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56 lines
1.5 KiB
56 lines
1.5 KiB
/* |
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* crit-bit tree implementation, does no allocations internally |
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* For more information on crit-bit trees: https://cr.yp.to/critbit.html |
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* Based on Adam Langley's adaptation of Dan Bernstein's public domain code |
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* git clone https://github.com/agl/critbit.git |
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* |
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* This is adapted to store arbitrary data (not just NUL-terminated C strings |
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* and allocates no memory internally. The user needs to allocate |
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* "struct cb_node" and fill cb_node.k[] with arbitrary match data |
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* for memcmp. |
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* If "klen" is variable, then it should be embedded into "c_node.k[]" |
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* Recursion is bound by the maximum value of "klen" used. |
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*/ |
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#ifndef CBTREE_H |
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#define CBTREE_H |
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#include "git-compat-util.h" |
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struct cb_node; |
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struct cb_node { |
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struct cb_node *child[2]; |
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/* |
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* n.b. uint32_t for `byte' is excessive for OIDs, |
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* we may consider shorter variants if nothing else gets stored. |
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*/ |
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uint32_t byte; |
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uint8_t otherbits; |
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uint8_t k[FLEX_ARRAY]; /* arbitrary data, unaligned */ |
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}; |
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struct cb_tree { |
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struct cb_node *root; |
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}; |
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enum cb_next { |
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CB_CONTINUE = 0, |
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CB_BREAK = 1 |
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}; |
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#define CBTREE_INIT { .root = NULL } |
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static inline void cb_init(struct cb_tree *t) |
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{ |
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t->root = NULL; |
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} |
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struct cb_node *cb_lookup(struct cb_tree *, const uint8_t *k, size_t klen); |
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struct cb_node *cb_insert(struct cb_tree *, struct cb_node *, size_t klen); |
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struct cb_node *cb_unlink(struct cb_tree *t, const uint8_t *k, size_t klen); |
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typedef enum cb_next (*cb_iter)(struct cb_node *, void *arg); |
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void cb_each(struct cb_tree *, const uint8_t *kpfx, size_t klen, |
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cb_iter, void *arg); |
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#endif /* CBTREE_H */
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