If you can't use a third party lib then write your own one! No need for a dll.
The basic idea is the have a file for each locale witch contains a mapping (key=value) for text resources.
The name of the file could be something like
resources_<locale>.txt
where <locale> could be something like en, fr, de etc.
When your program stars it reads first the resource file for specified locale.
Preferably you will have to store each key/value pair in a simple struct.
Your read function reads all key/value pair into a hash table witch offers a very good access speed. An alternative would be to sort the array containing the key/value pairs by key and then use binary search on lookup (not the best option, but far better than iterating over all entries each time).
Then you'll have to write a function get_text witch takes as argument the key of the text resource to be looked up an return the corresponding text in as read for the specified locale. You have to handle keys witch have no mapping, the simplest way would be to return key back.
Here is some sample code (using qsort and bsearch):
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#define DEFAULT_LOCALE "en"
#define NULL_ARG "[NULL]"
typedef struct localized_text {
char* key;
char* value;
} localized_text_t;
localized_text_t* localized_text_resources = NULL;
int counter = 0;
char* get_text(char*);
void read_localized_text_resources(char*);
char* read_line(FILE*);
void free_localized_text_resources();
int compare_keys(const void*, const void*);
void print_localized_text_resources();
int main(int argc, char** argv)
{
argv++;
argc--;
char* locale = DEFAULT_LOCALE;
if(! *argv) {
printf("No locale provided, default to %s\n", locale);
} else {
locale = *argv;
printf("Locale provided is %s\n", locale);
}
read_localized_text_resources(locale);
printf("\n%s, %s!\n", get_text("HELLO"), get_text("WORLD"));
printf("\n%s\n", get_text("foo"));
free_localized_text_resources();
return 0;
}
char* get_text(char* key)
{
char* text = NULL_ARG;
if(key) {
text = key;
localized_text_t tmp;
tmp.key = key;
localized_text_t* result = bsearch(&tmp, localized_text_resources, counter, sizeof(localized_text_t), compare_keys);
if(result) {
text = result->value;
}
}
return text;
}
void read_localized_text_resources(char* locale)
{
if(locale) {
char localized_text_resources_file_name[64];
sprintf(localized_text_resources_file_name, "resources_%s.txt", locale);
printf("Read localized text resources from file %s\n", localized_text_resources_file_name);
FILE* localized_text_resources_file = fopen(localized_text_resources_file_name, "r");
if(! localized_text_resources_file) {
perror(localized_text_resources_file_name);
exit(1);
}
int size = 10;
localized_text_resources = malloc(size * sizeof(localized_text_t));
if(! localized_text_resources) {
perror("Unable to allocate memory for text resources");
}
char* line;
while((line = read_line(localized_text_resources_file))) {
if(strlen(line) > 0) {
if(counter == size) {
size += 10;
localized_text_resources = realloc(localized_text_resources, size * sizeof(localized_text_t));
}
localized_text_resources[counter].key = line;
while(*line != '=') {
line++;
}
*line = '\0';
line++;
localized_text_resources[counter].value = line;
counter++;
}
}
qsort(localized_text_resources, counter, sizeof(localized_text_t), compare_keys);
// print_localized_text_resources();
printf("%d text resource(s) found in file %s\n", counter, localized_text_resources_file_name);
}
}
char* read_line(FILE* p_file)
{
int len = 10, i = 0, c = 0;
char* line = NULL;
if(p_file) {
line = malloc(len * sizeof(char));
c = fgetc(p_file);
while(c != EOF) {
if(i == len) {
len += 10;
line = realloc(line, len * sizeof(char));
}
line[i++] = c;
c = fgetc(p_file);
if(c == '\n' || c == '\r') {
break;
}
}
line[i] = '\0';
while(c == '\n' || c == '\r') {
c = fgetc(p_file);
}
if(c != EOF) {
ungetc(c, p_file);
}
if(strlen(line) == 0 && c == EOF) {
free(line);
line = NULL;
}
}
return line;
}
void free_localized_text_resources()
{
if(localized_text_resources) {
while(counter--) {
free(localized_text_resources[counter].key);
}
free(localized_text_resources);
}
}
int compare_keys(const void* e1, const void* e2)
{
return strcmp(((localized_text_t*) e1)->key, ((localized_text_t*) e2)->key);
}
void print_localized_text_resources()
{
int i = 0;
for(; i < counter; i++) {
printf("Key=%s value=%s\n", localized_text_resources[i].key, localized_text_resources[i].value);
}
}
Used with the following resource files
resources_en.txt
WORLD=World
HELLO=Hello
resources_de.txt
HELLO=Hallo
WORLD=Welt
resources_fr.txt
HELLO=Hello
WORLD=Monde
run
(1) out.exe /* default */
(2) out.exe en
(3) out.exe de
(4) out.exe fr
output
(1) Hello, World!
(2) Hello, World!
(3) Hallo, Welt!
(4) Hello, Monde!
