kv_store.c

Go to the documentation of this file.

/*
 * General purpose key-value store.
 * Copyright (C) 2026 Fabien-B <fabien-b@github.com> 
 * This file is part of paparazzi. See LICENCE file.
 */
 
#include "kv_store.h"
#include "string.h"
 
void kv_init(kv_store_t *kv, size_t capacity, size_t esize,
            uint32_t *keys, void *values, uint8_t *used) {
 
  kv->capacity = capacity;
  kv->esize = esize;
  kv->keys = keys;
  kv->values = (uint8_t *)values;
  kv->used = used;
 
  for (size_t i = 0; i < capacity; i++) {
    kv->used[i] = 0;
  }
}
 
static int kv_find(const kv_store_t *kv, uint32_t key, size_t *index) {
  for (size_t i = 0; i < kv->capacity; i++)
  {
    if (kv->used[i] && kv->keys[i] == key)
    {
      if (index)
      {
        *index = i;
      }
      return 1; // found
    }
  }
  return 0; // not found
}
 
int kv_exists(const kv_store_t *kv, uint32_t key) {
  return kv_find(kv, key, NULL);
}
 
int kv_set(kv_store_t *kv, uint32_t key, const void *value) {
  size_t index;
 
  // Update existing
  if (kv_find(kv, key, &index))
  {
    memcpy(&kv->values[index * kv->esize], value, kv->esize);
    return 0;
  }
 
  // Insert new
  for (size_t i = 0; i < kv->capacity; i++)
  {
    if (!kv->used[i])
    {
      kv->used[i] = 1;
      kv->keys[i] = key;
      memcpy(&kv->values[i * kv->esize], value, kv->esize);
      return 0;
    }
  }
  
  return -1;  // store full
}
 
void* kv_get(const kv_store_t *kv, uint32_t key) {
  size_t index;
 
  if (!kv_find(kv, key, &index))
    return NULL;
 
  return &kv->values[index * kv->esize];
}
 
int kv_remove(kv_store_t *kv, uint32_t key) {
  size_t index;
 
  if (!kv_find(kv, key, &index))
    return -1;
 
  kv->used[index] = 0;
  return 0;
}