[libxml2] move xz/lzma helpers to separate included files



commit 6bdc774350d11117849a53f7baf2bb7e26b00009
Author: Anders F Bjorklund <afb users sourceforge net>
Date:   Mon Sep 19 09:53:20 2011 +0200

    move xz/lzma helpers to separate included files

 xmlIO.c |  684 +--------------------------------------------------------------
 xzlib.c |  681 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 xzlib.h |    6 +
 3 files changed, 688 insertions(+), 683 deletions(-)
---
diff --git a/xmlIO.c b/xmlIO.c
index 7a6fb0b..4398791 100644
--- a/xmlIO.c
+++ b/xmlIO.c
@@ -1315,689 +1315,7 @@ xmlGzfileClose (void * context) {
  *		I/O for compressed file accesses			*
  *									*
  ************************************************************************/
-typedef void* xzFile;       /* opaque lzma file descriptor */
-static xzFile xzopen(const char *path, const char *mode);
-static xzFile xzdopen(int fd, const char *mode);
-static int xzread(xzFile file, void *buf, unsigned len);
-static int xzclose(xzFile file);
-/* values for xz_state how */
-#define LOOK 0      /* look for a gzip/lzma header */
-#define COPY 1      /* copy input directly */
-#define GZIP 2      /* decompress a gzip stream */
-#define LZMA 3      /* decompress a lzma stream */
-/* internal lzma file state data structure */
-typedef struct {
-    int mode;               /* see lzma modes above */
-    int fd;                 /* file descriptor */
-    char *path;             /* path or fd for error messages */
-    uint64_t pos;           /* current position in uncompressed data */
-    unsigned size;          /* buffer size, zero if not allocated yet */
-    unsigned want;          /* requested buffer size, default is BUFSIZ */
-    unsigned char *in;      /* input buffer */
-    unsigned char *out;     /* output buffer (double-sized when reading) */
-    unsigned char *next;    /* next output data to deliver or write */
-    unsigned have;          /* amount of output data unused at next */
-    int eof;                /* true if end of input file reached */
-    uint64_t start;         /* where the lzma data started, for rewinding */
-    uint64_t raw;           /* where the raw data started, for seeking */
-    int how;                /* 0: get header, 1: copy, 2: decompress */
-    int direct;             /* true if last read direct, false if lzma */
-        /* seek request */
-    uint64_t skip;          /* amount to skip (already rewound if backwards) */
-    int seek;               /* true if seek request pending */
-        /* error information */
-    int err;                /* error code */
-    char *msg;              /* error message */
-        /* lzma stream */
-    lzma_stream strm;       /* stream structure in-place (not a pointer) */
-#ifdef HAVE_ZLIB_H
-        /* zlib inflate or deflate stream */
-    z_stream zstrm;         /* stream structure in-place (not a pointer) */
-#endif
-} xz_state, *xz_statep;
-
-static void xz_error(xz_statep state, int err, const char *msg)
-{
-    /* free previously allocated message and clear */
-    if (state->msg != NULL) {
-        if (state->err != LZMA_MEM_ERROR)
-            free(state->msg);
-        state->msg = NULL;
-    }
-
-    /* set error code, and if no message, then done */
-    state->err = err;
-    if (msg == NULL)
-        return;
-
-    /* for an out of memory error, save as static string */
-    if (err == LZMA_MEM_ERROR) {
-        state->msg = (char *)msg;
-        return;
-    }
-
-    /* construct error message with path */
-    if ((state->msg = malloc(strlen(state->path) + strlen(msg) + 3)) == NULL) {
-        state->err = LZMA_MEM_ERROR;
-        state->msg = (char *)"out of memory";
-        return;
-    }
-    strcpy(state->msg, state->path);
-    strcat(state->msg, ": ");
-    strcat(state->msg, msg);
-    return;
-}
-
-static void xz_reset(xz_statep state)
-{
-    state->have = 0;                /* no output data available */
-    state->eof = 0;                 /* not at end of file */
-    state->how = LOOK;              /* look for gzip header */
-    state->direct = 1;              /* default for empty file */
-    state->seek = 0;                /* no seek request pending */
-    xz_error(state, LZMA_OK, NULL); /* clear error */
-    state->pos = 0;                 /* no uncompressed data yet */
-    state->strm.avail_in = 0;       /* no input data yet */
-#ifdef HAVE_ZLIB_H
-    state->zstrm.avail_in = 0;      /* no input data yet */
-#endif
-}
-
-static xzFile xz_open(const char *path, int fd, const char *mode ATTRIBUTE_UNUSED)
-{
-    xz_statep state;
-
-    /* allocate xzFile structure to return */
-    state = malloc(sizeof(xz_state));
-    if (state == NULL)
-        return NULL;
-    state->size = 0;            /* no buffers allocated yet */
-    state->want = BUFSIZ;       /* requested buffer size */
-    state->msg = NULL;          /* no error message yet */
-
-     /* save the path name for error messages */
-    state->path = malloc(strlen(path) + 1);
-    if (state->path == NULL) {
-        free(state);
-        return NULL;
-    }
-    strcpy(state->path, path);
-
-    /* open the file with the appropriate mode (or just use fd) */
-    state->fd = fd != -1 ? fd :
-        open(path,
-#ifdef O_LARGEFILE
-            O_LARGEFILE |
-#endif
-#ifdef O_BINARY
-            O_BINARY |
-#endif
-                O_RDONLY,
-            0666);
-    if (state->fd == -1) {
-        free(state->path);
-        free(state);
-        return NULL;
-    }
-
-    /* save the current position for rewinding (only if reading) */
-    state->start = lseek(state->fd, 0, SEEK_CUR);
-    if (state->start == (uint64_t) -1) state->start = 0;
-
-    /* initialize stream */
-    xz_reset(state);
-
-    /* return stream */
-    return (xzFile)state;
