[issue5863] bz2.BZ2File should accept other file-like objects.

Modules/_bz2module.c

-/*
-
-python-bz2 - python bz2 library interface
-
-Copyright (c) 2002  Gustavo Niemeyer <niemeyer@conectiva.com>
-Copyright (c) 2002  Python Software Foundation; All Rights Reserved
-
-*/
+/* _bz2 - Low-level Python interface to libbzip2. */
 
 #include "Python.h"

[Antoine Pitrou, 2011/03/13 17:31:28]

Since this is a new start, perhaps we should add
  #define PY_SSIZE_T_CLEAN
before including "Python.h"?
This will ensure no code in the module will rely on the old behaviour.

-#include <stdio.h>
+#include "structmember.h"
 #include <bzlib.h>
-#include "structmember.h"
-
-#ifdef WITH_THREAD
-#include "pythread.h"
-#endif
-
-static char __author__[] =
-"The bz2 python module was written by:\n\
-\n\
-    Gustavo Niemeyer <niemeyer@conectiva.com>\n\
-";
-
-/* Our very own off_t-like type, 64-bit if possible */
-/* copied from Objects/fileobject.c */
-#if !defined(HAVE_LARGEFILE_SUPPORT)
-typedef off_t Py_off_t;
-#elif SIZEOF_OFF_T >= 8
-typedef off_t Py_off_t;
-#elif SIZEOF_FPOS_T >= 8
-typedef fpos_t Py_off_t;
-#else
-#error "Large file support, but neither off_t nor fpos_t is large enough."
-#endif
-
-#define BUF(v) PyBytes_AS_STRING(v)
-
-#define MODE_CLOSED   0
-#define MODE_READ     1
-#define MODE_READ_EOF 2
-#define MODE_WRITE    3
-
-#define BZ2FileObject_Check(v)  (Py_TYPE(v) == &BZ2File_Type)
 
 
-#ifdef BZ_CONFIG_ERROR
-
-#if SIZEOF_LONG >= 8
-#define BZS_TOTAL_OUT(bzs) \
-    (((long)bzs->total_out_hi32 << 32) + bzs->total_out_lo32)
-#elif SIZEOF_LONG_LONG >= 8
-#define BZS_TOTAL_OUT(bzs) \
-    (((PY_LONG_LONG)bzs->total_out_hi32 << 32) + bzs->total_out_lo32)
-#else
-#define BZS_TOTAL_OUT(bzs) \
-    bzs->total_out_lo32
-#endif
-
-#else /* ! BZ_CONFIG_ERROR */
-
-#define BZ2_bzRead bzRead
-#define BZ2_bzReadOpen bzReadOpen
-#define BZ2_bzReadClose bzReadClose
-#define BZ2_bzWrite bzWrite
-#define BZ2_bzWriteOpen bzWriteOpen
-#define BZ2_bzWriteClose bzWriteClose
+#ifndef BZ_CONFIG_ERROR
 #define BZ2_bzCompress bzCompress
 #define BZ2_bzCompressInit bzCompressInit
 #define BZ2_bzCompressEnd bzCompressEnd
 #define BZ2_bzDecompress bzDecompress
 #define BZ2_bzDecompressInit bzDecompressInit
 #define BZ2_bzDecompressEnd bzDecompressEnd
+#endif  /* ! BZ_CONFIG_ERROR */
 
-#define BZS_TOTAL_OUT(bzs) bzs->total_out
-
-#endif /* ! BZ_CONFIG_ERROR */
-
-
-#ifdef WITH_THREAD
-#define ACQUIRE_LOCK(obj) do { \
-    if (!PyThread_acquire_lock(obj->lock, 0)) { \
-        Py_BEGIN_ALLOW_THREADS \
-        PyThread_acquire_lock(obj->lock, 1); \
-        Py_END_ALLOW_THREADS \
-    } } while(0)
-#define RELEASE_LOCK(obj) PyThread_release_lock(obj->lock)
-#else
-#define ACQUIRE_LOCK(obj)
-#define RELEASE_LOCK(obj)
-#endif
-
-/* Bits in f_newlinetypes */
-#define NEWLINE_UNKNOWN 0       /* No newline seen, yet */
-#define NEWLINE_CR 1            /* \r newline seen */
-#define NEWLINE_LF 2            /* \n newline seen */
-#define NEWLINE_CRLF 4          /* \r\n newline seen */
-
-/* ===================================================================== */
-/* Structure definitions. */
-
-typedef struct {
-    PyObject_HEAD
-    FILE *rawfp;
-
-    char* f_buf;                /* Allocated readahead buffer */
-    char* f_bufend;             /* Points after last occupied position */
-    char* f_bufptr;             /* Current buffer position */
-
-    BZFILE *fp;
-    int mode;
-    Py_off_t pos;
-    Py_off_t size;
-#ifdef WITH_THREAD
-    PyThread_type_lock lock;
-#endif
-} BZ2FileObject;
 
 typedef struct {
     PyObject_HEAD
     bz_stream bzs;
-    int running;
-#ifdef WITH_THREAD

[Antoine Pitrou, 2011/03/13 17:31:28]

As mentioned in Lib/bz2.py, I would keep the lock on the C side since it isn't
significantly more complicated, and it avoids having to write a Python wrapper
around the compressor and decompressor types.

-    PyThread_type_lock lock;
-#endif
-} BZ2CompObject;
+    int flushed;
+} Compressor;
 
 typedef struct {
     PyObject_HEAD
     bz_stream bzs;
-    int running;
+    int eof;
     PyObject *unused_data;
-#ifdef WITH_THREAD
-    PyThread_type_lock lock;
-#endif
-} BZ2DecompObject;
+} Decompressor;
 
-/* ===================================================================== */
-/* Utility functions. */
 
-/* Refuse regular I/O if there's data in the iteration-buffer.
- * Mixing them would cause data to arrive out of order, as the read*
- * methods don't use the iteration buffer. */
-static int
-check_iterbuffered(BZ2FileObject *f)
-{
-    if (f->f_buf != NULL &&
-        (f->f_bufend - f->f_bufptr) > 0 &&
-        f->f_buf[0] != '\0') {
-        PyErr_SetString(PyExc_ValueError,
-            "Mixing iteration and read methods would lose data");
-        return -1;
-    }
-    return 0;
-}
+/* Helper functions. */
 
 static int
-Util_CatchBZ2Error(int bzerror)
+catch_bz2_error(int bzerror)
 {
-    int ret = 0;
     switch(bzerror) {
         case BZ_OK:
+        case BZ_RUN_OK:
+        case BZ_FLUSH_OK:
+        case BZ_FINISH_OK:
         case BZ_STREAM_END:
-            break;
+            return 0;
 
 #ifdef BZ_CONFIG_ERROR
         case BZ_CONFIG_ERROR:
             PyErr_SetString(PyExc_SystemError,
-                            "the bz2 library was not compiled "
-                            "correctly");
-            ret = 1;
-            break;
+                            "libbzip2 was not compiled correctly");

[Antoine Pitrou, 2011/03/13 17:31:28]

Just a nit, but I'm not sure there's any point in renaming "the bz2 library" to
"libbzip2"?
(also, under Windows I'm not sure the library naming convention is the same as
under Unix)

+            return 1;
 #endif
-
         case BZ_PARAM_ERROR:
             PyErr_SetString(PyExc_ValueError,
-                            "the bz2 library has received wrong "
-                            "parameters");
-            ret = 1;
-            break;
-
+                            "Internal error - "
+                            "invalid parameters passed to libbzip2");
+            return 1;
         case BZ_MEM_ERROR:
             PyErr_NoMemory();
-            ret = 1;
-            break;
-
+            return 1;
         case BZ_DATA_ERROR:
         case BZ_DATA_ERROR_MAGIC:
-            PyErr_SetString(PyExc_IOError, "invalid data stream");
-            ret = 1;
-            break;
-
+            PyErr_SetString(PyExc_IOError, "Invalid data stream");
+            return 1;
         case BZ_IO_ERROR:
-            PyErr_SetString(PyExc_IOError, "unknown IO error");
-            ret = 1;
-            break;
-
+            PyErr_SetString(PyExc_IOError, "Unknown I/O error");
+            return 1;
         case BZ_UNEXPECTED_EOF:
             PyErr_SetString(PyExc_EOFError,
-                            "compressed file ended before the "
-                            "logical end-of-stream was detected");
-            ret = 1;
-            break;
-
+                            "Compressed file ended before the logical "
+                            "end-of-stream was detected");
+            return 1;
         case BZ_SEQUENCE_ERROR:
             PyErr_SetString(PyExc_RuntimeError,
-                            "wrong sequence of bz2 library "
-                            "commands used");
-            ret = 1;
-            break;
+                            "Internal error - "
+                            "Invalid sequence of commands sent to libbzip2");
+            return 1;
+        default:
+            PyErr_Format(PyExc_IOError,
+                         "Unrecognized error from libbzip2: %d", bzerror);

[Antoine Pitrou, 2011/03/13 17:31:28]

Out of curiousity, did you encounter this condition?

+            return 1;
     }
-    return ret;
 }
 
 #if BUFSIZ < 8192
 #define SMALLCHUNK 8192
 #else
 #define SMALLCHUNK BUFSIZ
 #endif
 
 #if SIZEOF_INT < 4
 #define BIGCHUNK  (512 * 32)
 #else
 #define BIGCHUNK  (512 * 1024)
 #endif
 
-/* This is a hacked version of Python's fileobject.c:new_buffersize(). */
-static size_t
-Util_NewBufferSize(size_t currentsize)
-{
-    if (currentsize > SMALLCHUNK) {
-        /* Keep doubling until we reach BIGCHUNK;
-           then keep adding BIGCHUNK. */
-        if (currentsize <= BIGCHUNK)
-            return currentsize + currentsize;
-        else
-            return currentsize + BIGCHUNK;
-    }
-    return currentsize + SMALLCHUNK;
-}
-
-/* This is a hacked version of Python's fileobject.c:get_line(). */
-static PyObject *
-Util_GetLine(BZ2FileObject *f, int n)
-{
-    char c;
-    char *buf, *end;
-    size_t total_v_size;        /* total # of slots in buffer */
-    size_t used_v_size;         /* # used slots in buffer */
-    size_t increment;       /* amount to increment the buffer */
-    PyObject *v;
+static int
+grow_buffer(PyObject **buf)
+{
+    size_t size = PyBytes_GET_SIZE(*buf);
+    if (size <= SMALLCHUNK)
+        return _PyBytes_Resize(buf, size + SMALLCHUNK);
+    else if (size <= BIGCHUNK)
+        return _PyBytes_Resize(buf, size * 2);
+    else
+        return _PyBytes_Resize(buf, size + BIGCHUNK);
+}
+
+
+/* Compressor class. */
+
+static PyObject *
+compress(Compressor *c, char *data, size_t len, int action)
+{
+    size_t data_size = 0;
+    PyObject *result;
+
+    result = PyBytes_FromStringAndSize(NULL, SMALLCHUNK);
+    if (result == NULL)
+        return NULL;
+    c->bzs.next_in = data;
+    c->bzs.avail_in = len;
+    c->bzs.next_out = PyBytes_AS_STRING(result);
+    c->bzs.avail_out = PyBytes_GET_SIZE(result);

[Antoine Pitrou, 2011/03/13 17:31:28]

Do note that avail_in and avail_out are 32-bit ints, and therefore this is not
64-bit clean. I guess you're just copying the old code here, but that would
deserve a separate patch later. Perhaps add a comment in the meantime.

