#include "gzguts.h"

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Functions
local int gz_load	OF ((gz_statep, unsigned char , unsigned, unsigned ))

local int gz_avail	OF ((gz_statep))

local int gz_skip	OF ((gz_statep, z_off64_t))

local int	gz_load (gz_statep state, unsigned char buf, unsigned len, unsigned have)

local int	gz_avail (gz_statep state)

local int	gz_look (gz_statep state)

local int	gz_decomp (gz_statep state)

local int	gz_fetch (gz_statep state)

local int	gz_skip (gz_statep state, z_off64_t len)

int ZEXPORT	gzread (gzFile file, voidp buf, unsigned len)

int ZEXPORT	gzgetc (gzFile file)

int ZEXPORT	gzgetc_ (gzFile file)

int ZEXPORT	gzungetc (int c, gzFile file)

char *ZEXPORT	gzgets (gzFile file, char *buf, int len)

int ZEXPORT	gzdirect (gzFile file)

int ZEXPORT	gzclose_r (gzFile file)

Function Documentation

local int gz_avail ( gz_statep state )

Definition at line 47 of file gzread.cc.

 {
     unsigned got;
     z_streamp strm = &(state->strm);
 
     if (state->err != Z_OK && state->err != Z_BUF_ERROR)
         return -1;
     if (state->eof == 0) {
         if (strm->avail_in) {       /* copy what's there to the start */
             unsigned char *p = state->in;
             unsigned const char *q = strm->next_in;
             unsigned n = strm->avail_in;
             do {
                 *p++ = *q++;
             } while (--n);
         }
         if (gz_load(state, state->in + strm->avail_in,
                     state->size - strm->avail_in, &got) == -1)
             return -1;
         strm->avail_in += got;
         strm->next_in = state->in;
     }
     return 0;
 }

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local int gz_decomp ( gz_statep state )

Definition at line 166 of file gzread.cc.

 {
     int ret = Z_OK;
     unsigned had;
     z_streamp strm = &(state->strm);
 
     /* fill output buffer up to end of deflate stream */
     had = strm->avail_out;
     do {
         /* get more input for inflate() */
         if (strm->avail_in == 0 && gz_avail(state) == -1)
             return -1;
         if (strm->avail_in == 0) {
             gz_error(state, Z_BUF_ERROR, "unexpected end of file");
             break;
         }
 
         /* decompress and handle errors */
         ret = inflate(strm, Z_NO_FLUSH);
         if (ret == Z_STREAM_ERROR || ret == Z_NEED_DICT) {
             gz_error(state, Z_STREAM_ERROR,
                      "internal error: inflate stream corrupt");
             return -1;
         }
         if (ret == Z_MEM_ERROR) {
             gz_error(state, Z_MEM_ERROR, "out of memory");
             return -1;
         }
         if (ret == Z_DATA_ERROR) {              /* deflate stream invalid */
             gz_error(state, Z_DATA_ERROR,
                      strm->msg == NULL ? "compressed data error" : strm->msg);
             return -1;
         }
     } while (strm->avail_out && ret != Z_STREAM_END);
 
     /* update available output */
     state->x.have = had - strm->avail_out;
     state->x.next = strm->next_out - state->x.have;
 
     /* if the gzip stream completed successfully, look for another */
     if (ret == Z_STREAM_END)
         state->how = LOOK;
 
     /* good decompression */
     return 0;
 }

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local int gz_fetch ( gz_statep state )

Definition at line 219 of file gzread.cc.

 {
     z_streamp strm = &(state->strm);
 
     do {
         switch(state->how) {
         case LOOK:      /* -> LOOK, COPY (only if never GZIP), or GZIP */
             if (gz_look(state) == -1)
                 return -1;
             if (state->how == LOOK)
                 return 0;
             break;
         case COPY:      /* -> COPY */
             if (gz_load(state, state->out, state->size << 1, &(state->x.have))
                     == -1)
                 return -1;
             state->x.next = state->out;
             return 0;
         case GZIP:      /* -> GZIP or LOOK (if end of gzip stream) */
             strm->avail_out = state->size << 1;
             strm->next_out = state->out;
             if (gz_decomp(state) == -1)
                 return -1;
         }
     } while (state->x.have == 0 && (!state->eof || strm->avail_in));
     return 0;
 }

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local int gz_load	(	gz_statep	state,
		unsigned char *	buf,
		unsigned	len,
		unsigned *	have
	)

Definition at line 20 of file gzread.cc.

 {
     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) {
         gz_error(state, Z_ERRNO, zstrerror());
         return -1;
     }
     if (ret == 0)
         state->eof = 1;
     return 0;
 }

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local int gz_look ( gz_statep state )

Definition at line 81 of file gzread.cc.

