Subversion Repositories FlightCtrl

/*-------------------------------------------------------------------------*/
/**
   @file        dictionary.c
   @author      N. Devillard
   @date        Aug 2000
   @version     $Revision: 1.23 $
   @brief       Implements a dictionary for string variables.

   This module implements a simple dictionary object, i.e. a list
   of string/string associations. This object is useful to store e.g.
   informations retrieved from a configuration file (ini files).
*/
/*--------------------------------------------------------------------------*/

/*
        $Id: dictionary.c,v 1.23 2002/06/17 09:30:46 ndevilla Exp $
        $Author: ndevilla $
        $Date: 2002/06/17 09:30:46 $
        $Revision: 1.23 $
*/

/*---------------------------------------------------------------------------
                                                                Includes
 ---------------------------------------------------------------------------*/

#include "dictionary.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>


/** Maximum value size for integers and doubles. */
#define MAXVALSZ        1024

/** Minimal allocated number of entries in a dictionary */
#define DICTMINSZ       128

/** Invalid key token */
#define DICT_INVALID_KEY    ((char*)-1)


/*---------------------------------------------------------------------------
                                                        Private functions
 ---------------------------------------------------------------------------*/

/* Doubles the allocated size associated to a pointer */
/* 'size' is the current allocated size. */
static void * mem_double(void * ptr, int size)
{
    void    *   newptr ;
 
    newptr = calloc(2*size, 1);
    memcpy(newptr, ptr, size);
    free(ptr);
    return newptr ;
}


/*---------------------------------------------------------------------------
                                                        Function codes
 ---------------------------------------------------------------------------*/

/*-------------------------------------------------------------------------*/
/**
  @brief        Compute the hash key for a string.
  @param        key             Character string to use for key.
  @return       1 unsigned int on at least 32 bits.

  This hash function has been taken from an Article in Dr Dobbs Journal.
  This is normally a collision-free function, distributing keys evenly.
  The key is stored anyway in the struct so that collision can be avoided
  by comparing the key itself in last resort.
 */
/*--------------------------------------------------------------------------*/

unsigned dictionary_hash(char * key)
{
        int                     len ;
        unsigned        hash ;
        int                     i ;

        len = strlen(key);
        for (hash=0, i=0 ; i<len ; i++) {
                hash += (unsigned)key[i] ;
                hash += (hash<<10);
                hash ^= (hash>>6) ;
        }
        hash += (hash <<3);
        hash ^= (hash >>11);
        hash += (hash <<15);
        return hash ;
}


/*-------------------------------------------------------------------------*/
/**
  @brief        Create a new dictionary object.
  @param        size    Optional initial size of the dictionary.
  @return       1 newly allocated dictionary objet.

  This function allocates a new dictionary object of given size and returns
  it. If you do not know in advance (roughly) the number of entries in the
  dictionary, give size=0.
 */
/*--------------------------------------------------------------------------*/

dictionary * dictionary_new(int size)
{
        dictionary      *       d ;

        /* If no size was specified, allocate space for DICTMINSZ */
        if (size<DICTMINSZ) size=DICTMINSZ ;

        if (!(d = (dictionary *)calloc(1, sizeof(dictionary)))) {
                return NULL;
        }
        d->size = size ;
        d->val  = (char **)calloc(size, sizeof(char*));
        d->key  = (char **)calloc(size, sizeof(char*));
        d->hash = (unsigned int *)calloc(size, sizeof(unsigned));
        return d ;
}


/*-------------------------------------------------------------------------*/
/**
  @brief        Delete a dictionary object
  @param        d       dictionary object to deallocate.
  @return       void

  Deallocate a dictionary object and all memory associated to it.
 */
/*--------------------------------------------------------------------------*/

void dictionary_del(dictionary * d)
{
        int             i ;

        if (d==NULL) return ;
        for (i=0 ; i<d->size ; i++) {
                if (d->key[i]!=NULL)
                        free(d->key[i]);
                if (d->val[i]!=NULL)
                        free(d->val[i]);
        }
        free(d->val);
        free(d->key);
        free(d->hash);
        free(d);
        return ;
}



/*-------------------------------------------------------------------------*/
/**
  @brief        Get a value from a dictionary.
  @param        d               dictionary object to search.
  @param        key             Key to look for in the dictionary.
  @param    def     Default value to return if key not found.
  @return       1 pointer to internally allocated character string.

