2 * LZ Decompression functions
4 * Copyright 1996 Marcus Meissner
7 * FIXME: return values might be wrong
15 #include <sys/types.h>
26 #define strdupW2A(x) STRING32_DupUniToAnsi(x)
27 #define strdupA2W(x) STRING32_DupAnsiToUni(x)
28 #define strcpyAW(a,b) STRING32_AnsiToUni(a,b)
30 /* The readahead length of the decompressor. Reading single bytes
31 * using _lread() would be SLOW.
35 /* Format of first 14 byte of LZ compressed file */
42 static BYTE LZMagic[8]={'S','Z','D','D',0x88,0xf0,0x27,0x33};
44 static struct lzstate {
45 HFILE lzfd; /* the handle used by the program */
46 HFILE realfd; /* the real filedescriptor */
47 CHAR lastchar; /* the last char of the filename */
49 DWORD reallength; /* the decompressed length of the file */
50 DWORD realcurrent; /* the position the decompressor currently is */
51 DWORD realwanted; /* the position the user wants to read from */
53 BYTE table[0x1000]; /* the rotating LZ table */
54 UINT curtabent; /* CURrent TABle ENTry */
56 BYTE stringlen; /* length and position of current string */
57 DWORD stringpos; /* from stringtable */
60 WORD bytetype; /* bitmask within blocks */
62 BYTE *get; /* GETLEN bytes */
63 DWORD getcur; /* current read */
64 DWORD getlen; /* length last got */
66 static int nroflzstates=0;
68 /* reads one compressed byte, including buffering */
69 #define GET(lzs,b) _lzget(lzs,&b)
70 #define GET_FLUSH(lzs) lzs->getcur=lzs->getlen;
73 _lzget(struct lzstate *lzs,BYTE *b) {
74 if (lzs->getcur<lzs->getlen) {
75 *b = lzs->get[lzs->getcur++];
78 int ret = FILE_Read(lzs->realfd,lzs->get,GETLEN);
89 /* internal function, reads lzheader
90 * returns BADINHANDLE for non filedescriptors
91 * return 0 for file not compressed using LZ
92 * return UNKNOWNALG for unknown algorithm
93 * returns lzfileheader in *head
96 read_header(HFILE fd,struct lzfileheader *head) {
99 if (_llseek(fd,0,SEEK_SET)==-1)
100 return LZERROR_BADINHANDLE;
102 /* We can't directly read the lzfileheader struct due to
103 * structure element alignment
105 if (FILE_Read(fd,buf,14)<14)
107 memcpy(head->magic,buf,8);
108 memcpy(&(head->compressiontype),buf+8,1);
109 memcpy(&(head->lastchar),buf+9,1);
111 /* FIXME: consider endianess on non-intel architectures */
112 memcpy(&(head->reallength),buf+10,4);
114 if (memcmp(head->magic,LZMagic,8))
116 if (head->compressiontype!='A')
117 return LZERROR_UNKNOWNALG;
121 * LZStart [LZEXPAND.7] [LZ32.6]
125 dprintf_file(stddeb,"LZStart(void)\n");
130 * LZInit [LZEXPAND.3] [LZ32.2]
132 * initializes internal decompression buffers, returns lzfiledescriptor.
133 * (return value the same as hfSrc, if hfSrc is not compressed)
134 * on failure, returns error code <0
135 * lzfiledescriptors range from 0x400 to 0x410 (only 16 open files per process)
136 * we use as much as we need, we just OR 0x400 to the passed HFILE.
