src/cbor/maps.c - master - githubmirror/libcbor

src/cbor/maps.c
139 строк4 KB
Pavel Kalvoda
Add cbor_map_get with parameterized equality function (#409)
22 мар 2026, 21:09
22 мар 2026, 21:09d5222af
/*
 * Copyright (c) 2014-2020 Pavel Kalvoda <me@pavelkalvoda.com>
 *
 * libcbor is free software; you can redistribute it and/or modify
 * it under the terms of the MIT license. See LICENSE for details.
 */

#include "maps.h"
#include "internal/memory_utils.h"

size_t cbor_map_size(const cbor_item_t* item) {
  CBOR_ASSERT(cbor_isa_map(item));
  return item->metadata.map_metadata.end_ptr;
}

size_t cbor_map_allocated(const cbor_item_t* item) {
  CBOR_ASSERT(cbor_isa_map(item));
  return item->metadata.map_metadata.allocated;
}

cbor_item_t* cbor_new_definite_map(size_t size) {
  cbor_item_t* item = _cbor_malloc(sizeof(cbor_item_t));
  _CBOR_NOTNULL(item);

  *item = (cbor_item_t){
      .refcount = 1,
      .type = CBOR_TYPE_MAP,
      .metadata = {.map_metadata = {.allocated = size,
                                    .type = _CBOR_METADATA_DEFINITE,
                                    .end_ptr = 0}},
      .data = _cbor_alloc_multiple(sizeof(struct cbor_pair), size)};
  _CBOR_DEPENDENT_NOTNULL(item, item->data);

  return item;
}

cbor_item_t* cbor_new_indefinite_map(void) {
  cbor_item_t* item = _cbor_malloc(sizeof(cbor_item_t));
  _CBOR_NOTNULL(item);

  *item = (cbor_item_t){
      .refcount = 1,
      .type = CBOR_TYPE_MAP,
      .metadata = {.map_metadata = {.allocated = 0,
                                    .type = _CBOR_METADATA_INDEFINITE,
                                    .end_ptr = 0}},
      .data = NULL};

  return item;
}

bool _cbor_map_add_key(cbor_item_t* item, cbor_item_t* key) {
  CBOR_ASSERT(cbor_isa_map(item));
  struct _cbor_map_metadata* metadata =
      (struct _cbor_map_metadata*)&item->metadata;
  if (cbor_map_is_definite(item)) {
    struct cbor_pair* data = cbor_map_handle(item);
    if (metadata->end_ptr >= metadata->allocated) {
      /* Don't realloc definite preallocated map */
      return false;
    }

    data[metadata->end_ptr].key = key;
    data[metadata->end_ptr++].value = NULL;
  } else {
    if (metadata->end_ptr >= metadata->allocated) {
      /* Exponential realloc */
      // Check for overflows first
      if (!_cbor_safe_to_multiply(CBOR_BUFFER_GROWTH, metadata->allocated)) {
        return false;
      }

      size_t new_allocation = metadata->allocated == 0
                                  ? 1
                                  : CBOR_BUFFER_GROWTH * metadata->allocated;

      unsigned char* new_data = _cbor_realloc_multiple(
          item->data, sizeof(struct cbor_pair), new_allocation);

      if (new_data == NULL) {
        return false;
      }

      item->data = new_data;
      metadata->allocated = new_allocation;
    }
    struct cbor_pair* data = cbor_map_handle(item);
    data[metadata->end_ptr].key = key;
    data[metadata->end_ptr++].value = NULL;
  }
  cbor_incref(key);
  return true;
}

bool _cbor_map_add_value(cbor_item_t* item, cbor_item_t* value) {
  CBOR_ASSERT(cbor_isa_map(item));
  cbor_incref(value);
  cbor_map_handle(item)[
      /* Move one back since we are assuming _add_key (which increased the ptr)
       * was the previous operation on this object */
      item->metadata.map_metadata.end_ptr - 1]
      .value = value;
  return true;
}

// TODO: Add a more convenient API like add(item, key, val)
bool cbor_map_add(cbor_item_t* item, struct cbor_pair pair) {
  CBOR_ASSERT(cbor_isa_map(item));
  if (!_cbor_map_add_key(item, pair.key)) return false;
  return _cbor_map_add_value(item, pair.value);
}

bool cbor_map_is_definite(const cbor_item_t* item) {
  CBOR_ASSERT(cbor_isa_map(item));
  return item->metadata.map_metadata.type == _CBOR_METADATA_DEFINITE;
}

bool cbor_map_is_indefinite(const cbor_item_t* item) {
  return !cbor_map_is_definite(item);
}

struct cbor_pair* cbor_map_handle(const cbor_item_t* item) {
  CBOR_ASSERT(cbor_isa_map(item));
  return (struct cbor_pair*)item->data;
}

cbor_item_t* cbor_map_get(const cbor_item_t* map, const cbor_item_t* key,
                          bool (*eq)(const cbor_item_t*, const cbor_item_t*)) {
  CBOR_ASSERT(cbor_isa_map(map));
  CBOR_ASSERT(key != NULL);
  CBOR_ASSERT(eq != NULL);
  struct cbor_pair* pairs = cbor_map_handle(map);
  for (size_t i = 0; i < cbor_map_size(map); i++) {
    if (eq(pairs[i].key, key)) {
      return cbor_incref(pairs[i].value);
    }
  }
  return NULL;
}