  This function locates a key in a dictionary and returns a pointer to its
  value, or the passed 'def' pointer if no such key can be found in
  dictionary. The returned character pointer points to data internal to the
  dictionary object, you should not try to free it or modify it.
 */
/*--------------------------------------------------------------------------*/
char * dictionary_get(dictionary * d, char * key, char * def)
{
        unsigned        hash ;
        int                     i ;

        hash = dictionary_hash(key);
        for (i=0 ; i<d->size ; i++) {
        if (d->key==NULL)
            continue ;
        /* Compare hash */
                if (hash==d->hash[i]) {
            /* Compare string, to avoid hash collisions */
            if (!strcmp(key, d->key[i])) {
                                return d->val[i] ;
                        }
                }
        }
        return def ;
}

/*-------------------------------------------------------------------------*/
/**
  @brief        Get a value from a dictionary, as a char.
  @param        d               dictionary object to search.
  @param        key             Key to look for in the dictionary.
  @param        def             Default value for the key if not found.
  @return       char   

  This function locates a key in a dictionary using dictionary_get,
  and returns the first char of the found string.
 */
/*--------------------------------------------------------------------------*/
char dictionary_getchar(dictionary * d, char * key, char def)
{
        char * v ;

        if ((v=dictionary_get(d,key,DICT_INVALID_KEY))==DICT_INVALID_KEY) {
                return def ;
        } else {
                return v[0] ;
        }
}


/*-------------------------------------------------------------------------*/
/**
  @brief        Get a value from a dictionary, as an int.
  @param        d               dictionary object to search.
  @param        key             Key to look for in the dictionary.
  @param        def             Default value for the key if not found.
  @return       int

  This function locates a key in a dictionary using dictionary_get,
  and applies atoi on it to return an int. If the value cannot be found
  in the dictionary, the default is returned.
 */
/*--------------------------------------------------------------------------*/
int dictionary_getint(dictionary * d, char * key, int def)
{
        char * v ;

        if ((v=dictionary_get(d,key,DICT_INVALID_KEY))==DICT_INVALID_KEY) {
                return def ;
        } else {
                return atoi(v);
        }
}

/*-------------------------------------------------------------------------*/
/**
  @brief                Get a value from a dictionary, as a double.
  @param        d               dictionary object to search.
  @param        key             Key to look for in the dictionary.
  @param        def             Default value for the key if not found.
  @return       double

  This function locates a key in a dictionary using dictionary_get,
  and applies atof on it to return a double. If the value cannot be found
  in the dictionary, the default is returned.
 */
/*--------------------------------------------------------------------------*/
double dictionary_getdouble(dictionary * d, char * key, double def)
{
        char * v ;

        if ((v=dictionary_get(d,key,DICT_INVALID_KEY))==DICT_INVALID_KEY) {
                return def ;
        } else {
                return atof(v);
        }
}


/*-------------------------------------------------------------------------*/
/**
  @brief        Set a value in a dictionary.
  @param        d               dictionary object to modify.
  @param        key             Key to modify or add.
  @param        val     Value to add.
  @return       void

  If the given key is found in the dictionary, the associated value is
  replaced by the provided one. If the key cannot be found in the
  dictionary, it is added to it.

  It is Ok to provide a NULL value for val, but NULL values for the dictionary
  or the key are considered as errors: the function will return immediately
  in such a case.

  Notice that if you dictionary_set a variable to NULL, a call to
  dictionary_get will return a NULL value: the variable will be found, and
  its value (NULL) is returned. In other words, setting the variable
  content to NULL is equivalent to deleting the variable from the
  dictionary. It is not possible (in this implementation) to have a key in
  the dictionary without value.
 */
/*--------------------------------------------------------------------------*/

void dictionary_set(dictionary * d, char * key, char * val)
{
        int                     i ;
        unsigned        hash ;

        if (d==NULL || key==NULL) return ;
       
        /* Compute hash for this key */
        hash = dictionary_hash(key) ;
        /* Find if value is already in blackboard */
        if (d->n>0) {
                for (i=0 ; i<d->size ; i++) {
            if (d->key[i]==NULL)
                continue ;
                        if (hash==d->hash[i]) { /* Same hash value */
                                if (!strcmp(key, d->key[i])) {   /* Same key */
                                        /* Found a value: modify and return */
                                        if (d->val[i]!=NULL)
                                                free(d->val[i]);
                    d->val[i] = val ? strdup(val) : NULL ;
                    /* Value has been modified: return */
                                        return ;
                                }
                        }
                }
        }
        /* Add a new value */
        /* See if dictionary needs to grow */
        if (d->n==d->size) {

                /* Reached maximum size: reallocate blackboard */
                d->val  = (char **)mem_double(d->val,  d->size * sizeof(char*)) ;
                d->key  = (char **)mem_double(d->key,  d->size * sizeof(char*)) ;
                d->hash = (unsigned int *)mem_double(d->hash, d->size * sizeof(unsigned)) ;

