Python RangeSet.size方法代码示例

# 需要导入模块: from rangelib import RangeSet [as 别名]
# 或者: from rangelib.RangeSet import size [as 别名]
class EmptyImage(Image):
  """A zero-length image."""

  def __init__(self):
    self.blocksize = 4096
    self.care_map = RangeSet()
    self.clobbered_blocks = RangeSet()
    self.extended = RangeSet()
    self.total_blocks = 0
    self.file_map = {}

  def RangeSha1(self, ranges):
    return sha1().hexdigest()

  def ReadRangeSet(self, ranges):
    return ()

  def TotalSha1(self, include_clobbered_blocks=False):
    # EmptyImage always carries empty clobbered_blocks, so
    # include_clobbered_blocks can be ignored.
    assert self.clobbered_blocks.size() == 0
    return sha1().hexdigest()

  def WriteRangeDataToFd(self, ranges, fd):
    raise ValueError("Can't write data from EmptyImage to file")

# 需要导入模块: from rangelib import RangeSet [as 别名]
# 或者: from rangelib.RangeSet import size [as 别名]
class DataImage(Image):
  """An image wrapped around a single string of data."""

  def __init__(self, data, trim=False, pad=False):
    self.data = data
    self.blocksize = 4096

    assert not (trim and pad)

    partial = len(self.data) % self.blocksize
    if partial > 0:
      if trim:
        self.data = self.data[:-partial]
      elif pad:
        self.data += '\0' * (self.blocksize - partial)
      else:
        raise ValueError(("data for DataImage must be multiple of %d bytes "
                          "unless trim or pad is specified") %
                         (self.blocksize,))

    assert len(self.data) % self.blocksize == 0

    self.total_blocks = len(self.data) / self.blocksize
    self.care_map = RangeSet(data=(0, self.total_blocks))
    self.clobbered_blocks = RangeSet()
    self.extended = RangeSet()

    zero_blocks = []
    nonzero_blocks = []
    reference = '\0' * self.blocksize

    for i in range(self.total_blocks):
      d = self.data[i*self.blocksize : (i+1)*self.blocksize]
      if d == reference:
        zero_blocks.append(i)
        zero_blocks.append(i+1)
      else:
        nonzero_blocks.append(i)
        nonzero_blocks.append(i+1)

    self.file_map = {"__ZERO": RangeSet(zero_blocks),
                     "__NONZERO": RangeSet(nonzero_blocks)}

  def ReadRangeSet(self, ranges):
    return [self.data[s*self.blocksize:e*self.blocksize] for (s, e) in ranges]

  def TotalSha1(self, include_clobbered_blocks=False):
    # DataImage always carries empty clobbered_blocks, so
    # include_clobbered_blocks can be ignored.
    assert self.clobbered_blocks.size() == 0
    return sha1(self.data).hexdigest()

# 需要导入模块: from rangelib import RangeSet [as 别名]
# 或者: from rangelib.RangeSet import size [as 别名]
    def AddTransfer(tgt_name, src_name, tgt_ranges, src_ranges, style, by_id,
                    split=False):
      """Wrapper function for adding a Transfer()."""

      # We specialize diff transfers only (which covers bsdiff/imgdiff/move);
      # otherwise add the Transfer() as is.
      if style != "diff" or not split:
        Transfer(tgt_name, src_name, tgt_ranges, src_ranges, style, by_id)
        return

      # Handle .odex files specially to analyze the block-wise difference. If
      # most of the blocks are identical with only few changes (e.g. header),
      # we will patch the changed blocks only. This avoids stashing unchanged
      # blocks while patching. We limit the analysis to files without size
      # changes only. This is to avoid sacrificing the OTA generation cost too
      # much.
      if (tgt_name.split(".")[-1].lower() == 'odex' and
          tgt_ranges.size() == src_ranges.size()):

        # 0.5 threshold can be further tuned. The tradeoff is: if only very
        # few blocks remain identical, we lose the opportunity to use imgdiff
        # that may have better compression ratio than bsdiff.
        crop_threshold = 0.5

        tgt_skipped = RangeSet()
        src_skipped = RangeSet()
        tgt_size = tgt_ranges.size()
        tgt_changed = 0
        for src_block, tgt_block in zip(src_ranges.next_item(),
                                        tgt_ranges.next_item()):
          src_rs = RangeSet(str(src_block))
          tgt_rs = RangeSet(str(tgt_block))
          if self.src.ReadRangeSet(src_rs) == self.tgt.ReadRangeSet(tgt_rs):
            tgt_skipped = tgt_skipped.union(tgt_rs)
            src_skipped = src_skipped.union(src_rs)
          else:
            tgt_changed += tgt_rs.size()

          # Terminate early if no clear sign of benefits.
          if tgt_changed > tgt_size * crop_threshold:
            break

        if tgt_changed < tgt_size * crop_threshold:
          assert tgt_changed + tgt_skipped.size() == tgt_size
          print('%10d %10d (%6.2f%%) %s' % (tgt_skipped.size(), tgt_size,
                tgt_skipped.size() * 100.0 / tgt_size, tgt_name))
          AddSplitTransfers(
              "%s-skipped" % (tgt_name,),
              "%s-skipped" % (src_name,),
              tgt_skipped, src_skipped, style, by_id)

          # Intentionally change the file extension to avoid being imgdiff'd as
          # the files are no longer in their original format.
          tgt_name = "%s-cropped" % (tgt_name,)
          src_name = "%s-cropped" % (src_name,)
          tgt_ranges = tgt_ranges.subtract(tgt_skipped)
          src_ranges = src_ranges.subtract(src_skipped)

          # Possibly having no changed blocks.
          if not tgt_ranges:
            return

      # Add the transfer(s).
      AddSplitTransfers(
          tgt_name, src_name, tgt_ranges, src_ranges, style, by_id)