+    for (;;) {
+        char *this_out;
+        int bzerror;
+
+        Py_BEGIN_ALLOW_THREADS
+        this_out = c->bzs.next_out;
+        bzerror = BZ2_bzCompress(&c->bzs, action);
+        data_size += c->bzs.next_out - this_out;
+        Py_END_ALLOW_THREADS
+        if (catch_bz2_error(bzerror))
+            goto error;
+
+        /* In regular compression mode, stop when input data is exhausted.
+           In flushing mode, stop when all buffered data has been flushed. */
+        if ((action == BZ_RUN && c->bzs.avail_in == 0) ||
+            (action == BZ_FINISH && bzerror == BZ_STREAM_END))
+            break;
+
+        if (c->bzs.avail_out == 0) {
+            if (grow_buffer(&result) < 0)
+                goto error;
+            c->bzs.next_out = PyBytes_AS_STRING(result) + data_size;
+            c->bzs.avail_out = PyBytes_GET_SIZE(result) - data_size;
+        }
+    }
+    if (data_size != PyBytes_GET_SIZE(result))
+        if (_PyBytes_Resize(&result, data_size) < 0)
+            goto error;
+    return result;
+
+error:
+    Py_XDECREF(result);
+    return NULL;
+}
+
+static PyObject *
+Compressor_compress(Compressor *self, PyObject *arg)
+{
+    Py_buffer buffer;
+    PyObject *result;
+
+    if (self->flushed) {
+        PyErr_SetString(PyExc_ValueError, "Compressor has been flushed");
+        return NULL;
+    }
+    if (PyObject_GetBuffer(arg, &buffer, PyBUF_SIMPLE) < 0)
+        return NULL;
+    result = compress(self, buffer.buf, buffer.len, BZ_RUN);
+    PyBuffer_Release(&buffer);
+    return result;
+}
+
+static PyObject *
+Compressor_flush(Compressor *self, PyObject *noargs)
+{
+    if (self->flushed) {
+        PyErr_SetString(PyExc_ValueError, "Repeated call to flush()");
+        return NULL;
+    }
+    self->flushed = 1;
+    return compress(self, NULL, 0, BZ_FINISH);
+}
+
+static int
+Compressor_init(Compressor *self, PyObject *args, PyObject *kwargs)
+{
+    int compresslevel = 9;
     int bzerror;
-    int bytes_read;
-
-    total_v_size = n > 0 ? n : 100;
-    v = PyBytes_FromStringAndSize((char *)NULL, total_v_size);
-    if (v == NULL)
-        return NULL;
-
-    buf = BUF(v);
-    end = buf + total_v_size;
-
+
+    if (!PyArg_ParseTuple(args, "|i:Compressor", &compresslevel))
+        return -1;
+    bzerror = BZ2_bzCompressInit(&self->bzs, compresslevel, 0, 0);
+    return catch_bz2_error(bzerror) ? -1 : 0;
+}
+
+static void
+Compressor_dealloc(Compressor *self)
+{
+    int bzerror = BZ2_bzCompressEnd(&self->bzs);
+    if (catch_bz2_error(bzerror))
+        PyErr_WriteUnraisable((PyObject *)self);
+    Py_TYPE(self)->tp_free((PyObject *)self);
+}
+
+static PyMethodDef Compressor_methods[] = {
+    {"compress", (PyCFunction)Compressor_compress, METH_O,
+     "Provide a block of data to the compressor."},

[Antoine Pitrou, 2011/03/13 17:31:28]

You could instead re-use the old, more precise docstrings. Also, using
PyDoc_STRVAR is preferred so as to make it easier to modify multi-line
docstrings.

