path: root/minilzip.c

/* Minilzip - Test program for the library lzlib
   Copyright (C) 2009-2024 Antonio Diaz Diaz.

   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 2 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/
/*
   Exit status: 0 for a normal exit, 1 for environmental problems
   (file not found, invalid command-line options, I/O errors, etc), 2 to
   indicate a corrupt or invalid input file, 3 for an internal consistency
   error (e.g., bug) which caused minilzip to panic.
*/

#define _FILE_OFFSET_BITS 64

#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>		/* SSIZE_MAX */
#include <signal.h>
#include <stdbool.h>
#include <stdint.h>		/* SIZE_MAX */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <utime.h>
#include <sys/stat.h>
#if defined __MSVCRT__ || defined __OS2__ || defined __DJGPP__
#include <io.h>
#if defined __MSVCRT__
#define fchmod(x,y) 0
#define fchown(x,y,z) 0
#define strtoull strtoul
#define SIGHUP SIGTERM
#define S_ISSOCK(x) 0
#ifndef S_IRGRP
#define S_IRGRP 0
#define S_IWGRP 0
#define S_IROTH 0
#define S_IWOTH 0
#endif
#endif
#if defined __DJGPP__
#define S_ISSOCK(x) 0
#define S_ISVTX 0
#endif
#endif

#include "carg_parser.h"
#include "lzlib.h"

#ifndef O_BINARY
#define O_BINARY 0
#endif

#if CHAR_BIT != 8
#error "Environments where CHAR_BIT != 8 are not supported."
#endif

#if ( defined  SIZE_MAX &&  SIZE_MAX < UINT_MAX ) || \
    ( defined SSIZE_MAX && SSIZE_MAX <  INT_MAX )
#error "Environments where 'size_t' is narrower than 'int' are not supported."
#endif

#ifndef max
  #define max(x,y) ((x) >= (y) ? (x) : (y))
#endif
#ifndef min
  #define min(x,y) ((x) <= (y) ? (x) : (y))
#endif

static void cleanup_and_fail( const int retval );
static void show_error( const char * const msg, const int errcode,
                        const bool help );
static void show_file_error( const char * const filename,
                             const char * const msg, const int errcode );
static void internal_error( const char * const msg );
static const char * const mem_msg = "Not enough memory.";

int verbosity = 0;

static const char * const program_name = "minilzip";
static const char * const program_year = "2024";
static const char * invocation_name = "minilzip";	/* default value */

static const struct { const char * from; const char * to; } known_extensions[] = {
  { ".lz",  ""     },
  { ".tlz", ".tar" },
  { 0,      0      } };

struct Lzma_options
  {
  int dictionary_size;		/* 4 KiB .. 512 MiB */
  int match_len_limit;		/* 5 .. 273 */
  };

enum Mode { m_compress, m_decompress, m_test };

/* Variables used in signal handler context.
   They are not declared volatile because the handler never returns. */
static char * output_filename = 0;
static int outfd = -1;
static bool delete_output_on_interrupt = false;


static void show_help( void )
  {
  printf( "Minilzip is a test program for the compression library lzlib, compatible\n"
          "with lzip 1.4 or newer.\n"
          "\nLzip is a lossless data compressor with a user interface similar to the one\n"
          "of gzip or bzip2. Lzip uses a simplified form of the 'Lempel-Ziv-Markov\n"
          "chain-Algorithm' (LZMA) stream format to maximize interoperability. The\n"
          "maximum dictionary size is 512 MiB so that any lzip file can be decompressed\n"
          "on 32-bit machines. Lzip provides accurate and robust 3-factor integrity\n"
          "checking. Lzip can compress about as fast as gzip (lzip -0) or compress most\n"
          "files more than bzip2 (lzip -9). Decompression speed is intermediate between\n"
          "gzip and bzip2. Lzip is better than gzip and bzip2 from a data recovery\n"
          "perspective. Lzip has been designed, written, and tested with great care to\n"
          "replace gzip and bzip2 as the standard general-purpose compressed format for\n"
          "Unix-like systems.\n"
          "\nUsage: %s [options] [files]\n", invocation_name );
  printf( "\nOptions:\n"
          "  -h, --help                     display this help and exit\n"
          "  -V, --version                  output version information and exit\n"
          "  -a, --trailing-error           exit with error status if trailing data\n"
          "  -b, --member-size=<bytes>      set member size limit in bytes\n"
          "  -c, --stdout                   write to standard output, keep input files\n"
          "  -d, --decompress               decompress, test compressed file integrity\n"
          "  -f, --force                    overwrite existing output files\n"
          "  -F, --recompress               force re-compression of compressed files\n"
          "  -k, --keep                     keep (don't delete) input files\n"
          "  -m, --match-length=<bytes>     set match length limit in bytes [36]\n"
          "  -o, --output=<file>            write to <file>, keep input files\n"
          "  -q, --quiet                    suppress all messages\n"
          "  -s, --dictionary-size=<bytes>  set dictionary size limit in bytes [8 MiB]\n"
          "  -S, --volume-size=<bytes>      set volume size limit in bytes\n"
          "  -t, --test                     test compressed file integrity\n"
          "  -v, --verbose                  be verbose (a 2nd -v gives more)\n"
          "  -0 .. -9                       set compression level [default 6]\n"
          "      --fast                     alias for -0\n"
          "      --best                     alias for -9\n"
          "      --loose-trailing           allow trailing data seeming corrupt header\n"
          "      --check-lib                compare version of lzlib.h with liblz.{a,so}\n"
          "\nIf no file names are given, or if a file is '-', minilzip compresses or\n"
          "decompresses from standard input to standard output.\n"
          "Numbers may be followed by a multiplier: k = kB = 10^3 = 1000,\n"
          "Ki = KiB = 2^10 = 1024, M = 10^6, Mi = 2^20, G = 10^9, Gi = 2^30, etc...\n"
          "Dictionary sizes 12 to 29 are interpreted as powers of two, meaning 2^12 to\n"
          "2^29 bytes.\n"
          "\nThe bidimensional parameter space of LZMA can't be mapped to a linear scale\n"
          "optimal for all files. If your files are large, very repetitive, etc, you\n"
          "may need to use the options --dictionary-size and --match-length directly\n"
          "to achieve optimal performance.\n"
          "\nTo extract all the files from archive 'foo.tar.lz', use the commands\n"
          "'tar -xf foo.tar.lz' or 'minilzip -cd foo.tar.lz | tar -xf -'.\n"
          "\nExit status: 0 for a normal exit, 1 for environmental problems\n"
          "(file not found, invalid command-line options, I/O errors, etc), 2 to\n"
          "indicate a corrupt or invalid input file, 3 for an internal consistency\n"
          "error (e.g., bug) which caused minilzip to panic.\n"
          "\nThe ideas embodied in lzlib are due to (at least) the following people:\n"
          "Abraham Lempel and Jacob Ziv (for the LZ algorithm), Andrei Markov (for the\n"
          "definition of Markov chains), G.N.N. Martin (for the definition of range\n"
          "encoding), Igor Pavlov (for putting all the above together in LZMA), and\n"
          "Julian Seward (for bzip2's CLI).\n"
          "\nReport bugs to lzip-bug@nongnu.org\n"
          "Lzlib home page: http://www.nongnu.org/lzip/lzlib.html\n" );
  }


