diff options
Diffstat (limited to 'libiberty/fibheap.c')
-rw-r--r-- | libiberty/fibheap.c | 254 |
1 files changed, 130 insertions, 124 deletions
diff --git a/libiberty/fibheap.c b/libiberty/fibheap.c index 3c8b347..7431e11 100644 --- a/libiberty/fibheap.c +++ b/libiberty/fibheap.c @@ -1,4 +1,3 @@ - /* A Fibonacci heap datatype. Copyright 1998, 1999, 2000, 2001 Free Software Foundation, Inc. Contributed by Daniel Berlin (dan@cgsoftware.com). @@ -20,13 +19,24 @@ along with GNU CC; see the file COPYING. If not, write to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ -/* Fibonacci heaps */ +#ifdef HAVE_CONFIG_H +#include "config.h" +#endif +#ifdef HAVE_LIMITS_H #include <limits.h> +#endif +#ifdef HAVE_STDLIB_H #include <stdlib.h> +#endif +#ifdef HAVE_STRING_H +#include <string.h> +#endif #include "libiberty.h" #include "fibheap.h" +#define FIBHEAPKEY_MIN LONG_MIN + static void fibheap_init PARAMS ((fibheap_t)); static void fibheap_ins_root PARAMS ((fibheap_t, fibnode_t)); static void fibheap_rem_root PARAMS ((fibheap_t, fibnode_t)); @@ -36,13 +46,25 @@ static void fibheap_cut PARAMS ((fibheap_t, fibnode_t, fibnode_t)); static void fibheap_cascading_cut PARAMS ((fibheap_t, fibnode_t)); static fibnode_t fibheap_extr_min_node PARAMS ((fibheap_t)); static int fibheap_compare PARAMS ((fibheap_t, fibnode_t, fibnode_t)); -static int fibheap_comp_data PARAMS ((fibheap_t, fibheapkey_t, void *, fibnode_t)); +static int fibheap_comp_data PARAMS ((fibheap_t, fibheapkey_t, void *, + fibnode_t)); static fibnode_t fibnode_new PARAMS ((void)); static void fibnode_init PARAMS ((fibnode_t)); static void fibnode_insert_after PARAMS ((fibnode_t, fibnode_t)); #define fibnode_insert_before(a, b) fibnode_insert_after (a->left, b) static fibnode_t fibnode_remove PARAMS ((fibnode_t)); + +/* Initialize the passed in fibonacci heap. */ +static inline void +fibheap_init (heap) + fibheap_t heap; +{ + heap->nodes = 0; + heap->min = NULL; + heap->root = NULL; +} + /* Create a new fibonacci heap. */ fibheap_t fibheap_new () @@ -57,14 +79,60 @@ fibheap_new () return result; } -/* Initialize the passed in fibonacci heap. */ -static void -fibheap_init (heap) +/* Initialize the passed in fibonacci heap node. */ +static inline void +fibnode_init (node) + fibnode_t node; +{ + node->degree = 0; + node->mark = 0; + node->parent = NULL; + node->child = NULL; + node->left = node; + node->right = node; + node->data = NULL; +} + +/* Create a new fibonacci heap node. */ +static inline fibnode_t +fibnode_new () +{ + fibnode_t e; + + if ((e = xmalloc (sizeof *e)) == NULL) + return NULL; + + fibnode_init (e); + + return e; +} + +static inline int +fibheap_compare (heap, a, b) + fibheap_t heap ATTRIBUTE_UNUSED; + fibnode_t a; + fibnode_t b; +{ + if (a->key < b->key) + return -1; + if (a->key > b->key) + return 1; + return 0; +} + +static inline int +fibheap_comp_data (heap, key, data, b) fibheap_t heap; + fibheapkey_t key; + void *data; + fibnode_t b; { - heap->nodes = 0; - heap->min = NULL; - heap->root = NULL; + struct fibnode a; + + a.key = key; + a.data = data; + + return fibheap_compare (heap, &a, b); } /* Insert DATA, with priority KEY, into HEAP. */ @@ -75,9 +143,11 @@ fibheap_insert (heap, key, data) void *data; { fibnode_t node; + /* Create the new node, if we fail, return NULL. */ if ((node = fibnode_new ()) == NULL) return NULL; + /* Set the node's data. */ node->data = data; node->key = key; @@ -85,8 +155,8 @@ fibheap_insert (heap, key, data) /* Insert it into the root list. */ fibheap_ins_root (heap, node); - /* If their was no minimum, or this key is less than the min, it's the new - min. */ + /* If their was no minimum, or this key is less than the min, + it's the new min. */ if (heap->min == NULL || node->key < heap->min->key) heap->min = node; @@ -123,28 +193,26 @@ fibheap_union (heapa, heapb) fibheap_t heapa; fibheap_t heapb; { - fibnode_t temp; + fibnode_t a_root, b_root, temp; /* If one of the heaps is empty, the union is just the other heap. */ - if (heapa->root == NULL || heapb->root == NULL) + if ((a_root = heapa->root) == NULL) { - if (heapa->root == NULL) - { - free (heapa); - return heapb; - } - else - { - free (heapb); - return heapa; - } + free (heapa); + return heapb; + } + if ((b_root = heapb->root) == NULL) + { + free (heapb); + return heapa; } + /* Merge them to the next nodes on the opposite chain. */ - heapa->root->left->right = heapb->root; - heapb->root->left->right = heapa->root; - temp = heapa->root->left; - heapa->root->left = heapb->root->left; - heapb->root->left = temp; + a_root->left->right = b_root; + b_root->left->right = a_root; + temp = a_root->left; + a_root->left = b_root->left; + b_root->left = temp; heapa->nodes += heapb->nodes; /* And set the new minimum, if it's changed. */ @@ -161,9 +229,8 @@ fibheap_extract_min (heap) fibheap_t heap; { fibnode_t z; - void *ret; + void *ret = NULL; - ret = NULL; /* If we don't have a min set, it means we have no nodes. */ if (heap->min != NULL) { @@ -177,31 +244,6 @@ fibheap_extract_min (heap) return ret; } -/* Replace the DATA associated with NODE. */ -void * -fibheap_replace_data (heap, node, data) - fibheap_t heap; - fibnode_t node; - void *data; -{ - return fibheap_replace_key_data (heap, node, node->key, data); -} - -/* Replace the KEY associated with NODE. */ -fibheapkey_t -fibheap_replace_key (heap, node, key) - fibheap_t heap; - fibnode_t node; - fibheapkey_t key; -{ - int ret; - - ret = node->key; - (void) fibheap_replace_key_data (heap, node, key, node->data); - - return ret; -} - /* Replace both the KEY and the DATA associated with NODE. */ void * fibheap_replace_key_data (heap, node, key, data) @@ -244,19 +286,41 @@ fibheap_replace_key_data (heap, node, key, data) return odata; } +/* Replace the DATA associated with NODE. */ +void * +fibheap_replace_data (heap, node, data) + fibheap_t heap; + fibnode_t node; + void *data; +{ + return fibheap_replace_key_data (heap, node, node->key, data); +} + +/* Replace the KEY associated with NODE. */ +fibheapkey_t +fibheap_replace_key (heap, node, key) + fibheap_t heap; + fibnode_t node; + fibheapkey_t key; +{ + int okey = node->key; + fibheap_replace_key_data (heap, node, key, node->data); + return okey; +} + /* Delete NODE from HEAP. */ void * fibheap_delete_node (heap, node) fibheap_t heap; fibnode_t node; { - void *k; + void *ret = node->data; + /* To perform delete, we just make it the min key, and extract. */ - k = node->data; - fibheap_replace_key (heap, node, LONG_MIN); + fibheap_replace_key (heap, node, FIBHEAPKEY_MIN); fibheap_extract_min (heap); - return k; + return ret; } /* Delete HEAP. */ @@ -278,32 +342,29 @@ fibheap_empty (heap) return heap->nodes == 0; } - /* Extract the minimum node of the heap. */ static fibnode_t fibheap_extr_min_node (heap) fibheap_t heap; { - fibnode_t ret; + fibnode_t ret = heap->min; fibnode_t x, y, orig; - ret = heap->min; - - orig = NULL; /* Attach the child list of the minimum node to the root list of the heap. If there is no child list, we don't do squat. */ - for (x = ret->child; x != orig && x != NULL;) + for (x = ret->child, orig = NULL; x != orig && x != NULL; x = y) { if (orig == NULL) orig = x; y = x->right; x->parent = NULL; fibheap_ins_root (heap, x); - x = y; } + /* Remove the old root. */ fibheap_rem_root (heap, ret); heap->nodes--; + /* If we are left with no nodes, then the min is NULL. */ if (heap->nodes == 0) heap->min = NULL; @@ -333,8 +394,9 @@ fibheap_ins_root (heap, node) node->right = node; return; } - /* Otherwise, insert it in the circular root list between the root and it's - right node. */ + + /* Otherwise, insert it in the circular root list between the root + and it's right node. */ fibnode_insert_after (heap->root, node); } @@ -450,33 +512,6 @@ fibheap_cascading_cut (heap, y) } } - -static fibnode_t -fibnode_new () -{ - fibnode_t e; - - if ((e = xmalloc (sizeof *e)) == NULL) - return NULL; - - fibnode_init (e); - - return e; -} - -static void -fibnode_init (node) - fibnode_t node; -{ - node->degree = 0; - node->mark = 0; - node->parent = NULL; - node->child = NULL; - node->left = node; - node->right = node; - node->data = NULL; -} - static void fibnode_insert_after (a, b) fibnode_t a; @@ -498,7 +533,6 @@ fibnode_insert_after (a, b) } } - static fibnode_t fibnode_remove (node) fibnode_t node; @@ -522,31 +556,3 @@ fibnode_remove (node) return ret; } - -static int -fibheap_compare (heap, a, b) - fibheap_t heap ATTRIBUTE_UNUSED; - fibnode_t a; - fibnode_t b; -{ - if (a->key < b->key) - return -1; - if (a->key > b->key) - return 1; - return 0; -} - -static int -fibheap_comp_data (heap, key, data, b) - fibheap_t heap; - fibheapkey_t key; - void *data; - fibnode_t b; -{ - struct fibnode a; - - a.key = key; - a.data = data; - - return fibheap_compare (heap, &a, b); -} |