Merge pull request RustPython#2444 from verhovsky/add-bz2

add bz2 from CPython 3.10.5

Author: youknowone

Cargo.lock

@@ -27,6 +27,7 @@ jit = ["rustpython-vm/jit"]
 threading = ["rustpython-vm/threading", "rustpython-stdlib/threading"]
 pylib = ["rustpython-vm/pylib"]
 zlib = ["stdlib", "rustpython-stdlib/zlib"]
+bz2 = ["stdlib", "rustpython-stdlib/bz2"]
 ssl = ["rustpython-stdlib/ssl"]
 ssl-vendor = ["rustpython-stdlib/ssl-vendor"]
 

Cargo.toml

@@ -0,0 +1,344 @@
+"""Interface to the libbzip2 compression library.
+
+This module provides a file interface, classes for incremental
+(de)compression, and functions for one-shot (de)compression.
+"""
+
+__all__ = ["BZ2File", "BZ2Compressor", "BZ2Decompressor",
+           "open", "compress", "decompress"]
+
+__author__ = "Nadeem Vawda <nadeem.vawda@gmail.com>"
+
+from builtins import open as _builtin_open
+import io
+import os
+import _compression
+
+from _bz2 import BZ2Compressor, BZ2Decompressor
+
+
+_MODE_CLOSED   = 0
+_MODE_READ     = 1
+# Value 2 no longer used
+_MODE_WRITE    = 3
+
+
+class BZ2File(_compression.BaseStream):
+
+    """A file object providing transparent bzip2 (de)compression.
+
+    A BZ2File can act as a wrapper for an existing file object, or refer
+    directly to a named file on disk.
+
+    Note that BZ2File provides a *binary* file interface - data read is
+    returned as bytes, and data to be written should be given as bytes.
+    """
+
+    def __init__(self, filename, mode="r", *, compresslevel=9):
+        """Open a bzip2-compressed file.
+
+        If filename is a str, bytes, or PathLike object, it gives the
+        name of the file to be opened. Otherwise, it should be a file
+        object, which will be used to read or write the compressed data.
+
+        mode can be 'r' for reading (default), 'w' for (over)writing,
+        'x' for creating exclusively, or 'a' for appending. These can
+        equivalently be given as 'rb', 'wb', 'xb', and 'ab'.
+
+        If mode is 'w', 'x' or 'a', compresslevel can be a number between 1
+        and 9 specifying the level of compression: 1 produces the least
+        compression, and 9 (default) produces the most compression.
+
+        If mode is 'r', the input file may be the concatenation of
+        multiple compressed streams.
+        """
+        self._fp = None
+        self._closefp = False
+        self._mode = _MODE_CLOSED
+
+        if not (1 <= compresslevel <= 9):
+            raise ValueError("compresslevel must be between 1 and 9")
+
+        if mode in ("", "r", "rb"):
+            mode = "rb"
+            mode_code = _MODE_READ
+        elif mode in ("w", "wb"):
+            mode = "wb"
+            mode_code = _MODE_WRITE
+            self._compressor = BZ2Compressor(compresslevel)
+        elif mode in ("x", "xb"):
+            mode = "xb"
+            mode_code = _MODE_WRITE
+            self._compressor = BZ2Compressor(compresslevel)
+        elif mode in ("a", "ab"):
+            mode = "ab"
+            mode_code = _MODE_WRITE
+            self._compressor = BZ2Compressor(compresslevel)
+        else:
+            raise ValueError("Invalid mode: %r" % (mode,))
+
+        if isinstance(filename, (str, bytes, os.PathLike)):
+            self._fp = _builtin_open(filename, mode)
+            self._closefp = True
+            self._mode = mode_code
+        elif hasattr(filename, "read") or hasattr(filename, "write"):
+            self._fp = filename
+            self._mode = mode_code
+        else:
+            raise TypeError("filename must be a str, bytes, file or PathLike object")
+
+        if self._mode == _MODE_READ:
+            raw = _compression.DecompressReader(self._fp,
+                BZ2Decompressor, trailing_error=OSError)
+            self._buffer = io.BufferedReader(raw)
+        else:
+            self._pos = 0
+
+    def close(self):
+        """Flush and close the file.
+
+        May be called more than once without error. Once the file is
+        closed, any other operation on it will raise a ValueError.
+        """
+        if self._mode == _MODE_CLOSED:
+            return
+        try:
+            if self._mode == _MODE_READ:
+                self._buffer.close()
