!nodep->parent) { s->root = NULL; } else { if (nodep->parent->left == nodep) nodep->parent->left = NULL; else { assert(nodep == nodep->parent->right); nodep->parent->right = NULL; } } nodep->parent = nodep->left = nodep->right = NULL; free(nodep); return; } /* Splits the node containing the bit at idx so that there is a node * that starts at the specified index. If no such node exists, a new * node at the specified index is created. Returns the new node. * * idx must start of a mask boundary. */ static struct node *node_split(struct sparsebit *s, sparsebit_idx_t idx) { struct node *nodep1, *nodep2; sparsebit_idx_t offset; sparsebit_num_t orig_num_after; assert(!(idx % MASK_BITS)); /* * Is there a node that describes the setting of idx? * If not, add it. */ nodep1 = node_find(s, idx); if (!nodep1) return node_add(s, idx); /* * All done if the starting index of the node is where the * split should occur. */ if (nodep1->idx == idx) return nodep1; /* * Split point not at start of mask, so it must be part of * bits described by num_after. */ /* * Calculate offset within num_after for where the split is * to occur. */ offset = idx - (nodep1->idx + MASK_BITS); orig_num_after = nodep1->num_after; /* * Add a new node to describe the bits starting at * the split point. */ nodep1->num_after = offset; nodep2 = node_add(s, idx); /* Move bits after the split point into the new node */ nodep2->num_after = orig_num_after - offset; if (nodep2->num_after >= MASK_BITS) { nodep2->mask = ~(mask_t) 0; nodep2->num_after -= MASK_BITS; } else { nodep2->mask = (1 << nodep2->num_after) - 1; nodep2->num_after = 0; } return nodep2; } /* Iteratively reduces the node pointed to by nodep and its adjacent * nodes into a more compact form. For example, a node with a mask with * all bits set adjacent to a previous node, will get combined into a * single node with an increased num_after setting. * * After each reduction, a further check is made to see if additional * reductions are possible with the new previous and next nodes. Note, * a search for a reduction is only done across the nodes nearest nodep * and those that became part of a reduction. Reductions beyond nodep * and the adjacent nodes that are reduced are not discovered. It is the * responsibility of the caller to pass a nodep that is within one node * of each possible reduction. * * This function does not fix the temporary violation of all invariants. * For example it does not fix the case where the bit settings described * by two or more nodes overlap. Such a violation introduces the potential * complication of a bit setting for a specific index having different settings * in different nodes. This would then introduce the further complication * of which node has the correct setting of the bit and thus such conditions * are not allowed. * * This function is designed to fix invariant violations that are introduced * by node_split() and by changes to the nodes mask or num_after members. * For example, when setting a bit within a nodes mask, the function that * sets the bit doesn't have to worry about whether the setting of that * bit caused the mask to have leading only or trailing only bits set. * Instead, the function can call node_reduce(), with nodep equal to the * node address that it set a mask bit in, and node_reduce() will notice * the cases of leading or trailing only bits and that there is an * adjacent node that the bit settings could be merged into. * * This implementation specifically detects and corrects violation of the * following invariants: * * + Node are only used to represent bits that are set. * Nodes with a mask of 0 and num_after of 0 are not allowed. * * + The setting of at least one bit is always described in a nodes * mask (mask >= 1). * * + A node with all mask bits set only occurs when the last bit * described by the previous node is not equal to this nodes * starting index - 1. All such occurrences of this condition are * avoided by moving the setting of the nodes mask bits into * the previous nodes num_after setting. */ static void node_reduce(struct sparsebit *s, struct node *nodep) { bool reduction_performed; do { reduction_performed = false; struct node *prev, *next, *tmp; /* 1) Potential reductions within the current node. */ /* Nodes with all bits cleared may be removed. */ if (nodep->mask == 0 && nodep->num_after == 0) { /* * About to remove the node pointed to by * nodep, which normally would cause a problem * for the next pass through the reduction loop, * because the node at the starting point no longer * exists. This potential problem is handled * by first remembering the location of the next * or previous nodes. Doesn't matter which, because * once the node at nodep is removed, there will be * no other nodes between prev and next. * * Note, the checks performed on nodep against both * both prev and next both check for an adjacent * node that can be reduced into a single node. As * such, after removing the node at nodep, doesn't * matter whether the nodep for the next pass * through the loop is equal to the previous pass * prev or next node. Either way, on the next pass * the one not selected will become either the * prev or