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/******************************************************************************
* swcomprs.cpp - code for class 'SWCompress'- a driver class that provides
* compression utilities.
*/
#include <string.h>
#include <stdlib.h>
#include <swcomprs.h>
SWORD_NAMESPACE_START
/******************************************************************************
* SWCompress Constructor - Initializes data for instance of SWCompress
*
*/
SWCompress::SWCompress()
{
buf = zbuf = 0;
Init();
}
/******************************************************************************
* SWCompress Destructor - Cleans up instance of SWCompress
*/
SWCompress::~SWCompress()
{
if (zbuf)
free(zbuf);
if (buf)
free(buf);
}
void SWCompress::Init()
{
if (buf)
free(buf);
if (zbuf)
free(zbuf);
buf = 0;
zbuf = 0;
direct = 0;
zlen = 0;
slen = 0;
zpos = 0;
pos = 0;
}
char *SWCompress::Buf(const char *ibuf, unsigned long *len) {
// setting an uncompressed buffer
if (ibuf) {
Init();
slen = (len) ? *len : strlen(ibuf);
buf = (char *) calloc(slen + 1, 1);
memcpy(buf, ibuf, slen);
}
// getting an uncompressed buffer
if (!buf) {
buf = (char *)calloc(1,1); // be sure we at least allocate an empty buf for return;
direct = 1;
Decode();
// slen = strlen(buf);
if (len)
*len = slen;
}
return buf;
}
char *SWCompress::zBuf(unsigned long *len, char *ibuf)
{
// setting a compressed buffer
if (ibuf) {
Init();
zbuf = (char *) malloc(*len);
memcpy(zbuf, ibuf, *len);
zlen = *len;
}
// getting a compressed buffer
if (!zbuf) {
direct = 0;
Encode();
}
*len = zlen;
return zbuf;
}
unsigned long SWCompress::GetChars(char *ibuf, unsigned long len)
{
if (direct) {
len = (((zlen - zpos) > (unsigned)len) ? len : zlen - zpos);
if (len > 0) {
memmove(ibuf, &zbuf[zpos], len);
zpos += len;
}
}
else {
// slen = strlen(buf);
len = (((slen - pos) > (unsigned)len) ? len : slen - pos);
if (len > 0) {
memmove(ibuf, &buf[pos], len);
pos += len;
}
}
return len;
}
unsigned long SWCompress::SendChars(char *ibuf, unsigned long len)
{
if (direct) {
if (buf) {
// slen = strlen(buf);
if ((pos + len) > (unsigned)slen) {
buf = (char *) realloc(buf, pos + len + 1024);
memset(&buf[pos], 0, len + 1024);
}
}
else buf = (char *)calloc(1, len + 1024);
memmove(&buf[pos], ibuf, len);
pos += len;
}
else {
if (zbuf) {
if ((zpos + len) > zlen) {
zbuf = (char *) realloc(zbuf, zpos + len + 1024);
zlen = zpos + len + 1024;
}
}
else {
zbuf = (char *)calloc(1, len + 1024);
zlen = len + 1024;
}
memmove(&zbuf[zpos], ibuf, len);
zpos += len;
}
return len;
}
/******************************************************************************
* SWCompress::Encode - This function "encodes" the input stream into the
* output stream.
* The GetChars() and SendChars() functions are
* used to separate this method from the actual
* i/o.
*/
void SWCompress::Encode(void)
{
cycleStream();
}
/******************************************************************************
* SWCompress::Decode - This function "decodes" the input stream into the
* output stream.
* The GetChars() and SendChars() functions are
* used to separate this method from the actual
* i/o.
*/
void SWCompress::Decode(void)
{
cycleStream();
}
void SWCompress::cycleStream() {
char buf[1024];
unsigned long len, totlen = 0;
do {
len = GetChars(buf, 1024);
if (len)
totlen += SendChars(buf, len);
} while (len == 1024);
zlen = slen = totlen;
}
SWORD_NAMESPACE_END
|