static void show_lzlib_version( void )
  {
  printf( "Using lzlib %s\n", LZ_version() );
#if !defined LZ_API_VERSION
  fputs( "LZ_API_VERSION is not defined.\n", stdout );
#elif LZ_API_VERSION >= 1012
  printf( "Using LZ_API_VERSION = %u\n", LZ_api_version() );
#else
  printf( "Compiled with LZ_API_VERSION = %u. "
          "Using an unknown LZ_API_VERSION\n", LZ_API_VERSION );
#endif
  }


static void show_version( void )
  {
  printf( "%s %s\n", program_name, PROGVERSION );
  printf( "Copyright (C) %s Antonio Diaz Diaz.\n", program_year );
  show_lzlib_version();
  printf( "License GPLv2+: GNU GPL version 2 or later <http://gnu.org/licenses/gpl.html>\n"
          "This is free software: you are free to change and redistribute it.\n"
          "There is NO WARRANTY, to the extent permitted by law.\n" );
  }


static inline void set_retval( int * retval, const int new_val )
  { if( *retval < new_val ) *retval = new_val; }


static int check_lzlib_ver()	/* <major>.<minor> or <major>.<minor>[a-z.-]* */
  {
#if defined LZ_API_VERSION && LZ_API_VERSION >= 1012
  const unsigned char * p = (unsigned char *)LZ_version_string;
  unsigned major = 0, minor = 0;
  while( major < 100000 && isdigit( *p ) )
    { major *= 10; major += *p - '0'; ++p; }
  if( *p == '.' ) ++p;
  else
out: { show_error( "Invalid LZ_version_string in lzlib.h", 0, false ); return 2; }
  while( minor < 100 && isdigit( *p ) )
    { minor *= 10; minor += *p - '0'; ++p; }
  if( *p && *p != '-' && *p != '.' && !islower( *p ) ) goto out;
  const unsigned version = major * 1000 + minor;
  if( LZ_API_VERSION != version )
    {
    if( verbosity >= 0 )
      fprintf( stderr, "%s: Version mismatch in lzlib.h: "
               "LZ_API_VERSION = %u, should be %u.\n",
               program_name, LZ_API_VERSION, version );
    return 2;
    }
#endif
  return 0;
  }


static int check_lib()
  {
  int retval = check_lzlib_ver();
  if( strcmp( LZ_version_string, LZ_version() ) != 0 )
    { set_retval( &retval, 1 );
      if( verbosity >= 0 )
        printf( "warning: LZ_version_string != LZ_version() (%s vs %s)\n",
                LZ_version_string, LZ_version() ); }
#if defined LZ_API_VERSION && LZ_API_VERSION >= 1012
  if( LZ_API_VERSION != LZ_api_version() )
    { set_retval( &retval, 1 );
      if( verbosity >= 0 )
        printf( "warning: LZ_API_VERSION != LZ_api_version() (%u vs %u)\n",
                LZ_API_VERSION, LZ_api_version() ); }
#endif
  if( verbosity >= 1 ) show_lzlib_version();
  return retval;
  }


/* assure at least a minimum size for buffer 'buf' */
static void * resize_buffer( void * buf, const unsigned min_size )
  {
  if( buf ) buf = realloc( buf, min_size );
  else buf = malloc( min_size );
  if( !buf ) { show_error( mem_msg, 0, false ); cleanup_and_fail( 1 ); }
  return buf;
  }


struct Pretty_print
  {
  const char * name;
  char * padded_name;
  const char * stdin_name;
  unsigned longest_name;
  bool first_post;
  };

static void Pp_init( struct Pretty_print * const pp,
                     const char * const filenames[], const int num_filenames )
  {
  pp->name = 0;
  pp->padded_name = 0;
  pp->stdin_name = "(stdin)";
  pp->longest_name = 0;
  pp->first_post = false;

  if( verbosity <= 0 ) return;
  const unsigned stdin_name_len = strlen( pp->stdin_name );
  int i;
  for( i = 0; i < num_filenames; ++i )
    {
    const char * const s = filenames[i];
    const unsigned len = (strcmp( s, "-" ) == 0) ? stdin_name_len : strlen( s );
    if( pp->longest_name < len ) pp->longest_name = len;
    }
  if( pp->longest_name == 0 ) pp->longest_name = stdin_name_len;
  }

static void Pp_set_name( struct Pretty_print * const pp,
                         const char * const filename )
  {
  unsigned name_len, padded_name_len, i = 0;

  if( filename && filename[0] && strcmp( filename, "-" ) != 0 )
    pp->name = filename;
  else pp->name = pp->stdin_name;
  name_len = strlen( pp->name );
  padded_name_len = max( name_len, pp->longest_name ) + 4;
  pp->padded_name = resize_buffer( pp->padded_name, padded_name_len + 1 );
  while( i < 2 ) pp->padded_name[i++] = ' ';
  while( i < name_len + 2 ) { pp->padded_name[i] = pp->name[i-2]; ++i; }
  pp->padded_name[i++] = ':';
  while( i < padded_name_len ) pp->padded_name[i++] = ' ';
  pp->padded_name[i] = 0;
  pp->first_post = true;
  }