-}
-
-xzFile xzopen(const char *path, const char *mode)
-{
-    return xz_open(path, -1, mode);
-}
-
-xzFile xzdopen(int fd, const char *mode)
-{
-    char *path;         /* identifier for error messages */
-    xzFile xz;
-
-    if (fd == -1 || (path = malloc(7 + 3 * sizeof(int))) == NULL)
-        return NULL;
-    sprintf(path, "<fd:%d>", fd);   /* for debugging */
-    xz = xz_open(path, fd, mode);
-    free(path);
-    return xz;
-}
-
-static int xz_load(xz_statep state, unsigned char *buf, unsigned len, unsigned *have)
-{
-    int ret;
-
-    *have = 0;
-    do {
-        ret = read(state->fd, buf + *have, len - *have);
-        if (ret <= 0)
-            break;
-        *have += ret;
-    } while (*have < len);
-    if (ret < 0) {
-        xz_error(state, -1, strerror(errno));
-        return -1;
-    }
-    if (ret == 0)
-        state->eof = 1;
-    return 0;
-}
-
-static int xz_avail(xz_statep state)
-{
-    lzma_stream *strm = &(state->strm);
-
-    if (state->err != LZMA_OK)
-        return -1;
-    if (state->eof == 0) {
-        if (xz_load(state, state->in, state->size,
-                (unsigned *)&(strm->avail_in)) == -1)
-            return -1;
-        strm->next_in = state->in;
-    }
-    return 0;
-}
-
-static int
-is_format_xz(xz_statep state)
-{
-    lzma_stream *strm = &(state->strm);
-
-	return strm->avail_in >= 6 && memcmp(state->in, "\3757zXZ", 6) == 0;
-}
-
-static int
-is_format_lzma(xz_statep state)
-{
-    lzma_stream *strm = &(state->strm);
-
-	lzma_filter filter;
-	lzma_options_lzma *opt;
-	uint32_t dict_size;
-	uint64_t uncompressed_size;
-	size_t i;
-
-	if (strm->avail_in < 13)
-		return 0;
-
-	filter.id = LZMA_FILTER_LZMA1;
-	if (lzma_properties_decode(&filter, NULL, state->in, 5) != LZMA_OK)
-		return 0;
-
-	opt = filter.options;
-	dict_size = opt->dict_size;
-	free(opt);
-
-	/* A hack to ditch tons of false positives: We allow only dictionary
-	 * sizes that are 2^n or 2^n + 2^(n-1) or UINT32_MAX. LZMA_Alone
-	 * created only files with 2^n, but accepts any dictionary size.
-	 * If someone complains, this will be reconsidered.
-	*/
-	if (dict_size != UINT32_MAX) {
-		uint32_t d = dict_size - 1;
-		d |= d >> 2;
-		d |= d >> 3;
-		d |= d >> 4;
-		d |= d >> 8;
-		d |= d >> 16;
-		++d;
-		if (d != dict_size || dict_size == 0)
-			return 0;
-	}
-
-	/* Another hack to ditch false positives: Assume that if the
-	 * uncompressed size is known, it must be less than 256 GiB.
-	 * Again, if someone complains, this will be reconsidered.
-	 */
-	uncompressed_size = 0;
-	for (i = 0; i < 8; ++i)
-		uncompressed_size |= (uint64_t)(state->in[5 + i]) << (i * 8);
-
-	if (uncompressed_size != UINT64_MAX
-			&& uncompressed_size > (UINT64_C(1) << 38))
-		return 0;
-
-	return 1;
-}
-
-#ifdef HAVE_ZLIB_H
-/* Get next byte from input, or -1 if end or error. */
-#define NEXT() ((strm->avail_in == 0 && xz_avail(state) == -1) ? -1 : \
-                (strm->avail_in == 0 ? -1 : \
-                 (strm->avail_in--, *(strm->next_in)++)))
-
-/* Get a four-byte little-endian integer and return 0 on success and the value
-   in *ret.  Otherwise -1 is returned and *ret is not modified. */
-static int gz_next4(xz_statep state, unsigned long *ret)
-{
-    int ch;
-    unsigned long val;
-    z_streamp strm = &(state->zstrm);
-
-    val = NEXT();
-    val += (unsigned)NEXT() << 8;
-    val += (unsigned long)NEXT() << 16;
-    ch = NEXT();
-    if (ch == -1)
-        return -1;
-    val += (unsigned long)ch << 24;
-    *ret = val;
-    return 0;
-}
-#endif
-
-static int xz_head(xz_statep state)
-{
-    lzma_stream *strm = &(state->strm);
-    lzma_stream init = LZMA_STREAM_INIT;
-    int flags;
-    unsigned len;
-
-    /* allocate read buffers and inflate memory */
-    if (state->size == 0) {
-        /* allocate buffers */
-        state->in = malloc(state->want);
-        state->out = malloc(state->want << 1);
-        if (state->in == NULL || state->out == NULL) {
-            if (state->out != NULL)
-                free(state->out);
-            if (state->in != NULL)
-                free(state->in);
-            xz_error(state, LZMA_MEM_ERROR, "out of memory");
-            return -1;
-        }
-        state->size = state->want;
-
-        /* allocate decoder memory */
-        state->strm = init;
-        state->strm.avail_in = 0;
-        state->strm.next_in = NULL;
-        if (lzma_auto_decoder(&state->strm, UINT64_MAX, 0) != LZMA_OK) {
-            free(state->out);
-            free(state->in);
-            state->size = 0;
-            xz_error(state, LZMA_MEM_ERROR, "out of memory");
-            return -1;
-       }
-
-#ifdef HAVE_ZLIB_H
-        /* allocate inflate memory */
-        state->zstrm.zalloc = Z_NULL;
-        state->zstrm.zfree = Z_NULL;
-        state->zstrm.opaque = Z_NULL;
-        state->zstrm.avail_in = 0;
-        state->zstrm.next_in = Z_NULL;
-        if (inflateInit2(&(state->zstrm), -15) != Z_OK) {    /* raw inflate */
-            free(state->out);
-            free(state->in);
-            state->size = 0;
-            xz_error(state, LZMA_MEM_ERROR, "out of memory");
-            return -1;
-        }
-#endif
-    }
-
-    /* get some data in the input buffer */
-    if (strm->avail_in == 0) {
-        if (xz_avail(state) == -1)
-            return -1;
-        if (strm->avail_in == 0)
-            return 0;
-    }
-
-     /* look for the xz magic header bytes */
-    if (is_format_xz(state) || is_format_lzma(state)) {
-            state->how = LZMA;
-            state->direct = 0;
-            return 0;
-    }
-
-#ifdef HAVE_ZLIB_H
-   /* look for the gzip magic header bytes 31 and 139 */
-    if (strm->next_in[0] == 31) {
-        strm->avail_in--;
-        strm->next_in++;
-        if (strm->avail_in == 0 && xz_avail(state) == -1)
