lz4_decompress.cc

/*
   Copyright (c) 2014, 2022, Oracle and/or its affiliates.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License, version 2.0,
   as published by the Free Software Foundation.

   This program is also distributed with certain software (including
   but not limited to OpenSSL) that is licensed under separate terms,
   as designated in a particular file or component or in included license
   documentation.  The authors of MySQL hereby grant you an additional
   permission to link the program and your derivative works with the
   separately licensed software that they have included with MySQL.

   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, version 2.0, for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA
*/

#include <my_global.h>
#include <welcome_copyright_notice.h>

#include "lz4frame.h"
#include <string.h>

static void usage()
{
  printf("%s  Ver 1.7 for %s at %s\n","lz4_decompress",SYSTEM_TYPE,
	 MACHINE_TYPE);
  puts(ORACLE_WELCOME_COPYRIGHT_NOTICE("2015"));
  puts("Decompress data compressed by mysqlpump using lz4 compression "
    "algorithm by reading from input file and writing uncompressed "
    "data to output file");
  printf("Usage: %s input_file output_file\n", "lz4_decompress");
}

static const int INPUT_BUFFER_SIZE= 1024 * 1024;
static const int OUTPUT_BUFFER_SIZE= 1024 * 1024;

int main(int argc, char **argv)
{
  if (argc != 3)
  {
    usage();
    exit(1);
  }
  FILE* input_file= fopen(argv[1], "rb");
  FILE* output_file= fopen(argv[2], "wb");
  if (input_file == NULL)
  {
    fprintf(stderr,
      "lz4_decompress: [Error] Cannot open input file for reading.\n"
      );
    exit(1);
  }
  if (output_file == NULL)
  {
    fprintf(stderr,
      "lz4_decompress: [Error] Cannot create output file.\n"
      );
    exit(1);
  }
  LZ4F_decompressionContext_t decompression_context;
  LZ4F_createDecompressionContext(&decompression_context, LZ4F_VERSION);
  char* input_buffer= new char[INPUT_BUFFER_SIZE];
  char* output_buffer= new char[OUTPUT_BUFFER_SIZE];
  bool is_eof= false;

  while (!is_eof)
  {
    int bytes_read= fread(input_buffer, 1, INPUT_BUFFER_SIZE, input_file);

    if (bytes_read < INPUT_BUFFER_SIZE)
    {
      is_eof= feof(input_file);
      if (!is_eof)
      {
        fprintf(stderr,
          "lz4_decompress: [Error] Encountered problem during reading input.\n"
          );
        exit(1);
      }
    }

    size_t bytes_processed= 0;

    for (;;)
    {
      size_t current_bytes_processed= bytes_read - bytes_processed;
      size_t bytes_to_write= OUTPUT_BUFFER_SIZE;
      size_t result= LZ4F_decompress(decompression_context, output_buffer,
        &bytes_to_write, input_buffer + bytes_processed,
        &current_bytes_processed, NULL);
      if (LZ4F_isError(result))
      {
        fprintf(stderr,
          "lz4_decompress: [Error] Encountered problem during decompression.\n"
          );
        exit(1);
      }
      bytes_processed+= current_bytes_processed;

      if (bytes_to_write == 0)
        break;

      fwrite(output_buffer, 1, bytes_to_write, output_file);
    }
  }

  LZ4F_freeDecompressionContext(decompression_context);
  delete[] input_buffer;
  delete[] output_buffer;
  fclose(input_file);
  fclose(output_file);
  exit(0);
}