 {
     z_streamp strm = &(state->strm);
 
     /* allocate read buffers and inflate memory */
     if (state->size == 0) {
         /* allocate buffers */
         state->in = (unsigned char *)malloc(state->want);
         state->out = (unsigned char *)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);
             gz_error(state, Z_MEM_ERROR, "out of memory");
             return -1;
         }
         state->size = state->want;
 
         /* allocate inflate memory */
         state->strm.zalloc = Z_NULL;
         state->strm.zfree = Z_NULL;
         state->strm.opaque = Z_NULL;
         state->strm.avail_in = 0;
         state->strm.next_in = Z_NULL;
         if (inflateInit2(&(state->strm), 15 + 16) != Z_OK) {    /* gunzip */
             free(state->out);
             free(state->in);
             state->size = 0;
             gz_error(state, Z_MEM_ERROR, "out of memory");
             return -1;
         }
     }
 
     /* get at least the magic bytes in the input buffer */
     if (strm->avail_in < 2) {
         if (gz_avail(state) == -1)
             return -1;
         if (strm->avail_in == 0)
             return 0;
     }
 
     /* look for gzip magic bytes -- if there, do gzip decoding (note: there is
        a logical dilemma here when considering the case of a partially written
        gzip file, to wit, if a single 31 byte is written, then we cannot tell
        whether this is a single-byte file, or just a partially written gzip
        file -- for here we assume that if a gzip file is being written, then
        the header will be written in a single operation, so that reading a
        single byte is sufficient indication that it is not a gzip file) */
     if (strm->avail_in > 1 &&
             strm->next_in[0] == 31 && strm->next_in[1] == 139) {
         inflateReset(strm);
         state->how = GZIP;
         state->direct = 0;
         return 0;
     }
 
     /* no gzip header -- if we were decoding gzip before, then this is trailing
        garbage.  Ignore the trailing garbage and finish. */
     if (state->direct == 0) {
         strm->avail_in = 0;
         state->eof = 1;
         state->x.have = 0;
         return 0;
     }
 
     /* doing raw i/o, 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->x.next = state->out;
     if (strm->avail_in) {
         memcpy(state->x.next, strm->next_in, strm->avail_in);
         state->x.have = strm->avail_in;
         strm->avail_in = 0;
     }
     state->how = COPY;
     state->direct = 1;
     return 0;
 }

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local int gz_skip	(	gz_statep	state,
		z_off64_t	len
	)

Definition at line 248 of file gzread.cc.

 {
     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->x.have) {
             n = GT_OFF(state->x.have) || (z_off64_t)state->x.have > len ?
                 (unsigned)len : state->x.have;
             state->x.have -= n;
             state->x.next += n;
             state->x.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 (gz_fetch(state) == -1)
                 return -1;
         }
     return 0;
 }

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int ZEXPORT gzclose_r ( gzFile file )

Definition at line 546 of file gzread.cc.

 {
     int ret, err;
     gz_statep state;
 
     /* get internal structure */
     if (file == NULL)
         return Z_STREAM_ERROR;
     state = (gz_statep)file;
 
     /* check that we're reading */
     if (state->mode != GZ_READ)
         return Z_STREAM_ERROR;
 
     /* free memory and close file */
     if (state->size) {
         inflateEnd(&(state->strm));
         free(state->out);
         free(state->in);
     }
     err = state->err == Z_BUF_ERROR ? Z_BUF_ERROR : Z_OK;
     gz_error(state, Z_OK, NULL);
     free(state->path);
     ret = close(state->fd);
     free(state);
     return ret ? Z_ERRNO : err;
 }

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int ZEXPORT gzdirect ( gzFile file )

Definition at line 527 of file gzread.cc.

 {
     gz_statep state;
 
     /* get internal structure */
     if (file == NULL)
         return 0;
     state = (gz_statep)file;
 
     /* if the state is not known, but we can find out, then do so (this is
        mainly for right after a gzopen() or gzdopen()) */
     if (state->mode == GZ_READ && state->how == LOOK && state->x.have == 0)
         (void)gz_look(state);
 
     /* return 1 if transparent, 0 if processing a gzip stream */
     return state->direct;
 }

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int ZEXPORT gzgetc ( gzFile file )

Definition at line 374 of file gzread.cc.

 {
     int ret;
     unsigned char buf[1];
     gz_statep state;
 
     /* get internal structure */
     if (file == NULL)
         return -1;
     state = (gz_statep)file;
 
     /* check that we're reading and that there's no (serious) error */
     if (state->mode != GZ_READ ||
         (state->err != Z_OK && state->err != Z_BUF_ERROR))
         return -1;
 
     /* try output buffer (no need to check for skip request) */
     if (state->x.have) {
         state->x.have--;
         state->x.pos++;
         return *(state->x.next)++;
     }
 
     /* nothing there -- try gzread() */
     ret = gzread(file, buf, 1);
     return ret < 1 ? -1 : buf[0];
 }

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int ZEXPORT gzgetc_ ( gzFile file )

Definition at line 402 of file gzread.cc.

 {
     return gzgetc(file);
 }

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char* ZEXPORT gzgets	(	gzFile	file,
		char *	buf,
		int	len
	)

Definition at line 466 of file gzread.cc.

