text: import logging
  import os
  import platform
  import sys
  from contextlib import contextmanager
  from fnmatch import fnmatch
  
  import six
  from patch import fromfile, fromstring
  
  from conans.client.output import ConanOutput
  from conans.errors import ConanException
  from conans.unicode import get_cwd
  from conans.util.fallbacks import default_output
  from conans.util.files import (_generic_algorithm_sum, load, save)
  
  UNIT_SIZE = 1000.0
  # Library extensions supported by collect_libs
  VALID_LIB_EXTENSIONS = (".so", ".lib", ".a", ".dylib", ".bc")
  
  
  @contextmanager
  def chdir(newdir):
      old_path = get_cwd()
      os.chdir(newdir)
      try:
          yield
      finally:
          os.chdir(old_path)
  
  
  def human_size(size_bytes):
      """
      format a size in bytes into a 'human' file size, e.g. B, KB, MB, GB, TB, PB
      Note that bytes will be reported in whole numbers but KB and above will have
      greater precision.  e.g. 43 B, 443 KB, 4.3 MB, 4.43 GB, etc
      """
  
      suffixes_table = [('B', 0), ('KB', 1), ('MB', 1), ('GB', 2), ('TB', 2), ('PB', 2)]
  
      num = float(size_bytes)
      for suffix, precision in suffixes_table:
          if num < UNIT_SIZE:
              break
          num /= UNIT_SIZE
  
      if precision == 0:
          formatted_size = "%d" % num
      else:
          formatted_size = str(round(num, ndigits=precision))
  
      return "%s%s" % (formatted_size, suffix)
  
  
  def unzip(filename, destination=".", keep_permissions=False, pattern=None, output=None):
      """
      Unzip a zipped file
      :param filename: Path to the zip file
      :param destination: Destination folder (or file for .gz files)
      :param keep_permissions: Keep the zip permissions. WARNING: Can be
      dangerous if the zip was not created in a NIX system, the bits could
      produce undefined permission schema. Use this option only if you are sure
      that the zip was created correctly.
      :param pattern: Extract only paths matching the pattern. This should be a
      Unix shell-style wildcard, see fnmatch documentation for more details.
      :param output: output
      :return:
      """
      output = default_output(output, 'conans.client.tools.files.unzip')
  
      if (filename.endswith(".tar.gz") or filename.endswith(".tgz") or
              filename.endswith(".tbz2") or filename.endswith(".tar.bz2") or
              filename.endswith(".tar")):
          return untargz(filename, destination, pattern)
      if filename.endswith(".gz"):
          import gzip
          with gzip.open(filename, 'rb') as f:
              file_content = f.read()
          target_name = filename[:-3] if destination == "." else destination
          save(target_name, file_content)
          return
      if filename.endswith(".tar.xz") or filename.endswith(".txz"):
          if six.PY2:
              raise ConanException("XZ format not supported in Python 2. Use Python 3 instead")
          return untargz(filename, destination, pattern)
  
      import zipfile
      full_path = os.path.normpath(os.path.join(get_cwd(), destination))
  
      if hasattr(sys.stdout, "isatty") and sys.stdout.isatty():
          def print_progress(the_size, uncomp_size):
              the_size = (the_size * 100.0 / uncomp_size) if uncomp_size != 0 else 0
              txt_msg = "Unzipping %d %%"
              if the_size > print_progress.last_size + 1:
                  output.rewrite_line(txt_msg % the_size)
                  print_progress.last_size = the_size
                  if int(the_size) == 99:
                      output.rewrite_line(txt_msg % 100)
                      output.writeln("")
      else:
          def print_progress(_, __):
              pass
  
      with zipfile.ZipFile(filename, "r") as z:
          if not pattern:
              zip_info = z.infolist()
          else:
              zip_info = [zi for zi in z.infolist() if fnmatch(zi.filename, pattern)]
          uncompress_size = sum((file_.file_size for file_ in zip_info))
          if uncompress_size > 100000:
              output.info("Unzipping %s, this can take a while" % human_size(uncompress_size))
          else:
              output.info("Unzipping %s" % human_size(uncompress_size))
          extracted_size = 0
  