static void Pp_reset( struct Pretty_print * const pp )
  { if( pp->name && pp->name[0] ) pp->first_post = true; }

static void Pp_show_msg( struct Pretty_print * const pp, const char * const msg )
  {
  if( verbosity < 0 ) return;
  if( pp->first_post )
    {
    pp->first_post = false;
    fputs( pp->padded_name, stderr );
    if( !msg ) fflush( stderr );
    }
  if( msg ) fprintf( stderr, "%s\n", msg );
  }


static void show_header( const unsigned dictionary_size )
  {
  enum { factor = 1024, n = 3 };
  const char * const prefix[n] = { "Ki", "Mi", "Gi" };
  const char * p = "";
  const char * np = "  ";
  unsigned num = dictionary_size;
  bool exact = ( num % factor == 0 );

  int i; for( i = 0; i < n && ( num > 9999 || ( exact && num >= factor ) ); ++i )
    { num /= factor; if( num % factor != 0 ) exact = false;
      p = prefix[i]; np = ""; }
  fprintf( stderr, "dict %s%4u %sB, ", np, num, p );
  }


/* separate numbers of 5 or more digits in groups of 3 digits using '_' */
static const char * format_num3( unsigned long long num )
  {
  enum { buffers = 8, bufsize = 4 * sizeof num, n = 10 };
  const char * const si_prefix = "kMGTPEZYRQ";
  const char * const binary_prefix = "KMGTPEZYRQ";
  static char buffer[buffers][bufsize];	/* circle of static buffers for printf */
  static int current = 0;
  int i;
  char * const buf = buffer[current++]; current %= buffers;
  char * p = buf + bufsize - 1;		/* fill the buffer backwards */
  *p = 0;	/* terminator */
  if( num > 1024 )
    {
    char prefix = 0;			/* try binary first, then si */
    for( i = 0; i < n && num != 0 && num % 1024 == 0; ++i )
      { num /= 1024; prefix = binary_prefix[i]; }
    if( prefix ) *(--p) = 'i';
    else
      for( i = 0; i < n && num != 0 && num % 1000 == 0; ++i )
        { num /= 1000; prefix = si_prefix[i]; }
    if( prefix ) *(--p) = prefix;
    }
  const bool split = num >= 10000;

  for( i = 0; ; )
    {
    *(--p) = num % 10 + '0'; num /= 10; if( num == 0 ) break;
    if( split && ++i >= 3 ) { i = 0; *(--p) = '_'; }
    }
  return p;
  }


void show_option_error( const char * const arg, const char * const msg,
                        const char * const option_name )
  {
  if( verbosity >= 0 )
    fprintf( stderr, "%s: '%s': %s option '%s'.\n",
             program_name, arg, msg, option_name );
  }


/* Recognized formats: <num>k, <num>Ki, <num>[MGTPEZYRQ][i] */
static unsigned long long getnum( const char * const arg,
                                  const char * const option_name,
                                  const unsigned long long llimit,
                                  const unsigned long long ulimit )
  {
  char * tail;
  errno = 0;
  unsigned long long result = strtoull( arg, &tail, 0 );
  if( tail == arg )
    { show_option_error( arg, "Bad or missing numerical argument in",
                         option_name ); exit( 1 ); }

  if( !errno && tail[0] )
    {
    const unsigned factor = ( tail[1] == 'i' ) ? 1024 : 1000;
    int exponent = 0;				/* 0 = bad multiplier */
    int i;
    switch( tail[0] )
      {
      case 'Q': exponent = 10; break;
      case 'R': exponent = 9; break;
      case 'Y': exponent = 8; break;
      case 'Z': exponent = 7; break;
      case 'E': exponent = 6; break;
      case 'P': exponent = 5; break;
      case 'T': exponent = 4; break;
      case 'G': exponent = 3; break;
      case 'M': exponent = 2; break;
      case 'K': if( factor == 1024 ) exponent = 1; break;
      case 'k': if( factor == 1000 ) exponent = 1; break;
      }
    if( exponent <= 0 )
      { show_option_error( arg, "Bad multiplier in numerical argument of",
                           option_name ); exit( 1 ); }
    for( i = 0; i < exponent; ++i )
      {
      if( ulimit / factor >= result ) result *= factor;
      else { errno = ERANGE; break; }
      }
    }
  if( !errno && ( result < llimit || result > ulimit ) ) errno = ERANGE;
  if( errno )
    {
    if( verbosity >= 0 )
      fprintf( stderr, "%s: '%s': Value out of limits [%s,%s] in "
               "option '%s'.\n", program_name, arg, format_num3( llimit ),
               format_num3( ulimit ), option_name );
    exit( 1 );
    }
  return result;
  }


static int get_dict_size( const char * const arg, const char * const option_name )
  {
  char * tail;
  const long bits = strtol( arg, &tail, 0 );
  if( bits >= LZ_min_dictionary_bits() &&
      bits <= LZ_max_dictionary_bits() && *tail == 0 )
    return 1 << bits;
  int dictionary_size = getnum( arg, option_name, LZ_min_dictionary_size(),
                                                  LZ_max_dictionary_size() );
  if( dictionary_size == 65535 ) ++dictionary_size;	/* no fast encoder */
  return dictionary_size;
  }


static void set_mode( enum Mode * const program_modep, const enum Mode new_mode )
  {
  if( *program_modep != m_compress && *program_modep != new_mode )
    {
    show_error( "Only one operation can be specified.", 0, true );
    exit( 1 );
    }
  *program_modep = new_mode;
  }


static int extension_index( const char * const name )
  {
  int eindex;
  for( eindex = 0; known_extensions[eindex].from; ++eindex )
    {
    const char * const ext = known_extensions[eindex].from;
    const unsigned name_len = strlen( name );
    const unsigned ext_len = strlen( ext );
    if( name_len > ext_len &&
        strncmp( name + name_len - ext_len, ext, ext_len ) == 0 )
      return eindex;
    }
  return -1;
  }


