LookupListC/lookup_list.h

#ifndef INCLUDED_LOOKUP_LIST_H
#define INCLUDED_LOOKUP_LIST_H

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <stdint.h>

// Both key and value will be string
typedef struct LookupList{
  char *key;
  char *value;
  struct LookupList *next;
} LookupList;

// return -1 on failure
int LookupList_add(LookupList **list ,char *key, char *value){
  // Search in list for key and change value
  LookupList *i = *list;
  while(i != NULL){
    if(strcmp(i->key, key) == 0 ){
      i->value = value;
      return 0;
    }
    i = i->next;
  }
  
  // Create new node if key not in list
  LookupList *node = (LookupList *) malloc(sizeof(LookupList));
  if(node == NULL) return -1;
  
  node->key = key;
  node->value = value;
  node->next = *list;
  *list = node;

  return 0;
}

// Does not try to free key and value strings
void LookupList_remove(LookupList **list, char *key){
  LookupList *a = *list;
  if(a == NULL) return;
  if(strcmp(key, a->key) == 0){
    *list = (*list)->next;
    free(a);
    return;
  }

  LookupList *b = a->next;
  while(b != NULL){
    if(strcmp(key, b->key) == 0){
      a->next = b->next;
      free(b);
      return;
    }
    
    a = b;
    b = b->next;
  }
}

char *LookupList_get(LookupList *list, char *key, char *r){
  while(list != NULL){
    if(strcmp(list->key, key) == 0 )
      return list->value;
    list = list->next;
  }
  return r;
}

void LookupList_print(LookupList *list){
  printf("{ ");
  while(list != NULL){
    printf("\"%s\" : \"%s\" ,", list->key, list->value);
    list = list->next;
  }
  printf("}\n");
}

// The binary will first have a uint32_t equal to the number of (key,value) pairs.
// Then we kill have char[] that are seperated using \0 in key1, value1, key2, value2, key3, value3 .... for all pairs.
void LookupList_store(LookupList *list, char *filename){
  uint32_t n = 0;
  LookupList *t = list;
  while(t != NULL){
    n += 1;
    t = t->next;
  }

  t = list;
  FILE *f = fopen(filename, "wb");
  fwrite(&n, sizeof(uint32_t), 1, f);
  for(int i = 0; i < n; i++){
    size_t len_key = 0;
    size_t len_value = 0;

    while(t->key[len_key++] != '\0');
    while(t->value[len_value++] != '\0');
    
    fwrite(t->key, sizeof(char), len_key, f);
    fwrite(t->value, sizeof(char), len_value, f);
    t = t->next;
  }
  fclose(f);
}

void LookupList_load(LookupList **l, char *filename){
  FILE *f = fopen(filename, "rb");
  assert(f != NULL);
  
  uint32_t n = 0;
  fread(&n, sizeof(uint32_t), 1, f);

  for(int i = 0; i < n; i++){

    size_t key_capacity = 10;
    char *key = (char *) malloc(sizeof(char) * key_capacity);
    assert(key != NULL);
    int j = 0;

    
    while(1){

      if((j+1) == key_capacity){
	key_capacity *= 2;
	key = (char *) realloc(key, sizeof(char) * key_capacity);
	assert(key != NULL);
      }
      
      fread((key + j), sizeof(char), 1, f);
      if (key[j] == '\0')
	break;
      
      j++;
    }

    size_t value_capacity = 10;
    char *value = (char *) malloc(sizeof(char) * value_capacity);
    assert(value != NULL);
    j = 0;

    while(1){
      if((j+1) == value_capacity){
	value_capacity *= 2;
	value = (char *) realloc(value, sizeof(char) * value_capacity);
	assert(value != NULL);
      }

      fread((value + j), sizeof(char), 1, f);
      if (value[j] == '\0')
	break;
      j++;
    }

    LookupList_add(l, key, value);
  }
  
  fclose(f);
}

#endif