2 * xzlib.c: front end for the transparent suport of lzma compression
3 * at the I/O layer, based on an example file from lzma project
5 * See Copyright for the status of this software.
7 * Anders F Bjorklund <afb@users.sourceforge.net>
19 #ifdef HAVE_SYS_TYPES_H
20 #include <sys/types.h>
22 #ifdef HAVE_SYS_STAT_H
40 #include <libxml/xmlmemory.h>
42 /* values for xz_state how */
43 #define LOOK 0 /* look for a gzip/lzma header */
44 #define COPY 1 /* copy input directly */
45 #define GZIP 2 /* decompress a gzip stream */
46 #define LZMA 3 /* decompress a lzma stream */
48 /* internal lzma file state data structure */
50 int mode; /* see lzma modes above */
51 int fd; /* file descriptor */
52 char *path; /* path or fd for error messages */
53 uint64_t pos; /* current position in uncompressed data */
54 unsigned int size; /* buffer size, zero if not allocated yet */
55 unsigned int want; /* requested buffer size, default is BUFSIZ */
56 unsigned char *in; /* input buffer */
57 unsigned char *out; /* output buffer (double-sized when reading) */
58 unsigned char *next; /* next output data to deliver or write */
59 unsigned int have; /* amount of output data unused at next */
60 int eof; /* true if end of input file reached */
61 uint64_t start; /* where the lzma data started, for rewinding */
62 uint64_t raw; /* where the raw data started, for seeking */
63 int how; /* 0: get header, 1: copy, 2: decompress */
64 int direct; /* true if last read direct, false if lzma */
66 uint64_t skip; /* amount to skip (already rewound if backwards) */
67 int seek; /* true if seek request pending */
68 /* error information */
69 int err; /* error code */
70 char *msg; /* error message */
72 int init; /* is the iniflate stream initialized */
73 lzma_stream strm; /* stream structure in-place (not a pointer) */
74 char padding1[32]; /* padding allowing to cope with possible
75 extensions of above structure without
76 too much side effect */
78 /* zlib inflate or deflate stream */
79 z_stream zstrm; /* stream structure in-place (not a pointer) */
81 char padding2[32]; /* padding allowing to cope with possible
82 extensions of above structure without
83 too much side effect */
84 } xz_state, *xz_statep;
87 xz_error(xz_statep state, int err, const char *msg)
89 /* free previously allocated message and clear */
90 if (state->msg != NULL) {
91 if (state->err != LZMA_MEM_ERROR)
96 /* set error code, and if no message, then done */
101 /* for an out of memory error, save as static string */
102 if (err == LZMA_MEM_ERROR) {
103 state->msg = (char *) msg;
107 /* construct error message with path */
109 xmlMalloc(strlen(state->path) + strlen(msg) + 3)) == NULL) {
110 state->err = LZMA_MEM_ERROR;
111 state->msg = (char *) "out of memory";
114 strcpy(state->msg, state->path);
115 strcat(state->msg, ": ");
116 strcat(state->msg, msg);
121 xz_reset(xz_statep state)
123 state->have = 0; /* no output data available */
124 state->eof = 0; /* not at end of file */
125 state->how = LOOK; /* look for gzip header */
126 state->direct = 1; /* default for empty file */
127 state->seek = 0; /* no seek request pending */
128 xz_error(state, LZMA_OK, NULL); /* clear error */
129 state->pos = 0; /* no uncompressed data yet */
130 state->strm.avail_in = 0; /* no input data yet */
132 state->zstrm.avail_in = 0; /* no input data yet */
137 xz_open(const char *path, int fd, const char *mode ATTRIBUTE_UNUSED)
141 /* allocate xzFile structure to return */
142 state = xmlMalloc(sizeof(xz_state));
145 state->size = 0; /* no buffers allocated yet */
146 state->want = BUFSIZ; /* requested buffer size */
147 state->msg = NULL; /* no error message yet */
148 state->init = 0; /* initialization of zlib data */
150 /* save the path name for error messages */
151 state->path = xmlMalloc(strlen(path) + 1);
152 if (state->path == NULL) {
156 strcpy(state->path, path);
158 /* open the file with the appropriate mode (or just use fd) */