+    {"flush",    (PyCFunction)Compressor_flush,    METH_NOARGS,
+     "Flush the buffers of the compressor."},
+    {NULL}
+};
+
+static PyTypeObject Compressor_Type = {
+    PyVarObject_HEAD_INIT(NULL, 0)
+    "_bz2.Compressor",                  /* tp_name */
+    sizeof(Compressor),                 /* tp_basicsize */
+    0,                                  /* tp_itemsize */
+    (destructor)Compressor_dealloc,     /* tp_dealloc */
+    0,                                  /* tp_print */
+    0,                                  /* tp_getattr */
+    0,                                  /* tp_setattr */
+    0,                                  /* tp_reserved */
+    0,                                  /* tp_repr */
+    0,                                  /* tp_as_number */
+    0,                                  /* tp_as_sequence */
+    0,                                  /* tp_as_mapping */
+    0,                                  /* tp_hash  */
+    0,                                  /* tp_call */
+    0,                                  /* tp_str */
+    0,                                  /* tp_getattro */
+    0,                                  /* tp_setattro */
+    0,                                  /* tp_as_buffer */
+    Py_TPFLAGS_DEFAULT,                 /* tp_flags */
+    "Wrapper for bz2 compression functions.", /* tp_doc */
+    0,                                  /* tp_traverse */
+    0,                                  /* tp_clear */
+    0,                                  /* tp_richcompare */
+    0,                                  /* tp_weaklistoffset */
+    0,                                  /* tp_iter */
+    0,                                  /* tp_iternext */
+    Compressor_methods,                 /* tp_methods */
+    0,                                  /* tp_members */
+    0,                                  /* tp_getset */
+    0,                                  /* tp_base */
+    0,                                  /* tp_dict */
+    0,                                  /* tp_descr_get */
+    0,                                  /* tp_descr_set */
+    0,                                  /* tp_dictoffset */
+    (initproc)Compressor_init,          /* tp_init */
+    0,                                  /* tp_alloc */
+    PyType_GenericNew,                  /* tp_new */
+};
+
+
+/* Decompressor class. */
+
+static PyObject *
+decompress(Decompressor *d, char *data, size_t len)
+{
+    size_t data_size = 0;
+    PyObject *result;
+
+    result = PyBytes_FromStringAndSize(NULL, SMALLCHUNK);
+    if (result == NULL)
+        return result;
+    d->bzs.next_in = data;
+    d->bzs.avail_in = len;
+    d->bzs.next_out = PyBytes_AS_STRING(result);
+    d->bzs.avail_out = PyBytes_GET_SIZE(result);
     for (;;) {
+        char *this_out;
+        int bzerror;
+
         Py_BEGIN_ALLOW_THREADS
-        do {
-            bytes_read = BZ2_bzRead(&bzerror, f->fp, &c, 1);
-            f->pos++;
-            if (bytes_read == 0)
-                break;
-            *buf++ = c;
-        } while (bzerror == BZ_OK && c != '\n' && buf != end);
+        this_out = d->bzs.next_out;
+        bzerror = BZ2_bzDecompress(&d->bzs);
+        data_size += d->bzs.next_out - this_out;
         Py_END_ALLOW_THREADS
+        if (catch_bz2_error(bzerror))
+            goto error;
         if (bzerror == BZ_STREAM_END) {
-            f->size = f->pos;
-            f->mode = MODE_READ_EOF;
-            break;
-        } else if (bzerror != BZ_OK) {
-            Util_CatchBZ2Error(bzerror);
-            Py_DECREF(v);
-            return NULL;
-        }
-        if (c == '\n')
-            break;
-        /* Must be because buf == end */
-        if (n > 0)
-            break;
-        used_v_size = total_v_size;
-        increment = total_v_size >> 2; /* mild exponential growth */
-        total_v_size += increment;
-        if (total_v_size > INT_MAX) {
-            PyErr_SetString(PyExc_OverflowError,
-                "line is longer than a Python string can hold");
-            Py_DECREF(v);
-            return NULL;
-        }
-        if (_PyBytes_Resize(&v, total_v_size) < 0) {
-            return NULL;
-        }
-        buf = BUF(v) + used_v_size;
-        end = BUF(v) + total_v_size;
-    }
-
-    used_v_size = buf - BUF(v);
-    if (used_v_size != total_v_size) {
-        if (_PyBytes_Resize(&v, used_v_size) < 0) {
-            v = NULL;
-        }
-    }
-    return v;
-}
-
-/* This is a hacked version of Python's fileobject.c:drop_readahead(). */
-static void
-Util_DropReadAhead(BZ2FileObject *f)
-{
-    if (f->f_buf != NULL) {
-        PyMem_Free(f->f_buf);
-        f->f_buf = NULL;
-    }
-}
-
-/* This is a hacked version of Python's fileobject.c:readahead(). */
-static int
-Util_ReadAhead(BZ2FileObject *f, int bufsize)
-{
-    int chunksize;
-    int bzerror;
-
-    if (f->f_buf != NULL) {
-        if((f->f_bufend - f->f_bufptr) >= 1)
-            return 0;
-        else
-            Util_DropReadAhead(f);
-    }
-    if (f->mode == MODE_READ_EOF) {
-        f->f_bufptr = f->f_buf;
-        f->f_bufend = f->f_buf;
-        return 0;
-    }
-    if ((f->f_buf = PyMem_Malloc(bufsize)) == NULL) {
-        PyErr_NoMemory();
-        return -1;
-    }
-    Py_BEGIN_ALLOW_THREADS
-    chunksize = BZ2_bzRead(&bzerror, f->fp, f->f_buf, bufsize);
-    Py_END_ALLOW_THREADS
-    f->pos += chunksize;
-    if (bzerror == BZ_STREAM_END) {
-        f->size = f->pos;
-        f->mode = MODE_READ_EOF;
-    } else if (bzerror != BZ_OK) {
-        Util_CatchBZ2Error(bzerror);
-        Util_DropReadAhead(f);
-        return -1;
-    }
-    f->f_bufptr = f->f_buf;
-    f->f_bufend = f->f_buf + chunksize;
-    return 0;
-}
-
-/* This is a hacked version of Python's
- * fileobject.c:readahead_get_line_skip(). */
-static PyBytesObject *
-Util_ReadAheadGetLineSkip(BZ2FileObject *f, int skip, int bufsize)
-{
-    PyBytesObject* s;
-    char *bufptr;
-    char *buf;
-    int len;
-
-    if (f->f_buf == NULL)
-        if (Util_ReadAhead(f, bufsize) < 0)
-            return NULL;
-
-    len = f->f_bufend - f->f_bufptr;
-    if (len == 0)
-        return (PyBytesObject *)
-            PyBytes_FromStringAndSize(NULL, skip);
-    bufptr = memchr(f->f_bufptr, '\n', len);
-    if (bufptr != NULL) {
-        bufptr++;                               /* Count the '\n' */
-        len = bufptr - f->f_bufptr;
-        s = (PyBytesObject *)
-            PyBytes_FromStringAndSize(NULL, skip+len);
-        if (s == NULL)
-            return NULL;
-        memcpy(PyBytes_AS_STRING(s)+skip, f->f_bufptr, len);
-        f->f_bufptr = bufptr;
-        if (bufptr == f->f_bufend)
-            Util_DropReadAhead(f);
-    } else {
-        bufptr = f->f_bufptr;
-        buf = f->f_buf;
-        f->f_buf = NULL;                /* Force new readahead buffer */
-        s = Util_ReadAheadGetLineSkip(f, skip+len,
-                                      bufsize + (bufsize>>2));
-        if (s == NULL) {
-            PyMem_Free(buf);
-            return NULL;
-        }
-        memcpy(PyBytes_AS_STRING(s)+skip, bufptr, len);
-        PyMem_Free(buf);
-    }
-    return s;
-}
-
-/* ===================================================================== */
-/* Methods of BZ2File. */
-
-PyDoc_STRVAR(BZ2File_read__doc__,
-"read([size]) -> string\n\
-\n\
-Read at most size uncompressed bytes, returned as a string. If the size\n\
-argument is negative or omitted, read until EOF is reached.\n\
-");
-
-/* This is a hacked version of Python's fileobject.c:file_read(). */
-static PyObject *
-BZ2File_read(BZ2FileObject *self, PyObject *args)
-{
-    long bytesrequested = -1;
-    size_t bytesread, buffersize, chunksize;
-    int bzerror;
-    PyObject *ret = NULL;
-
-    if (!PyArg_ParseTuple(args, "|l:read", &bytesrequested))
-        return NULL;
-
-    ACQUIRE_LOCK(self);
-    switch (self->mode) {
-        case MODE_READ:
-            break;
-        case MODE_READ_EOF:
-            ret = PyBytes_FromStringAndSize("", 0);
-            goto cleanup;
-        case MODE_CLOSED:
-            PyErr_SetString(PyExc_ValueError,
-                            "I/O operation on closed file");
-            goto cleanup;
-        default:
-            PyErr_SetString(PyExc_IOError,
-                            "file is not ready for reading");
-            goto cleanup;
-    }
-
-    /* refuse to mix with f.next() */
-    if (check_iterbuffered(self))
-        goto cleanup;
-
-    if (bytesrequested < 0)
-        buffersize = Util_NewBufferSize((size_t)0);
-    else
-        buffersize = bytesrequested;
-    if (buffersize > INT_MAX) {
-        PyErr_SetString(PyExc_OverflowError,
-                        "requested number of bytes is "
-                        "more than a Python string can hold");
-        goto cleanup;
-    }
-    ret = PyBytes_FromStringAndSize((char *)NULL, buffersize);
-    if (ret == NULL || buffersize == 0)
-        goto cleanup;
-    bytesread = 0;
-
-    for (;;) {
-        Py_BEGIN_ALLOW_THREADS
-        chunksize = BZ2_bzRead(&bzerror, self->fp,
-                               BUF(ret)+bytesread,
-                               buffersize-bytesread);
-        self->pos += chunksize;
-        Py_END_ALLOW_THREADS
-        bytesread += chunksize;
-        if (bzerror == BZ_STREAM_END) {
-            self->size = self->pos;
-            self->mode = MODE_READ_EOF;
-            break;
-        } else if (bzerror != BZ_OK) {
-            Util_CatchBZ2Error(bzerror);
-            Py_DECREF(ret);
-            ret = NULL;
-            goto cleanup;
-        }
-        if (bytesrequested < 0) {
-            buffersize = Util_NewBufferSize(buffersize);
-            if (_PyBytes_Resize(&ret, buffersize) < 0) {
-                ret = NULL;
-                goto cleanup;
+            d->eof = 1;
+            if (d->bzs.avail_in > 0) { /* Save leftover input to unused_data */
+                Py_CLEAR(d->unused_data);
+                d->unused_data = PyBytes_FromStringAndSize(d->bzs.next_in,
+                                                           d->bzs.avail_in);
+                if (d->unused_data == NULL)
+                    goto error;
             }
-        } else {
             break;
         }
-    }
-    if (bytesread != buffersize) {
-        if (_PyBytes_Resize(&ret, bytesread) < 0) {
-            ret = NULL;
+        if (d->bzs.avail_in == 0)
+            break;
+        if (d->bzs.avail_out == 0) {
+            if (grow_buffer(&result) < 0)
+                goto error;
+            d->bzs.next_out = PyBytes_AS_STRING(result) + data_size;
+            d->bzs.avail_out = PyBytes_GET_SIZE(result) - data_size;
         }
     }
-
-cleanup:
-    RELEASE_LOCK(self);
-    return ret;
-}
-
-PyDoc_STRVAR(BZ2File_readline__doc__,
-"readline([size]) -> string\n\
-\n\
-Return the next line from the file, as a string, retaining newline.\n\
-A non-negative size argument will limit the maximum number of bytes to\n\
-return (an incomplete line may be returned then). Return an empty\n\
-string at EOF.\n\
-");
-
-static PyObject *
-BZ2File_readline(BZ2FileObject *self, PyObject *args)
-{
-    PyObject *ret = NULL;
-    int sizehint = -1;
-
-    if (!PyArg_ParseTuple(args, "|i:readline", &sizehint))
-        return NULL;
-
-    ACQUIRE_LOCK(self);
-    switch (self->mode) {
-        case MODE_READ:
-            break;
-        case MODE_READ_EOF:
-            ret = PyBytes_FromStringAndSize("", 0);
-            goto cleanup;
-        case MODE_CLOSED:
-            PyErr_SetString(PyExc_ValueError,
-                            "I/O operation on closed file");
-            goto cleanup;
-        default:
-            PyErr_SetString(PyExc_IOError,
-                            "file is not ready for reading");
-            goto cleanup;
-    }
-
-    /* refuse to mix with f.next() */
-    if (check_iterbuffered(self))
-        goto cleanup;
-
-    if (sizehint == 0)
-        ret = PyBytes_FromStringAndSize("", 0);
-    else
-        ret = Util_GetLine(self, (sizehint < 0) ? 0 : sizehint);
-
-cleanup:
-    RELEASE_LOCK(self);
-    return ret;
-}
-
-PyDoc_STRVAR(BZ2File_readlines__doc__,
-"readlines([size]) -> list\n\
-\n\
-Call readline() repeatedly and return a list of lines read.\n\
-The optional size argument, if given, is an approximate bound on the\n\
-total number of bytes in the lines returned.\n\
-");
-
-/* This is a hacked version of Python's fileobject.c:file_readlines(). */
-static PyObject *
-BZ2File_readlines(BZ2FileObject *self, PyObject *args)
-{
-    long sizehint = 0;
-    PyObject *list = NULL;
-    PyObject *line;
-    char small_buffer[SMALLCHUNK];
-    char *buffer = small_buffer;
-    size_t buffersize = SMALLCHUNK;
-    PyObject *big_buffer = NULL;
-    size_t nfilled = 0;
-    size_t nread;
-    size_t totalread = 0;
-    char *p, *q, *end;
-    int err;
-    int shortread = 0;
+    if (data_size != PyBytes_GET_SIZE(result))
+        if (_PyBytes_Resize(&result, data_size) < 0)
+            goto error;
+    return result;
+
+error:
+    Py_XDECREF(result);
+    return NULL;
+}
+
+static PyObject *
+Decompressor_decompress(Decompressor *self, PyObject *arg)
+{
+    Py_buffer buffer;
+    PyObject *result;
+
+    if (self->eof) {
+        PyErr_SetString(PyExc_EOFError, "End of stream already reached");
+        return NULL;
+    }
+    if (PyObject_GetBuffer(arg, &buffer, PyBUF_SIMPLE) < 0)
+        return NULL;
+    result = decompress(self, buffer.buf, buffer.len);
+    PyBuffer_Release(&buffer);
+    return result;
+}
+
+static int
+Decompressor_init(Decompressor *self, PyObject *args, PyObject *kwargs)
+{
     int bzerror;
 
-    if (!PyArg_ParseTuple(args, "|l:readlines", &sizehint))
-        return NULL;
-
-    ACQUIRE_LOCK(self);
-    switch (self->mode) {
-        case MODE_READ:
-            break;
-        case MODE_READ_EOF:
-            list = PyList_New(0);
-            goto cleanup;
-        case MODE_CLOSED:
-            PyErr_SetString(PyExc_ValueError,
-                            "I/O operation on closed file");
-            goto cleanup;
-        default:
-            PyErr_SetString(PyExc_IOError,
-                            "file is not ready for reading");
-            goto cleanup;
-    }
-
-    /* refuse to mix with f.next() */
-    if (check_iterbuffered(self))
-        goto cleanup;
-
-    if ((list = PyList_New(0)) == NULL)
-        goto cleanup;
-
-    for (;;) {
-        Py_BEGIN_ALLOW_THREADS
-        nread = BZ2_bzRead(&bzerror, self->fp,
-                           buffer+nfilled, buffersize-nfilled);
-        self->pos += nread;
-        Py_END_ALLOW_THREADS
-        if (bzerror == BZ_STREAM_END) {
-            self->size = self->pos;
-            self->mode = MODE_READ_EOF;
-            if (nread == 0) {
-                sizehint = 0;
-                break;
-            }
-            shortread = 1;
-        } else if (bzerror != BZ_OK) {
-            Util_CatchBZ2Error(bzerror);
-          error:
-            Py_DECREF(list);
-            list = NULL;
-            goto cleanup;
-        }
-        totalread += nread;
-        p = memchr(buffer+nfilled, '\n', nread);
-        if (!shortread && p == NULL) {
-            /* Need a larger buffer to fit this line */
-            nfilled += nread;
-            buffersize *= 2;
-            if (buffersize > INT_MAX) {
-                PyErr_SetString(PyExc_OverflowError,
-                "line is longer than a Python string can hold");
-                goto error;
-            }
-            if (big_buffer == NULL) {
-                /* Create the big buffer */
-                big_buffer = PyBytes_FromStringAndSize(
-                    NULL, buffersize);
-                if (big_buffer == NULL)
-                    goto error;
-                buffer = PyBytes_AS_STRING(big_buffer);
-                memcpy(buffer, small_buffer, nfilled);
-            }
-            else {
-                /* Grow the big buffer */
-                if (_PyBytes_Resize(&big_buffer, buffersize) < 0){
-                    big_buffer = NULL;
-                    goto error;
-                }
-                buffer = PyBytes_AS_STRING(big_buffer);
-            }
-            continue;
-        }
-        end = buffer+nfilled+nread;
-        q = buffer;
-        while (p != NULL) {
-            /* Process complete lines */
-            p++;
-            line = PyBytes_FromStringAndSize(q, p-q);
-            if (line == NULL)
-                goto error;
-            err = PyList_Append(list, line);
-            Py_DECREF(line);
-            if (err != 0)
-                goto error;
-            q = p;
-            p = memchr(q, '\n', end-q);
-        }
-        /* Move the remaining incomplete line to the start */
-        nfilled = end-q;
-        memmove(buffer, q, nfilled);
-        if (sizehint > 0)
-            if (totalread >= (size_t)sizehint)
-                break;
-        if (shortread) {
-            sizehint = 0;
-            break;
-        }
-    }
-    if (nfilled != 0) {
-        /* Partial last line */
-        line = PyBytes_FromStringAndSize(buffer, nfilled);
-        if (line == NULL)
-            goto error;
-        if (sizehint > 0) {
-            /* Need to complete the last line */
-            PyObject *rest = Util_GetLine(self, 0);
-            if (rest == NULL) {
-                Py_DECREF(line);
-                goto error;
-            }
-            PyBytes_Concat(&line, rest);
-            Py_DECREF(rest);
-            if (line == NULL)
-                goto error;
-        }
-        err = PyList_Append(list, line);
-        Py_DECREF(line);
-        if (err != 0)
-            goto error;
-    }
-
-  cleanup:
-    RELEASE_LOCK(self);
-    if (big_buffer) {
-        Py_DECREF(big_buffer);
-    }
-    return list;
-}
-
-PyDoc_STRVAR(BZ2File_write__doc__,
-"write(data) -> None\n\
-\n\
-Write the 'data' string to file. Note that due to buffering, close() may\n\
-be needed before the file on disk reflects the data written.\n\
-");
-
-/* This is a hacked version of Python's fileobject.c:file_write(). */
-static PyObject *
-BZ2File_write(BZ2FileObject *self, PyObject *args)
-{
-    PyObject *ret = NULL;
-    Py_buffer pbuf;
-    char *buf;
-    int len;
+    self->unused_data = PyBytes_FromStringAndSize("", 0);
+    if (self->unused_data == NULL)
+        return -1;
+    bzerror = BZ2_bzDecompressInit(&self->bzs, 0, 0);
+    if (catch_bz2_error(bzerror)) {
+        Py_CLEAR(self->unused_data);
+        return -1;
+    }
+    return 0;
+}
+
+static void
+Decompressor_dealloc(Decompressor *self)
+{
     int bzerror;
 
