release/src-rt-6.x.4708/router/libxml2/xzlib.c

   1 /**
   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
   4  *
   5  * See Copyright for the status of this software.
   6  *
   7  * Anders F Bjorklund <afb@users.sourceforge.net>
   8  */
   9 #define IN_LIBXML
  10 #include "libxml.h"
  11 #ifdef HAVE_LZMA_H
  12
  13 #include <string.h>
  14 #ifdef HAVE_ERRNO_H
  15 #include <errno.h>
  16 #endif
  17
  18
  19 #ifdef HAVE_SYS_TYPES_H
  20 #include <sys/types.h>
  21 #endif
  22 #ifdef HAVE_SYS_STAT_H
  23 #include <sys/stat.h>
  24 #endif
  25 #ifdef HAVE_FCNTL_H
  26 #include <fcntl.h>
  27 #endif
  28 #ifdef HAVE_UNISTD_H
  29 #include <unistd.h>
  30 #endif
  31 #ifdef HAVE_STDLIB_H
  32 #include <stdlib.h>
  33 #endif
  34 #ifdef HAVE_ZLIB_H
  35 #include <zlib.h>
  36 #endif
  37 #include <lzma.h>
  38
  39 #include "xzlib.h"
  40 #include <libxml/xmlmemory.h>
  41
  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 */
  47
  48 /* internal lzma file state data structure */
  49 typedef struct {
  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 */
  65     /* seek request */
  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 */
  71     /* lzma stream */
  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 */
  77 #ifdef HAVE_ZLIB_H
  78     /* zlib inflate or deflate stream */
  79     z_stream zstrm;             /* stream structure in-place (not a pointer) */
  80 #endif
  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;
  85
  86 static void
  87 xz_error(xz_statep state, int err, const char *msg)
  88 {
  89     /* free previously allocated message and clear */
  90     if (state->msg != NULL) {
  91         if (state->err != LZMA_MEM_ERROR)
  92             xmlFree(state->msg);
  93         state->msg = NULL;
  94     }
  95
  96     /* set error code, and if no message, then done */
  97     state->err = err;
  98     if (msg == NULL)
  99         return;
 100
 101     /* for an out of memory error, save as static string */
 102     if (err == LZMA_MEM_ERROR) {
 103         state->msg = (char *) msg;
 104         return;
 105     }
 106
 107     /* construct error message with path */
 108     if ((state->msg =
 109          xmlMalloc(strlen(state->path) + strlen(msg) + 3)) == NULL) {
 110         state->err = LZMA_MEM_ERROR;
 111         state->msg = (char *) "out of memory";
 112         return;
 113     }
 114     strcpy(state->msg, state->path);
 115     strcat(state->msg, ": ");
 116     strcat(state->msg, msg);
 117     return;
 118 }
 119
 120 static void
 121 xz_reset(xz_statep state)
 122 {
 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 */
 131 #ifdef HAVE_ZLIB_H
 132     state->zstrm.avail_in = 0;  /* no input data yet */
 133 #endif
 134 }
 135
 136 static xzFile
 137 xz_open(const char *path, int fd, const char *mode ATTRIBUTE_UNUSED)
 138 {
 139     xz_statep state;
 140
 141     /* allocate xzFile structure to return */
 142     state = xmlMalloc(sizeof(xz_state));
 143     if (state == NULL)
 144         return NULL;
 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 */
 149
 150     /* save the path name for error messages */
 151     state->path = xmlMalloc(strlen(path) + 1);
 152     if (state->path == NULL) {
 153         xmlFree(state);
 154         return NULL;
 155     }
 156     strcpy(state->path, path);
 157
 158     /* open the file with the appropriate mode (or just use fd) */
 159     state->fd = fd != -1 ? fd : open(path,
 160 #ifdef O_LARGEFILE