next node. */ tmp = node_next(s, nodep); if (!tmp) tmp = node_prev(s, nodep); node_rm(s, nodep); nodep = tmp; reduction_performed = true; continue; } /* * When the mask is 0, can reduce the amount of num_after * bits by moving the initial num_after bits into the mask. */ if (nodep->mask == 0) { assert(nodep->num_after != 0); assert(nodep->idx + MASK_BITS > nodep->idx); nodep->idx += MASK_BITS; if (nodep->num_after >= MASK_BITS) { nodep->mask = ~0; nodep->num_after -= MASK_BITS; } else { nodep->mask = (1u << nodep->num_after) - 1; nodep->num_after = 0; } reduction_performed = true; continue; } /* * 2) Potential reductions between the current and * previous nodes. */ prev = node_prev(s, nodep); if (prev) { sparsebit_idx_t prev_highest_bit; /* Nodes with no bits set can be removed. */ if (prev->mask == 0 && prev->num_after == 0) { node_rm(s, prev); reduction_performed = true; continue; } /* * All mask bits set and previous node has * adjacent index. */ if (nodep->mask + 1 == 0 && prev->idx + MASK_BITS == nodep->idx) { prev->num_after += MASK_BITS + nodep->num_after; nodep->mask = 0; nodep->num_after = 0; reduction_performed = true; continue; } /* * Is node adjacent to previous node and the node * contains a single contiguous range of bits * starting from the beginning of the mask? */ prev_highest_bit = prev->idx + MASK_BITS - 1 + prev->num_after; if (prev_highest_bit + 1 == nodep->idx && (nodep->mask | (nodep->mask >> 1)) == nodep->mask) { /* * How many contiguous bits are there? * Is equal to the total number of set * bits, due to an earlier check that * there is a single contiguous range of * set bits. */ unsigned int num_contiguous = __builtin_popcount(nodep->mask); assert((num_contiguous > 0) && ((1ULL << num_contiguous) - 1) == nodep->mask); prev->num_after += num_contiguous; nodep->mask = 0; /* * For predictable performance, handle special * case where all mask bits are set and there * is a non-zero num_after setting. This code * is functionally correct without the following * conditionalized statements, but without them * the value of num_after is only reduced by * the number of mask bits per pass. There are * cases where num_after can be close to 2^64. * Without this code it could take nearly * (2^64) / 32 passes to perform the full * reduction. */ if (num_contiguous == MASK_BITS) { prev->num_after += nodep->num_after; nodep->num_after = 0; } reduction_performed = true; continue; } } /* * 3) Potential reductions between the current and * next nodes. */ next = node_next(s, nodep); if (next) { /* Nodes with no bits set can be removed. */ if (next->mask == 0 && next->num_after == 0) { node_rm(s, next); reduction_performed = true; continue; } /* * Is next node index adjacent to current node * and has a mask with all bits set? */ if (next->idx == nodep->idx + MASK_BITS + nodep->num_after && next->mask == ~(mask_t) 0) { nodep->num_after += MASK_BITS; next->mask = 0; nodep->num_after += next->num_after; next->num_after = 0; node_rm(s, next); next = NULL; reduction_performed = true; continue; } } } while (nodep && reduction_performed); } /* Returns whether the bit at the index given by idx, within the * sparsebit array is set or not. */ bool sparsebit_is_set(const struct sparsebit *s, sparsebit_idx_t idx) { struct node *nodep; /* Find the node that describes the setting of the bit at idx */ for (nodep = s->root; nodep; nodep = nodep->idx > idx ? nodep->left : nodep->right) if (idx >= nodep->idx && idx <= nodep->idx + MASK_BITS + nodep->num_after - 1) goto have_node; return false; have_node: /* Bit is set if it is any of the bits described by num_after */ if (nodep->num_after && idx >= nodep->idx + MASK_BITS) return true; /* Is the corresponding mask bit set */ assert(idx >= nodep->idx && idx - nodep->idx < MASK_BITS); return !!(nodep->mask & (1 << (idx - nodep->idx))); } /* Within the sparsebit array pointed to by s, sets the bit * at the index given by idx. */ static void bit_set(struct sparsebit *s, sparsebit_idx_t idx) { struct node *nodep; /* Skip bits that are already set */ if (sparsebit_is_set(s, idx)) return; /* * Get a node where the bit at idx is described by the mask. * The node_split will also create a node, if there isn't * already a node that describes the setting of bit. */ nodep = node_split(s, idx & -MASK_BITS); /* Set the bit within the nodes mask */ assert(idx >= nodep->idx && idx <= nodep->idx + MASK_BITS - 1); assert(!