-    if (!PyArg_ParseTuple(args, "y*:write", &pbuf))
-        return NULL;
-    buf = pbuf.buf;
-    len = pbuf.len;
-
-    ACQUIRE_LOCK(self);
-    switch (self->mode) {
-        case MODE_WRITE:
-            break;
-
-        case MODE_CLOSED:
-            PyErr_SetString(PyExc_ValueError,
-                            "I/O operation on closed file");
-            goto cleanup;
-
-        default:
-            PyErr_SetString(PyExc_IOError,
-                            "file is not ready for writing");
-            goto cleanup;
-    }
-
-    Py_BEGIN_ALLOW_THREADS
-    BZ2_bzWrite (&bzerror, self->fp, buf, len);
-    self->pos += len;
-    Py_END_ALLOW_THREADS
-
-    if (bzerror != BZ_OK) {
-        Util_CatchBZ2Error(bzerror);
-        goto cleanup;
-    }
-
-    Py_INCREF(Py_None);
-    ret = Py_None;
-
-cleanup:
-    PyBuffer_Release(&pbuf);
-    RELEASE_LOCK(self);
-    return ret;
-}
-
-PyDoc_STRVAR(BZ2File_writelines__doc__,
-"writelines(sequence_of_strings) -> None\n\
-\n\
-Write the sequence of strings to the file. Note that newlines are not\n\
-added. The sequence can be any iterable object producing strings. This is\n\
-equivalent to calling write() for each string.\n\
-");
-
-/* This is a hacked version of Python's fileobject.c:file_writelines(). */
-static PyObject *
-BZ2File_writelines(BZ2FileObject *self, PyObject *seq)
-{
-#define CHUNKSIZE 1000
-    PyObject *list = NULL;
-    PyObject *iter = NULL;
-    PyObject *ret = NULL;
-    PyObject *line;
-    int i, j, index, len, islist;
-    int bzerror;
-
-    ACQUIRE_LOCK(self);
-    switch (self->mode) {
-        case MODE_WRITE:
-            break;
-
-        case MODE_CLOSED:
-            PyErr_SetString(PyExc_ValueError,
-                            "I/O operation on closed file");
-            goto error;
-
-        default:
-            PyErr_SetString(PyExc_IOError,
-                            "file is not ready for writing");
-            goto error;
-    }
-
-    islist = PyList_Check(seq);
-    if  (!islist) {
-        iter = PyObject_GetIter(seq);
-        if (iter == NULL) {
-            PyErr_SetString(PyExc_TypeError,
-                "writelines() requires an iterable argument");
-            goto error;
-        }
-        list = PyList_New(CHUNKSIZE);
-        if (list == NULL)
-            goto error;
-    }
-
-    /* Strategy: slurp CHUNKSIZE lines into a private list,
-       checking that they are all strings, then write that list
-       without holding the interpreter lock, then come back for more. */
-    for (index = 0; ; index += CHUNKSIZE) {
-        if (islist) {
-            Py_XDECREF(list);
-            list = PyList_GetSlice(seq, index, index+CHUNKSIZE);
-            if (list == NULL)
-                goto error;
-            j = PyList_GET_SIZE(list);
-        }
-        else {
-            for (j = 0; j < CHUNKSIZE; j++) {
-                line = PyIter_Next(iter);
-                if (line == NULL) {
-                    if (PyErr_Occurred())
-                        goto error;
-                    break;
-                }
-                PyList_SetItem(list, j, line);
-            }
-        }
-        if (j == 0)
-            break;
-
-        /* Check that all entries are indeed byte strings. If not,
-           apply the same rules as for file.write() and
-           convert the rets to strings. This is slow, but
-           seems to be the only way since all conversion APIs
-           could potentially execute Python code. */
-        for (i = 0; i < j; i++) {
-            PyObject *v = PyList_GET_ITEM(list, i);
-            if (!PyBytes_Check(v)) {
-                const char *buffer;
-                Py_ssize_t len;
-                if (PyObject_AsCharBuffer(v, &buffer, &len)) {
-                    PyErr_SetString(PyExc_TypeError,
-                                    "writelines() "
-                                    "argument must be "
-                                    "a sequence of "
-                                    "bytes objects");
-                    goto error;
-                }
-                line = PyBytes_FromStringAndSize(buffer,
-                                                  len);
-                if (line == NULL)
-                    goto error;
-                Py_DECREF(v);
-                PyList_SET_ITEM(list, i, line);
-            }
-        }
-
-        /* Since we are releasing the global lock, the
-           following code may *not* execute Python code. */
-        Py_BEGIN_ALLOW_THREADS
-        for (i = 0; i < j; i++) {
-            line = PyList_GET_ITEM(list, i);
-            len = PyBytes_GET_SIZE(line);
-            BZ2_bzWrite (&bzerror, self->fp,
-                         PyBytes_AS_STRING(line), len);
-            if (bzerror != BZ_OK) {
-                Py_BLOCK_THREADS
-                Util_CatchBZ2Error(bzerror);
-                goto error;
-            }
-        }
-        Py_END_ALLOW_THREADS
-
-        if (j < CHUNKSIZE)
-            break;
-    }
-
-    Py_INCREF(Py_None);
-    ret = Py_None;
-
-  error:
-    RELEASE_LOCK(self);
-    Py_XDECREF(list);
-    Py_XDECREF(iter);
-    return ret;
-#undef CHUNKSIZE
-}
-
-PyDoc_STRVAR(BZ2File_seek__doc__,
-"seek(offset [, whence]) -> None\n\
-\n\
-Move to new file position. Argument offset is a byte count. Optional\n\
-argument whence defaults to 0 (offset from start of file, offset\n\
-should be >= 0); other values are 1 (move relative to current position,\n\
-positive or negative), and 2 (move relative to end of file, usually\n\
-negative, although many platforms allow seeking beyond the end of a file).\n\
-\n\
-Note that seeking of bz2 files is emulated, and depending on the parameters\n\
-the operation may be extremely slow.\n\
-");
-
-static PyObject *
-BZ2File_seek(BZ2FileObject *self, PyObject *args)
-{
-    int where = 0;
-    PyObject *offobj;
-    Py_off_t offset;
-    char small_buffer[SMALLCHUNK];
-    char *buffer = small_buffer;
-    size_t buffersize = SMALLCHUNK;
-    Py_off_t bytesread = 0;
-    size_t readsize;
-    int chunksize;
-    int bzerror;
-    PyObject *ret = NULL;
-
-    if (!PyArg_ParseTuple(args, "O|i:seek", &offobj, &where))
-        return NULL;
-#if !defined(HAVE_LARGEFILE_SUPPORT)
-    offset = PyLong_AsLong(offobj);
-#else
-    offset = PyLong_Check(offobj) ?
-        PyLong_AsLongLong(offobj) : PyLong_AsLong(offobj);
-#endif
-    if (PyErr_Occurred())
-        return NULL;
-
-    ACQUIRE_LOCK(self);
-    Util_DropReadAhead(self);
-    switch (self->mode) {
-        case MODE_READ:
-        case MODE_READ_EOF:
-            break;
-
-        case MODE_CLOSED:
-            PyErr_SetString(PyExc_ValueError,
-                            "I/O operation on closed file");
-            goto cleanup;
-
-        default:
-            PyErr_SetString(PyExc_IOError,
-                            "seek works only while reading");
-            goto cleanup;
-    }
-
-    if (where == 2) {
-        if (self->size == -1) {
-            assert(self->mode != MODE_READ_EOF);
-            for (;;) {
-                Py_BEGIN_ALLOW_THREADS
-                chunksize = BZ2_bzRead(&bzerror, self->fp,
-                                       buffer, buffersize);
-                self->pos += chunksize;
-                Py_END_ALLOW_THREADS
-
-                bytesread += chunksize;
-                if (bzerror == BZ_STREAM_END) {
-                    break;
-                } else if (bzerror != BZ_OK) {
-                    Util_CatchBZ2Error(bzerror);
-                    goto cleanup;
-                }
-            }
-            self->mode = MODE_READ_EOF;
-            self->size = self->pos;
-            bytesread = 0;
-        }
-        offset = self->size + offset;
-    } else if (where == 1) {
-        offset = self->pos + offset;
-    }
-
-    /* Before getting here, offset must be the absolute position the file
-     * pointer should be set to. */
-
-    if (offset >= self->pos) {
-        /* we can move forward */
-        offset -= self->pos;
-    } else {
-        /* we cannot move back, so rewind the stream */
-        BZ2_bzReadClose(&bzerror, self->fp);
-        if (bzerror != BZ_OK) {
-            Util_CatchBZ2Error(bzerror);
-            goto cleanup;
-        }
-        rewind(self->rawfp);
-        self->pos = 0;
-        self->fp = BZ2_bzReadOpen(&bzerror, self->rawfp,
-                                  0, 0, NULL, 0);
-        if (bzerror != BZ_OK) {
-            Util_CatchBZ2Error(bzerror);
-            goto cleanup;
-        }
-        self->mode = MODE_READ;
-    }
-
-    if (offset <= 0 || self->mode == MODE_READ_EOF)
-        goto exit;
-
-    /* Before getting here, offset must be set to the number of bytes
-     * to walk forward. */
-    for (;;) {
-        if (offset-bytesread > buffersize)
-            readsize = buffersize;
-        else
-            /* offset might be wider that readsize, but the result
-             * of the subtraction is bound by buffersize (see the
-             * condition above). buffersize is 8192. */
-            readsize = (size_t)(offset-bytesread);
-        Py_BEGIN_ALLOW_THREADS
-        chunksize = BZ2_bzRead(&bzerror, self->fp, buffer, readsize);
-        self->pos += chunksize;
-        Py_END_ALLOW_THREADS
-        bytesread += chunksize;
-        if (bzerror == BZ_STREAM_END) {
-            self->size = self->pos;
-            self->mode = MODE_READ_EOF;
-            break;
-        } else if (bzerror != BZ_OK) {
-            Util_CatchBZ2Error(bzerror);
-            goto cleanup;
-        }
-        if (bytesread == offset)
-            break;
-    }
-
-exit:
-    Py_INCREF(Py_None);
-    ret = Py_None;
-
-cleanup:
-    RELEASE_LOCK(self);
-    return ret;
-}
-
-PyDoc_STRVAR(BZ2File_tell__doc__,
-"tell() -> int\n\
-\n\
-Return the current file position, an integer (may be a long integer).\n\
-");
-
-static PyObject *
-BZ2File_tell(BZ2FileObject *self, PyObject *args)
-{
-    PyObject *ret = NULL;
-
-    if (self->mode == MODE_CLOSED) {
-        PyErr_SetString(PyExc_ValueError,
-                        "I/O operation on closed file");
-        goto cleanup;
-    }
-
-#if !defined(HAVE_LARGEFILE_SUPPORT)
-    ret = PyLong_FromLong(self->pos);
-#else
-    ret = PyLong_FromLongLong(self->pos);
-#endif
-
-cleanup:
-    return ret;
-}
-
-PyDoc_STRVAR(BZ2File_close__doc__,
-"close() -> None or (perhaps) an integer\n\
-\n\
-Close the file. Sets data attribute .closed to true. A closed file\n\
-cannot be used for further I/O operations. close() may be called more\n\
-than once without error.\n\
-");
-
-static PyObject *
-BZ2File_close(BZ2FileObject *self)
-{
-    PyObject *ret = NULL;
-    int bzerror = BZ_OK;
-
-    if (self->mode == MODE_CLOSED) {
-        Py_RETURN_NONE;
-    }
-
-    ACQUIRE_LOCK(self);
-    switch (self->mode) {
-        case MODE_READ:
-        case MODE_READ_EOF:
-            BZ2_bzReadClose(&bzerror, self->fp);
-            break;
-        case MODE_WRITE:
-            BZ2_bzWriteClose(&bzerror, self->fp,
-                             0, NULL, NULL);
-            break;
-    }
-    self->mode = MODE_CLOSED;
-    fclose(self->rawfp);
-    self->rawfp = NULL;
-    if (bzerror == BZ_OK) {
-        Py_INCREF(Py_None);
-        ret = Py_None;
-    }
-    else {
-        Util_CatchBZ2Error(bzerror);
-    }
-
-    RELEASE_LOCK(self);
-    return ret;
-}
-
-PyDoc_STRVAR(BZ2File_enter_doc,
-"__enter__() -> self.");
-
-static PyObject *
-BZ2File_enter(BZ2FileObject *self)
-{
-    if (self->mode == MODE_CLOSED) {
-        PyErr_SetString(PyExc_ValueError,
-            "I/O operation on closed file");
-        return NULL;
-    }
-    Py_INCREF(self);
-    return (PyObject *) self;
-}
-
-PyDoc_STRVAR(BZ2File_exit_doc,
-"__exit__(*excinfo) -> None.  Closes the file.");
-
-static PyObject *
-BZ2File_exit(BZ2FileObject *self, PyObject *args)
-{
-    PyObject *ret = PyObject_CallMethod((PyObject *) self, "close", NULL);
-    if (!ret)
-        /* If error occurred, pass through */
-        return NULL;
-    Py_DECREF(ret);
-    Py_RETURN_NONE;
-}
-
-
-static PyObject *BZ2File_getiter(BZ2FileObject *self);
-
-static PyMethodDef BZ2File_methods[] = {
-    {"read", (PyCFunction)BZ2File_read, METH_VARARGS, BZ2File_read__doc__},
-    {"readline", (PyCFunction)BZ2File_readline, METH_VARARGS, BZ2File_readline__doc__},
-    {"readlines", (PyCFunction)BZ2File_readlines, METH_VARARGS, BZ2File_readlines__doc__},
-    {"write", (PyCFunction)BZ2File_write, METH_VARARGS, BZ2File_write__doc__},
-    {"writelines", (PyCFunction)BZ2File_writelines, METH_O, BZ2File_writelines__doc__},
-    {"seek", (PyCFunction)BZ2File_seek, METH_VARARGS, BZ2File_seek__doc__},
-    {"tell", (PyCFunction)BZ2File_tell, METH_NOARGS, BZ2File_tell__doc__},
-    {"close", (PyCFunction)BZ2File_close, METH_NOARGS, BZ2File_close__doc__},
-    {"__enter__", (PyCFunction)BZ2File_enter, METH_NOARGS, BZ2File_enter_doc},
-    {"__exit__", (PyCFunction)BZ2File_exit, METH_VARARGS, BZ2File_exit_doc},
-    {NULL,              NULL}           /* sentinel */
-};
-
-
-/* ===================================================================== */
-/* Getters and setters of BZ2File. */
-
-static PyObject *
-BZ2File_get_closed(BZ2FileObject *self, void *closure)
-{
-    return PyLong_FromLong(self->mode == MODE_CLOSED);
-}
-
-static PyGetSetDef BZ2File_getset[] = {
-    {"closed", (getter)BZ2File_get_closed, NULL,
-                    "True if the file is closed"},
-    {NULL}      /* Sentinel */
-};
-
-
-/* ===================================================================== */
-/* Slot definitions for BZ2File_Type. */
-
-static int
-BZ2File_init(BZ2FileObject *self, PyObject *args, PyObject *kwargs)
-{
-    static char *kwlist[] = {"filename", "mode", "buffering",
-                             "compresslevel", 0};
-    PyObject *name_obj = NULL;
-    char *name;
-    char *mode = "r";
-    int buffering = -1;
-    int compresslevel = 9;
-    int bzerror;
-    int mode_char = 0;
-
-    self->size = -1;
-
-    if (!PyArg_ParseTupleAndKeywords(args, kwargs, "O&|sii:BZ2File",
-                                     kwlist, PyUnicode_FSConverter, &name_obj,
-                                     &mode, &buffering,
-                                     &compresslevel))
-        return -1;
-
-    name = PyBytes_AsString(name_obj);
-    if (compresslevel < 1 || compresslevel > 9) {
-        PyErr_SetString(PyExc_ValueError,
-                        "compresslevel must be between 1 and 9");
-        Py_DECREF(name_obj);
-        return -1;
-    }
-
-    for (;;) {
-        int error = 0;
-        switch (*mode) {
-            case 'r':
-            case 'w':
-                if (mode_char)
-                    error = 1;
-                mode_char = *mode;
-                break;
-
-            case 'b':
-                break;
-
-            default:
-                error = 1;
-                break;
-        }
-        if (error) {
-            PyErr_Format(PyExc_ValueError,
-                         "invalid mode char %c", *mode);
-            Py_DECREF(name_obj);
-            return -1;
-        }
-        mode++;
-        if (*mode == '\0')
-            break;
-    }
-
-    if (mode_char == 0) {
-        mode_char = 'r';
-    }
-
-    mode = (mode_char == 'r') ? "rb" : "wb";
-
-    self->rawfp = fopen(name, mode);
-    Py_DECREF(name_obj);
-    if (self->rawfp == NULL) {
-        PyErr_SetFromErrno(PyExc_IOError);
-        return -1;
-    }
-    /* XXX Ignore buffering */
-
-    /* From now on, we have stuff to dealloc, so jump to error label
-     * instead of returning */
-
-#ifdef WITH_THREAD
-    self->lock = PyThread_allocate_lock();
-    if (!self->lock) {
-        PyErr_SetString(PyExc_MemoryError, "unable to allocate lock");
-        goto error;
-    }
-#endif
-
-    if (mode_char == 'r')
-        self->fp = BZ2_bzReadOpen(&bzerror, self->rawfp,
-                                  0, 0, NULL, 0);
-    else
-        self->fp = BZ2_bzWriteOpen(&bzerror, self->rawfp,
-                                   compresslevel, 0, 0);
-
-    if (bzerror != BZ_OK) {
-        Util_CatchBZ2Error(bzerror);
-        goto error;
-    }
-
-    self->mode = (mode_char == 'r') ? MODE_READ : MODE_WRITE;
-
-    return 0;
-
-error:
-    fclose(self->rawfp);
-    self->rawfp = NULL;
-#ifdef WITH_THREAD
-    if (self->lock) {
-        PyThread_free_lock(self->lock);
-        self->lock = NULL;
-    }
-#endif
-    return -1;
-}
-
-static void
-BZ2File_dealloc(BZ2FileObject *self)
-{
-    int bzerror;
-#ifdef WITH_THREAD
-    if (self->lock)
-        PyThread_free_lock(self->lock);
-#endif
-    switch (self->mode) {
-        case MODE_READ:
-        case MODE_READ_EOF:
-            BZ2_bzReadClose(&bzerror, self->fp);
-            break;
-        case MODE_WRITE:
-            BZ2_bzWriteClose(&bzerror, self->fp,
-                             0, NULL, NULL);
-            break;
-    }
-    Util_DropReadAhead(self);
-    if (self->rawfp != NULL)
-        fclose(self->rawfp);
+    Py_CLEAR(self->unused_data);
+    bzerror = BZ2_bzDecompressEnd(&self->bzs);
+    if (catch_bz2_error(bzerror))
+        PyErr_WriteUnraisable((PyObject *)self);
     Py_TYPE(self)->tp_free((PyObject *)self);
 }
 
