lzss decoding EOF character issue - c

Question

I am using Okamura's implementation of lzss : https://oku.edu.mie-u.ac.jp/~okumura/compression/lzss.c
int enc_i = 0;
int getbit(int n, unsigned char *enco_buf) /* get n bits */
{
int i, x;
static int buf, mask = 0;
x = 0;
for (i = 0; i < n; i++) {
if (mask == 0) {
//if ((buf = fgetc(infile)) == EOF) return EOF;
//if ((buf = fgetc(infile)) == EOF) return EOF;
if((buf = enco_buf[enc_i]) == '\0') break;
//buf = enco_buf[enc_i];
enc_i++;
//printf("\nValue of enc : %d\n", enc_i);
mask = 128;
}
x <<= 1;
if (buf & mask) x++;
mask >>= 1;
}
return x;
}
void decode(unsigned char *enco_buf)
{
int i, j, k, r, c;
outfile = fopen ("test_lib.txt", "wb");
for (i = 0; i < N - F; i++) buffer[i] = ' ';
r = N - F;
while ((c = getbit(1, enco_buf)) != '\0') {
if (c) {
if ((c = getbit(8, enco_buf)) == '\0') break;
fputc(c, outfile);
buffer[r++] = c; r &= (N - 1);
} else {
if ((i = getbit(EI, enco_buf)) == '\0') break;
if ((j = getbit(EJ, enco_buf)) == '\0') break;
for (k = 0; k <= j + 1; k++) {
c = buffer[(i + k) & (N - 1)];
fputc(c, outfile);
buffer[r++] = c; r &= (N - 1);
}
}
}
fclose(outfile);
}
Rather than taking the input from file, I am taking an encoded buffer which I am passing to the function decode() which in-turns passes to getbit(). But it is decoding upto a certain number of bits ie. 43. What I am guessing is I put '\0' instead of EOF (as it was in file end marker) to detect string end. and that might be the problem where break statement is executed finding '\0'. It might not be true but It might be the case. The encoding part has no problem as I verified it with the original code. Can anyone suggest where might be the problem?
EDIT : source code:
/* LZSS encoder-decoder (Haruhiko Okumura; public domain) */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "lzss_lib.h"
#define EI 11 /* typically 10..13 */
#define EJ 4 /* typically 4..5 */
#define P 1 /* If match length <= P then output one character */
#define N (1 << EI) /* buffer size */
#define F ((1 << EJ) + 1) /* lookahead buffer size */
int bit_buffer = 0, bit_mask = 128;
unsigned long codecount = 0, textcount = 0;
unsigned char buffer[N * 2];
int payload_i = 0;
int enc_i = 0;
FILE *infile, *outfile;
void error(void)
{
printf("Output error\n"); exit(1);
}
void putbit1(unsigned char *put_buf0)
{
bit_buffer |= bit_mask;
if ((bit_mask >>= 1) == 0) {
put_buf0[payload_i] = bit_buffer;
payload_i++;
bit_buffer = 0; bit_mask = 128; codecount++;
}
}
void putbit0(unsigned char *put_buf1)
{
if ((bit_mask >>= 1) == 0) {
put_buf1[payload_i] = bit_buffer;
payload_i++;
bit_buffer = 0; bit_mask = 128; codecount++;
}
}
void flush_bit_buffer(unsigned char *flush_bit)
{
if (bit_mask != 128) {
flush_bit[payload_i] = bit_buffer;
codecount++;
}
}
void output1(int c, unsigned char *buf_output1)
{
int mask;
putbit1(buf_output1);
mask = 256;
while (mask >>= 1) {
if (c & mask) putbit1(buf_output1);
else putbit0(buf_output1);
}
}
void output2(int x, int y, unsigned char *buf_output2)
{
int mask;
putbit0(buf_output2);
mask = N;
while (mask >>= 1) {
if (x & mask) putbit1(buf_output2);
else putbit0(buf_output2);
}
mask = (1 << EJ);
while (mask >>= 1) {
if (y & mask) putbit1(buf_output2);
else putbit0(buf_output2);
}
}
void encode(unsigned char *string_buf, unsigned char *out_buf, unsigned long *out_buf_len)