static void set_c_outname( const char * const name, const bool force_ext,
                           const bool multifile )
  {
  output_filename = resize_buffer( output_filename, strlen( name ) + 5 +
                                   strlen( known_extensions[0].from ) + 1 );
  strcpy( output_filename, name );
  if( multifile ) strcat( output_filename, "00001" );
  if( force_ext || multifile )
    strcat( output_filename, known_extensions[0].from );
  }


static void set_d_outname( const char * const name, const int eindex )
  {
  const unsigned name_len = strlen( name );
  if( eindex >= 0 )
    {
    const char * const from = known_extensions[eindex].from;
    const unsigned from_len = strlen( from );
    if( name_len > from_len )
      {
      output_filename = resize_buffer( output_filename, name_len +
                                       strlen( known_extensions[eindex].to ) + 1 );
      strcpy( output_filename, name );
      strcpy( output_filename + name_len - from_len, known_extensions[eindex].to );
      return;
      }
    }
  output_filename = resize_buffer( output_filename, name_len + 4 + 1 );
  strcpy( output_filename, name );
  strcat( output_filename, ".out" );
  if( verbosity >= 1 )
    fprintf( stderr, "%s: %s: Can't guess original name -- using '%s'\n",
             program_name, name, output_filename );
  }


static int open_instream( const char * const name, struct stat * const in_statsp,
                          const enum Mode program_mode, const int eindex,
                          const bool one_to_one, const bool recompress )
  {
  if( program_mode == m_compress && !recompress && eindex >= 0 )
    {
    if( verbosity >= 0 )
      fprintf( stderr, "%s: %s: Input file already has '%s' suffix.\n",
               program_name, name, known_extensions[eindex].from );
    return -1;
    }
  int infd = open( name, O_RDONLY | O_BINARY );
  if( infd < 0 )
    show_file_error( name, "Can't open input file", errno );
  else
    {
    const int i = fstat( infd, in_statsp );
    const mode_t mode = in_statsp->st_mode;
    const bool can_read = ( i == 0 &&
                            ( S_ISBLK( mode ) || S_ISCHR( mode ) ||
                              S_ISFIFO( mode ) || S_ISSOCK( mode ) ) );
    if( i != 0 || ( !S_ISREG( mode ) && ( !can_read || one_to_one ) ) )
      {
      if( verbosity >= 0 )
        fprintf( stderr, "%s: %s: Input file is not a regular file%s.\n",
                 program_name, name, ( can_read && one_to_one ) ?
                 ",\n  and neither '-c' nor '-o' were specified" : "" );
      close( infd );
      infd = -1;
      }
    }
  return infd;
  }


static bool open_outstream( const bool force, const bool protect )
  {
  const mode_t usr_rw = S_IRUSR | S_IWUSR;
  const mode_t all_rw = usr_rw | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH;
  const mode_t outfd_mode = protect ? usr_rw : all_rw;
  int flags = O_CREAT | O_WRONLY | O_BINARY;
  if( force ) flags |= O_TRUNC; else flags |= O_EXCL;

  outfd = open( output_filename, flags, outfd_mode );
  if( outfd >= 0 ) delete_output_on_interrupt = true;
  else if( errno == EEXIST )
    show_file_error( output_filename,
                     "Output file already exists, skipping.", 0 );
  else
    show_file_error( output_filename, "Can't create output file", errno );
  return outfd >= 0;
  }


static void set_signals( void (*action)(int) )
  {
  signal( SIGHUP, action );
  signal( SIGINT, action );
  signal( SIGTERM, action );
  }


static void cleanup_and_fail( const int retval )
  {
  set_signals( SIG_IGN );			/* ignore signals */
  if( delete_output_on_interrupt )
    {
    delete_output_on_interrupt = false;
    show_file_error( output_filename, "Deleting output file, if it exists.", 0 );
    if( outfd >= 0 ) { close( outfd ); outfd = -1; }
    if( remove( output_filename ) != 0 && errno != ENOENT )
      show_error( "warning: deletion of output file failed", errno, false );
    }
  exit( retval );
  }


static void signal_handler( int sig )
  {
  if( sig ) {}				/* keep compiler happy */
  show_error( "Control-C or similar caught, quitting.", 0, false );
  cleanup_and_fail( 1 );
  }


static bool check_tty_in( const char * const input_filename, const int infd,
                          const enum Mode program_mode, int * const retval )
  {
  if( ( program_mode == m_decompress || program_mode == m_test ) &&
      isatty( infd ) )				/* for example /dev/tty */
    { show_file_error( input_filename,
                       "I won't read compressed data from a terminal.", 0 );
      close( infd ); set_retval( retval, 2 );
      if( program_mode != m_test ) cleanup_and_fail( *retval );
      return false; }
  return true;
  }

static bool check_tty_out( const enum Mode program_mode )
  {
  if( program_mode == m_compress && isatty( outfd ) )
    { show_file_error( output_filename[0] ?
                       output_filename : "(stdout)",
                       "I won't write compressed data to a terminal.", 0 );
      return false; }
  return true;
  }


/* Set permissions, owner, and times. */
static void close_and_set_permissions( const struct stat * const in_statsp )
  {
  bool warning = false;
  if( in_statsp )
    {
    const mode_t mode = in_statsp->st_mode;
    /* fchown in many cases returns with EPERM, which can be safely ignored. */
    if( fchown( outfd, in_statsp->st_uid, in_statsp->st_gid ) == 0 )
      { if( fchmod( outfd, mode ) != 0 ) warning = true; }
    else
      if( errno != EPERM ||
          fchmod( outfd, mode & ~( S_ISUID | S_ISGID | S_ISVTX ) ) != 0 )
        warning = true;
    }
  if( close( outfd ) != 0 )
    { show_file_error( output_filename, "Error closing output file", errno );
      cleanup_and_fail( 1 ); }
  outfd = -1;
  delete_output_on_interrupt = false;
  if( in_statsp )
    {
    struct utimbuf t;
    t.actime = in_statsp->st_atime;
    t.modtime = in_statsp->st_mtime;
    if( utime( output_filename, &t ) != 0 ) warning = true;
    }
  if( warning && verbosity >= 1 )
    show_file_error( output_filename,
                     "warning: can't change output file attributes", errno );
  }