-/* This is a hacked version of Python's fileobject.c:file_getiter(). */
-static PyObject *
-BZ2File_getiter(BZ2FileObject *self)
-{
-    if (self->mode == MODE_CLOSED) {
-        PyErr_SetString(PyExc_ValueError,
-                        "I/O operation on closed file");
-        return NULL;
-    }
-    Py_INCREF((PyObject*)self);
-    return (PyObject *)self;
-}
-
-/* This is a hacked version of Python's fileobject.c:file_iternext(). */
-#define READAHEAD_BUFSIZE 8192
-static PyObject *
-BZ2File_iternext(BZ2FileObject *self)
-{
-    PyBytesObject* ret;
-    ACQUIRE_LOCK(self);
-    if (self->mode == MODE_CLOSED) {
-        RELEASE_LOCK(self);
-        PyErr_SetString(PyExc_ValueError,
-                        "I/O operation on closed file");
-        return NULL;
-    }
-    ret = Util_ReadAheadGetLineSkip(self, 0, READAHEAD_BUFSIZE);
-    RELEASE_LOCK(self);
-    if (ret == NULL || PyBytes_GET_SIZE(ret) == 0) {
-        Py_XDECREF(ret);
-        return NULL;
-    }
-    return (PyObject *)ret;
-}
-
-/* ===================================================================== */
-/* BZ2File_Type definition. */
-
-PyDoc_VAR(BZ2File__doc__) =
-PyDoc_STR(
-"BZ2File(name [, mode='r', buffering=0, compresslevel=9]) -> file object\n\
-\n\
-Open a bz2 file. The mode can be 'r' or 'w', for reading (default) or\n\
-writing. When opened for writing, the file will be created if it doesn't\n\
-exist, and truncated otherwise. If the buffering argument is given, 0 means\n\
-unbuffered, and larger numbers specify the buffer size. If compresslevel\n\
-is given, must be a number between 1 and 9.\n\
-Data read is always returned in bytes; data written ought to be bytes.\n\
-");
-
-static PyTypeObject BZ2File_Type = {
+static PyMethodDef Decompressor_methods[] = {
+    {"decompress", (PyCFunction)Decompressor_decompress, METH_O,
+     "Provide a block of data to the decompressor."},
+    {NULL}
+};
+
+static PyMemberDef Decompressor_members[] = {
+    {"eof", T_INT, offsetof(Decompressor, eof), READONLY,
+     "True if the end-of-stream marker has been reached."},
+    {"unused_data", T_OBJECT_EX, offsetof(Decompressor, unused_data), READONLY,
+     "Data found after the end of the compressed stream."},
+    {NULL}
+};
+
+static PyTypeObject Decompressor_Type = {
     PyVarObject_HEAD_INIT(NULL, 0)
-    "bz2.BZ2File",              /*tp_name*/
-    sizeof(BZ2FileObject),      /*tp_basicsize*/
-    0,                          /*tp_itemsize*/
-    (destructor)BZ2File_dealloc, /*tp_dealloc*/
-    0,                          /*tp_print*/
-    0,                          /*tp_getattr*/
-    0,                          /*tp_setattr*/
-    0,                          /*tp_reserved*/
-    0,                          /*tp_repr*/
-    0,                          /*tp_as_number*/
-    0,                          /*tp_as_sequence*/
-    0,                          /*tp_as_mapping*/
-    0,                          /*tp_hash*/
-    0,                      /*tp_call*/
-    0,                      /*tp_str*/
-    PyObject_GenericGetAttr,/*tp_getattro*/
-    PyObject_GenericSetAttr,/*tp_setattro*/
-    0,                      /*tp_as_buffer*/
-    Py_TPFLAGS_DEFAULT|Py_TPFLAGS_BASETYPE, /*tp_flags*/
-    BZ2File__doc__,         /*tp_doc*/
-    0,                      /*tp_traverse*/
-    0,                      /*tp_clear*/
-    0,                      /*tp_richcompare*/
-    0,                      /*tp_weaklistoffset*/
-    (getiterfunc)BZ2File_getiter, /*tp_iter*/
-    (iternextfunc)BZ2File_iternext, /*tp_iternext*/
-    BZ2File_methods,        /*tp_methods*/
-    0,                          /*tp_members*/
-    BZ2File_getset,         /*tp_getset*/
-    0,                      /*tp_base*/
-    0,                      /*tp_dict*/
-    0,                      /*tp_descr_get*/
-    0,                      /*tp_descr_set*/
-    0,                      /*tp_dictoffset*/
-    (initproc)BZ2File_init, /*tp_init*/
-    PyType_GenericAlloc,    /*tp_alloc*/
-    PyType_GenericNew,      /*tp_new*/
-    PyObject_Free,          /*tp_free*/
-    0,                      /*tp_is_gc*/
-};
-
-
-/* ===================================================================== */
-/* Methods of BZ2Comp. */
-
-PyDoc_STRVAR(BZ2Comp_compress__doc__,
-"compress(data) -> string\n\
-\n\
-Provide more data to the compressor object. It will return chunks of\n\
-compressed data whenever possible. When you've finished providing data\n\
-to compress, call the flush() method to finish the compression process,\n\
-and return what is left in the internal buffers.\n\
-");
-
-static PyObject *
-BZ2Comp_compress(BZ2CompObject *self, PyObject *args)
-{
-    Py_buffer pdata;
-    char *data;
-    int datasize;
-    int bufsize = SMALLCHUNK;
-    PY_LONG_LONG totalout;
-    PyObject *ret = NULL;
-    bz_stream *bzs = &self->bzs;
-    int bzerror;
-
-    if (!PyArg_ParseTuple(args, "y*:compress", &pdata))
-        return NULL;
-    data = pdata.buf;
-    datasize = pdata.len;
-
-    if (datasize == 0) {
-        PyBuffer_Release(&pdata);
-        return PyBytes_FromStringAndSize("", 0);
-    }
-
-    ACQUIRE_LOCK(self);
-    if (!self->running) {
-        PyErr_SetString(PyExc_ValueError,
-                        "this object was already flushed");
-        goto error;
-    }
-
-    ret = PyBytes_FromStringAndSize(NULL, bufsize);
-    if (!ret)
-        goto error;
-
-    bzs->next_in = data;
-    bzs->avail_in = datasize;
-    bzs->next_out = BUF(ret);
-    bzs->avail_out = bufsize;
-
-    totalout = BZS_TOTAL_OUT(bzs);
-
-    for (;;) {
-        Py_BEGIN_ALLOW_THREADS
-        bzerror = BZ2_bzCompress(bzs, BZ_RUN);
-        Py_END_ALLOW_THREADS
-        if (bzerror != BZ_RUN_OK) {
-            Util_CatchBZ2Error(bzerror);
-            goto error;
-        }
-        if (bzs->avail_in == 0)
-            break; /* no more input data */
-        if (bzs->avail_out == 0) {
-            bufsize = Util_NewBufferSize(bufsize);
-            if (_PyBytes_Resize(&ret, bufsize) < 0) {
-                BZ2_bzCompressEnd(bzs);
-                goto error;
-            }
-            bzs->next_out = BUF(ret) + (BZS_TOTAL_OUT(bzs)
-                                        - totalout);
-            bzs->avail_out = bufsize - (bzs->next_out - BUF(ret));
-        }
-    }
-
-    if (_PyBytes_Resize(&ret,
-                       (Py_ssize_t)(BZS_TOTAL_OUT(bzs) - totalout)) < 0)
-        goto error;
-
-    RELEASE_LOCK(self);
-    PyBuffer_Release(&pdata);
-    return ret;
-
-error:
-    RELEASE_LOCK(self);
-    PyBuffer_Release(&pdata);
-    Py_XDECREF(ret);
-    return NULL;
-}
-
-PyDoc_STRVAR(BZ2Comp_flush__doc__,
-"flush() -> string\n\
-\n\
-Finish the compression process and return what is left in internal buffers.\n\
-You must not use the compressor object after calling this method.\n\
-");
-
-static PyObject *
-BZ2Comp_flush(BZ2CompObject *self)
-{
-    int bufsize = SMALLCHUNK;
-    PyObject *ret = NULL;
-    bz_stream *bzs = &self->bzs;
-    PY_LONG_LONG totalout;
-    int bzerror;
-
-    ACQUIRE_LOCK(self);
-    if (!self->running) {
-        PyErr_SetString(PyExc_ValueError, "object was already "
-                                          "flushed");
-        goto error;
-    }
-    self->running = 0;
-
-    ret = PyBytes_FromStringAndSize(NULL, bufsize);
-    if (!ret)
-        goto error;
-
-    bzs->next_out = BUF(ret);
-    bzs->avail_out = bufsize;
-
-    totalout = BZS_TOTAL_OUT(bzs);
-
-    for (;;) {
-        Py_BEGIN_ALLOW_THREADS
-        bzerror = BZ2_bzCompress(bzs, BZ_FINISH);
-        Py_END_ALLOW_THREADS
-        if (bzerror == BZ_STREAM_END) {
-            break;
-        } else if (bzerror != BZ_FINISH_OK) {
-            Util_CatchBZ2Error(bzerror);
-            goto error;
-        }
-        if (bzs->avail_out == 0) {
-            bufsize = Util_NewBufferSize(bufsize);
-            if (_PyBytes_Resize(&ret, bufsize) < 0)
-                goto error;
-            bzs->next_out = BUF(ret);
-            bzs->next_out = BUF(ret) + (BZS_TOTAL_OUT(bzs)
-                                        - totalout);
-            bzs->avail_out = bufsize - (bzs->next_out - BUF(ret));
-        }
-    }
-
-    if (bzs->avail_out != 0) {
-        if (_PyBytes_Resize(&ret,
-                    (Py_ssize_t)(BZS_TOTAL_OUT(bzs) - totalout)) < 0)
-            goto error;
-    }
-
-    RELEASE_LOCK(self);
-    return ret;
-
-error:
-    RELEASE_LOCK(self);
-    Py_XDECREF(ret);
-    return NULL;
-}
-
-static PyMethodDef BZ2Comp_methods[] = {
-    {"compress", (PyCFunction)BZ2Comp_compress, METH_VARARGS,
-     BZ2Comp_compress__doc__},
-    {"flush", (PyCFunction)BZ2Comp_flush, METH_NOARGS,
-     BZ2Comp_flush__doc__},
-    {NULL,              NULL}           /* sentinel */
-};
-
-
-/* ===================================================================== */
-/* Slot definitions for BZ2Comp_Type. */
-
-static int
-BZ2Comp_init(BZ2CompObject *self, PyObject *args, PyObject *kwargs)
-{
-    int compresslevel = 9;
-    int bzerror;
-    static char *kwlist[] = {"compresslevel", 0};
-
-    if (!PyArg_ParseTupleAndKeywords(args, kwargs, "|i:BZ2Compressor",
-                                     kwlist, &compresslevel))
-        return -1;
-
-    if (compresslevel < 1 || compresslevel > 9) {
-        PyErr_SetString(PyExc_ValueError,
-                        "compresslevel must be between 1 and 9");
-        goto error;
-    }
-
-#ifdef WITH_THREAD