-            return -1;
-        if (strm->avail_in && strm->next_in[0] == 139) {
-            /* we have a gzip header, woo hoo! */
-            strm->avail_in--;
-            strm->next_in++;
-
-            /* skip rest of header */
-            if (NEXT() != 8) {      /* compression method */
-                xz_error(state, LZMA_DATA_ERROR, "unknown compression method");
-                return -1;
-            }
-            flags = NEXT();
-            if (flags & 0xe0) {     /* reserved flag bits */
-                xz_error(state, LZMA_DATA_ERROR, "unknown header flags set");
-                return -1;
-            }
-            NEXT();                 /* modification time */
-            NEXT();
-            NEXT();
-            NEXT();
-            NEXT();                 /* extra flags */
-            NEXT();                 /* operating system */
-            if (flags & 4) {        /* extra field */
-                len = (unsigned)NEXT();
-                len += (unsigned)NEXT() << 8;
-                while (len--)
-                    if (NEXT() < 0)
-                        break;
-            }
-            if (flags & 8)          /* file name */
-                while (NEXT() > 0)
-                    ;
-            if (flags & 16)         /* comment */
-                while (NEXT() > 0)
-                    ;
-            if (flags & 2) {        /* header crc */
-                NEXT();
-                NEXT();
-            }
-            /* an unexpected end of file is not checked for here -- it will be
-               noticed on the first request for uncompressed data */
-
-            /* set up for decompression */
-            inflateReset(&state->zstrm);
-            state->zstrm.adler = crc32(0L, Z_NULL, 0);
-            state->how = GZIP;
-            state->direct = 0;
-            return 0;
-        }
-        else {
-            /* not a gzip file -- save first byte (31) and fall to raw i/o */
-            state->out[0] = 31;
-            state->have = 1;
-        }
-    }
-#endif
-
-    /* doing raw i/o, save start of raw data for seeking, copy any leftover
-       input to output -- this assumes that the output buffer is larger than
-       the input buffer, which also assures space for gzungetc() */
-    state->raw = state->pos;
-    state->next = state->out;
-    if (strm->avail_in) {
-        memcpy(state->next + state->have, strm->next_in, strm->avail_in);
-        state->have += strm->avail_in;
-        strm->avail_in = 0;
-    }
-    state->how = COPY;
-    state->direct = 1;
-    return 0;
-}
-
-static int xz_decomp(xz_statep state)
-{
-    int ret;
-    unsigned had;
-    unsigned long crc, len;
-    lzma_stream *strm = &(state->strm);
-
-    lzma_action action = LZMA_RUN;
-
-    /* fill output buffer up to end of deflate stream */
-    had = strm->avail_out;
-    do {
-        /* get more input for inflate() */
-        if (strm->avail_in == 0 && xz_avail(state) == -1)
-            return -1;
-        if (strm->avail_in == 0) {
-            xz_error(state, LZMA_DATA_ERROR, "unexpected end of file");
-            return -1;
-        }
-        if (state->eof)
-            action = LZMA_FINISH;
-        
-        /* decompress and handle errors */
-#ifdef HAVE_ZLIB_H
-        if (state->how == GZIP) {
-        state->zstrm.avail_in =  (uInt) state->strm.avail_in;
-        state->zstrm.next_in = (Bytef*) state->strm.next_in;
-        state->zstrm.avail_out = (uInt) state->strm.avail_out;
-        state->zstrm.next_out = (Bytef*) state->strm.next_out;
-        ret = inflate(&state->zstrm, Z_NO_FLUSH);
-        if (ret == Z_STREAM_ERROR || ret == Z_NEED_DICT) {
-            xz_error(state, Z_STREAM_ERROR,
-                      "internal error: inflate stream corrupt");
-            return -1;
-        }
-        if (ret == Z_MEM_ERROR) ret = LZMA_MEM_ERROR;
-        if (ret == Z_DATA_ERROR) ret = LZMA_DATA_ERROR;
-        if (ret == Z_STREAM_END) ret = LZMA_STREAM_END;
-        state->strm.avail_in = state->zstrm.avail_in;
-        state->strm.next_in = state->zstrm.next_in;
-        state->strm.avail_out = state->zstrm.avail_out;
-        state->strm.next_out = state->zstrm.next_out;
-        }
-        else /* state->how == LZMA */
-#endif
-	ret = lzma_code(strm, action);
-        if (ret == LZMA_MEM_ERROR) {
-            xz_error(state, LZMA_MEM_ERROR, "out of memory");
-            return -1;
-        }
-        if (ret == LZMA_DATA_ERROR) {
-            xz_error(state, LZMA_DATA_ERROR, "compressed data error");
-            return -1;
-        }
-    } while (strm->avail_out && ret != LZMA_STREAM_END);
-
-    /* update available output and crc check value */
-    state->have = had - strm->avail_out;
-    state->next = strm->next_out - state->have;
-#ifdef HAVE_ZLIB_H
-    state->zstrm.adler = crc32(state->zstrm.adler, state->next, state->have);
-#endif
-
-    if (ret == LZMA_STREAM_END) {
-#ifdef HAVE_ZLIB_H
-        if (state->how == GZIP) {
-        if (gz_next4(state, &crc) == -1 || gz_next4(state, &len) == -1) {
-            xz_error(state, LZMA_DATA_ERROR, "unexpected end of file");
-            return -1;
-        }
-        if (crc != state->zstrm.adler) {
-            xz_error(state, LZMA_DATA_ERROR, "incorrect data check");
-            return -1;
-        }
-        if (len != (state->zstrm.total_out & 0xffffffffL)) {
-            xz_error(state, LZMA_DATA_ERROR, "incorrect length check");
-            return -1;
-        }
-        state->strm.avail_in = 0;
-        state->strm.next_in = NULL;
-        state->strm.avail_out = 0;
-        state->strm.next_out = NULL;
-        }
-        else
-#endif
-        if ( strm->avail_in != 0 || !state->eof) {
-            xz_error(state, LZMA_DATA_ERROR, "trailing garbage");