(nodep->mask & (1 << (idx - nodep->idx)))); nodep->mask |= 1 << (idx - nodep->idx); s->num_set++; node_reduce(s, nodep); } /* Within the sparsebit array pointed to by s, clears the bit * at the index given by idx. */ static void bit_clear(struct sparsebit *s, sparsebit_idx_t idx) { struct node *nodep; /* Skip bits that are already cleared */ if (!sparsebit_is_set(s, idx)) return; /* Is there a node that describes the setting of this bit? */ nodep = node_find(s, idx); if (!nodep) return; /* * If a num_after bit, split the node, so that the bit is * part of a node mask. */ if (idx >= nodep->idx + MASK_BITS) nodep = node_split(s, idx & -MASK_BITS); /* * After node_split above, bit at idx should be within the mask. * Clear that bit. */ assert(idx >= nodep->idx && idx <= nodep->idx + MASK_BITS - 1); assert(nodep->mask & (1 << (idx - nodep->idx))); nodep->mask &= ~(1 << (idx - nodep->idx)); assert(s->num_set > 0 || sparsebit_all_set(s)); s->num_set--; node_reduce(s, nodep); } /* Recursively dumps to the FILE stream given by stream the contents * of the sub-tree of nodes pointed to by nodep. Each line of output * is prefixed by the number of spaces given by indent. On each * recursion, the indent amount is increased by 2. This causes nodes * at each level deeper into the binary search tree to be displayed * with a greater indent. */ static void dump_nodes(FILE *stream, struct node *nodep, unsigned int indent) { char *node_type; /* Dump contents of node */ if (!nodep->parent) node_type = "root"; else if (nodep == nodep->parent->left) node_type = "left"; else { assert(nodep == nodep->parent->right); node_type = "right"; } fprintf(stream, "%*s---- %s nodep: %p\n", indent, "", node_type, nodep); fprintf(stream, "%*s parent: %p left: %p right: %p\n", indent, "", nodep->parent, nodep->left, nodep->right); fprintf(stream, "%*s idx: 0x%lx mask: 0x%x num_after: 0x%lx\n", indent, "", nodep->idx, nodep->mask, nodep->num_after); /* If present, dump contents of left child nodes */ if (nodep->left) dump_nodes(stream, nodep->left, indent + 2); /* If present, dump contents of right child nodes */ if (nodep->right) dump_nodes(stream, nodep->right, indent + 2); } static inline sparsebit_idx_t node_first_set(struct node *nodep, int start) { mask_t leading = (mask_t)1 << start; int n1 = __builtin_ctz(nodep->mask & -leading); return nodep->idx + n1; } static inline sparsebit_idx_t node_first_clear(struct node *nodep, int start) { mask_t leading = (mask_t)1 << start; int n1 = __builtin_ctz(~nodep->mask & -leading); return nodep->idx + n1; } /* Dumps to the FILE stream specified by stream, the implementation dependent * internal state of s. Each line of output is prefixed with the number * of spaces given by indent. The output is completely implementation * dependent and subject to change. Output from this function should only * be used for diagnostic purposes. For example, this function can be * used by test cases after they detect an unexpected condition, as a means * to capture diagnostic information. */ static void sparsebit_dump_internal(FILE *stream, const struct sparsebit *s, unsigned int indent) { /* Dump the contents of s */ fprintf(stream, "%*sroot: %p\n", indent, "", s->root); fprintf(stream, "%*snum_set: 0x%lx\n", indent, "", s->num_set); if (s->root) dump_nodes(stream, s->root, indent); } /* Allocates and returns a new sparsebit array. The initial state * of the newly allocated sparsebit array has all bits cleared. */ struct sparsebit *sparsebit_alloc(void) { struct sparsebit *s; /* Allocate top level structure. */ s = calloc(1, sizeof(*s)); if (!s) { perror("calloc"); abort(); } return s; } /* Frees the implementation dependent data for the sparsebit array * pointed to by s and poisons the pointer to that data. */ void sparsebit_free(struct sparsebit **sbitp) { struct sparsebit *s = *sbitp; if (!s) return; sparsebit_clear_all(s); free(s); *sbitp = NULL; } /* Makes a copy of the sparsebit array given by s, to the sparsebit * array given by d. Note, d must have already been allocated via * sparsebit_alloc(). It can though already have bits set, which * if different from src will be cleared. */ void sparsebit_copy(struct sparsebit *d, const struct sparsebit *s) { /* First clear any bits already set in the destination */ sparsebit_clear_all(d); if (s->root) { d->root = node_copy_subtree(s->root); d->num_set = s->num_set; } } /* Returns whether num consecutive bits starting at idx are all set. */ bool sparsebit_is_set_num(const struct sparsebit *s, sparsebit_idx_t idx, sparsebit_num_t num) { sparsebit_idx_t next_cleared; assert(num > 0); assert(idx + num - 1 >= idx); /* With num > 0, the first bit must be set. */ if (!sparsebit_is_set(s, idx)) return false; /* Find the next cleared bit */ next_cleared = sparsebit_next_clear(s, idx); /* * If no cleared bits beyond idx, then there are at least num * set bits. idx + num doesn't wrap. Otherwise check if * there are enough set bits between idx and the next cleared bit. */ return next_cleared == 0 || next_cleared - idx >= num; } /* Returns whether the bit at the index given by idx. */ bool sparsebit_is_clear(const struct sparsebit *s, sparsebit_idx_t idx) { return !sparsebit_is_set(s, idx); } /* Returns whether num consecutive bits starting at idx are all cleared. */ bool sparsebit_is_clear_num(const struct sparsebit *s, sparsebit_idx_t idx, sparsebit_num_t num) { sparsebit_idx_t next_set; assert(num > 0); assert(idx + num - 1 >= idx); /* With num > 0, the first bit must be cleared. */ if (!sparsebit_is_clear(s, idx)) return false; /* Find the next set bit */ next_set = sparsebit_next_set(s, idx); /* * If no set bits beyond idx, then there are at least num * cleared bits. idx + num doesn't wrap. Otherwise check if * there are enough cleared bits between idx and the next set bit. */ return next_set == 0 || next_set - idx >= num; } /* Returns the total number of bits set. Note: 0 is also returned for * the case of all bits