81 lines
2.0 KiB
C
81 lines
2.0 KiB
C
#ifndef TREETRIE_H_f55a3f6d_ef43_45d3_bec3_496a196b5db1
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#define TREETRIE_H_f55a3f6d_ef43_45d3_bec3_496a196b5db1
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#ifdef __cplusplus
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extern "C" {
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#endif
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typedef enum tt_tag_t {
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TT_TAG_TAIL = 0,
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TT_TAG_BRANCH,
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TT_TAG_LEAF, /* only case where one of node a or b points to non-node */
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TT_TAG_NODE
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} tt_tag_t;
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typedef enum tt_reserved_node_idx_t {
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TT_ERROR = 0, /* invalid node index, means "no node at all", not even empty */
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TT_EMPTY, /* empty treetrie */
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TT_OK, /* terminal marker */
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TT_FIRST_VALID_NODE_IDX
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} tt_reserved_node_idx_t;
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typedef uint32_t tt_node_idx_t; /* N.B. tt_reserved_node_idx_t */
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typedef uint32_t tt_atom_t;
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typedef union tt_header_t {
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uint32_t next_free;
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struct {
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uint32_t refcount : 24;
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uint32_t index : 6;
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tt_tag_t tag : 2;
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} inuse;
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} tt_header_t;
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#define TT_REFCOUNT_LIMIT ((1 << 24) - 1)
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typedef struct tt_node_t {
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tt_node_idx_t a; /* always a real node idx */
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tt_node_idx_t b; /* a real node idx unless corresponding tag is TT_TAG_LEAF */
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} tt_node_t;
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typedef struct tt_arena_t {
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/* Fields for the Robin Hood hashset used for hashconsing of tt_nodes */
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unsigned int max_probe;
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unsigned int live_count;
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unsigned int table_length;
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tt_node_idx_t *table;
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tt_header_t *headers;
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tt_node_t *nodes;
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tt_node_idx_t free_chain;
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} tt_arena_t;
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extern int tt_arena_init(tt_arena_t *a);
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extern void tt_arena_done(tt_arena_t *a);
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/* Returns 0 if consing failed (because of out-of-memory).
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Otherwise, returns a nonzero index.
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Grabs na and nb (according to tag) IF it needs to allocate a new node, otherwise does not.
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DOES NOT increase the reference count of the returned node. */
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extern tt_node_idx_t tt_arena_cons(tt_arena_t *a,
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uint32_t tag,
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uint32_t index,
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tt_node_idx_t na,
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tt_node_idx_t nb);
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extern tt_node_idx_t tt_grab(tt_arena_t *a, tt_node_idx_t i);
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extern void tt_drop(tt_arena_t *a, tt_node_idx_t i);
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/* WARNING: private, unsafe */
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typedef uint32_t tt_hash_t;
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extern tt_hash_t tt_hash_node(tt_arena_t *a, tt_node_idx_t i);
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#ifdef __cplusplus
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}
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#endif
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#endif
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