-            return -1;
-        }
-        state->how = LOOK;      /* ready for next stream, once have is 0 (leave
-                                   state->direct unchanged to remember how) */
-    }
-
-    /* good decompression */
-    return 0;
-}
-
-static int xz_make(xz_statep state)
-{
-    lzma_stream *strm = &(state->strm);
-
-    if (state->how == LOOK) {           /* look for lzma / gzip header */
-        if (xz_head(state) == -1)
-            return -1;
-        if (state->have)                /* got some data from xz_head() */
-            return 0;
-    }
-    if (state->how == COPY) {           /* straight copy */
-        if (xz_load(state, state->out, state->size << 1, &(state->have)) == -1)
-            return -1;
-        state->next = state->out;
-    }
-    else if (state->how == LZMA || state->how == GZIP) {      /* decompress */
-        strm->avail_out = state->size << 1;
-        strm->next_out = state->out;
-        if (xz_decomp(state) == -1)
-            return -1;
-    }
-    return 0;
-}
-
-static int xz_skip(xz_statep state, uint64_t len)
-{
-    unsigned n;
-
-    /* skip over len bytes or reach end-of-file, whichever comes first */
-    while (len)
-        /* skip over whatever is in output buffer */
-        if (state->have) {
-            n = (uint64_t)state->have > len ?
-                (unsigned)len : state->have;
-            state->have -= n;
-            state->next += n;
-            state->pos += n;
-            len -= n;
-        }
-
-        /* output buffer empty -- return if we're at the end of the input */
-        else if (state->eof && state->strm.avail_in == 0)
-            break;
-
-        /* need more data to skip -- load up output buffer */
-        else {
-            /* get more output, looking for header if required */
-            if (xz_make(state) == -1)
-                return -1;
-        }
-    return 0;
-}
-
-int xzread(xzFile file, void *buf, unsigned len)
-{
-    unsigned got, n;
-    xz_statep state;
-    lzma_stream *strm;
-
-    /* get internal structure */
-    if (file == NULL)
-        return -1;
-    state = (xz_statep)file;
-    strm = &(state->strm);
-
-    /* check that we're reading and that there's no error */
-    if (state->err != LZMA_OK)
-        return -1;
-
-    /* since an int is returned, make sure len fits in one, otherwise return
-       with an error (this avoids the flaw in the interface) */
-    if ((int)len < 0) {
-        xz_error(state, LZMA_BUF_ERROR, "requested length does not fit in int");
-        return -1;
-    }
-
-    /* if len is zero, avoid unnecessary operations */
-    if (len == 0)
-        return 0;
-
-    /* process a skip request */
-    if (state->seek) {
-        state->seek = 0;
-        if (xz_skip(state, state->skip) == -1)
-            return -1;
-    }
-
-    /* get len bytes to buf, or less than len if at the end */
-    got = 0;
-    do {
-        /* first just try copying data from the output buffer */
-        if (state->have) {
-            n = state->have > len ? len : state->have;
-            memcpy(buf, state->next, n);
-            state->next += n;
-            state->have -= n;
-        }
-
-        /* output buffer empty -- return if we're at the end of the input */
-        else if (state->eof && strm->avail_in == 0)
-            break;
-
-        /* need output data -- for small len or new stream load up our output
-           buffer */
-        else if (state->how == LOOK || len < (state->size << 1)) {
-            /* get more output, looking for header if required */
-            if (xz_make(state) == -1)
-                return -1;
-            continue;       /* no progress yet -- go back to memcpy() above */
-            /* the copy above assures that we will leave with space in the
-               output buffer, allowing at least one gzungetc() to succeed */
-        }
-
-        /* large len -- read directly into user buffer */
-        else if (state->how == COPY) {      /* read directly */
-            if (xz_load(state, buf, len, &n) == -1)
-                return -1;
-        }
-
-        /* large len -- decompress directly into user buffer */
-        else {  /* state->how == LZMA */
-            strm->avail_out = len;
-            strm->next_out = buf;
-            if (xz_decomp(state) == -1)
-                return -1;
-            n = state->have;
-            state->have = 0;
-        }
-
-        /* update progress */
-        len -= n;
-        buf = (char *)buf + n;
-        got += n;
-        state->pos += n;
-    } while (len);
-
-    /* return number of bytes read into user buffer (will fit in int) */
-    return (int)got;
-}
-
-int xzclose(xzFile file)
-{
-    int ret;
-    xz_statep state;
-
-    /* get internal structure */
-    if (file == NULL)
-        return LZMA_DATA_ERROR;
-    state = (xz_statep)file;
-
-    /* free memory and close file */
-    if (state->size) {
-        lzma_end(&(state->strm));
-#ifdef HAVE_LIBZ_H
-        inflateEnd(&(state->zstrm));
-#endif
-        free(state->out);
-        free(state->in);
-    }
-    free(state->path);
-    ret = close(state->fd);
-    free(state);
-    return ret ? ret : LZMA_OK;
-}
-
+#include "xzlib.c"
 /**
  * xmlXzfileMatch:
  * @filename:  the URI for matching
diff --git a/xzlib.c b/xzlib.c
new file mode 100644
index 0000000..ba3dbf3
--- /dev/null
+++ b/xzlib.c
@@ -0,0 +1,681 @@
+#include "xzlib.h"
+
+/* values for xz_state how */
+#define LOOK 0      /* look for a gzip/lzma header */
+#define COPY 1      /* copy input directly */
+#define GZIP 2      /* decompress a gzip stream */
+#define LZMA 3      /* decompress a lzma stream */
+
+/* internal lzma file state data structure */
+typedef struct {
+    int mode;               /* see lzma modes above */