set. This is because with all bits set, there * is 1 additional bit set beyond what can be represented in the return * value. Use sparsebit_any_set(), instead of sparsebit_num_set() > 0, * to determine if the sparsebit array has any bits set. */ sparsebit_num_t sparsebit_num_set(const struct sparsebit *s) { return s->num_set; } /* Returns whether any bit is set in the sparsebit array. */ bool sparsebit_any_set(const struct sparsebit *s) { /* * Nodes only describe set bits. If any nodes then there * is at least 1 bit set. */ if (!s->root) return false; /* * Every node should have a non-zero mask. For now will * just assure that the root node has a non-zero mask, * which is a quick check that at least 1 bit is set. */ assert(s->root->mask != 0); assert(s->num_set > 0 || (s->root->num_after == ((sparsebit_num_t) 0) - MASK_BITS && s->root->mask == ~(mask_t) 0)); return true; } /* Returns whether all the bits in the sparsebit array are cleared. */ bool sparsebit_all_clear(const struct sparsebit *s) { return !sparsebit_any_set(s); } /* Returns whether all the bits in the sparsebit array are set. */ bool sparsebit_any_clear(const struct sparsebit *s) { return !sparsebit_all_set(s); } /* Returns the index of the first set bit. Abort if no bits are set. */ sparsebit_idx_t sparsebit_first_set(const struct sparsebit *s) { struct node *nodep; /* Validate at least 1 bit is set */ assert(sparsebit_any_set(s)); nodep = node_first(s); return node_first_set(nodep, 0); } /* Returns the index of the first cleared bit. Abort if * no bits are cleared. */ sparsebit_idx_t sparsebit_first_clear(const struct sparsebit *s) { struct node *nodep1, *nodep2; /* Validate at least 1 bit is cleared. */ assert(sparsebit_any_clear(s)); /* If no nodes or first node index > 0 then lowest cleared is 0 */ nodep1 = node_first(s); if (!nodep1 || nodep1->idx > 0) return 0; /* Does the mask in the first node contain any cleared bits. */ if (nodep1->mask != ~(mask_t) 0) return node_first_clear(nodep1, 0); /* * All mask bits set in first node. If there isn't a second node * then the first cleared bit is the first bit after the bits * described by the first node. */ nodep2 = node_next(s, nodep1); if (!nodep2) { /* * No second node. First cleared bit is first bit beyond * bits described by first node. */ assert(nodep1->mask == ~(mask_t) 0); assert(nodep1->idx + MASK_BITS + nodep1->num_after != (sparsebit_idx_t) 0); return nodep1->idx + MASK_BITS + nodep1->num_after; } /* * There is a second node. * If it is not adjacent to the first node, then there is a gap * of cleared bits between the nodes, and the first cleared bit * is the first bit within the gap. */ if (nodep1->idx + MASK_BITS + nodep1->num_after != nodep2->idx) return nodep1->idx + MASK_BITS + nodep1->num_after; /* * Second node is adjacent to the first node. * Because it is adjacent, its mask should be non-zero. If all * its mask bits are set, then with it being adjacent, it should * have had the mask bits moved into the num_after setting of the * previous node. */ return node_first_clear(nodep2, 0); } /* Returns index of next bit set within s after the index given by prev. * Returns 0 if there are no bits after prev that are set. */ sparsebit_idx_t sparsebit_next_set(const struct sparsebit *s, sparsebit_idx_t prev) { sparsebit_idx_t lowest_possible = prev + 1; sparsebit_idx_t start; struct node *nodep; /* A bit after the highest index can't be set. */ if (lowest_possible == 0) return 0; /* * Find the leftmost 'candidate' overlapping or to the right * of lowest_possible. */ struct node *candidate = NULL; /* True iff lowest_possible is within candidate */ bool contains = false; /* * Find node that describes setting of bit at lowest_possible. * If such a node doesn't exist, find the node with the lowest * starting index that is > lowest_possible. */ for (nodep = s->root; nodep;) { if ((nodep->idx + MASK_BITS + nodep->num_after - 1) >= lowest_possible) { candidate = nodep; if (candidate->idx <= lowest_possible) { contains = true; break; } nodep = nodep->left; } else { nodep = nodep->right; } } if (!candidate) return 0; assert(candidate->mask != 0); /* Does the candidate node describe the setting of lowest_possible? */ if (!contains) { /* * Candidate doesn't describe setting of bit at lowest_possible. * Candidate points to the first node with a starting index * > lowest_possible. */ assert(candidate->idx > lowest_possible); return node_first_set(candidate, 0); } /* * Candidate describes setting of bit at lowest_possible. * Note: although the node describes the setting of the bit * at lowest_possible, its possible that its setting and the * setting of all latter bits described by this node are 0. * For now, just handle the cases where this node describes * a bit at or after an index of lowest_possible that is set. */ start = lowest_possible - candidate->idx; if (start < MASK_BITS && candidate->mask >= (1 << start)) return node_first_set(candidate, start); if (candidate->num_after) { sparsebit_idx_t first_num_after_idx = candidate->idx + MASK_BITS; return lowest_possible < first_num_after_idx ? first_num_after_idx : lowest_possible; } /* * Although candidate node describes setting of bit