+            elif self._mode == _MODE_WRITE:
+                self._fp.write(self._compressor.flush())
+                self._compressor = None
+        finally:
+            try:
+                if self._closefp:
+                    self._fp.close()
+            finally:
+                self._fp = None
+                self._closefp = False
+                self._mode = _MODE_CLOSED
+                self._buffer = None
+
+    @property
+    def closed(self):
+        """True if this file is closed."""
+        return self._mode == _MODE_CLOSED
+
+    def fileno(self):
+        """Return the file descriptor for the underlying file."""
+        self._check_not_closed()
+        return self._fp.fileno()
+
+    def seekable(self):
+        """Return whether the file supports seeking."""
+        return self.readable() and self._buffer.seekable()
+
+    def readable(self):
+        """Return whether the file was opened for reading."""
+        self._check_not_closed()
+        return self._mode == _MODE_READ
+
+    def writable(self):
+        """Return whether the file was opened for writing."""
+        self._check_not_closed()
+        return self._mode == _MODE_WRITE
+
+    def peek(self, n=0):
+        """Return buffered data without advancing the file position.
+
+        Always returns at least one byte of data, unless at EOF.
+        The exact number of bytes returned is unspecified.
+        """
+        self._check_can_read()
+        # Relies on the undocumented fact that BufferedReader.peek()
+        # always returns at least one byte (except at EOF), independent
+        # of the value of n
+        return self._buffer.peek(n)
+
+    def read(self, size=-1):
+        """Read up to size uncompressed bytes from the file.
+
+        If size is negative or omitted, read until EOF is reached.
+        Returns b'' if the file is already at EOF.
+        """
+        self._check_can_read()
+        return self._buffer.read(size)
+
+    def read1(self, size=-1):
+        """Read up to size uncompressed bytes, while trying to avoid
+        making multiple reads from the underlying stream. Reads up to a
+        buffer's worth of data if size is negative.
+
+        Returns b'' if the file is at EOF.
+        """
+        self._check_can_read()
+        if size < 0:
+            size = io.DEFAULT_BUFFER_SIZE
+        return self._buffer.read1(size)
+
+    def readinto(self, b):
+        """Read bytes into b.
+
+        Returns the number of bytes read (0 for EOF).
+        """
+        self._check_can_read()
+        return self._buffer.readinto(b)
+
+    def readline(self, size=-1):
+        """Read a line of uncompressed bytes from the file.
+
+        The terminating newline (if present) is retained. If size is
+        non-negative, no more than size bytes will be read (in which
+        case the line may be incomplete). Returns b'' if already at EOF.
+        """
+        if not isinstance(size, int):
+            if not hasattr(size, "__index__"):
+                raise TypeError("Integer argument expected")
+            size = size.__index__()
+        self._check_can_read()
+        return self._buffer.readline(size)
+
+    def readlines(self, size=-1):
+        """Read a list of lines of uncompressed bytes from the file.
+
+        size can be specified to control the number of lines read: no
+        further lines will be read once the total size of the lines read
+        so far equals or exceeds size.
+        """
+        if not isinstance(size, int):
+            if not hasattr(size, "__index__"):
+                raise TypeError("Integer argument expected")
+            size = size.__index__()
+        self._check_can_read()
+        return self._buffer.readlines(size)
+
+    def write(self, data):
+        """Write a byte string to the file.
+
+        Returns the number of uncompressed bytes written, which is
+        always the length of data in bytes. Note that due to buffering,
+        the file on disk may not reflect the data written until close()
+        is called.
+        """
+        self._check_can_write()
+        if isinstance(data, (bytes, bytearray)):
+            length = len(data)
+        else:
