#include <stdio.h>
#include <stdlib.h>
#include "mhmt-types.h"
#include "mhmt-globals.h"
#include "mhmt-pack.h"
#include "mhmt-hash.h"
#include "mhmt-tb.h"
#include "mhmt-lz.h"
#include "mhmt-optimal.h"
#include "mhmt-emit.h"
// entry function to pack data
// returns zero if any error
ULONG pack(void)
{
ULONG (*get_lz_price)(OFFSET position, struct lzcode * lzcode) = NULL; // generates correct bitlen (price) of code
ULONG (*emit)(struct optchain * optch, ULONG actual_len) = NULL; // emits lzcode to the output bit/byte stream
ULONG success=1;
ULONG actual_len; // actual length of packing (to account for ZX headers containing last unpacked bytes)
UBYTE * hash;
struct optchain * optch=NULL;
static struct lzcode codes[MAX_CODES_SIZE]; // generate codes here; static to ensure it's not on the stack
UBYTE curr_byte, last_byte;
UWORD index;
OFFSET position;
// some preparations
//
if( wrk.packtype==PK_MLZ )
{
get_lz_price = &get_lz_price_megalz;
emit = &emit_megalz;
}
else if( wrk.packtype==PK_HRM )
{
get_lz_price = &get_lz_price_hrum;
emit = &emit_hrum;
}
else if( wrk.packtype==PK_HST )
{
get_lz_price = &get_lz_price_hrust;
emit = &emit_hrust;
}
else if( wrk.packtype==PK_ZX7 )
{
get_lz_price = &get_lz_price_zx7;
emit = &emit_zx7;
}
else
{
printf("mhmt-pack.c:pack() - format unsupported!\n"); return 0;
}
actual_len = wrk.inlen;
if( wrk.zxheader )
{
if( wrk.packtype==PK_HRM )
{
actual_len -= 5;
}
else if( wrk.packtype==PK_HST )
{
actual_len -= 6;
}
else
{
printf("mhmt-pack.c:pack() - there must be no zxheader for anything except hrust or hrum!\n"); return 0;
}
}
// initializations and preparations
init_tb();
hash = build_hash(wrk.indata, actual_len, wrk.prelen);
if( !hash )
{
printf("mhmt-pack.c:pack() - build_hash() failed!\n"); success = 0;
}
if( success )
{
optch = make_optch(actual_len);
if( !optch )
{
printf("mhmt-pack.c:pack() - can't make optchain array!\n"); success = 0;
}
}
// go packing!
if( success )
{
// fill TBs with prebinary date
if( wrk.prebin )
{
curr_byte=wrk.indata[0LL-wrk.prelen];
//
for(position=(1LL-wrk.prelen);position<=0;position++)
{
last_byte = curr_byte;
curr_byte = wrk.indata[position];
index = (last_byte<<8) + curr_byte;
if( !add_tb(index,position) )
{
printf("mhmt-pack.c:pack() - add_tb() failed!\n"); success = 0;
goto ERROR;
}
}
}
if( !wrk.greedy ) // default optimal coding
{
// go generating lzcodes byte-by-byte
//
curr_byte = wrk.indata[0];
//
for(position=1;position<(OFFSET)actual_len;position++)
{
last_byte = curr_byte;
curr_byte = wrk.indata[position];
// add current two-byter to the chains
index = (last_byte<<8) + curr_byte;
if( !add_tb(index,position) )
{
printf("mhmt-pack.c:pack() - add_tb() failed!\n"); success = 0;
goto ERROR;
}
// search lzcodes for given position
make_lz_codes(position, actual_len, hash, codes);
// update optimal chain with lzcodes
update_optch(position, codes, get_lz_price, optch);
}
// all input bytes scanned, chain built, so now reverse it (prepare for scanning in output generation part)
reverse_optch(optch, actual_len);
}
else // greedy coding
{
printf("mhmt-pack.c:pack() - greedy coding not supported!\n"); success = 0;
}
// data built, now emit packed file
success = success && (*emit)(optch, actual_len);
}
ERROR:
free_optch(optch);
destroy_hash(hash, wrk.prelen);
return success;
}