159 state->fd = fd != -1 ? fd : open(path,
167 if (state->fd == -1) {
168 xmlFree(state->path);
173 /* save the current position for rewinding (only if reading) */
174 state->start = lseek(state->fd, 0, SEEK_CUR);
175 if (state->start == (uint64_t) - 1)
178 /* initialize stream */
182 return (xzFile) state;
186 __libxml2_xzopen(const char *path, const char *mode)
188 return xz_open(path, -1, mode);
192 __libxml2_xzdopen(int fd, const char *mode)
194 char *path; /* identifier for error messages */
197 if (fd == -1 || (path = xmlMalloc(7 + 3 * sizeof(int))) == NULL)
199 sprintf(path, "<fd:%d>", fd); /* for debugging */
200 xz = xz_open(path, fd, mode);
206 xz_load(xz_statep state, unsigned char *buf, unsigned int len,
213 ret = read(state->fd, buf + *have, len - *have);
217 } while (*have < len);
219 xz_error(state, -1, strerror(errno));
228 xz_avail(xz_statep state)
230 lzma_stream *strm = &(state->strm);
232 if (state->err != LZMA_OK)
234 if (state->eof == 0) {
235 /* avail_in is size_t, which is not necessary sizeof(unsigned) */
236 unsigned tmp = strm->avail_in;
238 if (xz_load(state, state->in, state->size, &tmp) == -1) {
239 strm->avail_in = tmp;
242 strm->avail_in = tmp;
243 strm->next_in = state->in;
249 is_format_xz(xz_statep state)
251 lzma_stream *strm = &(state->strm);
253 return strm->avail_in >= 6 && memcmp(state->in, "\3757zXZ", 6) == 0;
257 is_format_lzma(xz_statep state)
259 lzma_stream *strm = &(state->strm);
262 lzma_options_lzma *opt;
264 uint64_t uncompressed_size;
267 if (strm->avail_in < 13)
270 filter.id = LZMA_FILTER_LZMA1;
271 if (lzma_properties_decode(&filter, NULL, state->in, 5) != LZMA_OK)
274 opt = filter.options;
275 dict_size = opt->dict_size;
276 free(opt); /* we can't use xmlFree on a string returned by zlib */
278 /* A hack to ditch tons of false positives: We allow only dictionary
279 * sizes that are 2^n or 2^n + 2^(n-1) or UINT32_MAX. LZMA_Alone
280 * created only files with 2^n, but accepts any dictionary size.
281 * If someone complains, this will be reconsidered.
283 if (dict_size != UINT32_MAX) {
284 uint32_t d = dict_size - 1;
292 if (d != dict_size || dict_size == 0)
296 /* Another hack to ditch false positives: Assume that if the
297 * uncompressed size is known, it must be less than 256 GiB.
298 * Again, if someone complains, this will be reconsidered.
300 uncompressed_size = 0;
301 for (i = 0; i < 8; ++i)
302 uncompressed_size |= (uint64_t) (state->in[5 + i]) << (i * 8);
304 if (uncompressed_size != UINT64_MAX
305 && uncompressed_size > (UINT64_C(1) << 38))
313 /* Get next byte from input, or -1 if end or error. */
314 #define NEXT() ((strm->avail_in == 0 && xz_avail(state) == -1) ? -1 : \
315 (strm->avail_in == 0 ? -1 : \
316 (strm->avail_in--, *(strm->next_in)++)))
318 /* Get a four-byte little-endian integer and return 0 on success and the value
319 in *ret. Otherwise -1 is returned and *ret is not modified. */
321 gz_next4(xz_statep state, unsigned long *ret)
325 z_streamp strm = &(state->zstrm);
328 val += (unsigned) NEXT() << 8;
329 val += (unsigned long) NEXT() << 16;
333 val += (unsigned long) ch << 24;
340 xz_head(xz_statep state)
342 lzma_stream *strm = &(state->strm);
343 lzma_stream init = LZMA_STREAM_INIT;
347 /* allocate read buffers and inflate memory */
348 if (state->size == 0) {
349 /* allocate buffers */
350 state->in = xmlMalloc(state->want);
351 state->out = xmlMalloc(state->want << 1);
352 if (state->in == NULL || state->out == NULL) {
353 if (state->out != NULL)
355 if (state->in != NULL)
357 xz_error(state, LZMA_MEM_ERROR, "out of memory");
360 state->size = state->want;
362 /* allocate decoder memory */
364 state->strm.avail_in = 0;
365 state->strm.next_in = NULL;
366 if (lzma_auto_decoder(&state->strm, UINT64_MAX, 0) != LZMA_OK) {
370 xz_error(state, LZMA_MEM_ERROR, "out of memory");
374 /* allocate inflate memory */
375 state->zstrm.zalloc = Z_NULL;
376 state->zstrm.zfree = Z_NULL;
