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+/*-------------------------------------------------------------------------*/
+/**
+ @file dictionary.c
+ @author N. Devillard
+ @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).
+*/
+/*--------------------------------------------------------------------------*/
+
+/*---------------------------------------------------------------------------
+ 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
+ ---------------------------------------------------------------------------*/
+
+/*-------------------------------------------------------------------------*/
+/**
+ @brief Duplicate a string
+ @param s String to duplicate
+ @return Pointer to a newly allocated string, to be freed with free()
+
+ This is a replacement for strdup(). This implementation is provided
+ for systems that do not have it.
+ */
+/*--------------------------------------------------------------------------*/
+static char * xstrdup(const char * s)
+{
+ char * t ;
+ size_t len ;
+ if (!s)
+ return NULL ;
+
+ len = strlen(s) + 1 ;
+ t = (char*) malloc(len) ;
+ if (t) {
+ memcpy(t, s, len) ;
+ }
+ return t ;
+}
+
+/*-------------------------------------------------------------------------*/
+/**
+ @brief Double the size of the dictionary
+ @param d Dictionary to grow
+ @return This function returns non-zero in case of failure
+ */
+/*--------------------------------------------------------------------------*/
+static int dictionary_grow(dictionary * d)
+{
+ char ** new_val ;
+ char ** new_key ;
+ unsigned * new_hash ;
+
+ new_val = (char**) calloc(d->size * 2, sizeof *d->val);
+ new_key = (char**) calloc(d->size * 2, sizeof *d->key);
+ new_hash = (unsigned*) calloc(d->size * 2, sizeof *d->hash);
+ if (!new_val || !new_key || !new_hash) {
+ /* An allocation failed, leave the dictionary unchanged */
+ if (new_val)
+ free(new_val);
+ if (new_key)
+ free(new_key);
+ if (new_hash)
+ free(new_hash);
+ return -1 ;
+ }
+ /* Initialize the newly allocated space */
+ memcpy(new_val, d->val, d->size * sizeof(char *));
+ memcpy(new_key, d->key, d->size * sizeof(char *));
+ memcpy(new_hash, d->hash, d->size * sizeof(unsigned));
+ /* Delete previous data */
+ free(d->val);
+ free(d->key);
+ free(d->hash);
+ /* Actually update the dictionary */
+ d->size *= 2 ;
+ d->val = new_val;
+ d->key = new_key;
+ d->hash = new_hash;
+ return 0 ;
+}
+
+/*---------------------------------------------------------------------------
+ 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(const char * key)
+{
+ size_t len ;
+ unsigned hash ;
+ size_t i ;
+
+ if (!key)
+ return 0 ;
+
+ 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(size_t size)
+{
+ dictionary * d ;
+
+ /* If no size was specified, allocate space for DICTMINSZ */
+ if (size<DICTMINSZ) size=DICTMINSZ ;
+
+ d = (dictionary*) calloc(1, sizeof *d) ;
+
+ if (d) {
+ d->size = size ;
+ d->val = (char**) calloc(size, sizeof *d->val);
+ d->key = (char**) calloc(size, sizeof *d->key);
+ d->hash = (unsigned*) calloc(size, sizeof *d->hash);
+ }
+ 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)
+{
+ ssize_t 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.
+ */
+/*--------------------------------------------------------------------------*/
+const char * dictionary_get(const dictionary * d, const char * key, const char * def)
+{
+ unsigned hash ;
+ ssize_t i ;
+
+ 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])) {
+ return d->val[i] ;
+ }
+ }
+ }
+ return def ;
+}
+
+/*-------------------------------------------------------------------------*/
+/**
+ @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 int 0 if Ok, anything else otherwise
+
+ 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.
+
+ This function returns non-zero in case of failure.
+ */
+/*--------------------------------------------------------------------------*/
+int dictionary_set(dictionary * d, const char * key, const char * val)
+{
+ ssize_t i ;
+ unsigned hash ;
+
+ if (d==NULL || key==NULL) return -1 ;
+
+ /* Compute hash for this key */
+ hash = dictionary_hash(key) ;
+ /* Find if value is already in dictionary */
+ 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 ? xstrdup(val) : NULL);
+ /* Value has been modified: return */
+ return 0 ;
+ }
+ }
+ }
+ }
+ /* Add a new value */
+ /* See if dictionary needs to grow */
+ if (d->n==d->size) {
+ /* Reached maximum size: reallocate dictionary */
+ if (dictionary_grow(d) != 0)
+ return -1;
+ }
+
+ /* Insert key in the first empty slot. Start at d->n and wrap at
+ d->size. Because d->n < d->size this will necessarily
+ terminate. */
+ for (i=d->n ; d->key[i] ; ) {
+ if(++i == d->size) i = 0;
+ }
+ /* Copy key */
+ d->key[i] = xstrdup(key);
+ d->val[i] = (val ? xstrdup(val) : NULL) ;
+ d->hash[i] = hash;
+ d->n ++ ;
+ return 0 ;
+}
+
+/*-------------------------------------------------------------------------*/
+/**
+ @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, const char * key)
+{
+ unsigned hash ;
+ ssize_t i ;
+
+ if (key == NULL || d == 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 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(const dictionary * d, FILE * out)
+{
+ ssize_t 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 ;
+}
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