          print_progress.last_size = -1
          if platform.system() == "Windows":
              for file_ in zip_info:
                  extracted_size += file_.file_size
                  print_progress(extracted_size, uncompress_size)
                  try:
                      z.extract(file_, full_path)
                  except Exception as e:
                      output.error("Error extract %s\n%s" % (file_.filename, str(e)))
          else:  # duplicated for, to avoid a platform check for each zipped file
              for file_ in zip_info:
                  extracted_size += file_.file_size
                  print_progress(extracted_size, uncompress_size)
                  try:
                      z.extract(file_, full_path)
                      if keep_permissions:
                          # Could be dangerous if the ZIP has been created in a non nix system
                          # https://bugs.python.org/issue15795
                          perm = file_.external_attr >> 16 & 0xFFF
                          os.chmod(os.path.join(full_path, file_.filename), perm)
                  except Exception as e:
                      output.error("Error extract %s\n%s" % (file_.filename, str(e)))
  
  
  def untargz(filename, destination=".", pattern=None):
      import tarfile
      with tarfile.TarFile.open(filename, 'r:*') as tarredgzippedFile:
          if not pattern:
              tarredgzippedFile.extractall(destination)
          else:
              members = list(filter(lambda m: fnmatch(m.name, pattern),
                                    tarredgzippedFile.getmembers()))
              tarredgzippedFile.extractall(destination, members=members)
  
  
  def check_with_algorithm_sum(algorithm_name, file_path, signature):
      real_signature = _generic_algorithm_sum(file_path, algorithm_name)
      if real_signature != signature.lower():
          raise ConanException("%s signature failed for '%s' file. \n"
                               " Provided signature: %s  \n"
                               " Computed signature: %s" % (algorithm_name,
                                                            os.path.basename(file_path),
                                                            signature,
                                                            real_signature))
  
  
  def check_sha1(file_path, signature):
      check_with_algorithm_sum("sha1", file_path, signature)
  
  
  def check_md5(file_path, signature):
      check_with_algorithm_sum("md5", file_path, signature)
  
  
  def check_sha256(file_path, signature):
      check_with_algorithm_sum("sha256", file_path, signature)
  
  
  def patch(base_path=None, patch_file=None, patch_string=None, strip=0, output=None):
      """Applies a diff from file (patch_file)  or string (patch_string)
      in base_path directory or current dir if None"""
  
      class PatchLogHandler(logging.Handler):
          def __init__(self):
              logging.Handler.__init__(self, logging.DEBUG)
              self.output = output or ConanOutput(sys.stdout, sys.stderr, color=True)
              self.patchname = patch_file if patch_file else "patch"
  
          def emit(self, record):
              logstr = self.format(record)
              if record.levelno == logging.WARN:
                  self.output.warn("%s: %s" % (self.patchname, logstr))
              else:
                  self.output.info("%s: %s" % (self.patchname, logstr))
  
      patchlog = logging.getLogger("patch")
      if patchlog:
          patchlog.handlers = []
          patchlog.addHandler(PatchLogHandler())
  
      if not patch_file and not patch_string:
          return
      if patch_file:
          patchset = fromfile(patch_file)
      else:
          patchset = fromstring(patch_string.encode())
  
      if not patchset:
          raise ConanException("Failed to parse patch: %s" % (patch_file if patch_file else "string"))
  
      def decode_clean(path, prefix):
          path = path.decode("utf-8").replace("\\", "/")
          if path.startswith(prefix):
              path = path[2:]
          return path
  
      def strip_path(path):
          tokens = path.split("/")
          if len(tokens) > 1:
              tokens = tokens[strip:]
          path = "/".join(tokens)
          if base_path:
              path = os.path.join(base_path, path)
          return path
      # account for new and deleted files, upstream dep won't fix them
      items = []
      for p in patchset:
          source = decode_clean(p.source, "a/")
          target = decode_clean(p.target, "b/")
          if "dev/null" in source:
              target = strip_path(target)
              hunks = [s.decode("utf-8") for s in p.hunks[0].text]
              new_file = "".join(hunk[1:] for hunk in hunks)
              save(target, new_file)
          elif "dev/null" in target:
              source = strip_path(source)
              os.unlink(source)
          else:
              items.append(p)
      patchset.items = items
  
      if not patchset.apply(root=base_path, strip=strip):
          raise ConanException("Failed to apply patch: %s" % patch_file)
  
  
  def _manage_text_not_found(search, file_path, strict, function_name, output):
      message = "%s didn't find pattern '%s' in '%s' file." % (function_name, search, file_path)
      if strict:
          raise ConanException(message)
      else:
          output.warn(message)
          return False
  
  
  def replace_in_file(file_path, search, replace, strict=True, output=None):
      output = default_output(output, 'conans.client.tools.files.replace_in_file')
  