/* Return the number of bytes really read.
   If (value returned < size) and (errno == 0), means EOF was reached.
*/
static int readblock( const int fd, uint8_t * const buf, const int size )
  {
  int sz = 0;
  errno = 0;
  while( sz < size )
    {
    const int n = read( fd, buf + sz, size - sz );
    if( n > 0 ) sz += n;
    else if( n == 0 ) break;				/* EOF */
    else if( errno != EINTR ) break;
    errno = 0;
    }
  return sz;
  }


/* Return the number of bytes really written.
   If (value returned < size), it is always an error.
*/
static int writeblock( const int fd, const uint8_t * const buf, const int size )
  {
  int sz = 0;
  errno = 0;
  while( sz < size )
    {
    const int n = write( fd, buf + sz, size - sz );
    if( n > 0 ) sz += n;
    else if( n < 0 && errno != EINTR ) break;
    errno = 0;
    }
  return sz;
  }


static bool next_filename( void )
  {
  const unsigned name_len = strlen( output_filename );
  const unsigned ext_len = strlen( known_extensions[0].from );
  int i, j;
  if( name_len >= ext_len + 5 )				/* "*00001.lz" */
    for( i = name_len - ext_len - 1, j = 0; j < 5; --i, ++j )
      {
      if( output_filename[i] < '9' ) { ++output_filename[i]; return true; }
      else output_filename[i] = '0';
      }
  return false;
  }


static int do_compress( struct LZ_Encoder * const encoder,
                        const unsigned long long member_size,
                        const unsigned long long volume_size, const int infd,
                        struct Pretty_print * const pp,
                        const struct stat * const in_statsp )
  {
  unsigned long long partial_volume_size = 0;
  enum { buffer_size = 65536 };
  uint8_t buffer[buffer_size];			/* read/write buffer */
  if( verbosity >= 1 ) Pp_show_msg( pp, 0 );

  while( true )
    {
    int in_size = 0;
    while( LZ_compress_write_size( encoder ) > 0 )
      {
      const int size = min( LZ_compress_write_size( encoder ), buffer_size );
      const int rd = readblock( infd, buffer, size );
      if( rd != size && errno )
        {
        Pp_show_msg( pp, 0 ); show_error( "Read error", errno, false );
        return 1;
        }
      if( rd > 0 && rd != LZ_compress_write( encoder, buffer, rd ) )
        internal_error( "library error (LZ_compress_write)." );
      if( rd < size ) LZ_compress_finish( encoder );
/*      else LZ_compress_sync_flush( encoder ); */
      in_size += rd;
      }
    const int out_size = LZ_compress_read( encoder, buffer, buffer_size );
    if( out_size < 0 )
      {
      Pp_show_msg( pp, 0 );
      if( verbosity >= 0 )
        fprintf( stderr, "%s: LZ_compress_read error: %s\n",
                 program_name, LZ_strerror( LZ_compress_errno( encoder ) ) );
      return 1;
      }
    else if( out_size > 0 )
      {
      const int wr = writeblock( outfd, buffer, out_size );
      if( wr != out_size )
        {
        Pp_show_msg( pp, 0 ); show_error( "Write error", errno, false );
        return 1;
        }
      }
    else if( in_size == 0 )
      internal_error( "library error (LZ_compress_read)." );
    if( LZ_compress_member_finished( encoder ) )
      {
      unsigned long long size;
      if( LZ_compress_finished( encoder ) == 1 ) break;
      if( volume_size > 0 )
        {
        partial_volume_size += LZ_compress_member_position( encoder );
        if( partial_volume_size >= volume_size - LZ_min_dictionary_size() )
          {
          partial_volume_size = 0;
          if( delete_output_on_interrupt )
            {
            close_and_set_permissions( in_statsp );
            if( !next_filename() )
              { Pp_show_msg( pp, "Too many volume files." ); return 1; }
            if( !open_outstream( true, in_statsp ) ) return 1;
            }
          }
        size = min( member_size, volume_size - partial_volume_size );
        }
      else
        size = member_size;
      if( LZ_compress_restart_member( encoder, size ) < 0 )
        {
        Pp_show_msg( pp, 0 );
        if( verbosity >= 0 )
          fprintf( stderr, "%s: LZ_compress_restart_member error: %s\n",
                   program_name, LZ_strerror( LZ_compress_errno( encoder ) ) );
        return 1;
        }
      }
    }

  if( verbosity >= 1 )
    {
    const unsigned long long in_size = LZ_compress_total_in_size( encoder );
    const unsigned long long out_size = LZ_compress_total_out_size( encoder );
    if( in_size == 0 || out_size == 0 )
      fputs( " no data compressed.\n", stderr );
    else
      fprintf( stderr, "%6.3f:1, %5.2f%% ratio, %5.2f%% saved, "
                       "%llu in, %llu out.\n",
               (double)in_size / out_size,
               ( 100.0 * out_size ) / in_size,
               100.0 - ( ( 100.0 * out_size ) / in_size ),
               in_size, out_size );
    }
  return 0;
  }


static int compress( const unsigned long long member_size,
                     const unsigned long long volume_size, const int infd,
                     const struct Lzma_options * const encoder_options,
                     struct Pretty_print * const pp,
                     const struct stat * const in_statsp )
  {
  struct LZ_Encoder * const encoder =
    LZ_compress_open( encoder_options->dictionary_size,
                      encoder_options->match_len_limit, ( volume_size > 0 ) ?
                      min( member_size, volume_size ) : member_size );
  int retval;

  if( !encoder || LZ_compress_errno( encoder ) != LZ_ok )
    {
    if( !encoder || LZ_compress_errno( encoder ) == LZ_mem_error )
      Pp_show_msg( pp, "Not enough memory. Try a smaller dictionary size." );
    else
      internal_error( "invalid argument to encoder." );
    retval = 1;
    }
  else retval = do_compress( encoder, member_size, volume_size,
                             infd, pp, in_statsp );
  LZ_compress_close( encoder );
  return retval;
  }