377 state->zstrm.opaque = Z_NULL;
378 state->zstrm.avail_in = 0;
379 state->zstrm.next_in = Z_NULL;
380 if (state->init == 0) {
381 if (inflateInit2(&(state->zstrm), -15) != Z_OK) {/* raw inflate */
385 xz_error(state, LZMA_MEM_ERROR, "out of memory");
393 /* get some data in the input buffer */
394 if (strm->avail_in == 0) {
395 if (xz_avail(state) == -1)
397 if (strm->avail_in == 0)
401 /* look for the xz magic header bytes */
402 if (is_format_xz(state) || is_format_lzma(state)) {
408 /* look for the gzip magic header bytes 31 and 139 */
409 if (strm->next_in[0] == 31) {
412 if (strm->avail_in == 0 && xz_avail(state) == -1)
414 if (strm->avail_in && strm->next_in[0] == 139) {
415 /* we have a gzip header, woo hoo! */
419 /* skip rest of header */
420 if (NEXT() != 8) { /* compression method */
421 xz_error(state, LZMA_DATA_ERROR,
422 "unknown compression method");
426 if (flags & 0xe0) { /* reserved flag bits */
427 xz_error(state, LZMA_DATA_ERROR,
428 "unknown header flags set");
431 NEXT(); /* modification time */
435 NEXT(); /* extra flags */
436 NEXT(); /* operating system */
437 if (flags & 4) { /* extra field */
438 len = (unsigned) NEXT();
439 len += (unsigned) NEXT() << 8;
444 if (flags & 8) /* file name */
446 if (flags & 16) /* comment */
448 if (flags & 2) { /* header crc */
452 /* an unexpected end of file is not checked for here -- it will be
453 * noticed on the first request for uncompressed data */
455 /* set up for decompression */
456 inflateReset(&state->zstrm);
457 state->zstrm.adler = crc32(0L, Z_NULL, 0);
462 /* not a gzip file -- save first byte (31) and fall to raw i/o */
469 /* doing raw i/o, save start of raw data for seeking, copy any leftover
470 * input to output -- this assumes that the output buffer is larger than
471 * the input buffer, which also assures space for gzungetc() */
472 state->raw = state->pos;
473 state->next = state->out;
474 if (strm->avail_in) {
475 memcpy(state->next + state->have, strm->next_in, strm->avail_in);
476 state->have += strm->avail_in;
485 xz_decomp(xz_statep state)
489 unsigned long crc, len;
490 lzma_stream *strm = &(state->strm);
492 lzma_action action = LZMA_RUN;
494 /* fill output buffer up to end of deflate stream */
495 had = strm->avail_out;
497 /* get more input for inflate() */
498 if (strm->avail_in == 0 && xz_avail(state) == -1)
500 if (strm->avail_in == 0) {
501 xz_error(state, LZMA_DATA_ERROR, "unexpected end of file");
505 action = LZMA_FINISH;
507 /* decompress and handle errors */
509 if (state->how == GZIP) {
510 state->zstrm.avail_in = (uInt) state->strm.avail_in;
511 state->zstrm.next_in = (Bytef *) state->strm.next_in;
512 state->zstrm.avail_out = (uInt) state->strm.avail_out;
513 state->zstrm.next_out = (Bytef *) state->strm.next_out;
514 ret = inflate(&state->zstrm, Z_NO_FLUSH);
515 if (ret == Z_STREAM_ERROR || ret == Z_NEED_DICT) {
516 xz_error(state, Z_STREAM_ERROR,
517 "internal error: inflate stream corrupt");
520 if (ret == Z_MEM_ERROR)
521 ret = LZMA_MEM_ERROR;
522 if (ret == Z_DATA_ERROR)
523 ret = LZMA_DATA_ERROR;
524 if (ret == Z_STREAM_END)
525 ret = LZMA_STREAM_END;
526 state->strm.avail_in = state->zstrm.avail_in;
527 state->strm.next_in = state->zstrm.next_in;
528 state->strm.avail_out = state->zstrm.avail_out;
529 state->strm.next_out = state->zstrm.next_out;
530 } else /* state->how == LZMA */
532 ret = lzma_code(strm, action);
533 if (ret == LZMA_MEM_ERROR) {
534 xz_error(state, LZMA_MEM_ERROR, "out of memory");
537 if (ret == LZMA_DATA_ERROR) {
538 xz_error(state, LZMA_DATA_ERROR, "compressed data error");
541 } while (strm->avail_out && ret != LZMA_STREAM_END);
543 /* update available output and crc check value */
544 state->have = had - strm->avail_out;
545 state->next = strm->next_out - state->have;
548 crc32(state->zstrm.adler, state->next, state->have);
551 if (ret == LZMA_STREAM_END) {
553 if (state->how == GZIP) {
554 if (gz_next4(state, &crc) == -1 || gz_next4(state, &len) == -1) {
