bzip2.c

高效率的一种通用压缩/解压程序

/*-----------------------------------------------------------*/
/*--- A block-sorting, lossless compressor        bzip2.c ---*/
/*-----------------------------------------------------------*/

/*--
  This file is a part of bzip2 and/or libbzip2, a program and
  library for lossless, block-sorting data compression.

  Copyright (C) 1996-1998 Julian R Seward.  All rights reserved.

  Redistribution and use in source and binary forms, with or without
  modification, are permitted provided that the following conditions
  are met:

  1. Redistributions of source code must retain the above copyright
     notice, this list of conditions and the following disclaimer.

  2. The origin of this software must not be misrepresented; you must 
     not claim that you wrote the original software.  If you use this 
     software in a product, an acknowledgment in the product 
     documentation would be appreciated but is not required.

  3. Altered source versions must be plainly marked as such, and must
     not be misrepresented as being the original software.

  4. The name of the author may not be used to endorse or promote 
     products derived from this software without specific prior written 
     permission.

  THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
  OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
  DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
  GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

  Julian Seward, Guildford, Surrey, UK.
  [e-mail]
  bzip2/libbzip2 version 0.9.0c of 18 October 1998

  This program is based on (at least) the work of:
     Mike Burrows
     David Wheeler
     Peter Fenwick
     Alistair Moffat
     Radford Neal
     Ian H. Witten
     Robert Sedgewick
     Jon L. Bentley

  For more information on these sources, see the manual.
--*/


/*----------------------------------------------------*/
/*--- IMPORTANT                                    ---*/
/*----------------------------------------------------*/

/*--
   WARNING:
      This program and library (attempts to) compress data by 
      performing several non-trivial transformations on it.  
      Unless you are 100% familiar with *all* the algorithms 
      contained herein, and with the consequences of modifying them, 
      you should NOT meddle with the compression or decompression 
      machinery.  Incorrect changes can and very likely *will* 
      lead to disasterous loss of data.

   DISCLAIMER:
      I TAKE NO RESPONSIBILITY FOR ANY LOSS OF DATA ARISING FROM THE
      USE OF THIS PROGRAM, HOWSOEVER CAUSED.

      Every compression of a file implies an assumption that the
      compressed file can be decompressed to reproduce the original.
      Great efforts in design, coding and testing have been made to
      ensure that this program works correctly.  However, the
      complexity of the algorithms, and, in particular, the presence
      of various special cases in the code which occur with very low
      but non-zero probability make it impossible to rule out the
      possibility of bugs remaining in the program.  DO NOT COMPRESS
      ANY DATA WITH THIS PROGRAM AND/OR LIBRARY UNLESS YOU ARE PREPARED 
      TO ACCEPT THE POSSIBILITY, HOWEVER SMALL, THAT THE DATA WILL 
      NOT BE RECOVERABLE.

      That is not to say this program is inherently unreliable.
      Indeed, I very much hope the opposite is true.  bzip2/libbzip2
      has been carefully constructed and extensively tested.

   PATENTS:
      To the best of my knowledge, bzip2/libbzip2 does not use any 
      patented algorithms.  However, I do not have the resources 
      available to carry out a full patent search.  Therefore I cannot 
      give any guarantee of the above statement.
--*/



/*----------------------------------------------------*/
/*--- and now for something much more pleasant :-) ---*/
/*----------------------------------------------------*/

/*---------------------------------------------*/
/*--
  Place a 1 beside your platform, and 0 elsewhere.
--*/

/*--
  Generic 32-bit Unix.
  Also works on 64-bit Unix boxes.
--*/
#define BZ_UNIX      1

/*--
  Win32, as seen by Jacob Navia's excellent
  port of (Chris Fraser & David Hanson)'s excellent
  lcc compiler.
--*/
#define BZ_LCCWIN32  0

