/*

python-bz2 - python bz2 library interface

Copyright (c) 2002 Gustavo Niemeyer <[email protected]>

Copyright (c) 2002 Python Software Foundation; All Rights Reserved

*/

#include "Python.h"

#include <stdio.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 <[email protected]>\n\

";

#define BUF(v) PyString_AS_STRING((PyStringObject *)v)

#define MODE_CLOSED 0

#define MODE_READ 1

#define MODE_READ_EOF 2

#define MODE_WRITE 3

#define BZ2FileObject_Check(v) ((v)->ob_type == &BZ2File_Type)

#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) \

(((LONG_LONG)bzs->total_out_hi32 << 32) + bzs->total_out_lo32)

#else

#define BZS_TOTAL_OUT(bzs) \

bzs->total_out_lo32;

#endif

#ifdef WITH_THREAD

#define ACQUIRE_LOCK(obj) PyThread_acquire_lock(obj->lock, 1)

#define RELEASE_LOCK(obj) PyThread_release_lock(obj->lock)

#else

#define ACQUIRE_LOCK(obj)

#define RELEASE_LOCK(obj)

#endif

#ifdef WITH_UNIVERSAL_NEWLINES

/* 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 */

#endif

/* ===================================================================== */

/* Structure definitions. */

typedef struct {

PyFileObject file;

BZFILE *fp;

int mode;

long pos;

long size;

#ifdef WITH_THREAD

PyThread_type_lock lock;

#endif

} BZ2FileObject;

typedef struct {

PyObject_HEAD

bz_stream bzs;

int running;

#ifdef WITH_THREAD

PyThread_type_lock lock;

#endif

} BZ2CompObject;

typedef struct {

PyObject_HEAD

bz_stream bzs;

int running;

PyObject *unused_data;

#ifdef WITH_THREAD

PyThread_type_lock lock;

#endif

} BZ2DecompObject;

/* ===================================================================== */

/* Utility functions. */

static int

Util_CatchBZ2Error(int bzerror)

{

int ret = 0;

switch(bzerror) {

case BZ_OK:

case BZ_STREAM_END:

break;

case BZ_CONFIG_ERROR:

PyErr_SetString(PyExc_SystemError,

"the bz2 library was not compiled "

"correctly");

ret = 1;

break;

case BZ_PARAM_ERROR:

PyErr_SetString(PyExc_ValueError,

"the bz2 library has received wrong "

"parameters");

ret = 1;

break;

case BZ_MEM_ERROR:

PyErr_NoMemory();

ret = 1;

break;

case BZ_DATA_ERROR:

case BZ_DATA_ERROR_MAGIC:

PyErr_SetString(PyExc_IOError, "invalid data stream");

ret = 1;

break;

case BZ_IO_ERROR:

PyErr_SetString(PyExc_IOError, "unknown IO error");

ret = 1;

break;

case BZ_UNEXPECTED_EOF:

PyErr_SetString(PyExc_EOFError,

"compressed file ended before the "

"logical end-of-stream was detected");

ret = 1;

break;

case BZ_SEQUENCE_ERROR:

PyErr_SetString(PyExc_RuntimeError,

"wrong sequence of bz2 library "

"commands used");

ret = 1;

break;

}

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 *self, 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;

int bzerror;

#ifdef WITH_UNIVERSAL_NEWLINES

int newlinetypes = ((PyFileObject*)self)->f_newlinetypes;

int skipnextlf = ((PyFileObject*)self)->f_skipnextlf;

int univ_newline = ((PyFileObject*)self)->f_univ_newline;

#endif

total_v_size = n > 0 ? n : 100;

v = PyString_FromStringAndSize((char *)NULL, total_v_size);

if (v == NULL)

return NULL;

buf = BUF(v);

end = buf + total_v_size;

for (;;) {

Py_BEGIN_ALLOW_THREADS

#ifdef WITH_UNIVERSAL_NEWLINES

if (univ_newline) {

while (1) {

BZ2_bzRead(&bzerror, self->fp, &c, 1);

self->pos++;

if (bzerror != BZ_OK || buf == end)

break;

if (skipnextlf) {

skipnextlf = 0;

if (c == '\n') {

/* Seeing a \n here with

* skipnextlf true means we

* saw a \r before.

*/

newlinetypes |= NEWLINE_CRLF;

BZ2_bzRead(&bzerror, self->fp,

&c, 1);

if (bzerror != BZ_OK)

break;

} else {

newlinetypes |= NEWLINE_CR;

}

}

if (c == '\r') {

skipnextlf = 1;

c = '\n';

} else if ( c == '\n')

newlinetypes |= NEWLINE_LF;

*buf++ = c;

if (c == '\n') break;

}

if (bzerror == BZ_STREAM_END && skipnextlf)

newlinetypes |= NEWLINE_CR;

} else /* If not universal newlines use the normal loop */

#endif

do {

BZ2_bzRead(&bzerror, self->fp, &c, 1);

self->pos++;

*buf++ = c;

} while (bzerror == BZ_OK && c != '\n' && buf != end);

Py_END_ALLOW_THREADS

#ifdef WITH_UNIVERSAL_NEWLINES

((PyFileObject*)self)->f_newlinetypes = newlinetypes;

((PyFileObject*)self)->f_skipnextlf = skipnextlf;

#endif

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(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 (_PyString_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)

_PyString_Resize(&v, used_v_size);

return v;

}

#ifndef WITH_UNIVERSAL_NEWLINES

#define Util_UnivNewlineRead(a,b,c,d,e) BZ2_bzRead(a,b,c,d)

#else

/* This is a hacked version of Python's

* fileobject.c:Py_UniversalNewlineFread(). */

size_t

Util_UnivNewlineRead(int *bzerror, BZFILE *stream,

char* buf, size_t n, BZ2FileObject *fobj)

{

char *dst = buf;

PyFileObject *f = (PyFileObject *)fobj;

int newlinetypes, skipnextlf;

assert(buf != NULL);

assert(stream != NULL);

if (!f->f_univ_newline)

return BZ2_bzRead(bzerror, stream, buf, n);

newlinetypes = f->f_newlinetypes;

skipnextlf = f->f_skipnextlf;

/* Invariant: n is the number of bytes remaining to be filled

* in the buffer.