static int do_decompress( struct LZ_Decoder * const decoder, const int infd,
                struct Pretty_print * const pp, const bool ignore_trailing,
                const bool loose_trailing, const bool testing )
  {
  enum { buffer_size = 65536 };
  uint8_t buffer[buffer_size];			/* read/write buffer */
  unsigned long long total_in = 0;		/* to detect library stall */
  bool first_member;

  for( first_member = true; ; )
    {
    const int max_in_size =
      min( LZ_decompress_write_size( decoder ), buffer_size );
    int in_size = 0, out_size = 0;
    if( max_in_size > 0 )
      {
      in_size = readblock( infd, buffer, max_in_size );
      if( in_size != max_in_size && errno )
        {
        Pp_show_msg( pp, 0 ); show_error( "Read error", errno, false );
        return 1;
        }
      if( in_size > 0 && in_size != LZ_decompress_write( decoder, buffer, in_size ) )
        internal_error( "library error (LZ_decompress_write)." );
      if( in_size < max_in_size ) LZ_decompress_finish( decoder );
      }
    while( true )
      {
      const int rd =
        LZ_decompress_read( decoder, (outfd >= 0) ? buffer : 0, buffer_size );
      if( rd > 0 )
        {
        out_size += rd;
        if( outfd >= 0 )
          {
          const int wr = writeblock( outfd, buffer, rd );
          if( wr != rd )
            {
            Pp_show_msg( pp, 0 ); show_error( "Write error", errno, false );
            return 1;
            }
          }
        }
      else if( rd < 0 ) { out_size = rd; break; }
      if( LZ_decompress_member_finished( decoder ) == 1 )
        {
        if( verbosity >= 1 )
          {
          const unsigned long long data_size = LZ_decompress_data_position( decoder );
          const unsigned long long member_size = LZ_decompress_member_position( decoder );
          if( verbosity >= 2 || ( verbosity == 1 && first_member ) )
            Pp_show_msg( pp, 0 );
          if( verbosity >= 2 )
            {
            if( verbosity >= 4 )
              show_header( LZ_decompress_dictionary_size( decoder ) );
            if( data_size == 0 || member_size == 0 )
              fputs( "no data compressed. ", stderr );
            else
              fprintf( stderr, "%6.3f:1, %5.2f%% ratio, %5.2f%% saved. ",
                     (double)data_size / member_size,
                     ( 100.0 * member_size ) / data_size,
                     100.0 - ( ( 100.0 * member_size ) / data_size ) );
            if( verbosity >= 4 )
              fprintf( stderr, "CRC %08X, ", LZ_decompress_data_crc( decoder ) );
            if( verbosity >= 3 )
              fprintf( stderr, "%9llu out, %8llu in. ", data_size, member_size );
            fputs( testing ? "ok\n" : "done\n", stderr ); Pp_reset( pp );
            }
          }
        first_member = false;		/* member decompressed successfully */
        }
      if( rd <= 0 ) break;
      }
    if( out_size < 0 || ( first_member && out_size == 0 ) )
      {
      const unsigned long long member_pos = LZ_decompress_member_position( decoder );
      const enum LZ_Errno lz_errno = LZ_decompress_errno( decoder );
      if( lz_errno == LZ_library_error )
        internal_error( "library error (LZ_decompress_read)." );
      if( member_pos <= 6 )
        {
        if( lz_errno == LZ_unexpected_eof )
          {
          if( first_member )
            show_file_error( pp->name, "File ends unexpectedly at member header.", 0 );
          else
            Pp_show_msg( pp, "Truncated header in multimember file." );
          return 2;
          }
        else if( lz_errno == LZ_data_error )
          {
          if( member_pos == 4 )
            { if( verbosity >= 0 )
              { Pp_show_msg( pp, 0 );
                fprintf( stderr, "Version %d member format not supported.\n",
                         LZ_decompress_member_version( decoder ) ); } }
          else if( member_pos == 5 )
            Pp_show_msg( pp, "Invalid dictionary size in member header." );
          else if( first_member )	/* for lzlib older than 1.10 */
            Pp_show_msg( pp, "Bad version or dictionary size in member header." );
          else if( !loose_trailing )
            Pp_show_msg( pp, "Corrupt header in multimember file." );
          else if( !ignore_trailing )
            Pp_show_msg( pp, "Trailing data not allowed." );
          else break;				/* trailing data */
          return 2;
          }
        }
      if( lz_errno == LZ_header_error )
        {
        if( first_member )
          show_file_error( pp->name,
                           "Bad magic number (file not in lzip format).", 0 );
        else if( !ignore_trailing )
          Pp_show_msg( pp, "Trailing data not allowed." );
        else break;				/* trailing data */
        return 2;
        }
      if( lz_errno == LZ_mem_error ) { Pp_show_msg( pp, mem_msg ); return 1; }
      if( verbosity >= 0 )
        {
        Pp_show_msg( pp, 0 );
        fprintf( stderr, "%s at pos %llu\n", ( lz_errno == LZ_unexpected_eof ) ?
                 "File ends unexpectedly" : "Decoder error",
                 LZ_decompress_total_in_size( decoder ) );
        }
      return 2;
      }
    if( LZ_decompress_finished( decoder ) == 1 ) break;
    if( in_size == 0 && out_size == 0 )
      {
      const unsigned long long size = LZ_decompress_total_in_size( decoder );
      if( total_in == size ) internal_error( "library error (stalled)." );
      total_in = size;
      }
    }
  if( verbosity == 1 ) fputs( testing ? "ok\n" : "done\n", stderr );
  return 0;
  }


static int decompress( const int infd, struct Pretty_print * const pp,
                       const bool ignore_trailing,
                       const bool loose_trailing, const bool testing )
  {
  struct LZ_Decoder * const decoder = LZ_decompress_open();
  int retval;

  if( !decoder || LZ_decompress_errno( decoder ) != LZ_ok )
    { Pp_show_msg( pp, mem_msg ); retval = 1; }
  else retval = do_decompress( decoder, infd, pp, ignore_trailing,
                               loose_trailing, testing );
  LZ_decompress_close( decoder );
  return retval;
  }