at * the index of lowest_possible, all bits at that index and * latter that are described by candidate are cleared. With * this, the next bit is the first bit in the next node, if * such a node exists. If a next node doesn't exist, then * there is no next set bit. */ candidate = node_next(s, candidate); if (!candidate) return 0; return node_first_set(candidate, 0); } /* Returns index of next bit cleared within s after the index given by prev. * Returns 0 if there are no bits after prev that are cleared. */ sparsebit_idx_t sparsebit_next_clear(const struct sparsebit *s, sparsebit_idx_t prev) { sparsebit_idx_t lowest_possible = prev + 1; sparsebit_idx_t idx; struct node *nodep1, *nodep2; /* A bit after the highest index can't be set. */ if (lowest_possible == 0) return 0; /* * Does a node describing the setting of lowest_possible exist? * If not, the bit at lowest_possible is cleared. */ nodep1 = node_find(s, lowest_possible); if (!nodep1) return lowest_possible; /* Does a mask bit in node 1 describe the next cleared bit. */ for (idx = lowest_possible - nodep1->idx; idx < MASK_BITS; idx++) if (!(nodep1->mask & (1 << idx))) return nodep1->idx + idx; /* * Next cleared bit is not described by node 1. If there * isn't a next node, then next cleared bit is described * by bit after the bits described by the first node. */ nodep2 = node_next(s, nodep1); if (!nodep2) return nodep1->idx + MASK_BITS + nodep1->num_after; /* * There is a second node. * If it is not adjacent to the first node, then there is a gap * of cleared bits between the nodes, and the next cleared bit * is the first bit within the gap. */ if (nodep1->idx + MASK_BITS + nodep1->num_after != nodep2->idx) return nodep1->idx + MASK_BITS + nodep1->num_after; /* * Second node is adjacent to the first node. * Because it is adjacent, its mask should be non-zero. If all * its mask bits are set, then with it being adjacent, it should * have had the mask bits moved into the num_after setting of the * previous node. */ return node_first_clear(nodep2, 0); } /* Starting with the index 1 greater than the index given by start, finds * and returns the index of the first sequence of num consecutively set * bits. Returns a value of 0 of no such sequence exists. */ sparsebit_idx_t sparsebit_next_set_num(const struct sparsebit *s, sparsebit_idx_t start, sparsebit_num_t num) { sparsebit_idx_t idx; assert(num >= 1); for (idx = sparsebit_next_set(s, start); idx != 0 && idx + num - 1 >= idx; idx = sparsebit_next_set(s, idx)) { assert(sparsebit_is_set(s, idx)); /* * Does the sequence of bits starting at idx consist of * num set bits? */ if (sparsebit_is_set_num(s, idx, num)) return idx; /* * Sequence of set bits at idx isn't large enough. * Skip this entire sequence of set bits. */ idx = sparsebit_next_clear(s, idx); if (idx == 0) return 0; } return 0; } /* Starting with the index 1 greater than the index given by start, finds * and returns the index of the first sequence of num consecutively cleared * bits. Returns a value of 0 of no such sequence exists. */ sparsebit_idx_t sparsebit_next_clear_num(const struct sparsebit *s, sparsebit_idx_t start, sparsebit_num_t num) { sparsebit_idx_t idx; assert(num >= 1); for (idx = sparsebit_next_clear(s, start); idx != 0 && idx + num - 1 >= idx; idx = sparsebit_next_clear(s, idx)) { assert(sparsebit_is_clear(s, idx)); /* * Does the sequence of bits starting at idx consist of * num cleared bits? */ if (sparsebit_is_clear_num(s, idx, num)) return idx; /* * Sequence of cleared bits at idx isn't large enough. * Skip this entire sequence of cleared bits. */ idx = sparsebit_next_set(s, idx); if (idx == 0) return 0; } return 0; } /* Sets the bits * in the inclusive range idx through idx + num - 1. */ void sparsebit_set_num(struct sparsebit *s, sparsebit_idx_t start, sparsebit_num_t num) { struct node *nodep, *next; unsigned int n1; sparsebit_idx_t idx; sparsebit_num_t n; sparsebit_idx_t middle_start, middle_end; assert(num > 0); assert(start + num - 1 >= start); /* * Leading - bits before first mask boundary. * * TODO(lhuemill): With some effort it may be possible to * replace the following loop with a sequential sequence * of statements. High level sequence would be: * * 1. Use node_split() to force node that describes setting * of idx to be within the mask portion of a node. * 2. Form mask of bits to be set. * 3. Determine number of mask bits already set in the node * and store in a local variable named num_already_set. * 4. Set the appropriate mask bits within the node. * 5. Increment struct sparsebit_pvt num_set member * by the number of bits that were actually set. * Exclude from the counts bits that were already set. * 6. Before returning to the caller, use node_reduce() to * handle the multiple corner cases that this method * introduces. */ for (idx = start, n = num; n > 0 && idx % MASK_BITS != 0; idx++, n--) bit_set(s, idx); /* Middle - bits spanning one or more entire mask */ middle_start = idx; middle_end = middle_start + (n & -MASK_BITS) - 1; if (n >= MASK_BITS) { nodep = node_split(s, middle_start); /* * As needed, split just after end of middle bits. * No split needed if end of middle bits is at highest * supported bit index. */ if (middle_end + 1 > middle_end) (void) node_split(s, middle_end + 1); /* Delete nodes that only describe bits within the middle. */ for (next = node_next(s, nodep); next && (next->idx < middle_end); next = node_next(s, nodep)) { assert(next->idx + MASK_BITS + next->num_after - 1 <= middle_end); node_rm(s, next); next = NULL; } /* As needed set each of the mask bits */ for (n1 = 0; n1 < MASK_BITS; n1++) { if (!