 {
     unsigned left, n;
     char *str;
     unsigned char *eol;
     gz_statep state;
 
     /* check parameters and get internal structure */
     if (file == NULL || buf == NULL || len < 1)
         return NULL;
     state = (gz_statep)file;
 
     /* check that we're reading and that there's no (serious) error */
     if (state->mode != GZ_READ ||
         (state->err != Z_OK && state->err != Z_BUF_ERROR))
         return NULL;
 
     /* process a skip request */
     if (state->seek) {
         state->seek = 0;
         if (gz_skip(state, state->skip) == -1)
             return NULL;
     }
 
     /* copy output bytes up to new line or len - 1, whichever comes first --
        append a terminating zero to the string (we don't check for a zero in
        the contents, let the user worry about that) */
     str = buf;
     left = (unsigned)len - 1;
     if (left) do {
         /* assure that something is in the output buffer */
         if (state->x.have == 0 && gz_fetch(state) == -1)
             return NULL;                /* error */
         if (state->x.have == 0) {       /* end of file */
             state->past = 1;            /* read past end */
             break;                      /* return what we have */
         }
 
         /* look for end-of-line in current output buffer */
         n = state->x.have > left ? left : state->x.have;
         eol = (unsigned char *)memchr(state->x.next, '\n', n);
         if (eol != NULL)
             n = (unsigned)(eol - state->x.next) + 1;
 
         /* copy through end-of-line, or remainder if not found */
         memcpy(buf, state->x.next, n);
         state->x.have -= n;
         state->x.next += n;
         state->x.pos += n;
         left -= n;
         buf += n;
     } while (left && eol == NULL);
 
     /* return terminated string, or if nothing, end of file */
     if (buf == str)
         return NULL;
     buf[0] = 0;
     return str;
 }

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int ZEXPORT gzread	(	gzFile	file,
		voidp	buf,
		unsigned	len
	)

Definition at line 278 of file gzread.cc.

 {
     unsigned got, n;
     gz_statep state;
     z_streamp strm;
 
     /* get internal structure */
     if (file == NULL)
         return -1;
     state = (gz_statep)file;
     strm = &(state->strm);
 
     /* check that we're reading and that there's no (serious) error */
     if (state->mode != GZ_READ ||
             (state->err != Z_OK && state->err != Z_BUF_ERROR))
         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) {
         gz_error(state, Z_DATA_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 (gz_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->x.have) {
             n = state->x.have > len ? len : state->x.have;
             memcpy(buf, state->x.next, n);
             state->x.next += n;
             state->x.have -= n;
         }
 
         /* output buffer empty -- return if we're at the end of the input */
         else if (state->eof && strm->avail_in == 0) {
             state->past = 1;        /* tried to read past end */
             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 (gz_fetch(state) == -1)
                 return -1;
             continue;       /* no progress yet -- go back to copy 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 (gz_load(state, (unsigned char *)buf, len, &n) == -1)
                 return -1;
         }
 
         /* large len -- decompress directly into user buffer */
         else {  /* state->how == GZIP */
             strm->avail_out = len;
             strm->next_out = (unsigned char *)buf;
             if (gz_decomp(state) == -1)
                 return -1;
             n = state->x.have;
             state->x.have = 0;
         }
 
         /* update progress */
         len -= n;
         buf = (char *)buf + n;
         got += n;
         state->x.pos += n;
     } while (len);
 
     /* return number of bytes read into user buffer (will fit in int) */
     return (int)got;
 }

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int ZEXPORT gzungetc	(	int	c,
		gzFile	file
	)

Definition at line 408 of file gzread.cc.

 {
     gz_statep state;
 
     /* get internal structure */
     if (file == NULL)
         return -1;
     state = (gz_statep)file;
 
     /* check that we're reading and that there's no (serious) error */
     if (state->mode != GZ_READ ||
         (state->err != Z_OK && state->err != Z_BUF_ERROR))
         return -1;
 
     /* process a skip request */
     if (state->seek) {
         state->seek = 0;
         if (gz_skip(state, state->skip) == -1)
             return -1;
     }
 
     /* can't push EOF */
     if (c < 0)
         return -1;
 
     /* if output buffer empty, put byte at end (allows more pushing) */
     if (state->x.have == 0) {
         state->x.have = 1;
         state->x.next = state->out + (state->size << 1) - 1;
         state->x.next[0] = c;
         state->x.pos--;
         state->past = 0;
         return c;
     }
 
     /* if no room, give up (must have already done a gzungetc()) */
     if (state->x.have == (state->size << 1)) {
         gz_error(state, Z_DATA_ERROR, "out of room to push characters");
         return -1;
     }
 
     /* slide output data if needed and insert byte before existing data */
     if (state->x.next == state->out) {
         unsigned char *src = state->out + state->x.have;
         unsigned char *dest = state->out + (state->size << 1);
         while (src > state->out)
             *--dest = *--src;
         state->x.next = dest;
     }
     state->x.have++;
     state->x.next--;
     state->x.next[0] = c;
     state->x.pos--;
     state->past = 0;
     return c;
 }

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local int gz_load OF ( (gz_statep, unsigned char *, unsigned, unsigned *) )

local int gz_avail OF ( (gz_statep) )

local int gz_skip OF ( (gz_statep, z_off64_t) )

Functions

Function Documentation