 161                                      O_LARGEFILE |
 162 #endif
 163 #ifdef O_BINARY
 164                                      O_BINARY |
 165 #endif
 166                                      O_RDONLY, 0666);
 167     if (state->fd == -1) {
 168         xmlFree(state->path);
 169         xmlFree(state);
 170         return NULL;
 171     }
 172
 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)
 176         state->start = 0;
 177
 178     /* initialize stream */
 179     xz_reset(state);
 180
 181     /* return stream */
 182     return (xzFile) state;
 183 }
 184
 185 xzFile
 186 __libxml2_xzopen(const char *path, const char *mode)
 187 {
 188     return xz_open(path, -1, mode);
 189 }
 190
 191 xzFile
 192 __libxml2_xzdopen(int fd, const char *mode)
 193 {
 194     char *path;                 /* identifier for error messages */
 195     xzFile xz;
 196
 197     if (fd == -1 || (path = xmlMalloc(7 + 3 * sizeof(int))) == NULL)
 198         return NULL;
 199     sprintf(path, "<fd:%d>", fd);       /* for debugging */
 200     xz = xz_open(path, fd, mode);
 201     xmlFree(path);
 202     return xz;
 203 }
 204
 205 static int
 206 xz_load(xz_statep state, unsigned char *buf, unsigned int len,
 207         unsigned int *have)
 208 {
 209     int ret;
 210
 211     *have = 0;
 212     do {
 213         ret = read(state->fd, buf + *have, len - *have);
 214         if (ret <= 0)
 215             break;
 216         *have += ret;
 217     } while (*have < len);
 218     if (ret < 0) {
 219         xz_error(state, -1, strerror(errno));
 220         return -1;
 221     }
 222     if (ret == 0)
 223         state->eof = 1;
 224     return 0;
 225 }
 226
 227 static int
 228 xz_avail(xz_statep state)
 229 {
 230     lzma_stream *strm = &(state->strm);
 231
 232     if (state->err != LZMA_OK)
 233         return -1;
 234     if (state->eof == 0) {
 235         /* avail_in is size_t, which is not necessary sizeof(unsigned) */
 236         unsigned tmp = strm->avail_in;
 237
 238         if (xz_load(state, state->in, state->size, &tmp) == -1) {
 239             strm->avail_in = tmp;
 240             return -1;
 241         }
 242         strm->avail_in = tmp;
 243         strm->next_in = state->in;
 244     }
 245     return 0;
 246 }
 247
 248 static int
 249 is_format_xz(xz_statep state)
 250 {
 251     lzma_stream *strm = &(state->strm);
 252
 253     return strm->avail_in >= 6 && memcmp(state->in, "\3757zXZ", 6) == 0;
 254 }
 255
 256 static int
 257 is_format_lzma(xz_statep state)
 258 {
 259     lzma_stream *strm = &(state->strm);
 260
 261     lzma_filter filter;
 262     lzma_options_lzma *opt;
 263     uint32_t dict_size;
 264     uint64_t uncompressed_size;
 265     size_t i;
 266
 267     if (strm->avail_in < 13)
 268         return 0;
 269
 270     filter.id = LZMA_FILTER_LZMA1;
 271     if (lzma_properties_decode(&filter, NULL, state->in, 5) != LZMA_OK)
 272         return 0;
 273
 274     opt = filter.options;
 275     dict_size = opt->dict_size;
 276     free(opt); /* we can't use xmlFree on a string returned by zlib */
 277
 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.
 282      */
 283     if (dict_size != UINT32_MAX) {
 284         uint32_t d = dict_size - 1;
 285
 286         d |= d >> 2;
 287         d |= d >> 3;
 288         d |= d >> 4;
 289         d |= d >> 8;
 290         d |= d >> 16;
 291         ++d;
 292         if (d != dict_size || dict_size == 0)
 293             return 0;
 294     }
 295
 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.