138 * since _llseek uses the same types as libc.lseek, we just use the macros of
142 LZInit(HFILE hfSrc) {
143 struct lzfileheader head;
147 dprintf_file(stddeb,"LZInit(%d)\n",hfSrc);
148 ret=read_header(hfSrc,&head);
150 _llseek(hfSrc,0,SEEK_SET);
151 return ret?ret:hfSrc;
153 lzstates=xrealloc(lzstates,(++nroflzstates)*sizeof(struct lzstate));
154 lzs = lzstates+(nroflzstates-1);
156 memset(lzs,'\0',sizeof(*lzs));
158 lzs->lzfd = hfSrc | 0x400;
159 lzs->lastchar = head.lastchar;
160 lzs->reallength = head.reallength;
162 lzs->get = xmalloc(GETLEN);
166 /* Yes, preinitialize with spaces */
167 memset(lzs->table,' ',0x1000);
168 /* Yes, start 16 byte from the END of the table */
169 lzs->curtabent = 0xff0;
174 * LZDone [LZEXPAND.9] [LZ32.8]
179 dprintf_file(stddeb,"LZDone()\n");
183 * GetExpandedName [LZEXPAND.10]
185 * gets the full filename of the compressed file 'in' by opening it
186 * and reading the header
188 * "file." is being translated to "file"
189 * "file.bl_" (with lastchar 'a') is being translated to "file.bla"
190 * "FILE.BL_" (with lastchar 'a') is being translated to "FILE.BLA"
194 GetExpandedName16(LPCSTR in,LPSTR out) {
195 struct lzfileheader head;
198 INT fnislowercased,ret,len;
201 dprintf_file(stddeb,"GetExpandedName(%s)\n",in);
202 fd=OpenFile(in,&ofs,OF_READ);
204 return LZERROR_BADINHANDLE;
205 ret=read_header(fd,&head);
208 return LZERROR_BADINHANDLE;
211 /* This line will crash if the caller hasn't allocated enough memory
216 /* look for directory prefix and skip it. */
218 while (NULL!=(t=strpbrk(s,"/\\:")))
221 /* now mangle the basename */
223 /* FIXME: hmm. shouldn't happen? */
224 fprintf(stddeb,__FILE__":GetExpandedFileName(), specified a directory or what? (%s)\n",in);
228 /* see if we should use lowercase or uppercase on the last char */
236 fnislowercased=islower(*t);
239 if (isalpha(head.lastchar)) {
241 head.lastchar=tolower(head.lastchar);
243 head.lastchar=toupper(head.lastchar);
246 /* now look where to replace the last character */
247 if (NULL!=(t=strchr(s,'.'))) {
253 t[len]=head.lastchar;
255 } /* else no modification necessary */
261 * GetExpandedNameW [LZ32.11]
264 GetExpandedName32W(LPCWSTR in,LPWSTR out) {
268 xout = malloc(lstrlen32W(in)+3);
270 ret = GetExpandedName16(xin,xout);
279 * GetExpandedNameA [LZ32.9]
282 GetExpandedName32A(LPCSTR in,LPSTR out) {
283 return GetExpandedName16(in,out);
287 * LZRead [LZEXPAND.5] [LZ32.4]
288 * just as normal read, but reads from LZ special fd and uncompresses.
291 LZRead16(HFILE fd,SEGPTR segbuf,UINT16 toread) {
292 dprintf_file(stddeb,"LZRead16(%d,%08lx,%d)\n",fd,(DWORD)segbuf,toread);
293 return LZRead32(fd,(LPBYTE)PTR_SEG_TO_LIN(segbuf),toread);
297 LZRead32(HFILE fd,LPVOID vbuf,UINT32 toread) {
303 dprintf_file(stddeb,"LZRead32(%d,%p,%d)\n",fd,buf,toread);
305 for (i=0;i<nroflzstates;i++)
306 if (lzstates[i].lzfd==fd)
309 return FILE_Read(fd,buf,toread);
312 /* The decompressor itself is in a define, cause we need it twice
313 * in this function. (the decompressed byte will be in b)
315 #define DECOMPRESS_ONE_BYTE \
316 if (lzs->stringlen) { \
317 b = lzs->table[lzs->stringpos]; \
318 lzs->stringpos = (lzs->stringpos+1)&0xFFF; \
321 if (!(lzs->bytetype&0x100)) { \
323 return toread-howmuch; \
324 lzs->bytetype = b|0xFF00; \
326 if (lzs->bytetype & 1) { \
328 return toread-howmuch; \
332 if (1!=GET(lzs,b1)) \
333 return toread-howmuch; \
334 if (1!=GET(lzs,b2)) \
335 return toread-howmuch; \
339 * where CAB is the stringoffset in the table\
340 * and D+3 is the len of the string \
342 lzs->stringpos = b1|((b2&0xf0)<<4); \
343 lzs->stringlen = (b2&0xf)+2; \
344 /* 3, but we use a byte already below ... */\
345 b = lzs->table[lzs->stringpos];\
346 lzs->stringpos = (lzs->stringpos+1)&0xFFF;\
350 /* store b in table */ \
351 lzs->table[lzs->curtabent++]= b; \
352 lzs->curtabent &= 0xFFF; \
355 /* if someone has seeked, we have to bring the decompressor
358 if (lzs->realcurrent!=lzs->realwanted) {
359 /* if the wanted position is before the current position
360 * I see no easy way to unroll ... We have to restart at
361 * the beginning. *sigh*
363 if (lzs->realcurrent>lzs->realwanted) {
364 /* flush decompressor state */
365 _llseek(lzs->realfd,14,SEEK_SET);
370 memset(lzs->table,' ',0x1000);
371 lzs->curtabent = 0xFF0;
373 while (lzs->realcurrent<lzs->realwanted) {
385 #undef DECOMPRESS_ONE_BYTE
389 * LZSeek [LZEXPAND.4] [LZ32.3]
391 * works as the usual _llseek
395 LZSeek(HFILE fd,LONG off,INT32 type) {
400 dprintf_file(stddeb,"LZSeek(%d,%ld,%d)\n",fd,off,type);
401 for (i=0;i<nroflzstates;i++)
402 if (lzstates[i].lzfd==fd)
404 /* not compressed? just use normal _llseek() */
406 return _llseek(fd,off,type);
408 newwanted = lzs->realwanted;
410 case 1: /* SEEK_CUR */
413 case 2: /* SEEK_END */
414 newwanted = lzs->reallength-off;
416 default:/* SEEK_SET */
420 if (newwanted>lzs->reallength)
421 return LZERROR_BADVALUE;
423 return LZERROR_BADVALUE;
424 lzs->realwanted = newwanted;
429 * LZCopy [LZEXPAND.1] [LZ32.0]
431 * Copies everything from src to dest
432 * if src is a LZ compressed file, it will be uncompressed.
