You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
39 lines
930 B
39 lines
930 B
//
|
|
// defmisc.c
|
|
//
|
|
#include "deflate.h"
|
|
#include <string.h>
|
|
#include <stdio.h>
|
|
#include <crtdbg.h>
|
|
|
|
|
|
//
|
|
// Fix the frequency data of the provided literal and distance trees such that no
|
|
// element has a zero frequency. We must never allow the cumulative frequency of
|
|
// either tree to be >= 65536, so we divide all of the frequencies by two to make
|
|
// sure.
|
|
//
|
|
void NormaliseFrequencies(USHORT *literal_tree_freq, USHORT *dist_tree_freq)
|
|
{
|
|
int i;
|
|
|
|
// don't allow any zero frequency items to exist
|
|
// also make sure we don't overflow 65535 cumulative frequency
|
|
for (i = 0; i < MAX_DIST_TREE_ELEMENTS; i++)
|
|
{
|
|
// avoid overflow
|
|
dist_tree_freq[i] >>= 1;
|
|
|
|
if (dist_tree_freq[i] == 0)
|
|
dist_tree_freq[i] = 1;
|
|
}
|
|
|
|
for (i = 0; i < MAX_LITERAL_TREE_ELEMENTS; i++)
|
|
{
|
|
// avoid overflow
|
|
literal_tree_freq[i] >>= 1;
|
|
|
|
if (literal_tree_freq[i] == 0)
|
|
literal_tree_freq[i] = 1;
|
|
}
|
|
}
|