#ifdef _WIN32
#define BZ_LCCWIN32 1
#define BZ_UNIX 0
#endif


/*---------------------------------------------*/
/*--
  Some stuff for all platforms.
--*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <math.h>
#include "bzlib.h"

#define ERROR_IF_EOF(i)       { if ((i) == EOF)  ioError(); }
#define ERROR_IF_NOT_ZERO(i)  { if ((i) != 0)    ioError(); }
#define ERROR_IF_MINUS_ONE(i) { if ((i) == (-1)) ioError(); }


/*---------------------------------------------*/
/*--
   Platform-specific stuff.
--*/

#if BZ_UNIX
#   include <sys/types.h>
#   include <utime.h>
#   include <unistd.h>
#   include <sys/stat.h>
#   include <sys/times.h>

#   define PATH_SEP    '/'
#   define MY_LSTAT    lstat
#   define MY_S_IFREG  S_ISREG
#   define MY_STAT     stat

#   define APPEND_FILESPEC(root, name) \
      root=snocString((root), (name))

#   define SET_BINARY_MODE(fd) /**/

#   ifdef __GNUC__
#      define NORETURN __attribute__ ((noreturn))
#   else
#      define NORETURN /**/
#   endif
#endif



#if BZ_LCCWIN32
#   include <io.h>
#   include <fcntl.h>
#   include <sys\stat.h>

#   define NORETURN       /**/
#   define PATH_SEP       '\\'
#   define MY_LSTAT       _stat
#   define MY_STAT        _stat
#   define MY_S_IFREG(x)  ((x) & _S_IFREG)

#   if 0
   /*-- lcc-win32 seems to expand wildcards itself --*/
#   define APPEND_FILESPEC(root, spec)                \
      do {                                            \
         if ((spec)[0] == '-') {                      \
            root = snocString((root), (spec));        \
         } else {                                     \
            struct _finddata_t c_file;                \
            long hFile;                               \
            hFile = _findfirst((spec), &c_file);      \
            if ( hFile == -1L ) {                     \
               root = snocString ((root), (spec));    \
            } else {                                  \
               int anInt = 0;                         \
               while ( anInt == 0 ) {                 \
                  root = snocString((root),           \
                            &c_file.name[0]);         \
                  anInt = _findnext(hFile, &c_file);  \
               }                                      \
            }                                         \
         }                                            \
      } while ( 0 )
#   else
#   define APPEND_FILESPEC(root, name)                \
      root = snocString ((root), (name))
#   endif

#   define SET_BINARY_MODE(fd)                        \
      do {                                            \
         int retVal = setmode ( fileno ( fd ),        \
                               O_BINARY );            \
         ERROR_IF_MINUS_ONE ( retVal );               \
      } while ( 0 )

#endif


/*---------------------------------------------*/
/*--
  Some more stuff for all platforms :-)
--*/

typedef char            Char;
typedef unsigned char   Bool;
typedef unsigned char   UChar;
typedef int             Int32;
typedef unsigned int    UInt32;
typedef short           Int16;
typedef unsigned short  UInt16;
                                       
#define True  ((Bool)1)
#define False ((Bool)0)

/*--
  IntNative is your platform's `native' int size.
  Only here to avoid probs with 64-bit platforms.
--*/
typedef int IntNative;


/*---------------------------------------------------*/
/*--- Misc (file handling) data decls             ---*/
/*---------------------------------------------------*/

Int32   verbosity;
Bool    keepInputFiles, smallMode;
Bool    forceOverwrite, testFailsExist;
Int32   numFileNames, numFilesProcessed, blockSize100k;


/*-- source modes; F==file, I==stdin, O==stdout --*/
#define SM_I2O           1
#define SM_F2O           2
#define SM_F2F           3

/*-- operation modes --*/
#define OM_Z             1
#define OM_UNZ           2
#define OM_TEST          3

Int32   opMode;
Int32   srcMode;