433 * will return the number of bytes written to dest or errors.
436 LZCopy(HFILE src,HFILE dest) {
441 INT32 (*xread)(HFILE,LPVOID,UINT32);
443 dprintf_file(stddeb,"LZCopy(%d,%d)\n",src,dest);
444 for (i=0;i<nroflzstates;i++)
445 if (src==lzstates[i].lzfd)
448 /* not compressed? just copy */
455 ret=xread(src,buf,BUFLEN);
464 wret = _lwrite(dest,buf,ret);
466 return LZERROR_WRITE;
472 /* reverses GetExpandedPathname */
473 static LPSTR LZEXPAND_MangleName( LPCSTR fn )
476 char *mfn = (char *)xmalloc( strlen(fn) + 3 ); /* "._" and \0 */
478 if (!(p = strrchr( mfn, '\\' ))) p = mfn;
479 if ((p = strchr( p, '.' )))
482 if (strlen(p) < 3) strcat( p, "_" ); /* append '_' */
483 else p[strlen(p)-1] = '_'; /* replace last character */
485 else strcat( mfn, "._" ); /* append "._" */
490 * LZOpenFile [LZEXPAND.2]
491 * Opens a file. If not compressed, open it as a normal file.
494 LZOpenFile16(LPCSTR fn,LPOFSTRUCT ofs,UINT16 mode) {
497 dprintf_file(stddeb,"LZOpenFile(%s,%p,%d)\n",fn,ofs,mode);
498 /* 0x70 represents all OF_SHARE_* flags, ignore them for the check */
499 fd=OpenFile(fn,ofs,mode);
502 LPSTR mfn = LZEXPAND_MangleName(fn);
503 fd = OpenFile(mfn,ofs,mode);
506 if ((mode&~0x70)!=OF_READ)
517 * LZOpenFileA [LZ32.1]
520 LZOpenFile32A(LPCSTR fn,LPOFSTRUCT ofs,UINT32 mode) {
521 return LZOpenFile16(fn,ofs,mode);
525 * LZOpenFileW [LZ32.10]
528 LZOpenFile32W(LPCWSTR fn,LPOFSTRUCT ofs,UINT32 mode) {
534 ret = LZOpenFile16(xfn,ofs,mode);
536 if (ret!=HFILE_ERROR) {
537 /* ofs->szPathName is an array with the OFSTRUCT */
538 yfn = strdupA2W(ofs->szPathName);
539 memcpy(ofs->szPathName,yfn,lstrlen32W(yfn)*2+2);
546 * LZClose [LZEXPAND.6] [LZ32.5]
552 dprintf_file(stddeb,"LZClose(%d)\n",fd);
553 for (i=0;i<nroflzstates;i++)
554 if (lzstates[i].lzfd==fd)
556 if (i==nroflzstates) {
561 free(lzstates[i].get);
562 _lclose(lzstates[i].realfd);
563 memcpy(lzstates+i,lzstates+i+1,sizeof(struct lzstate)*(nroflzstates-i-1));
565 lzstates=xrealloc(lzstates,sizeof(struct lzstate)*nroflzstates);
569 * CopyLZFile [LZEXPAND.8] [LZ32.7]
571 * Copy src to dest (including uncompressing src).
572 * NOTE: Yes. This is exactly the same function as LZCopy.
575 CopyLZFile(HFILE src,HFILE dest) {
576 dprintf_file(stddeb,"CopyLZFile(%d,%d)\n",src,dest);
577 return LZCopy(src,dest);