555 xz_error(state, LZMA_DATA_ERROR, "unexpected end of file");
558 if (crc != state->zstrm.adler) {
559 xz_error(state, LZMA_DATA_ERROR, "incorrect data check");
562 if (len != (state->zstrm.total_out & 0xffffffffL)) {
563 xz_error(state, LZMA_DATA_ERROR, "incorrect length check");
566 state->strm.avail_in = 0;
567 state->strm.next_in = NULL;
568 state->strm.avail_out = 0;
569 state->strm.next_out = NULL;
572 if (strm->avail_in != 0 || !state->eof) {
573 xz_error(state, LZMA_DATA_ERROR, "trailing garbage");
576 state->how = LOOK; /* ready for next stream, once have is 0 (leave
577 * state->direct unchanged to remember how) */
580 /* good decompression */
585 xz_make(xz_statep state)
587 lzma_stream *strm = &(state->strm);
589 if (state->how == LOOK) { /* look for lzma / gzip header */
590 if (xz_head(state) == -1)
592 if (state->have) /* got some data from xz_head() */
595 if (state->how == COPY) { /* straight copy */
596 if (xz_load(state, state->out, state->size << 1, &(state->have)) ==
599 state->next = state->out;
600 } else if (state->how == LZMA || state->how == GZIP) { /* decompress */
601 strm->avail_out = state->size << 1;
602 strm->next_out = state->out;
603 if (xz_decomp(state) == -1)
610 xz_skip(xz_statep state, uint64_t len)
614 /* skip over len bytes or reach end-of-file, whichever comes first */
616 /* skip over whatever is in output buffer */
618 n = (uint64_t) state->have > len ?
619 (unsigned) len : state->have;
626 /* output buffer empty -- return if we're at the end of the input */
627 else if (state->eof && state->strm.avail_in == 0)
630 /* need more data to skip -- load up output buffer */
632 /* get more output, looking for header if required */
633 if (xz_make(state) == -1)
640 __libxml2_xzread(xzFile file, void *buf, unsigned len)
646 /* get internal structure */
649 state = (xz_statep) file;
650 strm = &(state->strm);
652 /* check that we're reading and that there's no error */
653 if (state->err != LZMA_OK)
656 /* since an int is returned, make sure len fits in one, otherwise return
657 * with an error (this avoids the flaw in the interface) */
659 xz_error(state, LZMA_BUF_ERROR,
660 "requested length does not fit in int");
664 /* if len is zero, avoid unnecessary operations */
668 /* process a skip request */
671 if (xz_skip(state, state->skip) == -1)
675 /* get len bytes to buf, or less than len if at the end */
678 /* first just try copying data from the output buffer */
680 n = state->have > len ? len : state->have;
681 memcpy(buf, state->next, n);
686 /* output buffer empty -- return if we're at the end of the input */
687 else if (state->eof && strm->avail_in == 0)
690 /* need output data -- for small len or new stream load up our output
692 else if (state->how == LOOK || len < (state->size << 1)) {
693 /* get more output, looking for header if required */
694 if (xz_make(state) == -1)
696 continue; /* no progress yet -- go back to memcpy() above */
697 /* the copy above assures that we will leave with space in the
698 * output buffer, allowing at least one gzungetc() to succeed */
701 /* large len -- read directly into user buffer */
702 else if (state->how == COPY) { /* read directly */
703 if (xz_load(state, buf, len, &n) == -1)
707 /* large len -- decompress directly into user buffer */
708 else { /* state->how == LZMA */
709 strm->avail_out = len;
710 strm->next_out = buf;
711 if (xz_decomp(state) == -1)
717 /* update progress */
719 buf = (char *) buf + n;
724 /* return number of bytes read into user buffer (will fit in int) */
729 __libxml2_xzclose(xzFile file)
734 /* get internal structure */
736 return LZMA_DATA_ERROR;
737 state = (xz_statep) file;
739 /* free memory and close file */
741 lzma_end(&(state->strm));
743 if (state->init == 1)
744 inflateEnd(&(state->zstrm));
750 xmlFree(state->path);
751 ret = close(state->fd);
753 return ret ? ret : LZMA_OK;
755 #endif /* HAVE_LZMA_H */