(nodep->mask & (1 << n1))) { nodep->mask |= 1 << n1; s->num_set++; } } s->num_set -= nodep->num_after; nodep->num_after = middle_end - middle_start + 1 - MASK_BITS; s->num_set += nodep->num_after; node_reduce(s, nodep); } idx = middle_end + 1; n -= middle_end - middle_start + 1; /* Trailing - bits at and beyond last mask boundary */ assert(n < MASK_BITS); for (; n > 0; idx++, n--) bit_set(s, idx); } /* Clears the bits * in the inclusive range idx through idx + num - 1. */ void sparsebit_clear_num(struct sparsebit *s, sparsebit_idx_t start, sparsebit_num_t num) { struct node *nodep, *next; unsigned int n1; sparsebit_idx_t idx; sparsebit_num_t n; sparsebit_idx_t middle_start, middle_end; assert(num > 0); assert(start + num - 1 >= start); /* Leading - bits before first mask boundary */ for (idx = start, n = num; n > 0 && idx % MASK_BITS != 0; idx++, n--) bit_clear(s, idx); /* Middle - bits spanning one or more entire mask */ middle_start = idx; middle_end = middle_start + (n & -MASK_BITS) - 1; if (n >= MASK_BITS) { nodep = node_split(s, middle_start); /* * As needed, split just after end of middle bits. * No split needed if end of middle bits is at highest * supported bit index. */ if (middle_end + 1 > middle_end) (void) node_split(s, middle_end + 1); /* Delete nodes that only describe bits within the middle. */ for (next = node_next(s, nodep); next && (next->idx < middle_end); next = node_next(s, nodep)) { assert(next->idx + MASK_BITS + next->num_after - 1 <= middle_end); node_rm(s, next); next = NULL; } /* As needed clear each of the mask bits */ for (n1 = 0; n1 < MASK_BITS; n1++) { if (nodep->mask & (1 << n1)) { nodep->mask &= ~(1 << n1); s->num_set--; } } /* Clear any bits described by num_after */ s->num_set -= nodep->num_after; nodep->num_after = 0; /* * Delete the node that describes the beginning of * the middle bits and perform any allowed reductions * with the nodes prev or next of nodep. */ node_reduce(s, nodep); nodep = NULL; } idx = middle_end + 1; n -= middle_end - middle_start + 1; /* Trailing - bits at and beyond last mask boundary */ assert(n < MASK_BITS); for (; n > 0; idx++, n--) bit_clear(s, idx); } /* Sets the bit at the index given by idx. */ void sparsebit_set(struct sparsebit *s, sparsebit_idx_t idx) { sparsebit_set_num(s, idx, 1); } /* Clears the bit at the index given by idx. */ void sparsebit_clear(struct sparsebit *s, sparsebit_idx_t idx) { sparsebit_clear_num(s, idx, 1); } /* Sets the bits in the entire addressable range of the sparsebit array. */ void sparsebit_set_all(struct sparsebit *s) { sparsebit_set(s, 0); sparsebit_set_num(s, 1, ~(sparsebit_idx_t) 0); assert(sparsebit_all_set(s)); } /* Clears the bits in the entire addressable range of the sparsebit array. */ void sparsebit_clear_all(struct sparsebit *s) { sparsebit_clear(s, 0); sparsebit_clear_num(s, 1, ~(sparsebit_idx_t) 0); assert(!sparsebit_any_set(s)); } static size_t display_range(FILE *stream, sparsebit_idx_t low, sparsebit_idx_t high, bool prepend_comma_space) { char *fmt_str; size_t sz; /* Determine the printf format string */ if (low == high) fmt_str = prepend_comma_space ? ", 0x%lx" : "0x%lx"; else fmt_str = prepend_comma_space ? ", 0x%lx:0x%lx" : "0x%lx:0x%lx"; /* * When stream is NULL, just determine the size of what would * have been printed, else print the range. */ if (!stream) sz = snprintf(NULL, 0, fmt_str, low, high); else sz = fprintf(stream, fmt_str, low, high); return sz; } /* Dumps to the FILE stream given by stream, the bit settings * of s. Each line of output is prefixed with the number of * spaces given by indent. The length of each line is implementation * dependent and does not depend on the indent amount. The following * is an example output of a sparsebit array that has bits: * * 0x5, 0x8, 0xa:0xe, 0x12 * * This corresponds to a sparsebit whose bits 5, 8, 10, 11, 12, 13, 14, 18 * are set. Note that a ':', instead of a '-' is used to specify a range of * contiguous bits. This is done because '-' is used to specify command-line * options, and sometimes ranges are specified as command-line arguments. */ void sparsebit_dump(FILE *stream, const struct sparsebit *s, unsigned int indent) { size_t current_line_len = 0; size_t sz; struct node *nodep; if (!sparsebit_any_set(s)) return; /* Display initial indent */ fprintf(stream, "%*s", indent, ""); /* For each node */ for (nodep = node_first(s); nodep; nodep = node_next(s, nodep)) { unsigned int n1; sparsebit_idx_t low, high; /* For each group of bits in the mask */ for (n1 = 0; n1 < MASK_BITS; n1++) { if (nodep->mask & (1 << n1)) { low = high = nodep->idx + n1; for (; n1 < MASK_BITS; n1++) { if (nodep->mask & (1 << n1)) high = nodep->idx + n1; else break; } if ((n1 == MASK_BITS) && nodep->num_after) high += nodep->num_after; /* * How much room will it take to display * this range. */ sz = display_range(NULL, low, high, current_line_len != 0); /* * If there is not enough room, display * a newline plus the indent of the next * line. */ if (current_line_len + sz > DUMP_LINE_MAX) { fputs("\n", stream); fprintf(stream, "%*s", indent, ""); current_line_len = 0; } /* Display the range */ sz = display_range(stream, low, high, current_line_len != 0); current_line_len += sz; } } /* * If num_after and most significant-bit of mask is not * set, then still need to display a range for the bits * described by num_after. */ if (!