-    self->lock = PyThread_allocate_lock();
-    if (!self->lock) {
-        PyErr_SetString(PyExc_MemoryError, "unable to allocate lock");
-        goto error;
-    }
-#endif
-
-    memset(&self->bzs, 0, sizeof(bz_stream));
-    bzerror = BZ2_bzCompressInit(&self->bzs, compresslevel, 0, 0);
-    if (bzerror != BZ_OK) {
-        Util_CatchBZ2Error(bzerror);
-        goto error;
-    }
-
-    self->running = 1;
-
-    return 0;
-error:
-#ifdef WITH_THREAD
-    if (self->lock) {
-        PyThread_free_lock(self->lock);
-        self->lock = NULL;
-    }
-#endif
-    return -1;
-}
-
-static void
-BZ2Comp_dealloc(BZ2CompObject *self)
-{
-#ifdef WITH_THREAD
-    if (self->lock)
-        PyThread_free_lock(self->lock);
-#endif
-    BZ2_bzCompressEnd(&self->bzs);
-    Py_TYPE(self)->tp_free((PyObject *)self);
-}
-
-
-/* ===================================================================== */
-/* BZ2Comp_Type definition. */
-
-PyDoc_STRVAR(BZ2Comp__doc__,
-"BZ2Compressor([compresslevel=9]) -> compressor object\n\
-\n\
-Create a new compressor object. This object may be used to compress\n\
-data sequentially. If you want to compress data in one shot, use the\n\
-compress() function instead. The compresslevel parameter, if given,\n\
-must be a number between 1 and 9.\n\
-");
-
-static PyTypeObject BZ2Comp_Type = {
-    PyVarObject_HEAD_INIT(NULL, 0)
-    "bz2.BZ2Compressor",        /*tp_name*/
-    sizeof(BZ2CompObject),      /*tp_basicsize*/
-    0,                          /*tp_itemsize*/
-    (destructor)BZ2Comp_dealloc, /*tp_dealloc*/
-    0,                          /*tp_print*/
-    0,                          /*tp_getattr*/
-    0,                          /*tp_setattr*/
-    0,                          /*tp_reserved*/
-    0,                          /*tp_repr*/
-    0,                          /*tp_as_number*/
-    0,                          /*tp_as_sequence*/
-    0,                          /*tp_as_mapping*/
-    0,                          /*tp_hash*/
-    0,                      /*tp_call*/
-    0,                      /*tp_str*/
-    PyObject_GenericGetAttr,/*tp_getattro*/
-    PyObject_GenericSetAttr,/*tp_setattro*/
-    0,                      /*tp_as_buffer*/
-    Py_TPFLAGS_DEFAULT|Py_TPFLAGS_BASETYPE, /*tp_flags*/
-    BZ2Comp__doc__,         /*tp_doc*/
-    0,                      /*tp_traverse*/
-    0,                      /*tp_clear*/
-    0,                      /*tp_richcompare*/
-    0,                      /*tp_weaklistoffset*/
-    0,                      /*tp_iter*/
-    0,                      /*tp_iternext*/
-    BZ2Comp_methods,        /*tp_methods*/
-    0,                      /*tp_members*/
-    0,                      /*tp_getset*/
-    0,                      /*tp_base*/
-    0,                      /*tp_dict*/
-    0,                      /*tp_descr_get*/
-    0,                      /*tp_descr_set*/
-    0,                      /*tp_dictoffset*/
-    (initproc)BZ2Comp_init, /*tp_init*/
-    PyType_GenericAlloc,    /*tp_alloc*/
-    PyType_GenericNew,      /*tp_new*/
-    PyObject_Free,          /*tp_free*/
-    0,                      /*tp_is_gc*/
-};
-
-
-/* ===================================================================== */
-/* Members of BZ2Decomp. */
-
-#undef OFF
-#define OFF(x) offsetof(BZ2DecompObject, x)
-
-static PyMemberDef BZ2Decomp_members[] = {
-    {"unused_data", T_OBJECT, OFF(unused_data), READONLY},
-    {NULL}      /* Sentinel */
-};
-
-
-/* ===================================================================== */
-/* Methods of BZ2Decomp. */
-
-PyDoc_STRVAR(BZ2Decomp_decompress__doc__,
-"decompress(data) -> string\n\
-\n\
-Provide more data to the decompressor object. It will return chunks\n\
-of decompressed data whenever possible. If you try to decompress data\n\
-after the end of stream is found, EOFError will be raised. If any data\n\
-was found after the end of stream, it'll be ignored and saved in\n\
-unused_data attribute.\n\
-");
-
-static PyObject *
-BZ2Decomp_decompress(BZ2DecompObject *self, PyObject *args)
-{
-    Py_buffer pdata;
-    char *data;
-    int datasize;
-    int bufsize = SMALLCHUNK;
-    PY_LONG_LONG totalout;
-    PyObject *ret = NULL;
-    bz_stream *bzs = &self->bzs;
-    int bzerror;
-
-    if (!PyArg_ParseTuple(args, "y*:decompress", &pdata))
-        return NULL;
-    data = pdata.buf;
-    datasize = pdata.len;
-
-    ACQUIRE_LOCK(self);
-    if (!self->running) {
-        PyErr_SetString(PyExc_EOFError, "end of stream was "
-                                        "already found");
-        goto error;
-    }
-
-    ret = PyBytes_FromStringAndSize(NULL, bufsize);
-    if (!ret)
-        goto error;
-
-    bzs->next_in = data;
-    bzs->avail_in = datasize;
-    bzs->next_out = BUF(ret);
-    bzs->avail_out = bufsize;
-
-    totalout = BZS_TOTAL_OUT(bzs);
-
-    for (;;) {
-        Py_BEGIN_ALLOW_THREADS
-        bzerror = BZ2_bzDecompress(bzs);
-        Py_END_ALLOW_THREADS
-        if (bzerror == BZ_STREAM_END) {
-            if (bzs->avail_in != 0) {
-                Py_DECREF(self->unused_data);
-                self->unused_data =
-                    PyBytes_FromStringAndSize(bzs->next_in,
-                                               bzs->avail_in);
-            }
-            self->running = 0;
-            break;
-        }
-        if (bzerror != BZ_OK) {
-            Util_CatchBZ2Error(bzerror);
-            goto error;
-        }
-        if (bzs->avail_in == 0)
-            break; /* no more input data */
-        if (bzs->avail_out == 0) {
-            bufsize = Util_NewBufferSize(bufsize);
-            if (_PyBytes_Resize(&ret, bufsize) < 0) {
-                BZ2_bzDecompressEnd(bzs);
-                goto error;
-            }
-            bzs->next_out = BUF(ret);
-            bzs->next_out = BUF(ret) + (BZS_TOTAL_OUT(bzs)
-                                        - totalout);
-            bzs->avail_out = bufsize - (bzs->next_out - BUF(ret));
-        }
-    }
-
-    if (bzs->avail_out != 0) {
-        if (_PyBytes_Resize(&ret,
-                    (Py_ssize_t)(BZS_TOTAL_OUT(bzs) - totalout)) < 0)
-            goto error;
-    }
-
-    RELEASE_LOCK(self);
-    PyBuffer_Release(&pdata);
-    return ret;
-
-error:
-    RELEASE_LOCK(self);
-    PyBuffer_Release(&pdata);
-    Py_XDECREF(ret);
-    return NULL;
-}
-
-static PyMethodDef BZ2Decomp_methods[] = {
-    {"decompress", (PyCFunction)BZ2Decomp_decompress, METH_VARARGS, BZ2Decomp_decompress__doc__},
-    {NULL,              NULL}           /* sentinel */
-};
-
-
-/* ===================================================================== */
-/* Slot definitions for BZ2Decomp_Type. */
-
-static int
-BZ2Decomp_init(BZ2DecompObject *self, PyObject *args, PyObject *kwargs)
-{
-    int bzerror;
-
-    if (!PyArg_ParseTuple(args, ":BZ2Decompressor"))
-        return -1;
-
-#ifdef WITH_THREAD
-    self->lock = PyThread_allocate_lock();
-    if (!self->lock) {
-        PyErr_SetString(PyExc_MemoryError, "unable to allocate lock");
-        goto error;
-    }
-#endif
-
-    self->unused_data = PyBytes_FromStringAndSize("", 0);
-    if (!self->unused_data)
-        goto error;
-
-    memset(&self->bzs, 0, sizeof(bz_stream));
-    bzerror = BZ2_bzDecompressInit(&self->bzs, 0, 0);
-    if (bzerror != BZ_OK) {
-        Util_CatchBZ2Error(bzerror);
-        goto error;
-    }
-
-    self->running = 1;
-
-    return 0;
-
-error:
-#ifdef WITH_THREAD
-    if (self->lock) {
-        PyThread_free_lock(self->lock);
-        self->lock = NULL;
-    }
-#endif
-    Py_CLEAR(self->unused_data);
-    return -1;
-}
-
-static void
-BZ2Decomp_dealloc(BZ2DecompObject *self)
-{
-#ifdef WITH_THREAD
-    if (self->lock)
-        PyThread_free_lock(self->lock);
-#endif
-    Py_XDECREF(self->unused_data);
-    BZ2_bzDecompressEnd(&self->bzs);
-    Py_TYPE(self)->tp_free((PyObject *)self);
-}
-
-
-/* ===================================================================== */
-/* BZ2Decomp_Type definition. */
-
-PyDoc_STRVAR(BZ2Decomp__doc__,
-"BZ2Decompressor() -> decompressor object\n\
-\n\
-Create a new decompressor object. This object may be used to decompress\n\
-data sequentially. If you want to decompress data in one shot, use the\n\
-decompress() function instead.\n\
-");
-
-static PyTypeObject BZ2Decomp_Type = {
-    PyVarObject_HEAD_INIT(NULL, 0)
-    "bz2.BZ2Decompressor",      /*tp_name*/
-    sizeof(BZ2DecompObject), /*tp_basicsize*/
-    0,                          /*tp_itemsize*/
-    (destructor)BZ2Decomp_dealloc, /*tp_dealloc*/
-    0,                          /*tp_print*/
-    0,                          /*tp_getattr*/
-    0,                          /*tp_setattr*/
-    0,                          /*tp_reserved*/
-    0,                          /*tp_repr*/
-    0,                          /*tp_as_number*/
-    0,                          /*tp_as_sequence*/
-    0,                          /*tp_as_mapping*/
-    0,                          /*tp_hash*/
-    0,                      /*tp_call*/
-    0,                      /*tp_str*/
-    PyObject_GenericGetAttr,/*tp_getattro*/
-    PyObject_GenericSetAttr,/*tp_setattro*/
-    0,                      /*tp_as_buffer*/
-    Py_TPFLAGS_DEFAULT|Py_TPFLAGS_BASETYPE, /*tp_flags*/
-    BZ2Decomp__doc__,       /*tp_doc*/
-    0,                      /*tp_traverse*/
-    0,                      /*tp_clear*/
-    0,                      /*tp_richcompare*/