                /* Double size */
                d->size *= 2 ;
        }

    /* Insert key in the first empty slot */
    for (i=0 ; i<d->size ; i++) {
        if (d->key[i]==NULL) {
            /* Add key here */
            break ;
        }
    }
        /* Copy key */
        d->key[i]  = strdup(key);
    d->val[i]  = val ? strdup(val) : NULL ;
        d->hash[i] = hash;
        d->n ++ ;
        return ;
}

/*-------------------------------------------------------------------------*/
/**
  @brief        Delete a key in a dictionary
  @param        d               dictionary object to modify.
  @param        key             Key to remove.
  @return   void

  This function deletes a key in a dictionary. Nothing is done if the
  key cannot be found.
 */
/*--------------------------------------------------------------------------*/
void dictionary_unset(dictionary * d, char * key)
{
        unsigned        hash ;
        int                     i ;

        if (key == NULL) {
                return;
        }

        hash = dictionary_hash(key);
        for (i=0 ; i<d->size ; i++) {
        if (d->key[i]==NULL)
            continue ;
        /* Compare hash */
                if (hash==d->hash[i]) {
            /* Compare string, to avoid hash collisions */
            if (!strcmp(key, d->key[i])) {
                /* Found key */
                break ;
                        }
                }
        }
    if (i>=d->size)
        /* Key not found */
        return ;

    free(d->key[i]);
    d->key[i] = NULL ;
    if (d->val[i]!=NULL) {
        free(d->val[i]);
        d->val[i] = NULL ;
    }
    d->hash[i] = 0 ;
    d->n -- ;
    return ;
}


/*-------------------------------------------------------------------------*/
/**
  @brief        Set a key in a dictionary, providing an int.
  @param        d               Dictionary to update.
  @param        key             Key to modify or add
  @param        val             Integer value to store (will be stored as a string).
  @return       void

  This helper function calls dictionary_set() with the provided integer
  converted to a string using %d.
 */
/*--------------------------------------------------------------------------*/


void dictionary_setint(dictionary * d, char * key, int val)
{
        char    sval[MAXVALSZ];
        sprintf(sval, "%d", val);
        dictionary_set(d, key, sval);
}


/*-------------------------------------------------------------------------*/
/**
  @brief        Set a key in a dictionary, providing a double.
  @param        d               Dictionary to update.
  @param        key             Key to modify or add
  @param        val             Double value to store (will be stored as a string).
  @return       void

  This helper function calls dictionary_set() with the provided double
  converted to a string using %g.
 */
/*--------------------------------------------------------------------------*/


void dictionary_setdouble(dictionary * d, char * key, double val)
{
        char    sval[MAXVALSZ];
        sprintf(sval, "%g", val);
        dictionary_set(d, key, sval);
}



/*-------------------------------------------------------------------------*/
/**
  @brief        Dump a dictionary to an opened file pointer.
  @param        d       Dictionary to dump
  @param        f       Opened file pointer.
  @return       void

  Dumps a dictionary onto an opened file pointer. Key pairs are printed out
  as @c [Key]=[Value], one per line. It is Ok to provide stdout or stderr as
  output file pointers.
 */
/*--------------------------------------------------------------------------*/

void dictionary_dump(dictionary * d, FILE * out)
{
        int             i ;

        if (d==NULL || out==NULL) return ;
        if (d->n<1) {
                fprintf(out, "empty dictionary\n");
                return ;
        }
        for (i=0 ; i<d->size ; i++) {
        if (d->key[i]) {
            fprintf(out, "%20s\t[%s]\n",
                    d->key[i],
                    d->val[i] ? d->val[i] : "UNDEF");
        }
        }
        return ;
}



/* Example code */
#ifdef TESTDIC
#define NVALS 20000
int main(int argc, char *argv[])
{
        dictionary      *       d ;
        char    *       val ;
        int                     i ;
        char            cval[90] ;

        /* allocate blackboard */
        printf("allocating...\n");
        d = dictionary_new(0);
       
        /* Set values in blackboard */
        printf("setting %d values...\n", NVALS);
        for (i=0 ; i<NVALS ; i++) {
                sprintf(cval, "%04d", i);
                dictionary_set(d, cval, "salut");
        }
        printf("getting %d values...\n", NVALS);
        for (i=0 ; i<NVALS ; i++) {
                sprintf(cval, "%04d", i);
                val = dictionary_get(d, cval, DICT_INVALID_KEY);
                if (val==DICT_INVALID_KEY) {
                        printf("cannot get value for key [%s]\n", cval);
                }
        }
    printf("unsetting %d values...\n", NVALS);
        for (i=0 ; i<NVALS ; i++) {
                sprintf(cval, "%04d", i);
                dictionary_unset(d, cval);
        }
    if (d->n != 0) {
        printf("error deleting values\n");
    }

        printf("deallocating...\n");
        dictionary_del(d);
        return 0 ;
}
#endif
/* vim: set ts=4 et sw=4 tw=75 */