538835d2ac
Use the same pattern for cb_init() as the one established in the recent refactoring of other such patterns in5726a6b401(*.c *_init(): define in terms of corresponding *_INIT macro, 2021-07-01). It has been pointed out[1] that we could perhaps use this C99 replacement of using a compound literal for all of these: *t = (struct cb_tree){ 0 }; But let's just stick to the existing pattern established in5726a6b401for now, we can leave another weather balloon for some other time. 1. http://lore.kernel.org/git/ef724a3a-a4b8-65d3-c928-13a7d78f189a@gmail.com Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
58 lines
1.6 KiB
C
58 lines
1.6 KiB
C
/*
|
|
* crit-bit tree implementation, does no allocations internally
|
|
* For more information on crit-bit trees: https://cr.yp.to/critbit.html
|
|
* Based on Adam Langley's adaptation of Dan Bernstein's public domain code
|
|
* git clone https://github.com/agl/critbit.git
|
|
*
|
|
* This is adapted to store arbitrary data (not just NUL-terminated C strings
|
|
* and allocates no memory internally. The user needs to allocate
|
|
* "struct cb_node" and fill cb_node.k[] with arbitrary match data
|
|
* for memcmp.
|
|
* If "klen" is variable, then it should be embedded into "c_node.k[]"
|
|
* Recursion is bound by the maximum value of "klen" used.
|
|
*/
|
|
#ifndef CBTREE_H
|
|
#define CBTREE_H
|
|
|
|
#include "git-compat-util.h"
|
|
|
|
struct cb_node;
|
|
struct cb_node {
|
|
struct cb_node *child[2];
|
|
/*
|
|
* n.b. uint32_t for `byte' is excessive for OIDs,
|
|
* we may consider shorter variants if nothing else gets stored.
|
|
*/
|
|
uint32_t byte;
|
|
uint8_t otherbits;
|
|
uint8_t k[FLEX_ARRAY]; /* arbitrary data, unaligned */
|
|
};
|
|
|
|
struct cb_tree {
|
|
struct cb_node *root;
|
|
};
|
|
|
|
enum cb_next {
|
|
CB_CONTINUE = 0,
|
|
CB_BREAK = 1
|
|
};
|
|
|
|
#define CBTREE_INIT { 0 }
|
|
|
|
static inline void cb_init(struct cb_tree *t)
|
|
{
|
|
struct cb_tree blank = CBTREE_INIT;
|
|
memcpy(t, &blank, sizeof(*t));
|
|
}
|
|
|
|
struct cb_node *cb_lookup(struct cb_tree *, const uint8_t *k, size_t klen);
|
|
struct cb_node *cb_insert(struct cb_tree *, struct cb_node *, size_t klen);
|
|
struct cb_node *cb_unlink(struct cb_tree *t, const uint8_t *k, size_t klen);
|
|
|
|
typedef enum cb_next (*cb_iter)(struct cb_node *, void *arg);
|
|
|
|
void cb_each(struct cb_tree *, const uint8_t *kpfx, size_t klen,
|
|
cb_iter, void *arg);
|
|
|
|
#endif /* CBTREE_H */
|