+    int fd;                 /* file descriptor */
+    char *path;             /* path or fd for error messages */
+    uint64_t pos;           /* current position in uncompressed data */
+    unsigned size;          /* buffer size, zero if not allocated yet */
+    unsigned want;          /* requested buffer size, default is BUFSIZ */
+    unsigned char *in;      /* input buffer */
+    unsigned char *out;     /* output buffer (double-sized when reading) */
+    unsigned char *next;    /* next output data to deliver or write */
+    unsigned have;          /* amount of output data unused at next */
+    int eof;                /* true if end of input file reached */
+    uint64_t start;         /* where the lzma data started, for rewinding */
+    uint64_t raw;           /* where the raw data started, for seeking */
+    int how;                /* 0: get header, 1: copy, 2: decompress */
+    int direct;             /* true if last read direct, false if lzma */
+        /* seek request */
+    uint64_t skip;          /* amount to skip (already rewound if backwards) */
+    int seek;               /* true if seek request pending */
+        /* error information */
+    int err;                /* error code */
+    char *msg;              /* error message */
+        /* lzma stream */
+    lzma_stream strm;       /* stream structure in-place (not a pointer) */
+#ifdef HAVE_ZLIB_H
+        /* zlib inflate or deflate stream */
+    z_stream zstrm;         /* stream structure in-place (not a pointer) */
+#endif
+} xz_state, *xz_statep;
+
+static void xz_error(xz_statep state, int err, const char *msg)
+{
+    /* free previously allocated message and clear */
+    if (state->msg != NULL) {
+        if (state->err != LZMA_MEM_ERROR)
+            free(state->msg);
+        state->msg = NULL;
+    }
+
+    /* set error code, and if no message, then done */
+    state->err = err;
+    if (msg == NULL)
+        return;
+
+    /* for an out of memory error, save as static string */
+    if (err == LZMA_MEM_ERROR) {
+        state->msg = (char *)msg;
+        return;
+    }
+
+    /* construct error message with path */
+    if ((state->msg = malloc(strlen(state->path) + strlen(msg) + 3)) == NULL) {
+        state->err = LZMA_MEM_ERROR;
+        state->msg = (char *)"out of memory";
+        return;
+    }
+    strcpy(state->msg, state->path);
+    strcat(state->msg, ": ");
+    strcat(state->msg, msg);
+    return;
+}
+
+static void xz_reset(xz_statep state)
+{
+    state->have = 0;                /* no output data available */
+    state->eof = 0;                 /* not at end of file */
+    state->how = LOOK;              /* look for gzip header */
+    state->direct = 1;              /* default for empty file */
+    state->seek = 0;                /* no seek request pending */
+    xz_error(state, LZMA_OK, NULL); /* clear error */
+    state->pos = 0;                 /* no uncompressed data yet */
+    state->strm.avail_in = 0;       /* no input data yet */
+#ifdef HAVE_ZLIB_H
+    state->zstrm.avail_in = 0;      /* no input data yet */
+#endif
+}
+
+static xzFile xz_open(const char *path, int fd, const char *mode ATTRIBUTE_UNUSED)
+{
+    xz_statep state;
+
+    /* allocate xzFile structure to return */
+    state = malloc(sizeof(xz_state));
+    if (state == NULL)
+        return NULL;
+    state->size = 0;            /* no buffers allocated yet */
+    state->want = BUFSIZ;       /* requested buffer size */
+    state->msg = NULL;          /* no error message yet */
+
+     /* save the path name for error messages */
+    state->path = malloc(strlen(path) + 1);
+    if (state->path == NULL) {
+        free(state);
+        return NULL;
+    }
+    strcpy(state->path, path);
+
+    /* open the file with the appropriate mode (or just use fd) */
+    state->fd = fd != -1 ? fd :
+        open(path,
+#ifdef O_LARGEFILE
+            O_LARGEFILE |
+#endif
+#ifdef O_BINARY
+            O_BINARY |
+#endif
+                O_RDONLY,
+            0666);
+    if (state->fd == -1) {
+        free(state->path);
+        free(state);
+        return NULL;
+    }
+
+    /* save the current position for rewinding (only if reading) */
+    state->start = lseek(state->fd, 0, SEEK_CUR);
+    if (state->start == (uint64_t) -1) state->start = 0;
+
+    /* initialize stream */
+    xz_reset(state);
+
+    /* return stream */
+    return (xzFile)state;
+}
+
+xzFile xzopen(const char *path, const char *mode)
+{
+    return xz_open(path, -1, mode);
+}
+
+xzFile xzdopen(int fd, const char *mode)
+{
+    char *path;         /* identifier for error messages */
+    xzFile xz;
+
+    if (fd == -1 || (path = malloc(7 + 3 * sizeof(int))) == NULL)
+        return NULL;
+    sprintf(path, "<fd:%d>", fd);   /* for debugging */
+    xz = xz_open(path, fd, mode);
+    free(path);
+    return xz;
+}
+
+static int xz_load(xz_statep state, unsigned char *buf, unsigned len, unsigned *have)
+{
+    int ret;
+
+    *have = 0;
+    do {
+        ret = read(state->fd, buf + *have, len - *have);
+        if (ret <= 0)
+            break;
+        *have += ret;
+    } while (*have < len);
+    if (ret < 0) {
+        xz_error(state, -1, strerror(errno));
+        return -1;
+    }
+    if (ret == 0)
+        state->eof = 1;
+    return 0;
+}
+
+static int xz_avail(xz_statep state)
+{
+    lzma_stream *strm = &(state->strm);
+
+    if (state->err != LZMA_OK)
+        return -1;
+    if (state->eof == 0) {
+        if (xz_load(state, state->in, state->size,
+                (unsigned *)&(strm->avail_in)) == -1)
+            return -1;
+        strm->next_in = state->in;
+    }
+    return 0;
+}
+
+static int
+is_format_xz(xz_statep state)
+{
+    lzma_stream *strm = &(state->strm);
+
