manual_3.html

bzip2是一个免费的

</pre></td></tr></table></P><P>

<HR SIZE="6">
<A NAME="SEC27"></A>
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="manual_3.html#SEC26"> &lt; </A>]</TD>
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="manual_3.html#SEC28"> &gt; </A>]</TD>
<TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT">[ &lt;&lt; ]</TD>
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="manual.html#SEC_Top"> Up </A>]</TD>
<TD VALIGN="MIDDLE" ALIGN="LEFT">[ &gt;&gt; ]</TD>
<TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="manual.html#SEC_Top">Top</A>]</TD>
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="manual_toc.html#SEC_Contents">Contents</A>]</TD>
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="manual_abt.html#SEC_About"> ? </A>]</TD>
</TR></TABLE>
<H3> 3.4.2 <CODE>BZ2_bzRead</CODE> </H3>
<!--docid::SEC27::-->
<TABLE><tr><td>&nbsp;</td><td class=example><pre>   int BZ2_bzRead ( int *bzerror, BZFILE *b, void *buf, int len );
</pre></td></tr></table>Reads up to <CODE>len</CODE> (uncompressed) bytes from the compressed file 
<CODE>b</CODE> into
the buffer <CODE>buf</CODE>.  If the read was successful, 
<CODE>bzerror</CODE> is set to <CODE>BZ_OK</CODE>
and the number of bytes read is returned.  If the logical end-of-stream
was detected, <CODE>bzerror</CODE> will be set to <CODE>BZ_STREAM_END</CODE>, 
and the number
of bytes read is returned.  All other <CODE>bzerror</CODE> values denote an error.
<P>

<CODE>BZ2_bzRead</CODE> will supply <CODE>len</CODE> bytes,
unless the logical stream end is detected
or an error occurs.  Because of this, it is possible to detect the 
stream end by observing when the number of bytes returned is 
less than the number
requested.  Nevertheless, this is regarded as inadvisable; you should
instead check <CODE>bzerror</CODE> after every call and watch out for
<CODE>BZ_STREAM_END</CODE>.
</P><P>

Internally, <CODE>BZ2_bzRead</CODE> copies data from the compressed file in chunks
of size <CODE>BZ_MAX_UNUSED</CODE> bytes
before decompressing it.  If the file contains more bytes than strictly
needed to reach the logical end-of-stream, <CODE>BZ2_bzRead</CODE> will almost certainly
read some of the trailing data before signalling <CODE>BZ_SEQUENCE_END</CODE>.
To collect the read but unused data once <CODE>BZ_SEQUENCE_END</CODE> has 
appeared, call <CODE>BZ2_bzReadGetUnused</CODE> immediately before <CODE>BZ2_bzReadClose</CODE>.
</P><P>

Possible assignments to <CODE>bzerror</CODE>:
<TABLE><tr><td>&nbsp;</td><td class=display><pre style="font-family: serif">      <CODE>BZ_PARAM_ERROR</CODE>
         if <CODE>b</CODE> is <CODE>NULL</CODE> or <CODE>buf</CODE> is <CODE>NULL</CODE> or <CODE>len &#60; 0</CODE>
      <CODE>BZ_SEQUENCE_ERROR</CODE> 
         if <CODE>b</CODE> was opened with <CODE>BZ2_bzWriteOpen</CODE>
      <CODE>BZ_IO_ERROR</CODE> 
         if there is an error reading from the compressed file
      <CODE>BZ_UNEXPECTED_EOF</CODE> 
         if the compressed file ended before the logical end-of-stream was detected
      <CODE>BZ_DATA_ERROR</CODE> 
         if a data integrity error was detected in the compressed stream
      <CODE>BZ_DATA_ERROR_MAGIC</CODE>
         if the stream does not begin with the requisite header bytes (ie, is not 
         a <CODE>bzip2</CODE> data file).  This is really a special case of <CODE>BZ_DATA_ERROR</CODE>.
      <CODE>BZ_MEM_ERROR</CODE> 
         if insufficient memory was available
      <CODE>BZ_STREAM_END</CODE> 
         if the logical end of stream was detected.
      <CODE>BZ_OK</CODE>
         otherwise.
</pre></td></tr></table></P><P>

Possible return values:
<TABLE><tr><td>&nbsp;</td><td class=display><pre style="font-family: serif">      number of bytes read
         if <CODE>bzerror</CODE> is <CODE>BZ_OK</CODE> or <CODE>BZ_STREAM_END</CODE>
      undefined
         otherwise
</pre></td></tr></table></P><P>

Allowable next actions:
<TABLE><tr><td>&nbsp;</td><td class=display><pre style="font-family: serif">      collect data from <CODE>buf</CODE>, then <CODE>BZ2_bzRead</CODE> or <CODE>BZ2_bzReadClose</CODE>
         if <CODE>bzerror</CODE> is <CODE>BZ_OK</CODE> 
      collect data from <CODE>buf</CODE>, then <CODE>BZ2_bzReadClose</CODE> or <CODE>BZ2_bzReadGetUnused</CODE> 
         if <CODE>bzerror</CODE> is <CODE>BZ_SEQUENCE_END</CODE>   
      <CODE>BZ2_bzReadClose</CODE> 
         otherwise
</pre></td></tr></table></P><P>