#define FILE_NAME_LEN 1034

Int32   longestFileName;
Char    inName[FILE_NAME_LEN];
Char    outName[FILE_NAME_LEN];
Char    *progName;
Char    progNameReally[FILE_NAME_LEN];
FILE    *outputHandleJustInCase;
Int32   workFactor;

void    panic                 ( Char* )   NORETURN;
void    ioError               ( void )    NORETURN;
void    outOfMemory           ( void )    NORETURN;
void    blockOverrun          ( void )    NORETURN;
void    badBlockHeader        ( void )    NORETURN;
void    badBGLengths          ( void )    NORETURN;
void    crcError              ( void )    NORETURN;
void    bitStreamEOF          ( void )    NORETURN;
void    cleanUpAndFail        ( Int32 )   NORETURN;
void    compressedStreamEOF   ( void )    NORETURN;

void    copyFileName ( Char*, Char* );
void*   myMalloc ( Int32 );



/*---------------------------------------------------*/
/*--- Processing of complete files and streams    ---*/
/*---------------------------------------------------*/

/*---------------------------------------------*/
Bool myfeof ( FILE* f )
{
   Int32 c = fgetc ( f );
   if (c == EOF) return True;
   ungetc ( c, f );
   return False;
}


/*---------------------------------------------*/
void compressStream ( FILE *stream, FILE *zStream )
{
   BZFILE* bzf = NULL;
   UChar   ibuf[5000];
   Int32   nIbuf;
   UInt32  nbytes_in, nbytes_out;
   Int32   bzerr, bzerr_dummy, ret;

   SET_BINARY_MODE(stream);
   SET_BINARY_MODE(zStream);

   if (ferror(stream)) goto errhandler_io;
   if (ferror(zStream)) goto errhandler_io;

   bzf = bzWriteOpen ( &bzerr, zStream, 
                       blockSize100k, verbosity, workFactor );   
   if (bzerr != BZ_OK) goto errhandler;

   if (verbosity >= 2) fprintf ( stderr, "\n" );

   while (True) {

      if (myfeof(stream)) break;
      nIbuf = fread ( ibuf, sizeof(UChar), 5000, stream );
      if (ferror(stream)) goto errhandler_io;
      if (nIbuf > 0) bzWrite ( &bzerr, bzf, (void*)ibuf, nIbuf );
      if (bzerr != BZ_OK) goto errhandler;

   }

   bzWriteClose ( &bzerr, bzf, 0, &nbytes_in, &nbytes_out );
   if (bzerr != BZ_OK) goto errhandler;

   if (ferror(zStream)) goto errhandler_io;
   ret = fflush ( zStream );
   if (ret == EOF) goto errhandler_io;
   if (zStream != stdout) {
      ret = fclose ( zStream );
      if (ret == EOF) goto errhandler_io;
   }
   if (ferror(stream)) goto errhandler_io;
   ret = fclose ( stream );
   if (ret == EOF) goto errhandler_io;

   if (nbytes_in == 0) nbytes_in = 1;

   if (verbosity >= 1)
      fprintf ( stderr, "%6.3f:1, %6.3f bits/byte, "
                        "%5.2f%% saved, %d in, %d out.\n",
                (float)nbytes_in / (float)nbytes_out,
                (8.0 * (float)nbytes_out) / (float)nbytes_in,
                100.0 * (1.0 - (float)nbytes_out / (float)nbytes_in),
                nbytes_in,
                nbytes_out
              );

   return;

   errhandler:
   bzWriteClose ( &bzerr_dummy, bzf, 1, &nbytes_in, &nbytes_out );
   switch (bzerr) {
      case BZ_MEM_ERROR:
         outOfMemory ();
      case BZ_IO_ERROR:
         errhandler_io:
         ioError(); break;
      default:
         panic ( "compress:unexpected error" );
   }

   panic ( "compress:end" );
   /*notreached*/
}



/*---------------------------------------------*/
Bool uncompressStream ( FILE *zStream, FILE *stream )
{
   BZFILE* bzf = NULL;
   Int32   bzerr, bzerr_dummy, ret, nread, streamNo, i;
   UChar   obuf[5000];
   UChar   unused[BZ_MAX_UNUSED];
   Int32   nUnused;
   UChar*  unusedTmp;

   nUnused = 0;
   streamNo = 0;