 299      */
 300     uncompressed_size = 0;
 301     for (i = 0; i < 8; ++i)
 302         uncompressed_size |= (uint64_t) (state->in[5 + i]) << (i * 8);
 303
 304     if (uncompressed_size != UINT64_MAX
 305         && uncompressed_size > (UINT64_C(1) << 38))
 306         return 0;
 307
 308     return 1;
 309 }
 310
 311 #ifdef HAVE_ZLIB_H
 312
 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)++)))
 317
 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. */
 320 static int
 321 gz_next4(xz_statep state, unsigned long *ret)
 322 {
 323     int ch;
 324     unsigned long val;
 325     z_streamp strm = &(state->zstrm);
 326
 327     val = NEXT();
 328     val += (unsigned) NEXT() << 8;
 329     val += (unsigned long) NEXT() << 16;
 330     ch = NEXT();
 331     if (ch == -1)
 332         return -1;
 333     val += (unsigned long) ch << 24;
 334     *ret = val;
 335     return 0;
 336 }
 337 #endif
 338
 339 static int
 340 xz_head(xz_statep state)
 341 {
 342     lzma_stream *strm = &(state->strm);
 343     lzma_stream init = LZMA_STREAM_INIT;
 344     int flags;
 345     unsigned len;
 346
 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)
 354                 xmlFree(state->out);
 355             if (state->in != NULL)
 356                 xmlFree(state->in);
 357             xz_error(state, LZMA_MEM_ERROR, "out of memory");
 358             return -1;
 359         }
 360         state->size = state->want;
 361
 362         /* allocate decoder memory */
 363         state->strm = init;
 364         state->strm.avail_in = 0;
 365         state->strm.next_in = NULL;
 366         if (lzma_auto_decoder(&state->strm, UINT64_MAX, 0) != LZMA_OK) {
 367             xmlFree(state->out);
 368             xmlFree(state->in);
 369             state->size = 0;
 370             xz_error(state, LZMA_MEM_ERROR, "out of memory");
 371             return -1;
 372         }
 373 #ifdef HAVE_ZLIB_H
 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 */
 382                 xmlFree(state->out);
 383                 xmlFree(state->in);
 384                 state->size = 0;
 385                 xz_error(state, LZMA_MEM_ERROR, "out of memory");
 386                 return -1;
 387             }
 388             state->init = 1;
 389         }
 390 #endif
 391     }
 392
 393     /* get some data in the input buffer */
 394     if (strm->avail_in == 0) {
 395         if (xz_avail(state) == -1)
 396             return -1;
 397         if (strm->avail_in == 0)
 398             return 0;
 399     }
 400
 401     /* look for the xz magic header bytes */
 402     if (is_format_xz(state) || is_format_lzma(state)) {
 403         state->how = LZMA;
 404         state->direct = 0;
 405         return 0;
 406     }
 407 #ifdef HAVE_ZLIB_H
 408     /* look for the gzip magic header bytes 31 and 139 */
 409     if (strm->next_in[0] == 31) {
 410         strm->avail_in--;
 411         strm->next_in++;
 412         if (strm->avail_in == 0 && xz_avail(state) == -1)
 413             return -1;
 414         if (strm->avail_in && strm->next_in[0] == 139) {
 415             /* we have a gzip header, woo hoo! */
 416             strm->avail_in--;
 417             strm->next_in++;
 418
 419             /* skip rest of header */
 420             if (NEXT() != 8) {  /* compression method */
 421                 xz_error(state, LZMA_DATA_ERROR,
 422                          "unknown compression method");
 423                 return -1;
 424             }
 425             flags = NEXT();
 426             if (flags & 0xe0) { /* reserved flag bits */
 427                 xz_error(state, LZMA_DATA_ERROR,
 428                          "unknown header flags set");
 429                 return -1;
 430             }
 431             NEXT();             /* modification time */
 432             NEXT();
 433             NEXT();
 434             NEXT();
 435             NEXT();             /* extra flags */
 436             NEXT();             /* operating system */
 437             if (flags & 4) {    /* extra field */
 438                 len = (unsigned) NEXT();
 439                 len += (unsigned) NEXT() << 8;
 440                 while (len--)
 441                     if (NEXT() < 0)
 442                         break;
 443             }
 444             if (flags & 8)      /* file name */
 445                 while (NEXT() > 0) ;
 446             if (flags & 16)     /* comment */
 447                 while (NEXT() > 0) ;
 448             if (flags & 2) {    /* header crc */
 449                 NEXT();
 450                 NEXT();
 451             }