<HR SIZE="6">
<A NAME="SEC28"></A>
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="manual_3.html#SEC27"> &lt; </A>]</TD>
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="manual_3.html#SEC29"> &gt; </A>]</TD>
<TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT">[ &lt;&lt; ]</TD>
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="manual.html#SEC_Top"> Up </A>]</TD>
<TD VALIGN="MIDDLE" ALIGN="LEFT">[ &gt;&gt; ]</TD>
<TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="manual.html#SEC_Top">Top</A>]</TD>
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="manual_toc.html#SEC_Contents">Contents</A>]</TD>
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="manual_abt.html#SEC_About"> ? </A>]</TD>
</TR></TABLE>
<H3> 3.4.3 <CODE>BZ2_bzReadGetUnused</CODE> </H3>
<!--docid::SEC28::-->
<TABLE><tr><td>&nbsp;</td><td class=example><pre>   void BZ2_bzReadGetUnused ( int* bzerror, BZFILE *b, 
                              void** unused, int* nUnused );
</pre></td></tr></table>Returns data which was read from the compressed file but was not needed
to get to the logical end-of-stream.  <CODE>*unused</CODE> is set to the address
of the data, and <CODE>*nUnused</CODE> to the number of bytes.  <CODE>*nUnused</CODE> will
be set to a value between <CODE>0</CODE> and <CODE>BZ_MAX_UNUSED</CODE> inclusive.
<P>

This function may only be called once <CODE>BZ2_bzRead</CODE> has signalled 
<CODE>BZ_STREAM_END</CODE> but before <CODE>BZ2_bzReadClose</CODE>.
</P><P>

Possible assignments to <CODE>bzerror</CODE>:
<TABLE><tr><td>&nbsp;</td><td class=display><pre style="font-family: serif">      <CODE>BZ_PARAM_ERROR</CODE> 
         if <CODE>b</CODE> is <CODE>NULL</CODE> 
         or <CODE>unused</CODE> is <CODE>NULL</CODE> or <CODE>nUnused</CODE> is <CODE>NULL</CODE>
      <CODE>BZ_SEQUENCE_ERROR</CODE> 
         if <CODE>BZ_STREAM_END</CODE> has not been signalled
         or if <CODE>b</CODE> was opened with <CODE>BZ2_bzWriteOpen</CODE>
     <CODE>BZ_OK</CODE>
         otherwise
</pre></td></tr></table></P><P>

Allowable next actions:
<TABLE><tr><td>&nbsp;</td><td class=display><pre style="font-family: serif">      <CODE>BZ2_bzReadClose</CODE>
</pre></td></tr></table></P><P>

<HR SIZE="6">
<A NAME="SEC29"></A>
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="manual_3.html#SEC28"> &lt; </A>]</TD>
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="manual_3.html#SEC30"> &gt; </A>]</TD>
<TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT">[ &lt;&lt; ]</TD>
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="manual.html#SEC_Top"> Up </A>]</TD>
<TD VALIGN="MIDDLE" ALIGN="LEFT">[ &gt;&gt; ]</TD>
<TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="manual.html#SEC_Top">Top</A>]</TD>
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="manual_toc.html#SEC_Contents">Contents</A>]</TD>
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="manual_abt.html#SEC_About"> ? </A>]</TD>
</TR></TABLE>
<H3> 3.4.4 <CODE>BZ2_bzReadClose</CODE> </H3>
<!--docid::SEC29::-->
<TABLE><tr><td>&nbsp;</td><td class=example><pre>   void BZ2_bzReadClose ( int *bzerror, BZFILE *b );
</pre></td></tr></table>Releases all memory pertaining to the compressed file <CODE>b</CODE>.  
<CODE>BZ2_bzReadClose</CODE> does not call <CODE>fclose</CODE> on the underlying file
handle, so you should do that yourself if appropriate.
<CODE>BZ2_bzReadClose</CODE> should be called to clean up after all error
situations.
<P>

Possible assignments to <CODE>bzerror</CODE>:
<TABLE><tr><td>&nbsp;</td><td class=display><pre style="font-family: serif">      <CODE>BZ_SEQUENCE_ERROR</CODE> 
         if <CODE>b</CODE> was opened with <CODE>BZ2_bzOpenWrite</CODE> 
      <CODE>BZ_OK</CODE> 
         otherwise
</pre></td></tr></table></P><P>

Allowable next actions:
<TABLE><tr><td>&nbsp;</td><td class=display><pre style="font-family: serif">      none
</pre></td></tr></table></P><P>

