int main(int argc, char *argv[])
{
int c, encoding = 0, decoding = 0;
char *input_filename = NULL;
char output_filename[512] = {0};
if(argc == 1)
{
lz78_trace("Options:");
lz78_trace("-e <input filename> - encoding by lz78");
lz78_trace("-d <input filename> - decoding by lz78");
return -1;
}
while((c = getopt(argc, argv, "e:d:")) != -1)
{
switch(c)
{
case 'e': encoding = 1; input_filename = optarg; break;
case 'd': decoding = 1; input_filename = optarg; break;
default:
return -1;
}
}
if (!encoding && !decoding)
{
lz78_trace("Encoding or decoding action is not present");
return -1;
}
if (!input_filename)
{
lz78_trace("Input filename is not present");
return -1;
}
if (encoding)
{
snprintf(output_filename, sizeof(output_filename),
"%s"LZ78_ENCODE_EXP, input_filename);
if (!lz78_pack(input_filename, output_filename))
get_encoding_profit(input_filename, output_filename);
}
if (decoding)
{
snprintf(output_filename, sizeof(output_filename),
"%s"LZ78_DECODE_EXP, input_filename);
lz78_unpack(input_filename, output_filename);
}
return 0;
}
int lz78_pack(const char *input_file, const char *output_file)
{
FILE *i_fd, *o_fd;
lz78_dict_t dictionary;
lz78_elem_t new_elem;
lz78_elem_t *rep_elem;
char key[LZ78_MAX_DICT_STR_LEN * 2];
i_fd = fopen(input_file, "r");
if (!i_fd)
{
lz78_trace("failed to open '%s'", input_file);
return -1;
}
o_fd = fopen(output_file, "w");
if (!o_fd)
{
lz78_trace("failed to create '%s'", output_file);
fclose(i_fd);
return -1;
}
memset(&dictionary, 0, sizeof(dictionary));
memset(&new_elem, 0, sizeof(new_elem));
while(1)
{
if (fgets(new_elem.string, 2, i_fd) == NULL)
break;
sprintf(key, "%s%s", new_elem.rep? new_elem.rep->string:"", new_elem.string);
rep_elem = lz78_dict_find(&dictionary, key);
if (rep_elem)
{
new_elem.rep = rep_elem;
continue;
}
lz78_dict_add_elem(&dictionary, &new_elem);
memset(&new_elem, 0, sizeof(new_elem));
}
lz78_dict_print(&dictionary);
lz78_write_encode(o_fd, &dictionary);
fclose(i_fd);
fclose(o_fd);
return 0;
}
int lz78_unpack(const char *input_file, const char *output_file)
{
FILE *i_fd, *o_fd;
lz78_dict_t dictionary;
lz78_elem_t new_elem;
lz78_elem_t *rep_elem;
i_fd = fopen(input_file, "r");
if (!i_fd)
{
lz78_trace("failed to open '%s'", input_file);
return -1;
}
o_fd = fopen(output_file, "w");
if (!o_fd)
{
lz78_trace("failed to create '%s'", output_file);
fclose(i_fd);
return -1;
}
memset(&dictionary, 0, sizeof(dictionary));
memset(&new_elem, 0, sizeof(new_elem));
while(1)
{
if (fgets(new_elem.string, 3, i_fd) == NULL)
break;
rep_elem = lz78_dict_get(&dictionary, atoi(new_elem.string));
if (rep_elem)
new_elem.rep = rep_elem;
memcpy(new_elem.string, &new_elem.string[1], strlen(new_elem.string)-1);
new_elem.string[strlen(new_elem.string)-1] = '\0';
lz78_dict_add_elem(&dictionary, &new_elem);
memset(&new_elem, 0, sizeof(new_elem));
}
lz78_dict_print(&dictionary);
lz78_write_decode(o_fd, &dictionary);
fclose(i_fd);
fclose(o_fd);
return 0;
}
static void get_encoding_profit(const char *input, const char *output)
{
FILE *i_fd, *o_fd;
long input_file_size, output_file_size;
float pack_profit;
i_fd = fopen(input, "r");
if (!i_fd)
{
lz78_trace("failed to open '%s'", input);
return;
}
o_fd = fopen(output, "r");
if (!o_fd)
{
lz78_trace("failed to open '%s'", output);
fclose(i_fd);
return;
}
fseek(i_fd, 0L, SEEK_END);
input_file_size = ftell(i_fd);
fseek(o_fd, 0L, SEEK_END);
output_file_size = ftell(o_fd);
pack_profit = 100 - (float)output_file_size/(float)input_file_size * 100;
lz78_trace("input file size: %ld", input_file_size);
lz78_trace("output file size: %ld", output_file_size);
lz78_trace("pack profit: %.2f", pack_profit);
fclose(i_fd);
fclose(o_fd);
}