+            # accept any data that supports the buffer protocol
+            data = memoryview(data)
+            length = data.nbytes
+
+        compressed = self._compressor.compress(data)
+        self._fp.write(compressed)
+        self._pos += length
+        return length
+
+    def writelines(self, seq):
+        """Write a sequence of byte strings to the file.
+
+        Returns the number of uncompressed bytes written.
+        seq can be any iterable yielding byte strings.
+
+        Line separators are not added between the written byte strings.
+        """
+        return _compression.BaseStream.writelines(self, seq)
+
+    def seek(self, offset, whence=io.SEEK_SET):
+        """Change the file position.
+
+        The new position is specified by offset, relative to the
+        position indicated by whence. Values for whence are:
+
+            0: start of stream (default); offset must not be negative
+            1: current stream position
+            2: end of stream; offset must not be positive
+
+        Returns the new file position.
+
+        Note that seeking is emulated, so depending on the parameters,
+        this operation may be extremely slow.
+        """
+        self._check_can_seek()
+        return self._buffer.seek(offset, whence)
+
+    def tell(self):
+        """Return the current file position."""
+        self._check_not_closed()
+        if self._mode == _MODE_READ:
+            return self._buffer.tell()
+        return self._pos
+
+
+def open(filename, mode="rb", compresslevel=9,
+         encoding=None, errors=None, newline=None):
+    """Open a bzip2-compressed file in binary or text mode.
+
+    The filename argument can be an actual filename (a str, bytes, or
+    PathLike object), or an existing file object to read from or write
+    to.
+
+    The mode argument can be "r", "rb", "w", "wb", "x", "xb", "a" or
+    "ab" for binary mode, or "rt", "wt", "xt" or "at" for text mode.
+    The default mode is "rb", and the default compresslevel is 9.
+
+    For binary mode, this function is equivalent to the BZ2File
+    constructor: BZ2File(filename, mode, compresslevel). In this case,
+    the encoding, errors and newline arguments must not be provided.
+
+    For text mode, a BZ2File object is created, and wrapped in an
+    io.TextIOWrapper instance with the specified encoding, error
+    handling behavior, and line ending(s).
+
+    """
+    if "t" in mode:
+        if "b" in mode:
+            raise ValueError("Invalid mode: %r" % (mode,))
+    else:
+        if encoding is not None:
+            raise ValueError("Argument 'encoding' not supported in binary mode")
+        if errors is not None:
+            raise ValueError("Argument 'errors' not supported in binary mode")
+        if newline is not None:
+            raise ValueError("Argument 'newline' not supported in binary mode")
+
+    bz_mode = mode.replace("t", "")
+    binary_file = BZ2File(filename, bz_mode, compresslevel=compresslevel)
+
+    if "t" in mode:
+        encoding = io.text_encoding(encoding)
+        return io.TextIOWrapper(binary_file, encoding, errors, newline)
+    else:
+        return binary_file
+
+
+def compress(data, compresslevel=9):
+    """Compress a block of data.
+
+    compresslevel, if given, must be a number between 1 and 9.
+
+    For incremental compression, use a BZ2Compressor object instead.
+    """
+    comp = BZ2Compressor(compresslevel)
+    return comp.compress(data) + comp.flush()
+
+
+def decompress(data):
+    """Decompress a block of data.
+
+    For incremental decompression, use a BZ2Decompressor object instead.
+    """
+    results = []
+    while data:
+        decomp = BZ2Decompressor()
+        try:
+            res = decomp.decompress(data)
+        except OSError:
+            if results:
+                break  # Leftover data is not a valid bzip2 stream; ignore it.
+            else:
+                raise  # Error on the first iteration; bail out.
+        results.append(res)
+        if not decomp.eof:
+            raise ValueError("Compressed data ended before the "
+                             "end-of-stream marker was reached")
+        data = decomp.unused_data
+    return b"".join(results)