   SET_BINARY_MODE(stream);
   SET_BINARY_MODE(zStream);

   if (ferror(stream)) goto errhandler_io;
   if (ferror(zStream)) goto errhandler_io;

   while (True) {

      bzf = bzReadOpen ( 
               &bzerr, zStream, verbosity, 
               (int)smallMode, unused, nUnused
            );
      if (bzf == NULL || bzerr != BZ_OK) goto errhandler;
      streamNo++;

      while (bzerr == BZ_OK) {
         nread = bzRead ( &bzerr, bzf, obuf, 5000 );
         if (bzerr == BZ_DATA_ERROR_MAGIC) goto errhandler;
         if ((bzerr == BZ_OK || bzerr == BZ_STREAM_END) && nread > 0)
            fwrite ( obuf, sizeof(UChar), nread, stream );
         if (ferror(stream)) goto errhandler_io;
      }
      if (bzerr != BZ_STREAM_END) goto errhandler;

      bzReadGetUnused ( &bzerr, bzf, (void**)(&unusedTmp), &nUnused );
      if (bzerr != BZ_OK) panic ( "decompress:bzReadGetUnused" );

      for (i = 0; i < nUnused; i++) unused[i] = unusedTmp[i];

      bzReadClose ( &bzerr, bzf );
      if (bzerr != BZ_OK) panic ( "decompress:bzReadGetUnused" );

      if (nUnused == 0 && myfeof(zStream)) break;

   }

   if (ferror(zStream)) goto errhandler_io;
   ret = fclose ( zStream );
   if (ret == EOF) goto errhandler_io;

   if (ferror(stream)) goto errhandler_io;
   ret = fflush ( stream );
   if (ret != 0) goto errhandler_io;
   if (stream != stdout) {
      ret = fclose ( stream );
      if (ret == EOF) goto errhandler_io;
   }
   if (verbosity >= 2) fprintf ( stderr, "\n    " );
   return True;

   errhandler:
   bzReadClose ( &bzerr_dummy, bzf );
   switch (bzerr) {
      case BZ_IO_ERROR:
         errhandler_io:
         ioError(); break;
      case BZ_DATA_ERROR:
         crcError();
      case BZ_MEM_ERROR:
         outOfMemory();
      case BZ_UNEXPECTED_EOF:
         compressedStreamEOF();
      case BZ_DATA_ERROR_MAGIC:
         if (streamNo == 1) {
            return False;
         } else {
            fprintf ( stderr, 
                      "\n%s: %s: trailing garbage after EOF ignored\n",
                      progName, inName );
            return True;       
         }
      default:
         panic ( "decompress:unexpected error" );
   }

   panic ( "decompress:end" );
   return True; /*notreached*/
}


/*---------------------------------------------*/
Bool testStream ( FILE *zStream )
{
   BZFILE* bzf = NULL;
   Int32   bzerr, bzerr_dummy, ret, nread, streamNo, i;
   UChar   obuf[5000];
   UChar   unused[BZ_MAX_UNUSED];
   Int32   nUnused;
   UChar*  unusedTmp;

   nUnused = 0;
   streamNo = 0;

   SET_BINARY_MODE(zStream);
   if (ferror(zStream)) goto errhandler_io;

   while (True) {

      bzf = bzReadOpen ( 
               &bzerr, zStream, verbosity, 
               (int)smallMode, unused, nUnused
            );
      if (bzf == NULL || bzerr != BZ_OK) goto errhandler;
      streamNo++;