static void show_error( const char * const msg, const int errcode,
                        const bool help )
  {
  if( verbosity < 0 ) return;
  if( msg && msg[0] )
    fprintf( stderr, "%s: %s%s%s\n", program_name, msg,
             ( errcode > 0 ) ? ": " : "",
             ( errcode > 0 ) ? strerror( errcode ) : "" );
  if( help )
    fprintf( stderr, "Try '%s --help' for more information.\n",
             invocation_name );
  }


static void show_file_error( const char * const filename,
                             const char * const msg, const int errcode )
  {
  if( verbosity >= 0 )
    fprintf( stderr, "%s: %s: %s%s%s\n", program_name, filename, msg,
             ( errcode > 0 ) ? ": " : "",
             ( errcode > 0 ) ? strerror( errcode ) : "" );
  }


static void internal_error( const char * const msg )
  {
  if( verbosity >= 0 )
    fprintf( stderr, "%s: internal error: %s\n", program_name, msg );
  exit( 3 );
  }


int main( const int argc, const char * const argv[] )
  {
  /* Mapping from gzip/bzip2 style 0..9 compression levels to the
     corresponding LZMA compression parameters. */
  const struct Lzma_options option_mapping[] =
    {
    {   65535,  16 },		/* -0 (65535,16 chooses fast encoder) */
    { 1 << 20,   5 },		/* -1 */
    { 3 << 19,   6 },		/* -2 */
    { 1 << 21,   8 },		/* -3 */
    { 3 << 20,  12 },		/* -4 */
    { 1 << 22,  20 },		/* -5 */
    { 1 << 23,  36 },		/* -6 */
    { 1 << 24,  68 },		/* -7 */
    { 3 << 23, 132 },		/* -8 */
    { 1 << 25, 273 } };		/* -9 */
  struct Lzma_options encoder_options = option_mapping[6];  /* default = "-6" */
  const unsigned long long max_member_size = 0x0008000000000000ULL; /* 2 PiB */
  const unsigned long long max_volume_size = 0x4000000000000000ULL; /* 4 EiB */
  unsigned long long member_size = max_member_size;
  unsigned long long volume_size = 0;
  const char * default_output_filename = "";
  enum Mode program_mode = m_compress;
  int i;
  bool force = false;
  bool ignore_trailing = true;
  bool keep_input_files = false;
  bool loose_trailing = false;
  bool recompress = false;
  bool to_stdout = false;
  if( argc > 0 ) invocation_name = argv[0];

  enum { opt_chk = 256, opt_lt };
  const struct ap_Option options[] =
    {
    { '0', "fast",              ap_no  },
    { '1', 0,                   ap_no  },
    { '2', 0,                   ap_no  },
    { '3', 0,                   ap_no  },
    { '4', 0,                   ap_no  },
    { '5', 0,                   ap_no  },
    { '6', 0,                   ap_no  },
    { '7', 0,                   ap_no  },
    { '8', 0,                   ap_no  },
    { '9', "best",              ap_no  },
    { 'a', "trailing-error",    ap_no  },
    { 'b', "member-size",       ap_yes },
    { 'c', "stdout",            ap_no  },
    { 'd', "decompress",        ap_no  },
    { 'f', "force",             ap_no  },
    { 'F', "recompress",        ap_no  },
    { 'h', "help",              ap_no  },
    { 'k', "keep",              ap_no  },
    { 'm', "match-length",      ap_yes },
    { 'n', "threads",           ap_yes },
    { 'o', "output",            ap_yes },
    { 'q', "quiet",             ap_no  },
    { 's', "dictionary-size",   ap_yes },
    { 'S', "volume-size",       ap_yes },
    { 't', "test",              ap_no  },
    { 'v', "verbose",           ap_no  },
    { 'V', "version",           ap_no  },
    { opt_chk, "check-lib",     ap_no  },
    { opt_lt, "loose-trailing", ap_no  },
    {  0, 0,                    ap_no  } };

  /* static because valgrind complains and memory management in C sucks */
  static struct Arg_parser parser;
  if( !ap_init( &parser, argc, argv, options, 0 ) )
    { show_error( mem_msg, 0, false ); return 1; }
  if( ap_error( &parser ) )				/* bad option */
    { show_error( ap_error( &parser ), 0, true ); return 1; }

  int argind = 0;
  for( ; argind < ap_arguments( &parser ); ++argind )
    {
    const int code = ap_code( &parser, argind );
    if( !code ) break;					/* no more options */
    const char * const pn = ap_parsed_name( &parser, argind );
    const char * const arg = ap_argument( &parser, argind );
    switch( code )
      {
      case '0': case '1': case '2': case '3': case '4':
      case '5': case '6': case '7': case '8': case '9':
                encoder_options = option_mapping[code-'0']; break;
      case 'a': ignore_trailing = false; break;
      case 'b': member_size = getnum( arg, pn, 100000, max_member_size ); break;
      case 'c': to_stdout = true; break;
      case 'd': set_mode( &program_mode, m_decompress ); break;
      case 'f': force = true; break;
      case 'F': recompress = true; break;
      case 'h': show_help(); return 0;
      case 'k': keep_input_files = true; break;
      case 'm': encoder_options.match_len_limit =
                  getnum( arg, pn, LZ_min_match_len_limit(),
                                   LZ_max_match_len_limit() ); break;
      case 'n': break;
      case 'o': if( strcmp( arg, "-" ) == 0 ) to_stdout = true;
                else { default_output_filename = arg; } break;
      case 'q': verbosity = -1; break;
      case 's': encoder_options.dictionary_size = get_dict_size( arg, pn );
                break;
      case 'S': volume_size = getnum( arg, pn, 100000, max_volume_size ); break;
      case 't': set_mode( &program_mode, m_test ); break;
      case 'v': if( verbosity < 4 ) ++verbosity; break;
      case 'V': show_version(); return 0;
      case opt_chk: return check_lib();
      case opt_lt: loose_trailing = true; break;
      default: internal_error( "uncaught option." );
      }
    } /* end process options */

  if( strcmp( PROGVERSION, LZ_version_string ) != 0 )
    internal_error( "wrong PROGVERSION." );
#if !defined LZ_API_VERSION || LZ_API_VERSION < 1012
#error "lzlib 1.12 or newer needed."
#else
  if( LZ_api_version() < 1012 )	/* minilzip passes null to LZ_decompress_read */
    { show_error( "lzlib 1.12 or newer needed. Try --check-lib.", 0, false );
      return 1; }
  if( LZ_api_version() != LZ_API_VERSION ) show_error(
    "warning: wrong library API version. Try --check-lib.", 0, false );
  else
#endif
  if( strcmp( LZ_version_string, LZ_version() ) != 0 ) show_error(
    "warning: wrong library version_string. Try --check-lib.", 0, false );