-    0,                      /*tp_weaklistoffset*/
-    0,                      /*tp_iter*/
-    0,                      /*tp_iternext*/
-    BZ2Decomp_methods,      /*tp_methods*/
-    BZ2Decomp_members,      /*tp_members*/
-    0,                      /*tp_getset*/
-    0,                      /*tp_base*/
-    0,                      /*tp_dict*/
-    0,                      /*tp_descr_get*/
-    0,                      /*tp_descr_set*/
-    0,                      /*tp_dictoffset*/
-    (initproc)BZ2Decomp_init, /*tp_init*/
-    PyType_GenericAlloc,    /*tp_alloc*/
-    PyType_GenericNew,      /*tp_new*/
-    PyObject_Free,          /*tp_free*/
-    0,                      /*tp_is_gc*/
-};
-
-
-/* ===================================================================== */
-/* Module functions. */
-
-PyDoc_STRVAR(bz2_compress__doc__,
-"compress(data [, compresslevel=9]) -> string\n\
-\n\
-Compress data in one shot. If you want to compress data sequentially,\n\
-use an instance of BZ2Compressor instead. The compresslevel parameter, if\n\
-given, must be a number between 1 and 9.\n\
-");
-
-static PyObject *
-bz2_compress(PyObject *self, PyObject *args, PyObject *kwargs)
-{
-    int compresslevel=9;
-    Py_buffer pdata;
-    char *data;
-    int datasize;
-    int bufsize;
-    PyObject *ret = NULL;
-    bz_stream _bzs;
-    bz_stream *bzs = &_bzs;
-    int bzerror;
-    static char *kwlist[] = {"data", "compresslevel", 0};
-
-    if (!PyArg_ParseTupleAndKeywords(args, kwargs, "y*|i",
-                                     kwlist, &pdata,
-                                     &compresslevel))
-        return NULL;
-    data = pdata.buf;
-    datasize = pdata.len;
-
-    if (compresslevel < 1 || compresslevel > 9) {
-        PyErr_SetString(PyExc_ValueError,
-                        "compresslevel must be between 1 and 9");
-        PyBuffer_Release(&pdata);
-        return NULL;
-    }
-
-    /* Conforming to bz2 manual, this is large enough to fit compressed
-     * data in one shot. We will check it later anyway. */
-    bufsize = datasize + (datasize/100+1) + 600;
-
-    ret = PyBytes_FromStringAndSize(NULL, bufsize);
-    if (!ret) {
-        PyBuffer_Release(&pdata);
-        return NULL;
-    }
-
-    memset(bzs, 0, sizeof(bz_stream));
-
-    bzs->next_in = data;
-    bzs->avail_in = datasize;
-    bzs->next_out = BUF(ret);
-    bzs->avail_out = bufsize;
-
-    bzerror = BZ2_bzCompressInit(bzs, compresslevel, 0, 0);
-    if (bzerror != BZ_OK) {
-        Util_CatchBZ2Error(bzerror);
-        PyBuffer_Release(&pdata);
-        Py_DECREF(ret);
-        return NULL;
-    }
-
-    for (;;) {
-        Py_BEGIN_ALLOW_THREADS
-        bzerror = BZ2_bzCompress(bzs, BZ_FINISH);
-        Py_END_ALLOW_THREADS
-        if (bzerror == BZ_STREAM_END) {
-            break;
-        } else if (bzerror != BZ_FINISH_OK) {
-            BZ2_bzCompressEnd(bzs);
-            Util_CatchBZ2Error(bzerror);
-            PyBuffer_Release(&pdata);
-            Py_DECREF(ret);
-            return NULL;
-        }
-        if (bzs->avail_out == 0) {
-            bufsize = Util_NewBufferSize(bufsize);
-            if (_PyBytes_Resize(&ret, bufsize) < 0) {
-                BZ2_bzCompressEnd(bzs);
-                PyBuffer_Release(&pdata);
-                return NULL;
-            }
-            bzs->next_out = BUF(ret) + BZS_TOTAL_OUT(bzs);
-            bzs->avail_out = bufsize - (bzs->next_out - BUF(ret));
-        }
-    }
-
-    if (bzs->avail_out != 0) {
-        if (_PyBytes_Resize(&ret, (Py_ssize_t)BZS_TOTAL_OUT(bzs)) < 0) {
-            ret = NULL;
-        }
-    }
-    BZ2_bzCompressEnd(bzs);
-
-    PyBuffer_Release(&pdata);
-    return ret;
-}
-
-PyDoc_STRVAR(bz2_decompress__doc__,
-"decompress(data) -> decompressed data\n\
-\n\
-Decompress data in one shot. If you want to decompress data sequentially,\n\
-use an instance of BZ2Decompressor instead.\n\
-");
-
-static PyObject *
-bz2_decompress(PyObject *self, PyObject *args)
-{
-    Py_buffer pdata;
-    char *data;
-    int datasize;
-    int bufsize = SMALLCHUNK;
-    PyObject *ret;
-    bz_stream _bzs;
-    bz_stream *bzs = &_bzs;
-    int bzerror;
-
-    if (!PyArg_ParseTuple(args, "y*:decompress", &pdata))
-        return NULL;
-    data = pdata.buf;
-    datasize = pdata.len;
-
-    if (datasize == 0) {
-        PyBuffer_Release(&pdata);
-        return PyBytes_FromStringAndSize("", 0);
-    }
-
-    ret = PyBytes_FromStringAndSize(NULL, bufsize);
-    if (!ret) {
-        PyBuffer_Release(&pdata);
-        return NULL;
-    }
-
-    memset(bzs, 0, sizeof(bz_stream));
-
-    bzs->next_in = data;
-    bzs->avail_in = datasize;
-    bzs->next_out = BUF(ret);
-    bzs->avail_out = bufsize;
-
-    bzerror = BZ2_bzDecompressInit(bzs, 0, 0);
-    if (bzerror != BZ_OK) {
-        Util_CatchBZ2Error(bzerror);
-        Py_DECREF(ret);
-        PyBuffer_Release(&pdata);
-        return NULL;
-    }
-
-    for (;;) {
-        Py_BEGIN_ALLOW_THREADS
-        bzerror = BZ2_bzDecompress(bzs);
-        Py_END_ALLOW_THREADS
-        if (bzerror == BZ_STREAM_END) {
-            break;
-        } else if (bzerror != BZ_OK) {
-            BZ2_bzDecompressEnd(bzs);
-            Util_CatchBZ2Error(bzerror);
-            PyBuffer_Release(&pdata);
-            Py_DECREF(ret);
-            return NULL;
-        }
-        if (bzs->avail_in == 0) {
-            BZ2_bzDecompressEnd(bzs);
-            PyErr_SetString(PyExc_ValueError,
-                            "couldn't find end of stream");
-            PyBuffer_Release(&pdata);
-            Py_DECREF(ret);
-            return NULL;
-        }
-        if (bzs->avail_out == 0) {
-            bufsize = Util_NewBufferSize(bufsize);
-            if (_PyBytes_Resize(&ret, bufsize) < 0) {
-                BZ2_bzDecompressEnd(bzs);
-                PyBuffer_Release(&pdata);
-                return NULL;
-            }
-            bzs->next_out = BUF(ret) + BZS_TOTAL_OUT(bzs);
-            bzs->avail_out = bufsize - (bzs->next_out - BUF(ret));
-        }
-    }
-
-    if (bzs->avail_out != 0) {
-        if (_PyBytes_Resize(&ret, (Py_ssize_t)BZS_TOTAL_OUT(bzs)) < 0) {
-            ret = NULL;
-        }
-    }
-    BZ2_bzDecompressEnd(bzs);
-    PyBuffer_Release(&pdata);
-
-    return ret;
-}
-
-static PyMethodDef bz2_methods[] = {
-    {"compress", (PyCFunction) bz2_compress, METH_VARARGS|METH_KEYWORDS,
-        bz2_compress__doc__},
-    {"decompress", (PyCFunction) bz2_decompress, METH_VARARGS,
-        bz2_decompress__doc__},
-    {NULL,              NULL}           /* sentinel */
-};
-
-/* ===================================================================== */
-/* Initialization function. */
-
-PyDoc_STRVAR(bz2__doc__,
-"The python bz2 module provides a comprehensive interface for\n\
-the bz2 compression library. It implements a complete file\n\
-interface, one shot (de)compression functions, and types for\n\
-sequential (de)compression.\n\
-");
-
-
-static struct PyModuleDef bz2module = {
+    "_bz2.Decompressor",                /* tp_name */
+    sizeof(Decompressor),               /* tp_basicsize */
+    0,                                  /* tp_itemsize */
+    (destructor)Decompressor_dealloc,   /* tp_dealloc */
+    0,                                  /* tp_print */
+    0,                                  /* tp_getattr */
+    0,                                  /* tp_setattr */
+    0,                                  /* tp_reserved */
+    0,                                  /* tp_repr */
+    0,                                  /* tp_as_number */
+    0,                                  /* tp_as_sequence */
+    0,                                  /* tp_as_mapping */
+    0,                                  /* tp_hash  */
+    0,                                  /* tp_call */
+    0,                                  /* tp_str */
+    0,                                  /* tp_getattro */
+    0,                                  /* tp_setattro */
+    0,                                  /* tp_as_buffer */
+    Py_TPFLAGS_DEFAULT,                 /* tp_flags */
+    "Wrapper for bz2 decompression functions.", /* tp_doc */
+    0,                                  /* tp_traverse */
+    0,                                  /* tp_clear */
+    0,                                  /* tp_richcompare */
+    0,                                  /* tp_weaklistoffset */
+    0,                                  /* tp_iter */
+    0,                                  /* tp_iternext */
+    Decompressor_methods,            /* tp_methods */
+    Decompressor_members,            /* tp_members */
+    0,                                  /* tp_getset */
+    0,                                  /* tp_base */
+    0,                                  /* tp_dict */
+    0,                                  /* tp_descr_get */
+    0,                                  /* tp_descr_set */
+    0,                                  /* tp_dictoffset */
+    (initproc)Decompressor_init,        /* tp_init */
+    0,                                  /* tp_alloc */
+    PyType_GenericNew,                  /* tp_new */
+};
+
+
+/* Module initialization. */
+
+static struct PyModuleDef _bz2module = {
     PyModuleDef_HEAD_INIT,
-    "bz2",
-    bz2__doc__,
+    "_bz2",
+    NULL,
     -1,
-    bz2_methods,
-    NULL,
-    NULL,
-    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
     NULL
 };
 
