dictionary.h File Reference

Implements a dictionary for string variables. More...

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

Go to the source code of this file.

Data Structures
struct	_dictionary_
	Dictionary object. More...
Typedefs
typedef _dictionary_	dictionary
	Dictionary object.
Functions
unsigned	dictionary_hash (char *key)
	Compute the hash key for a string.
dictionary *	dictionary_new (int size)
	Create a new dictionary object.
void	dictionary_del (dictionary *vd)
	Delete a dictionary object.
char *	dictionary_get (dictionary *d, char *key, char *def)
	Get a value from a dictionary.
char	dictionary_getchar (dictionary *d, char *key, char def)
	Get a value from a dictionary, as a char.
int	dictionary_getint (dictionary *d, char *key, int def)
	Get a value from a dictionary, as an int.
double	dictionary_getdouble (dictionary *d, char *key, double def)
	Get a value from a dictionary, as a double.
void	dictionary_set (dictionary *vd, char *key, char *val)
	Set a value in a dictionary.
void	dictionary_unset (dictionary *d, char *key)
	Delete a key in a dictionary.
void	dictionary_setint (dictionary *d, char *key, int val)
	Set a key in a dictionary, providing an int.
void	dictionary_setdouble (dictionary *d, char *key, double val)
	Set a key in a dictionary, providing a double.
void	dictionary_dump (dictionary *d, FILE *out)
	Dump a dictionary to an opened file pointer.

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Detailed Description

Implements a dictionary for string variables.

Author:

N. Devillard

Date:

Aug 2000

Version:

Revision

1.11

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).

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Typedef Documentation

typedef struct _dictionary_ dictionary

Dictionary object. This object contains a list of string/string associations. Each association is identified by a unique string key. Looking up values in the dictionary is speeded up by the use of a (hopefully collision-free) hash function.

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Function Documentation

void dictionary_del (  dictionary *  d  )

Delete a dictionary object. Parameters: d  dictionary object to deallocate. Returns: void Deallocate a dictionary object and all memory associated to it.

void dictionary_dump (  dictionary *  d, FILE *  out )

Dump a dictionary to an opened file pointer. Parameters: d  Dictionary to dump f  Opened file pointer. Returns: void Dumps a dictionary onto an opened file pointer. Key pairs are printed out as [Key]=[Value], one per line. It is Ok to provide stdout or stderr as output file pointers.

char* dictionary_get (  dictionary *  d, char *  key, char *  def )

Get a value from a dictionary. Parameters: d  dictionary object to search. key  Key to look for in the dictionary. def  Default value to return if key not found. Returns: 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_getchar (  dictionary *  d, char *  key, char  def )

Get a value from a dictionary, as a char. Parameters: d  dictionary object to search. key  Key to look for in the dictionary. def  Default value for the key if not found. Returns: char This function locates a key in a dictionary using dictionary_get, and returns the first char of the found string.

double dictionary_getdouble (  dictionary *  d, char *  key, double  def )

Get a value from a dictionary, as a double. Parameters: d  dictionary object to search. key  Key to look for in the dictionary. def  Default value for the key if not found. Returns: 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.

int dictionary_getint (  dictionary *  d, char *  key, int  def )

Get a value from a dictionary, as an int. Parameters: d  dictionary object to search. key  Key to look for in the dictionary. def  Default value for the key if not found. Returns: 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.

unsigned dictionary_hash (  char *  key  )

Compute the hash key for a string. Parameters: key  Character string to use for key. Returns: 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.

dictionary* dictionary_new (  int  size  )

Create a new dictionary object. Parameters: size  Optional initial size of the dictionary. Returns: 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.

void dictionary_set (  dictionary *  d, char *  key, char *  val )

Set a value in a dictionary. Parameters: d  dictionary object to modify. key  Key to modify or add. val  Value to add. Returns: 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_setdouble (  dictionary *  d, char *  key, double  val )

Set a key in a dictionary, providing a double. Parameters: d  Dictionary to update. key  Key to modify or add val  Double value to store (will be stored as a string). Returns: void This helper function calls dictionary_set() with the provided double converted to a string using g.

void dictionary_setint (  dictionary *  d, char *  key, int  val )

Set a key in a dictionary, providing an int. Parameters: d  Dictionary to update. key  Key to modify or add val  Integer value to store (will be stored as a string). Returns: void This helper function calls dictionary_set() with the provided integer converted to a string using d.

void dictionary_unset (  dictionary *  d, char *  key )

Delete a key in a dictionary. Parameters: d  dictionary object to modify. key  Key to remove. Returns: void This function deletes a key in a dictionary. Nothing is done if the key cannot be found.

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