#if defined __MSVCRT__ || defined __OS2__ || defined __DJGPP__
  setmode( STDIN_FILENO, O_BINARY );
  setmode( STDOUT_FILENO, O_BINARY );
#endif

  static const char ** filenames = 0;
  int num_filenames = max( 1, ap_arguments( &parser ) - argind );
  filenames = resize_buffer( filenames, num_filenames * sizeof filenames[0] );
  filenames[0] = "-";

  bool filenames_given = false;
  for( i = 0; argind + i < ap_arguments( &parser ); ++i )
    {
    filenames[i] = ap_argument( &parser, argind + i );
    if( strcmp( filenames[i], "-" ) != 0 ) filenames_given = true;
    }

  if( program_mode == m_compress )
    {
    if( volume_size > 0 && !to_stdout && default_output_filename[0] &&
        num_filenames > 1 )
      { show_error( "Only can compress one file when using '-o' and '-S'.",
                    0, true ); return 1; }
    }
  else volume_size = 0;
  if( program_mode == m_test ) to_stdout = false;	/* apply overrides */
  if( program_mode == m_test || to_stdout ) default_output_filename = "";

  output_filename = resize_buffer( output_filename, 1 );
  output_filename[0] = 0;
  if( to_stdout && program_mode != m_test )	/* check tty only once */
    { outfd = STDOUT_FILENO; if( !check_tty_out( program_mode ) ) return 1; }
  else outfd = -1;

  const bool to_file = !to_stdout && program_mode != m_test &&
                       default_output_filename[0];
  if( !to_stdout && program_mode != m_test && ( filenames_given || to_file ) )
    set_signals( signal_handler );

  static struct Pretty_print pp;
  Pp_init( &pp, filenames, num_filenames );

  int failed_tests = 0;
  int retval = 0;
  const bool one_to_one = !to_stdout && program_mode != m_test && !to_file;
  bool stdin_used = false;
  struct stat in_stats;
  for( i = 0; i < num_filenames; ++i )
    {
    const char * input_filename = "";
    int infd;

    Pp_set_name( &pp, filenames[i] );
    if( strcmp( filenames[i], "-" ) == 0 )
      {
      if( stdin_used ) continue; else stdin_used = true;
      infd = STDIN_FILENO;
      if( !check_tty_in( pp.name, infd, program_mode, &retval ) ) continue;
      if( one_to_one ) { outfd = STDOUT_FILENO; output_filename[0] = 0; }
      }
    else
      {
      const int eindex = extension_index( input_filename = filenames[i] );
      infd = open_instream( input_filename, &in_stats, program_mode,
                            eindex, one_to_one, recompress );
      if( infd < 0 ) { set_retval( &retval, 1 ); continue; }
      if( !check_tty_in( pp.name, infd, program_mode, &retval ) ) continue;
      if( one_to_one )			/* open outfd after checking infd */
        {
        if( program_mode == m_compress )
          set_c_outname( input_filename, true, volume_size > 0 );
        else set_d_outname( input_filename, eindex );
        if( !open_outstream( force, true ) )
          { close( infd ); set_retval( &retval, 1 ); continue; }
        }
      }

    if( one_to_one && !check_tty_out( program_mode ) )
      { set_retval( &retval, 1 ); return retval; }	/* don't delete a tty */

    if( to_file && outfd < 0 )		/* open outfd after checking infd */
      {
      if( program_mode == m_compress ) set_c_outname( default_output_filename,
                                       false, volume_size > 0 );
      else
        { output_filename = resize_buffer( output_filename,
                            strlen( default_output_filename ) + 1 );
          strcpy( output_filename, default_output_filename ); }
      if( !open_outstream( force, false ) || !check_tty_out( program_mode ) )
        return 1;	/* check tty only once and don't try to delete a tty */
      }

    const struct stat * const in_statsp =
      ( input_filename[0] && one_to_one ) ? &in_stats : 0;
    int tmp;
    if( program_mode == m_compress )
      tmp = compress( member_size, volume_size, infd, &encoder_options, &pp,
                      in_statsp );
    else
      tmp = decompress( infd, &pp, ignore_trailing, loose_trailing,
                        program_mode == m_test );
    if( close( infd ) != 0 )
      { show_file_error( pp.name, "Error closing input file", errno );
        set_retval( &tmp, 1 ); }
    set_retval( &retval, tmp );
    if( tmp )
      { if( program_mode != m_test ) cleanup_and_fail( retval );
        else ++failed_tests; }

    if( delete_output_on_interrupt && one_to_one )
      close_and_set_permissions( in_statsp );
    if( input_filename[0] && !keep_input_files && one_to_one &&
        ( program_mode != m_compress || volume_size == 0 ) )
      remove( input_filename );
    }
  if( delete_output_on_interrupt )					/* -o */
    close_and_set_permissions( ( retval == 0 && !stdin_used &&
      filenames_given && num_filenames == 1 ) ? &in_stats : 0 );
  else if( outfd >= 0 && close( outfd ) != 0 )				/* -c */
    {
    show_error( "Error closing stdout", errno, false );
    set_retval( &retval, 1 );
    }
  if( failed_tests > 0 && verbosity >= 1 && num_filenames > 1 )
    fprintf( stderr, "%s: warning: %d %s failed the test.\n",
             program_name, failed_tests,
             ( failed_tests == 1 ) ? "file" : "files" );
  free( output_filename );
  free( filenames );
  ap_free( &parser );
  return retval;
  }