+	return strm->avail_in >= 6 && memcmp(state->in, "\3757zXZ", 6) == 0;
+}
+
+static int
+is_format_lzma(xz_statep state)
+{
+    lzma_stream *strm = &(state->strm);
+
+	lzma_filter filter;
+	lzma_options_lzma *opt;
+	uint32_t dict_size;
+	uint64_t uncompressed_size;
+	size_t i;
+
+	if (strm->avail_in < 13)
+		return 0;
+
+	filter.id = LZMA_FILTER_LZMA1;
+	if (lzma_properties_decode(&filter, NULL, state->in, 5) != LZMA_OK)
+		return 0;
+
+	opt = filter.options;
+	dict_size = opt->dict_size;
+	free(opt);
+
+	/* A hack to ditch tons of false positives: We allow only dictionary
+	 * sizes that are 2^n or 2^n + 2^(n-1) or UINT32_MAX. LZMA_Alone
+	 * created only files with 2^n, but accepts any dictionary size.
+	 * If someone complains, this will be reconsidered.
+	*/
+	if (dict_size != UINT32_MAX) {
+		uint32_t d = dict_size - 1;
+		d |= d >> 2;
+		d |= d >> 3;
+		d |= d >> 4;
+		d |= d >> 8;
+		d |= d >> 16;
+		++d;
+		if (d != dict_size || dict_size == 0)
+			return 0;
+	}
+
+	/* Another hack to ditch false positives: Assume that if the
+	 * uncompressed size is known, it must be less than 256 GiB.
+	 * Again, if someone complains, this will be reconsidered.
+	 */
+	uncompressed_size = 0;
+	for (i = 0; i < 8; ++i)
+		uncompressed_size |= (uint64_t)(state->in[5 + i]) << (i * 8);
+
+	if (uncompressed_size != UINT64_MAX
+			&& uncompressed_size > (UINT64_C(1) << 38))
+		return 0;
+
+	return 1;
+}
+
+#ifdef HAVE_ZLIB_H
+/* Get next byte from input, or -1 if end or error. */
+#define NEXT() ((strm->avail_in == 0 && xz_avail(state) == -1) ? -1 : \
+                (strm->avail_in == 0 ? -1 : \
+                 (strm->avail_in--, *(strm->next_in)++)))
+
+/* Get a four-byte little-endian integer and return 0 on success and the value
+   in *ret.  Otherwise -1 is returned and *ret is not modified. */
+static int gz_next4(xz_statep state, unsigned long *ret)
+{
+    int ch;
+    unsigned long val;
+    z_streamp strm = &(state->zstrm);
+
+    val = NEXT();
+    val += (unsigned)NEXT() << 8;
+    val += (unsigned long)NEXT() << 16;
+    ch = NEXT();
+    if (ch == -1)
+        return -1;
+    val += (unsigned long)ch << 24;
+    *ret = val;
+    return 0;
+}
+#endif
+
+static int xz_head(xz_statep state)
+{
+    lzma_stream *strm = &(state->strm);
+    lzma_stream init = LZMA_STREAM_INIT;
+    int flags;
+    unsigned len;
+
+    /* allocate read buffers and inflate memory */
+    if (state->size == 0) {
+        /* allocate buffers */
+        state->in = malloc(state->want);
+        state->out = malloc(state->want << 1);
+        if (state->in == NULL || state->out == NULL) {
+            if (state->out != NULL)
+                free(state->out);
+            if (state->in != NULL)
+                free(state->in);
+            xz_error(state, LZMA_MEM_ERROR, "out of memory");
+            return -1;
+        }
+        state->size = state->want;
+
+        /* allocate decoder memory */
+        state->strm = init;
+        state->strm.avail_in = 0;
+        state->strm.next_in = NULL;
+        if (lzma_auto_decoder(&state->strm, UINT64_MAX, 0) != LZMA_OK) {
+            free(state->out);
+            free(state->in);
+            state->size = 0;
+            xz_error(state, LZMA_MEM_ERROR, "out of memory");
+            return -1;
+       }
+
+#ifdef HAVE_ZLIB_H
+        /* allocate inflate memory */
+        state->zstrm.zalloc = Z_NULL;
+        state->zstrm.zfree = Z_NULL;
+        state->zstrm.opaque = Z_NULL;
+        state->zstrm.avail_in = 0;
+        state->zstrm.next_in = Z_NULL;
+        if (inflateInit2(&(state->zstrm), -15) != Z_OK) {    /* raw inflate */
+            free(state->out);
+            free(state->in);
+            state->size = 0;
+            xz_error(state, LZMA_MEM_ERROR, "out of memory");
+            return -1;
+        }
+#endif
+    }
+
+    /* get some data in the input buffer */
+    if (strm->avail_in == 0) {
+        if (xz_avail(state) == -1)
+            return -1;
+        if (strm->avail_in == 0)
+            return 0;
+    }
+
+     /* look for the xz magic header bytes */
+    if (is_format_xz(state) || is_format_lzma(state)) {
+            state->how = LZMA;
+            state->direct = 0;
+            return 0;
+    }
+
+#ifdef HAVE_ZLIB_H
+   /* look for the gzip magic header bytes 31 and 139 */
+    if (strm->next_in[0] == 31) {
+        strm->avail_in--;
+        strm->next_in++;
+        if (strm->avail_in == 0 && xz_avail(state) == -1)
+            return -1;
+        if (strm->avail_in && strm->next_in[0] == 139) {
+            /* we have a gzip header, woo hoo! */
+            strm->avail_in--;
+            strm->next_in++;
+
+            /* skip rest of header */
+            if (NEXT() != 8) {      /* compression method */
+                xz_error(state, LZMA_DATA_ERROR, "unknown compression method");
+                return -1;
+            }
+            flags = NEXT();
+            if (flags & 0xe0) {     /* reserved flag bits */
+                xz_error(state, LZMA_DATA_ERROR, "unknown header flags set");
+                return -1;
+            }
+            NEXT();                 /* modification time */
+            NEXT();
+            NEXT();
+            NEXT();
+            NEXT();                 /* extra flags */
+            NEXT();                 /* operating system */
+            if (flags & 4) {        /* extra field */
+                len = (unsigned)NEXT();
+                len += (unsigned)NEXT() << 8;
+                while (len--)
+                    if (NEXT() < 0)
+                        break;
+            }
+            if (flags & 8)          /* file name */
+                while (NEXT() > 0)
+                    ;
+            if (flags & 16)         /* comment */
+                while (NEXT() > 0)