 PyMODINIT_FUNC
-PyInit_bz2(void)
+PyInit__bz2(void)
 {
     PyObject *m;
 
-    if (PyType_Ready(&BZ2File_Type) < 0)
+    if (PyType_Ready(&Compressor_Type) < 0)
         return NULL;
-    if (PyType_Ready(&BZ2Comp_Type) < 0)
-        return NULL;
-    if (PyType_Ready(&BZ2Decomp_Type) < 0)
+    if (PyType_Ready(&Decompressor_Type) < 0)
         return NULL;
 
-    m = PyModule_Create(&bz2module);
+    m = PyModule_Create(&_bz2module);
     if (m == NULL)
         return NULL;
 
-    PyModule_AddObject(m, "__author__", PyUnicode_FromString(__author__));
+    Py_INCREF(&Compressor_Type);
+    PyModule_AddObject(m, "Compressor", (PyObject *)&Compressor_Type);
 
-    Py_INCREF(&BZ2File_Type);
-    PyModule_AddObject(m, "BZ2File", (PyObject *)&BZ2File_Type);
+    Py_INCREF(&Decompressor_Type);
+    PyModule_AddObject(m, "Decompressor", (PyObject *)&Decompressor_Type);
 
-    Py_INCREF(&BZ2Comp_Type);
-    PyModule_AddObject(m, "BZ2Compressor", (PyObject *)&BZ2Comp_Type);
-
-    Py_INCREF(&BZ2Decomp_Type);
-    PyModule_AddObject(m, "BZ2Decompressor", (PyObject *)&BZ2Decomp_Type);
     return m;
 }