      content = load(file_path)
      if -1 == content.find(search):
          _manage_text_not_found(search, file_path, strict, "replace_in_file", output=output)
      content = content.replace(search, replace)
      content = content.encode("utf-8")
      with open(file_path, "wb") as handle:
          handle.write(content)
  
  
  def replace_path_in_file(file_path, search, replace, strict=True, windows_paths=None, output=None):
      output = default_output(output, 'conans.client.tools.files.replace_path_in_file')
  
      if windows_paths is False or (windows_paths is None and platform.system() != "Windows"):
          return replace_in_file(file_path, search, replace, strict=strict, output=output)
  
      def normalized_text(text):
          return text.replace("\\", "/").lower()
  
      content = load(file_path)
      normalized_content = normalized_text(content)
      normalized_search = normalized_text(search)
      index = normalized_content.find(normalized_search)
      if index == -1:
          return _manage_text_not_found(search, file_path, strict, "replace_path_in_file",
                                        output=output)
  
      while index != -1:
          content = content[:index] + replace + content[index + len(search):]
          normalized_content = normalized_text(content)
          index = normalized_content.find(normalized_search)
  
      content = content.encode("utf-8")
      with open(file_path, "wb") as handle:
          handle.write(content)
  
      return True
  
  
  def replace_prefix_in_pc_file(pc_file, new_prefix):
      content = load(pc_file)
      lines = []
      for line in content.splitlines():
          if line.startswith("prefix="):
              lines.append('prefix=%s' % new_prefix)
          else:
              lines.append(line)
      save(pc_file, "\n".join(lines))
  
  
  def _path_equals(path1, path2):
      path1 = os.path.normpath(path1)
      path2 = os.path.normpath(path2)
      if platform.system() == "Windows":
          path1 = path1.lower().replace("sysnative", "system32")
          path2 = path2.lower().replace("sysnative", "system32")
      return path1 == path2
  
  
  def collect_libs(conanfile, folder=None):
      if not conanfile.package_folder:
          return []
      if folder:
          lib_folders = [os.path.join(conanfile.package_folder, folder)]
      else:
          lib_folders = [os.path.join(conanfile.package_folder, folder)
                         for folder in conanfile.cpp_info.libdirs]
      result = []
      for lib_folder in lib_folders:
          if not os.path.exists(lib_folder):
              conanfile.output.warn("Lib folder doesn't exist, can't collect libraries: "
                                    "{0}".format(lib_folder))
              continue
          files = os.listdir(lib_folder)
          for f in files:
              name, ext = os.path.splitext(f)
              if ext in VALID_LIB_EXTENSIONS:
                  if ext != ".lib" and name.startswith("lib"):
                      name = name[3:]
                  if name in result:
                      conanfile.output.warn("Library '%s' was either already found in a previous "
                                            "'conanfile.cpp_info.libdirs' folder or appears several "
                                            "times with a different file extension" % name)
                  else:
                      result.append(name)
      result.sort()
      return result
  
  
  def which(filename):
      """ same affect as posix which command or shutil.which from python3 """
      def verify(filepath):
          if os.path.isfile(filepath) and os.access(filepath, os.X_OK):
              return os.path.join(path, filename)
          return None
  
      def _get_possible_filenames(filename):
          extensions_win = (os.getenv("PATHEXT", ".COM;.EXE;.BAT;.CMD").split(";")
                            if "." not in filename else [])
          extensions = [".sh"] if platform.system() != "Windows" else extensions_win
          extensions.insert(1, "")  # No extension
          return ["%s%s" % (filename, entry.lower()) for entry in extensions]
  
      possible_names = _get_possible_filenames(filename)
      for path in os.environ["PATH"].split(os.pathsep):
          for name in possible_names:
              filepath = os.path.abspath(os.path.join(path, name))
              if verify(filepath):
                  return filepath
              if platform.system() == "Windows":
                  filepath = filepath.lower()
                  if "system32" in filepath:
                      # python return False for os.path.exists of exes in System32 but with SysNative
                      trick_path = filepath.replace("system32", "sysnative")
                      if verify(trick_path):
                          return trick_path
  
      return None
  
  
  def _replace_with_separator(filepath, sep):
      tmp = load(filepath)
      ret = sep.join(tmp.splitlines())
      if tmp.endswith("\n"):
          ret += sep
      save(filepath, ret)
  
  
  def unix2dos(filepath):
      _replace_with_separator(filepath, "\r\n")
  
  
  def dos2unix(filepath):
      _replace_with_separator(filepath, "\n")
  