+                    ;
+            if (flags & 2) {        /* header crc */
+                NEXT();
+                NEXT();
+            }
+            /* an unexpected end of file is not checked for here -- it will be
+               noticed on the first request for uncompressed data */
+
+            /* set up for decompression */
+            inflateReset(&state->zstrm);
+            state->zstrm.adler = crc32(0L, Z_NULL, 0);
+            state->how = GZIP;
+            state->direct = 0;
+            return 0;
+        }
+        else {
+            /* not a gzip file -- save first byte (31) and fall to raw i/o */
+            state->out[0] = 31;
+            state->have = 1;
+        }
+    }
+#endif
+
+    /* doing raw i/o, save start of raw data for seeking, copy any leftover
+       input to output -- this assumes that the output buffer is larger than
+       the input buffer, which also assures space for gzungetc() */
+    state->raw = state->pos;
+    state->next = state->out;
+    if (strm->avail_in) {
+        memcpy(state->next + state->have, strm->next_in, strm->avail_in);
+        state->have += strm->avail_in;
+        strm->avail_in = 0;
+    }
+    state->how = COPY;
+    state->direct = 1;
+    return 0;
+}
+
+static int xz_decomp(xz_statep state)
+{
+    int ret;
+    unsigned had;
+    unsigned long crc, len;
+    lzma_stream *strm = &(state->strm);
+
+    lzma_action action = LZMA_RUN;
+
+    /* fill output buffer up to end of deflate stream */
+    had = strm->avail_out;
+    do {
+        /* get more input for inflate() */
+        if (strm->avail_in == 0 && xz_avail(state) == -1)
+            return -1;
+        if (strm->avail_in == 0) {
+            xz_error(state, LZMA_DATA_ERROR, "unexpected end of file");
+            return -1;
+        }
+        if (state->eof)
+            action = LZMA_FINISH;
+        
+        /* decompress and handle errors */
+#ifdef HAVE_ZLIB_H
+        if (state->how == GZIP) {
+        state->zstrm.avail_in =  (uInt) state->strm.avail_in;
+        state->zstrm.next_in = (Bytef*) state->strm.next_in;
+        state->zstrm.avail_out = (uInt) state->strm.avail_out;
+        state->zstrm.next_out = (Bytef*) state->strm.next_out;
+        ret = inflate(&state->zstrm, Z_NO_FLUSH);
+        if (ret == Z_STREAM_ERROR || ret == Z_NEED_DICT) {
+            xz_error(state, Z_STREAM_ERROR,
+                      "internal error: inflate stream corrupt");
+            return -1;
+        }
+        if (ret == Z_MEM_ERROR) ret = LZMA_MEM_ERROR;
+        if (ret == Z_DATA_ERROR) ret = LZMA_DATA_ERROR;
+        if (ret == Z_STREAM_END) ret = LZMA_STREAM_END;
+        state->strm.avail_in = state->zstrm.avail_in;
+        state->strm.next_in = state->zstrm.next_in;
+        state->strm.avail_out = state->zstrm.avail_out;
+        state->strm.next_out = state->zstrm.next_out;
+        }
+        else /* state->how == LZMA */
+#endif
+	ret = lzma_code(strm, action);
+        if (ret == LZMA_MEM_ERROR) {
+            xz_error(state, LZMA_MEM_ERROR, "out of memory");
+            return -1;
+        }
+        if (ret == LZMA_DATA_ERROR) {
+            xz_error(state, LZMA_DATA_ERROR, "compressed data error");
+            return -1;
+        }
+    } while (strm->avail_out && ret != LZMA_STREAM_END);
+
+    /* update available output and crc check value */
+    state->have = had - strm->avail_out;
+    state->next = strm->next_out - state->have;
+#ifdef HAVE_ZLIB_H
+    state->zstrm.adler = crc32(state->zstrm.adler, state->next, state->have);
+#endif
+
+    if (ret == LZMA_STREAM_END) {
+#ifdef HAVE_ZLIB_H
+        if (state->how == GZIP) {
+        if (gz_next4(state, &crc) == -1 || gz_next4(state, &len) == -1) {
+            xz_error(state, LZMA_DATA_ERROR, "unexpected end of file");
+            return -1;
+        }
+        if (crc != state->zstrm.adler) {
+            xz_error(state, LZMA_DATA_ERROR, "incorrect data check");
+            return -1;
+        }
+        if (len != (state->zstrm.total_out & 0xffffffffL)) {
+            xz_error(state, LZMA_DATA_ERROR, "incorrect length check");
+            return -1;
+        }
+        state->strm.avail_in = 0;
+        state->strm.next_in = NULL;
+        state->strm.avail_out = 0;
+        state->strm.next_out = NULL;
+        }
+        else
+#endif
+        if ( strm->avail_in != 0 || !state->eof) {
+            xz_error(state, LZMA_DATA_ERROR, "trailing garbage");
+            return -1;
+        }
+        state->how = LOOK;      /* ready for next stream, once have is 0 (leave
+                                   state->direct unchanged to remember how) */
+    }
+
+    /* good decompression */
+    return 0;
+}
+
+static int xz_make(xz_statep state)
+{
+    lzma_stream *strm = &(state->strm);
+
+    if (state->how == LOOK) {           /* look for lzma / gzip header */
+        if (xz_head(state) == -1)
+            return -1;
+        if (state->have)                /* got some data from xz_head() */
+            return 0;
+    }
+    if (state->how == COPY) {           /* straight copy */
+        if (xz_load(state, state->out, state->size << 1, &(state->have)) == -1)
+            return -1;
+        state->next = state->out;
+    }
+    else if (state->how == LZMA || state->how == GZIP) {      /* decompress */
+        strm->avail_out = state->size << 1;
+        strm->next_out = state->out;
+        if (xz_decomp(state) == -1)
+            return -1;
+    }
+    return 0;
+}
+
+static int xz_skip(xz_statep state, uint64_t len)
+{
+    unsigned n;
+
+    /* skip over len bytes or reach end-of-file, whichever comes first */
+    while (len)
+        /* skip over whatever is in output buffer */
+        if (state->have) {
+            n = (uint64_t)state->have > len ?