{
int i, j, f1, x, y, r, s, bufferend, c, tt;
tt = 0;
for (i = 0; i < N - F; i++) buffer[i] = ' ';
for (i = N - F; i < N * 2; i++) {
if((c = string_buf[tt]) == '\0') break;
buffer[i] = c; textcount++; tt++;
}
bufferend = i; r = N - F; s = 0;
while (r < bufferend) {
f1 = (F <= bufferend - r) ? F : bufferend - r;
x = 0; y = 1; c = buffer[r];
for (i = r - 1; i >= s; i--)
if (buffer[i] == c) {
for (j = 1; j < f1; j++)
if (buffer[i + j] != buffer[r + j]) break;
if (j > y) {
x = i; y = j;
}
}
if (y <= P) { y = 1; output1(c, out_buf); }
else output2(x & (N - 1), y - 2, out_buf);
r += y; s += y;
if (r >= N * 2 - F) {
for (i = 0; i < N; i++) buffer[i] = buffer[i + N];
bufferend -= N; r -= N; s -= N;
while (bufferend < N * 2) {
if((c = string_buf[tt]) == '\0') break;
buffer[bufferend++] = c; textcount++; tt++;
}
}
}
flush_bit_buffer(out_buf);
*out_buf_len = codecount;
printf("text: %ld bytes\n", textcount);
printf("code: %ld bytes (%ld%%)\n", codecount, (codecount * 100) / textcount);
}
int getbit(int n, unsigned char *enco_buf) /* get n bits */
{
int i, x;
static int buf, mask = 0;
x = 0;
for (i = 0; i < n; i++) {
if (mask == 0) {
//if ((buf = fgetc(infile)) == EOF) return EOF;
//if ((buf = fgetc(infile)) == EOF) return EOF;
if((buf = enco_buf[enc_i]) == '\0') break;
//buf = enco_buf[enc_i];
enc_i++;
printf("\nValue of enc : %d\n", enc_i);
mask = 128;
}
x <<= 1;
if (buf & mask) x++;
mask >>= 1;
}
return x;
}
void decode(unsigned char *enco_buf)
{
int i, j, k, r, c;
outfile = fopen ("test_lib.txt", "wb");
for (i = 0; i < N - F; i++) buffer[i] = ' ';
r = N - F;
while ((c = getbit(1, enco_buf)) != '\0') {
if (c) {
if ((c = getbit(8, enco_buf)) == '\0') break;
fputc(c, outfile);
buffer[r++] = c; r &= (N - 1);
} else {
if ((i = getbit(EI, enco_buf)) == '\0') break;
if ((j = getbit(EJ, enco_buf)) == '\0') break;
for (k = 0; k <= j + 1; k++) {
c = buffer[(i + k) & (N - 1)];
fputc(c, outfile);
buffer[r++] = c; r &= (N - 1);
}
}
}
fclose(outfile);
}
and the test example :
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "lzss_lib.h"
unsigned char compr_data[4096];
unsigned long pw = 0;
unsigned long payload_len = 0;
volatile int errno;
unsigned char *unc_data = "d(2306):AuthorisationScheme:RADIUSserveratfd04:bd3:80e8:1::1usingPAPD/6LoWPANd(2306):WritingModule:SecurityConfigD/6LoWPANd(2306):WritingModule:RunCoordinatorD/6LoWPANd(2306):RequestingmoduleaddressD/6LoWPANd(2306):WritingModule:GetAddressD/smartcard-jni(2781):SmartCard_state_update_callback:status=6D/SmartCardNative(2781):status=6D/smartcard(2781):PN532Smartcard_loop_threadexitD/smartcard-jni(2781):SmartCard_loop_thread:SMARTCARD_STATUS_ABORTD/smartcard(2781):Smartcard_loop_uninitD/smartcard(2781):2D/serialcomm_pn532(2781):PN532:Readingfrom/dev/ttyUSB0-->D/smartcard(2781):Received(0x3)fromPN532:(dataBuf[0]:0x1)(0x1f5988)D/smartcard(2781):ReceivedStatusfromPN532:OK(cmd:0x2)D/smartcard-jni(2781):SmartCard_listener_update_callbackD/smartcard(2781):Received(0x1c2)fromPN532:(dataBuf[0]:0x32)(0x1f5988)D/smartcard(2781):vd(2306):AuthorisationScheme:RADIUSserveratfd04:bd3:80e8:1::1usingPAPD/6LoWPANd(2306):";
FILE *outfile;
int main(void) {
memset (compr_data, '\0', sizeof(compr_data));
encode(unc_data, compr_data, &payload_len);
decode(compr_data);
return 0;
}