 452             /* an unexpected end of file is not checked for here -- it will be
 453              * noticed on the first request for uncompressed data */
 454
 455             /* set up for decompression */
 456             inflateReset(&state->zstrm);
 457             state->zstrm.adler = crc32(0L, Z_NULL, 0);
 458             state->how = GZIP;
 459             state->direct = 0;
 460             return 0;
 461         } else {
 462             /* not a gzip file -- save first byte (31) and fall to raw i/o */
 463             state->out[0] = 31;
 464             state->have = 1;
 465         }
 466     }
 467 #endif
 468
 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;
 477         strm->avail_in = 0;
 478     }
 479     state->how = COPY;
 480     state->direct = 1;
 481     return 0;
 482 }
 483
 484 static int
 485 xz_decomp(xz_statep state)
 486 {
 487     int ret;
 488     unsigned had;
 489     unsigned long crc, len;
 490     lzma_stream *strm = &(state->strm);
 491
 492     lzma_action action = LZMA_RUN;
 493
 494     /* fill output buffer up to end of deflate stream */
 495     had = strm->avail_out;
 496     do {
 497         /* get more input for inflate() */
 498         if (strm->avail_in == 0 && xz_avail(state) == -1)
 499             return -1;
 500         if (strm->avail_in == 0) {
 501             xz_error(state, LZMA_DATA_ERROR, "unexpected end of file");
 502             return -1;
 503         }
 504         if (state->eof)
 505             action = LZMA_FINISH;
 506
 507         /* decompress and handle errors */
 508 #ifdef HAVE_ZLIB_H
 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");
 518                 return -1;
 519             }
 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 */
 531 #endif
 532             ret = lzma_code(strm, action);
 533         if (ret == LZMA_MEM_ERROR) {
 534             xz_error(state, LZMA_MEM_ERROR, "out of memory");
 535             return -1;
 536         }
 537         if (ret == LZMA_DATA_ERROR) {
 538             xz_error(state, LZMA_DATA_ERROR, "compressed data error");
 539             return -1;
 540         }
 541     } while (strm->avail_out && ret != LZMA_STREAM_END);
 542
 543     /* update available output and crc check value */
 544     state->have = had - strm->avail_out;
 545     state->next = strm->next_out - state->have;
 546 #ifdef HAVE_ZLIB_H
 547     state->zstrm.adler =
 548         crc32(state->zstrm.adler, state->next, state->have);
 549 #endif
 550
 551     if (ret == LZMA_STREAM_END) {
 552 #ifdef HAVE_ZLIB_H
 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");
 556                 return -1;
 557             }
 558             if (crc != state->zstrm.adler) {
 559                 xz_error(state, LZMA_DATA_ERROR, "incorrect data check");
 560                 return -1;
 561             }
 562             if (len != (state->zstrm.total_out & 0xffffffffL)) {
 563                 xz_error(state, LZMA_DATA_ERROR, "incorrect length check");
 564                 return -1;
 565             }
 566             state->strm.avail_in = 0;
 567             state->strm.next_in = NULL;
 568             state->strm.avail_out = 0;
 569             state->strm.next_out = NULL;
 570         } else
 571 #endif
 572         if (strm->avail_in != 0 || !state->eof) {
 573             xz_error(state, LZMA_DATA_ERROR, "trailing garbage");
 574             return -1;
 575         }
 576         state->how = LOOK;      /* ready for next stream, once have is 0 (leave
 577                                  * state->direct unchanged to remember how) */
 578     }
 579
 580     /* good decompression */
 581     return 0;
 582 }
 583
 584 static int
 585 xz_make(xz_statep state)
 586 {
 587     lzma_stream *strm = &(state->strm);
 588
 589     if (state->how == LOOK) {   /* look for lzma / gzip header */
 590         if (xz_head(state) == -1)
 591             return -1;
 592         if (state->have)        /* got some data from xz_head() */
 593             return 0;
 594     }
 595     if (state->how == COPY) {   /* straight copy */
 596         if (xz_load(state, state->out, state->size << 1, &(state->have)) ==
 597             -1)
 598             return -1;
 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)
 604             return -1;
 605     }
 606     return 0;
 607 }
 608
 609 static int
 610 xz_skip(xz_statep state, uint64_t len)
 611 {
 612     unsigned n;
 613
 614     /* skip over len bytes or reach end-of-file, whichever comes first */
 615     while (len)
 616         /* skip over whatever is in output buffer */
 617         if (state->have) {
 618             n = (uint64_t) state->have > len ?