(nodep->mask & (1 << (MASK_BITS - 1))) && nodep->num_after) { low = nodep->idx + MASK_BITS; high = nodep->idx + MASK_BITS + nodep->num_after - 1; /* * How much room will it take to display * this range. */ sz = display_range(NULL, low, high, current_line_len != 0); /* * If there is not enough room, display * a newline plus the indent of the next * line. */ if (current_line_len + sz > DUMP_LINE_MAX) { fputs("\n", stream); fprintf(stream, "%*s", indent, ""); current_line_len = 0; } /* Display the range */ sz = display_range(stream, low, high, current_line_len != 0); current_line_len += sz; } } fputs("\n", stream); } /* Validates the internal state of the sparsebit array given by * s. On error, diagnostic information is printed to stderr and * abort is called. */ void sparsebit_validate_internal(const struct sparsebit *s) { bool error_detected = false; struct node *nodep, *prev = NULL; sparsebit_num_t total_bits_set = 0; unsigned int n1; /* For each node */ for (nodep = node_first(s); nodep; prev = nodep, nodep = node_next(s, nodep)) { /* * Increase total bits set by the number of bits set * in this node. */ for (n1 = 0; n1 < MASK_BITS; n1++) if (nodep->mask & (1 << n1)) total_bits_set++; total_bits_set += nodep->num_after; /* * Arbitrary choice as to whether a mask of 0 is allowed * or not. For diagnostic purposes it is beneficial to * have only one valid means to represent a set of bits. * To support this an arbitrary choice has been made * to not allow a mask of zero. */ if (nodep->mask == 0) { fprintf(stderr, "Node mask of zero, " "nodep: %p nodep->mask: 0x%x", nodep, nodep->mask); error_detected = true; break; } /* * Validate num_after is not greater than the max index * - the number of mask bits. The num_after member * uses 0-based indexing and thus has no value that * represents all bits set. This limitation is handled * by requiring a non-zero mask. With a non-zero mask, * MASK_BITS worth of bits are described by the mask, * which makes the largest needed num_after equal to: * * (~(sparsebit_num_t) 0) - MASK_BITS + 1 */ if (nodep->num_after > (~(sparsebit_num_t) 0) - MASK_BITS + 1) { fprintf(stderr, "num_after too large, " "nodep: %p nodep->num_after: 0x%lx", nodep, nodep->num_after); error_detected = true; break; } /* Validate node index is divisible by the mask size */ if (nodep->idx % MASK_BITS) { fprintf(stderr, "Node index not divisible by " "mask size,\n" " nodep: %p nodep->idx: 0x%lx " "MASK_BITS: %lu\n", nodep, nodep->idx, MASK_BITS); error_detected = true; break; } /* * Validate bits described by node don't wrap beyond the * highest supported index. */ if ((nodep->idx + MASK_BITS + nodep->num_after - 1) < nodep->idx) { fprintf(stderr, "Bits described by node wrap " "beyond highest supported index,\n" " nodep: %p nodep->idx: 0x%lx\n" " MASK_BITS: %lu nodep->num_after: 0x%lx", nodep, nodep->idx, MASK_BITS, nodep->num_after); error_detected = true; break; } /* Check parent pointers. */ if (nodep->left) { if (nodep->left->parent != nodep) { fprintf(stderr, "Left child parent pointer " "doesn't point to this node,\n" " nodep: %p nodep->left: %p " "nodep->left->parent: %p", nodep, nodep->left, nodep->left->parent); error_detected = true; break; } } if (nodep->right) { if (nodep->right->parent != nodep) { fprintf(stderr, "Right child parent pointer " "doesn't point to this node,\n" " nodep: %p nodep->right: %p " "nodep->right->parent: %p", nodep, nodep->right, nodep->right->parent); error_detected = true; break; } } if (!nodep->parent) { if (s->root != nodep) { fprintf(stderr, "Unexpected root node, " "s->root: %p nodep: %p", s->root, nodep); error_detected = true; break; } } if (prev) { /* * Is index of previous node before index of * current node? */ if (prev->idx >= nodep->idx) { fprintf(stderr, "Previous node index " ">= current node index,\n" " prev: %p prev->idx: 0x%lx\n" " nodep: %p nodep->idx: 0x%lx", prev, prev->idx, nodep, nodep->idx); error_detected = true; break; } /* * Nodes occur in asscending order, based on each * nodes starting index. */ if ((prev->idx + MASK_BITS + prev->num_after - 1) >= nodep->idx) { fprintf(stderr, "Previous node bit range " "overlap with current node bit range,\n" " prev: %p prev->idx: 0x%lx " "prev->num_after: 0x%lx\n" " nodep: %p nodep->idx: 0x%lx " "nodep->num_after: 0x%lx\n" " MASK_BITS: %lu", prev, prev->idx, prev->num_after, nodep, nodep->idx, nodep->num_after, MASK_BITS); error_detected = true; break; } /* * When the node has all mask bits set, it shouldn't * be adjacent to the last bit described by the * previous node. */ if (nodep->mask == ~(mask_t) 0 && prev->idx + MASK_BITS + prev->num_after == nodep->idx) { fprintf(stderr, "Current node has mask with " "all bits set and is adjacent to the " "previous node,\n" " prev: %p prev->idx: 0x%lx " "prev->num_after: 0x%lx\n" " nodep: %p nodep->idx: 0x%lx " "nodep->num_after: 0x%lx\n" " MASK_BITS: %lu", prev, prev->idx, prev->num_after, nodep, nodep->idx, nodep->num_after, MASK_BITS); error_detected = true; break; } } } if (!error_detected) { /* * Is sum of bits set in each node equal to the count * of total bits set. */ if (s->num_set != total_bits_set) { fprintf(stderr, "Number of bits set mismatch,\n" " s->num_set: 0x%lx total_bits_set: 0x%lx", s->num_set, total_bits_set); error_detected = true; } } if (error_detected) { fputs(" dump_internal:\n", stderr); sparsebit_dump_internal(stderr, s, 4); abort(); } } #ifdef FUZZ /* A simple but effective fuzzing driver. Look for bugs with the help * of some invariants and of a trivial representation of sparsebit. * Just use 512 bytes of /dev/zero and /dev/urandom as inputs, and let * afl-fuzz do the magic. :) */ #include <stdlib.h> struct range { sparsebit_idx_t first, last; bool set; }; struct sparsebit *s; struct range ranges[1000]; int num_ranges; static bool get_value(sparsebit_idx_t idx) { int i; for (i = num_ranges; --i >= 0; ) if (ranges[i].first <= idx && idx <= ranges[i].last) return ranges[i].set; return false; } static void operate(int code, sparsebit_idx_t first, sparsebit_idx_t last) { sparsebit_num_t num; sparsebit_idx_t next; if (first < last) { num = last - first + 1; } else { num = first - last + 1; first = last; last = first + num - 1; } switch (code) { case 0: sparsebit_set(s, first); assert(sparsebit_is_set(s, first)); assert(!sparsebit_is_clear(s, first)); assert(sparsebit_any_set(s)); assert(!sparsebit_all_clear(s)); if (get_value(first)) return; if (num_ranges == 1000) exit(0); ranges[num_ranges++] = (struct range) { .first = first, .last = first, .set = true }; break; case 1: sparsebit_clear(s, first); assert(!sparsebit_is_set(s, first)); assert(sparsebit_is_clear(s, first)); assert(sparsebit_any_clear(s)); assert(!sparsebit_all_set(s)); if (!get_value(first)) return; if (num_ranges == 1000) exit(0); ranges[num_ranges++] = (struct range) { .first = first, .last = first, .set = false }; break; case 2: assert(sparsebit_is_set(s, first) == get_value(first)); assert(sparsebit_is_clear(s, first) == !get_value(first)); break; case 3: if (sparsebit_any_set(s)) assert(get_value(sparsebit_first_set(s))); if (sparsebit_any_clear(s)) assert(!get_value(sparsebit_first_clear(s))); sparsebit_set_all(s); assert(!sparsebit_any_clear(s)); assert(sparsebit_all_set(s)); num_ranges = 0; ranges[num_ranges++] = (struct range) { .first = 0, .last = ~(sparsebit_idx_t)0, .set = true }; break; case 4: if (sparsebit_any_set(s)) assert(get_value(sparsebit_first_set(s))); if (sparsebit_any_clear(s)) assert(!get_value(sparsebit_first_clear(s))); sparsebit_clear_all(s); assert(!sparsebit_any_set(s)); assert(sparsebit_all_clear(s)); num_ranges = 0; break; case 5: next = sparsebit_next_set(s, first); assert(next == 0 || next > first); assert(next == 0 || get_value(next)); break; case 6: next = sparsebit_next_clear(s, first); assert(next == 0 || next > first); assert(next == 0 || !get_value(next)); break; case 7: next = sparsebit_next_clear(s, first); if (sparsebit_is_set_num(s, first, num)) { assert(next == 0 || next > last); if (first) next = sparsebit_next_set(s, first - 1); else if (sparsebit_any_set(s)) next = sparsebit_first_set(s); else return; assert(next == first); } else { assert(sparsebit_is_clear(s, first) || next <= last); } break; case 8: next = sparsebit_next_set(s, first); if (sparsebit_is_clear_num(s, first, num)) { assert(next == 0 || next > last); if (first) next = sparsebit_next_clear(s, first - 1); else if (sparsebit_any_clear(s)) next = sparsebit_first_clear(s); else return; assert(next == first); } else { assert(sparsebit_is_set(s, first) || next <= last); } break; case 9: sparsebit_set_num(s, first, num); assert(sparsebit_is_set_num(s, first, num)); assert(!sparsebit_is_clear_num(s, first, num)); assert(sparsebit_any_set(s)); assert(!sparsebit_all_clear(s)); if (num_ranges == 1000) exit(0); ranges[num_ranges++] = (struct range) { .first = first, .last = last, .set = true }; break; case 10: sparsebit_clear_num(s, first, num); assert(!sparsebit_is_set_num(s, first, num)); assert(sparsebit_is_clear_num(s, first, num)); assert(sparsebit_any_clear(s)); assert(!sparsebit_all_set(s)); if (num_ranges == 1000) exit(0); ranges[num_ranges++] = (struct range) { .first = first, .last = last, .set = false }; break; case 11: sparsebit_validate_internal(s); break; default: break; } } unsigned char get8(void) { int ch; ch = getchar(); if (ch == EOF) exit(0); return ch; } uint64_t get64(void) { uint64_t x; x = get8(); x = (x << 8) | get8(); x = (x << 8) | get8(); x = (x << 8) | get8(); x = (x << 8) | get8(); x = (x << 8) | get8(); x = (x << 8) | get8(); return (x << 8) | get8(); } int main(void) { s = sparsebit_alloc(); for (;;) { uint8_t op = get8() & 0xf; uint64_t first = get64(); uint64_t last = get64(); operate(op, first, last); } } #endif
