kaguya
99 lines
1.7 KiB
C++
99 lines
1.7 KiB
C++
#include <mlibc/search.hpp>
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#include <frg/string.hpp>
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#include <stdlib.h>
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#include <stdint.h>
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#include <errno.h>
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struct _ENTRY {
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ENTRY entry;
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bool used;
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};
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namespace mlibc {
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int hcreate_r(size_t num_entries, struct hsearch_data *htab) {
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if(!htab) {
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errno = EINVAL;
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return 0;
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}
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htab->table = static_cast<_ENTRY*>(calloc(num_entries, sizeof(_ENTRY)));
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if(!htab->table) {
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errno = ENOMEM;
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return 0;
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}
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htab->filled = 0;
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htab->size = num_entries;
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return 1;
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}
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void hdestroy_r(struct hsearch_data *htab) {
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if(!htab) {
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errno = EINVAL;
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return;
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}
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free(htab->table);
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htab->table = nullptr;
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htab->size = 0;
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htab->filled = 0;
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}
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int hsearch_r(ENTRY item, ACTION action, ENTRY **ret, struct hsearch_data *htab) {
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auto key = frg::string_view{item.key};
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auto hash = frg::hash<frg::string_view>{}(key);
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size_t bucket_index = hash % htab->size;
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size_t start = bucket_index;
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while(true) {
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auto &bucket = htab->table[bucket_index];
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if(bucket.used) {
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if(bucket.entry.key == key) {
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*ret = &bucket.entry;
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return 1;
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}
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} else if(action == FIND) {
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errno = ESRCH;
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*ret = nullptr;
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return 0;
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}
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bucket_index = (bucket_index + 1) % htab->size;
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if(bucket_index == start) {
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if(action == FIND) {
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errno = ESRCH;
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*ret = nullptr;
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return 0;
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} else {
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break;
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}
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}
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}
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// insert a new entry.
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if(htab->size == htab->filled) {
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errno = ENOMEM;
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return 0;
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}
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++htab->filled;
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bucket_index = start;
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while(true) {
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auto &bucket = htab->table[bucket_index];
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if(!bucket.used) {
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bucket.used = true;
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bucket.entry = item;
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*ret = &bucket.entry;
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break;
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}
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bucket_index = (bucket_index + 1) % htab->size;
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}
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return 1;
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}
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} // namespace mlibc
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