<HR SIZE="6">
<A NAME="SEC30"></A>
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="manual_3.html#SEC29"> &lt; </A>]</TD>
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="manual_3.html#SEC31"> &gt; </A>]</TD>
<TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT">[ &lt;&lt; ]</TD>
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="manual.html#SEC_Top"> Up </A>]</TD>
<TD VALIGN="MIDDLE" ALIGN="LEFT">[ &gt;&gt; ]</TD>
<TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="manual.html#SEC_Top">Top</A>]</TD>
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="manual_toc.html#SEC_Contents">Contents</A>]</TD>
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="manual_abt.html#SEC_About"> ? </A>]</TD>
</TR></TABLE>
<H3> 3.4.5 <CODE>BZ2_bzWriteOpen</CODE> </H3>
<!--docid::SEC30::-->
<TABLE><tr><td>&nbsp;</td><td class=example><pre>   BZFILE *BZ2_bzWriteOpen ( int *bzerror, FILE *f, 
                             int blockSize100k, int verbosity,
                             int workFactor );
</pre></td></tr></table>Prepare to write compressed data to file handle <CODE>f</CODE>.  
<CODE>f</CODE> should refer to
a file which has been opened for writing, and for which the error
indicator (<CODE>ferror(f)</CODE>)is not set.  
<P>

For the meaning of parameters <CODE>blockSize100k</CODE>,
<CODE>verbosity</CODE> and <CODE>workFactor</CODE>, see
<BR> <CODE>BZ2_bzCompressInit</CODE>.
</P><P>

All required memory is allocated at this stage, so if the call
completes successfully, <CODE>BZ_MEM_ERROR</CODE> cannot be signalled by a
subsequent call to <CODE>BZ2_bzWrite</CODE>.
</P><P>

Possible assignments to <CODE>bzerror</CODE>:
<TABLE><tr><td>&nbsp;</td><td class=display><pre style="font-family: serif">      <CODE>BZ_CONFIG_ERROR</CODE>
         if the library has been mis-compiled
      <CODE>BZ_PARAM_ERROR</CODE> 
         if <CODE>f</CODE> is <CODE>NULL</CODE> 
         or <CODE>blockSize100k &#60; 1</CODE> or <CODE>blockSize100k &#62; 9</CODE>
      <CODE>BZ_IO_ERROR</CODE> 
         if <CODE>ferror(f)</CODE> is nonzero
      <CODE>BZ_MEM_ERROR</CODE> 
         if insufficient memory is available
      <CODE>BZ_OK</CODE> 
         otherwise
</pre></td></tr></table></P><P>

Possible return values:
<TABLE><tr><td>&nbsp;</td><td class=display><pre style="font-family: serif">      Pointer to an abstract <CODE>BZFILE</CODE>  
         if <CODE>bzerror</CODE> is <CODE>BZ_OK</CODE>   
      <CODE>NULL</CODE> 
         otherwise
</pre></td></tr></table></P><P>

Allowable next actions:
<TABLE><tr><td>&nbsp;</td><td class=display><pre style="font-family: serif">      <CODE>BZ2_bzWrite</CODE> 
         if <CODE>bzerror</CODE> is <CODE>BZ_OK</CODE> 
         (you could go directly to <CODE>BZ2_bzWriteClose</CODE>, but this would be pretty pointless)
      <CODE>BZ2_bzWriteClose</CODE> 
         otherwise
</pre></td></tr></table></P><P>

<HR SIZE="6">
<A NAME="SEC31"></A>
<TABLE CELLPADDING=1 CELLSPACING=1 BORDER=0>
<TR><TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="manual_3.html#SEC30"> &lt; </A>]</TD>
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="manual_3.html#SEC32"> &gt; </A>]</TD>
<TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT">[ &lt;&lt; ]</TD>
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="manual.html#SEC_Top"> Up </A>]</TD>
<TD VALIGN="MIDDLE" ALIGN="LEFT">[ &gt;&gt; ]</TD>
<TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT"> &nbsp; <TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="manual.html#SEC_Top">Top</A>]</TD>
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="manual_toc.html#SEC_Contents">Contents</A>]</TD>
<TD VALIGN="MIDDLE" ALIGN="LEFT">[Index]</TD>
<TD VALIGN="MIDDLE" ALIGN="LEFT">[<A HREF="manual_abt.html#SEC_About"> ? </A>]</TD>
</TR></TABLE>
<H3> 3.4.6 <CODE>BZ2_bzWrite</CODE> </H3>
<!--docid::SEC31::-->
<TABLE><tr><td>&nbsp;</td><td class=example><pre>   void BZ2_bzWrite ( int *bzerror, BZFILE *b, void *buf, int len );
</pre></td></tr></table>Absorbs <CODE>len</CODE> bytes from the buffer <CODE>buf</CODE>, eventually to be
compressed and written to the file.
<P>

Possible assignments to <CODE>bzerror</CODE>:
<TABLE><tr><td>&nbsp;</td><td class=display><pre style="font-family: serif">      <CODE>BZ_PARAM_ERROR</CODE> 
         if <CODE>b</CODE> is <CODE>NULL</CODE> or <CODE>buf</CODE> is <CODE>NULL</CODE> or <CODE>len &#60; 0</CODE>
      <CODE>BZ_SEQUENCE_ERROR</CODE> 
         if b was opened with <CODE>BZ2_bzReadOpen</CODE>
      <CODE>BZ_IO_ERROR</CODE> 
         if there is an error writing the compressed file.
      <CODE>BZ_OK</CODE> 
         otherwise
</pre></td></tr></table></P><P>

<HR SIZE=