+                (unsigned)len : state->have;
+            state->have -= n;
+            state->next += n;
+            state->pos += n;
+            len -= n;
+        }
+
+        /* output buffer empty -- return if we're at the end of the input */
+        else if (state->eof && state->strm.avail_in == 0)
+            break;
+
+        /* need more data to skip -- load up output buffer */
+        else {
+            /* get more output, looking for header if required */
+            if (xz_make(state) == -1)
+                return -1;
+        }
+    return 0;
+}
+
+int xzread(xzFile file, void *buf, unsigned len)
+{
+    unsigned got, n;
+    xz_statep state;
+    lzma_stream *strm;
+
+    /* get internal structure */
+    if (file == NULL)
+        return -1;
+    state = (xz_statep)file;
+    strm = &(state->strm);
+
+    /* check that we're reading and that there's no error */
+    if (state->err != LZMA_OK)
+        return -1;
+
+    /* since an int is returned, make sure len fits in one, otherwise return
+       with an error (this avoids the flaw in the interface) */
+    if ((int)len < 0) {
+        xz_error(state, LZMA_BUF_ERROR, "requested length does not fit in int");
+        return -1;
+    }
+
+    /* if len is zero, avoid unnecessary operations */
+    if (len == 0)
+        return 0;
+
+    /* process a skip request */
+    if (state->seek) {
+        state->seek = 0;
+        if (xz_skip(state, state->skip) == -1)
+            return -1;
+    }
+
+    /* get len bytes to buf, or less than len if at the end */
+    got = 0;
+    do {
+        /* first just try copying data from the output buffer */
+        if (state->have) {
+            n = state->have > len ? len : state->have;
+            memcpy(buf, state->next, n);
+            state->next += n;
+            state->have -= n;
+        }
+
+        /* output buffer empty -- return if we're at the end of the input */
+        else if (state->eof && strm->avail_in == 0)
+            break;
+
+        /* need output data -- for small len or new stream load up our output
+           buffer */
+        else if (state->how == LOOK || len < (state->size << 1)) {
+            /* get more output, looking for header if required */
+            if (xz_make(state) == -1)
+                return -1;
+            continue;       /* no progress yet -- go back to memcpy() above */
+            /* the copy above assures that we will leave with space in the
+               output buffer, allowing at least one gzungetc() to succeed */
+        }
+
+        /* large len -- read directly into user buffer */
+        else if (state->how == COPY) {      /* read directly */
+            if (xz_load(state, buf, len, &n) == -1)
+                return -1;
+        }
+
+        /* large len -- decompress directly into user buffer */
+        else {  /* state->how == LZMA */
+            strm->avail_out = len;
+            strm->next_out = buf;
+            if (xz_decomp(state) == -1)
+                return -1;
+            n = state->have;
+            state->have = 0;
+        }
+
+        /* update progress */
+        len -= n;
+        buf = (char *)buf + n;
+        got += n;
+        state->pos += n;
+    } while (len);
+
+    /* return number of bytes read into user buffer (will fit in int) */
+    return (int)got;
+}
+
+int xzclose(xzFile file)
+{
+    int ret;
+    xz_statep state;
+
+    /* get internal structure */
+    if (file == NULL)
+        return LZMA_DATA_ERROR;
+    state = (xz_statep)file;
+
+    /* free memory and close file */
+    if (state->size) {
+        lzma_end(&(state->strm));
+#ifdef HAVE_LIBZ_H
+        inflateEnd(&(state->zstrm));
+#endif
+        free(state->out);
+        free(state->in);
+    }
+    free(state->path);
+    ret = close(state->fd);
+    free(state);
+    return ret ? ret : LZMA_OK;
+}
+
diff --git a/xzlib.h b/xzlib.h
new file mode 100644
index 0000000..2adb7b3
--- /dev/null
+++ b/xzlib.h
@@ -0,0 +1,6 @@
+typedef void* xzFile;       /* opaque lzma file descriptor */
+
+static xzFile xzopen(const char *path, const char *mode);
+static xzFile xzdopen(int fd, const char *mode);
+static int xzread(xzFile file, void *buf, unsigned len);
+static int xzclose(xzFile file);



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