1 files changed, 120 insertions, 0 deletions
diff --git a/archive_reader.h b/archive_reader.h
new file mode 100644
index 0000000..e8963e0
--- /dev/null
+++ b/archive_reader.h
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+/* Tarlz - Archiver with multimember lzip compression
+   Copyright (C) 2013-2024 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/>.
+*/
+
+struct Archive_descriptor
+  {
+  const std::string name;
+  const char * const namep;		// printable archive name
+  const int infd;
+  const Lzip_index lzip_index;
+  const bool seekable;
+  const bool indexed;		// archive is a compressed regular file
+
+  Archive_descriptor( const std::string & archive_name );
+  };
+
+
+class Archive_reader_base	// base of serial and indexed readers
+  {
+public:
+  const Archive_descriptor & ad;
+protected:
+  LZ_Decoder * decoder;		// destructor closes it if needed
+  const char * e_msg_;		// message for show_file_error
+  int e_code_;			// copy of errno
+  int e_size_;			// partial size read in case of read error
+  bool e_skip_;			// corrupt header skipped
+  bool fatal_;
+
+  int err( const int retval, const char * const msg = "", const int code = 0,
+           const int size = 0, const bool skip = false )
+    { e_msg_ = msg; e_code_ = code; e_size_ = size; e_skip_ = skip;
+      if( retval >= 0 ) return retval;
+      fatal_ = true; if( !*e_msg_ ) e_msg_ = "Fatal error"; return -retval; }
+
+  Archive_reader_base( const Archive_descriptor & d )
+    : ad( d ), decoder( 0 ), e_msg_( "" ), e_code_( 0 ), e_size_( 0 ),
+      e_skip_( false ), fatal_( false ) {}
+
+public:
+  virtual ~Archive_reader_base()
+    { if( decoder != 0 ) LZ_decompress_close( decoder ); }
+
+  const char * e_msg() const { return e_msg_; }
+  int e_code() const { return e_code_; }
+  int e_size() const { return e_size_; }
+  bool e_skip() const { return e_skip_; }
+  bool fatal() const { return fatal_; }
+
+  /* Read 'size' uncompressed bytes, decompressing the input if needed.
+     Return value: 0 = OK, 1 = OOM or read error, 2 = EOF or invalid data.
+     If !OK, fills all the e_* variables. */
+  virtual int read( uint8_t * const buf, const int size ) = 0;
+
+  int parse_records( Extended & extended, const Tar_header header,
+                     Resizable_buffer & rbuf, const char * const default_msg,
+                     const bool permissive );
+  };
+
+
+class Archive_reader : public Archive_reader_base	// serial reader
+  {
+  bool first_read;
+  bool uncompressed_seekable;		// value set by first read call
+  bool at_eof;
+
+public:
+  Archive_reader( const Archive_descriptor & d )
+    : Archive_reader_base( d ), first_read( true ),
+      uncompressed_seekable( false ), at_eof( false ) {}
+
+  int read( uint8_t * const buf, const int size );
+  int skip_member( const Extended & extended );
+  };
+
+
+/* If the archive is compressed seekable (indexed), several indexed readers
+   can be constructed sharing the same Archive_descriptor, for example to
+   decode the archive in parallel.
+*/
+class Archive_reader_i : public Archive_reader_base	// indexed reader
+  {
+  long long data_pos_;		// current decompressed position in archive
+  long long mdata_end_;		// current member decompressed end
+  long long archive_pos;	// current position in archive for pread
+  long member_id;		// current member unless reading beyond
+
+public:
+  Archive_reader_i( const Archive_descriptor & d )
+    : Archive_reader_base( d ),
+      data_pos_( 0 ), mdata_end_( 0 ), archive_pos( 0 ), member_id( 0 )
+    {
+    decoder = LZ_decompress_open();
+    if( !decoder || LZ_decompress_errno( decoder ) != LZ_ok )
+      { LZ_decompress_close( decoder ); decoder = 0; fatal_ = true; }
+    }
+
+  long long data_pos() const { return data_pos_; }
+  long long mdata_end() const { return mdata_end_; }
+  bool at_member_end() const { return data_pos_ == mdata_end_; }
+
+  // Resets decoder and sets position to the start of the member.
+  void set_member( const long i );
+
+  int read( uint8_t * const buf, const int size );
+  int skip_member( const Extended & extended );
+  };