 619                 (unsigned) len : state->have;
 620             state->have -= n;
 621             state->next += n;
 622             state->pos += n;
 623             len -= n;
 624         }
 625
 626     /* output buffer empty -- return if we're at the end of the input */
 627         else if (state->eof && state->strm.avail_in == 0)
 628             break;
 629
 630     /* need more data to skip -- load up output buffer */
 631         else {
 632             /* get more output, looking for header if required */
 633             if (xz_make(state) == -1)
 634                 return -1;
 635         }
 636     return 0;
 637 }
 638
 639 int
 640 __libxml2_xzread(xzFile file, void *buf, unsigned len)
 641 {
 642     unsigned got, n;
 643     xz_statep state;
 644     lzma_stream *strm;
 645
 646     /* get internal structure */
 647     if (file == NULL)
 648         return -1;
 649     state = (xz_statep) file;
 650     strm = &(state->strm);
 651
 652     /* check that we're reading and that there's no error */
 653     if (state->err != LZMA_OK)
 654         return -1;
 655
 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) */
 658     if ((int) len < 0) {
 659         xz_error(state, LZMA_BUF_ERROR,
 660                  "requested length does not fit in int");
 661         return -1;
 662     }
 663
 664     /* if len is zero, avoid unnecessary operations */
 665     if (len == 0)
 666         return 0;
 667
 668     /* process a skip request */
 669     if (state->seek) {
 670         state->seek = 0;
 671         if (xz_skip(state, state->skip) == -1)
 672             return -1;
 673     }
 674
 675     /* get len bytes to buf, or less than len if at the end */
 676     got = 0;
 677     do {
 678         /* first just try copying data from the output buffer */
 679         if (state->have) {
 680             n = state->have > len ? len : state->have;
 681             memcpy(buf, state->next, n);
 682             state->next += n;
 683             state->have -= n;
 684         }
 685
 686         /* output buffer empty -- return if we're at the end of the input */
 687         else if (state->eof && strm->avail_in == 0)
 688             break;
 689
 690         /* need output data -- for small len or new stream load up our output
 691          * buffer */
 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)
 695                 return -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 */
 699         }
 700
 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)
 704                 return -1;
 705         }
 706
 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)
 712                 return -1;
 713             n = state->have;
 714             state->have = 0;
 715         }
 716
 717         /* update progress */
 718         len -= n;
 719         buf = (char *) buf + n;
 720         got += n;
 721         state->pos += n;
 722     } while (len);
 723
 724     /* return number of bytes read into user buffer (will fit in int) */
 725     return (int) got;
 726 }
 727
 728 int
 729 __libxml2_xzclose(xzFile file)
 730 {
 731     int ret;
 732     xz_statep state;
 733
 734     /* get internal structure */
 735     if (file == NULL)
 736         return LZMA_DATA_ERROR;
 737     state = (xz_statep) file;
 738
 739     /* free memory and close file */
 740     if (state->size) {
 741         lzma_end(&(state->strm));
 742 #ifdef HAVE_ZLIB_H
 743         if (state->init == 1)
 744             inflateEnd(&(state->zstrm));
 745         state->init = 0;
 746 #endif
 747         xmlFree(state->out);
 748         xmlFree(state->in);
 749     }
 750     xmlFree(state->path);
 751     ret = close(state->fd);
 752     xmlFree(state);
 753     return ret ? ret : LZMA_OK;
 754 }
 755 #endif /* HAVE_LZMA_H */