*/

while (n) {

size_t nread;

int shortread;

char *src = dst;

nread = BZ2_bzRead(bzerror, stream, dst, n);

assert(nread <= n);

n -= nread; /* assuming 1 byte out for each in; will adjust */

shortread = n != 0; /* true iff EOF or error */

while (nread--) {

char c = *src++;

if (c == '\r') {

/* Save as LF and set flag to skip next LF. */

*dst++ = '\n';

skipnextlf = 1;

}

else if (skipnextlf && c == '\n') {

/* Skip LF, and remember we saw CR LF. */

skipnextlf = 0;

newlinetypes |= NEWLINE_CRLF;

++n;

}

else {

/* Normal char to be stored in buffer. Also

* update the newlinetypes flag if either this

* is an LF or the previous char was a CR.

*/

if (c == '\n')

newlinetypes |= NEWLINE_LF;

else if (skipnextlf)

newlinetypes |= NEWLINE_CR;

*dst++ = c;

skipnextlf = 0;

}

}

if (shortread) {

/* If this is EOF, update type flags. */

if (skipnextlf && *bzerror == BZ_STREAM_END)

newlinetypes |= NEWLINE_CR;

break;

}

}

f->f_newlinetypes = newlinetypes;

f->f_skipnextlf = skipnextlf;

return dst - buf;

}

#endif

/* This is a hacked version of Python's fileobject.c:drop_readahead(). */

static void

Util_DropReadAhead(BZ2FileObject *self)

{

PyFileObject *f = (PyFileObject*)self;

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 *self, int bufsize)

{

int chunksize;

int bzerror;

PyFileObject *f = (PyFileObject*)self;

if (f->f_buf != NULL) {

if((f->f_bufend - f->f_bufptr) >= 1)

return 0;

else

Util_DropReadAhead(self);

}

if (self->mode == MODE_READ_EOF) {

return -1;

}

if ((f->f_buf = PyMem_Malloc(bufsize)) == NULL) {

return -1;

}

Py_BEGIN_ALLOW_THREADS

chunksize = Util_UnivNewlineRead(&bzerror, self->fp, f->f_buf,

bufsize, self);

Py_END_ALLOW_THREADS

self->pos += chunksize;

if (bzerror == BZ_STREAM_END) {

self->size = self->pos;

self->mode = MODE_READ_EOF;

} else if (bzerror != BZ_OK) {

Util_CatchBZ2Error(bzerror);

Util_DropReadAhead(self);

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 PyStringObject *

Util_ReadAheadGetLineSkip(BZ2FileObject *bf, int skip, int bufsize)

{

PyFileObject *f = (PyFileObject*)bf;

PyStringObject* s;

char *bufptr;

char *buf;

int len;

if (f->f_buf == NULL)

if (Util_ReadAhead(bf, bufsize) < 0)

return NULL;

len = f->f_bufend - f->f_bufptr;

if (len == 0)

return (PyStringObject *)

PyString_FromStringAndSize(NULL, skip);

bufptr = memchr(f->f_bufptr, '\n', len);

if (bufptr != NULL) {

bufptr++; /* Count the '\n' */

len = bufptr - f->f_bufptr;

s = (PyStringObject *)

PyString_FromStringAndSize(NULL, skip+len);

if (s == NULL)

return NULL;

memcpy(PyString_AS_STRING(s)+skip, f->f_bufptr, len);

f->f_bufptr = bufptr;

if (bufptr == f->f_bufend)

Util_DropReadAhead(bf);

} else {

bufptr = f->f_bufptr;

buf = f->f_buf;

f->f_buf = NULL; /* Force new readahead buffer */

s = Util_ReadAheadGetLineSkip(

bf, skip+len, bufsize + (bufsize>>2) );

if (s == NULL) {

PyMem_Free(buf);

return NULL;

}

memcpy(PyString_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 = PyString_FromString("");

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;

}

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 = PyString_FromStringAndSize((char *)NULL, buffersize);

if (ret == NULL)

goto cleanup;

bytesread = 0;

for (;;) {

Py_BEGIN_ALLOW_THREADS

chunksize = Util_UnivNewlineRead(&bzerror, self->fp,

BUF(ret)+bytesread,

buffersize-bytesread,

self);

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 (_PyString_Resize(&ret, buffersize) < 0)

goto cleanup;

} else {

break;

}

}

if (bytesread != buffersize)

_PyString_Resize(&ret, bytesread);

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 = PyString_FromString("");

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;

}

if (sizehint == 0)

ret = PyString_FromString("");

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;

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;

}

if ((list = PyList_New(0)) == NULL)

goto cleanup;

for (;;) {

Py_BEGIN_ALLOW_THREADS

nread = Util_UnivNewlineRead(&bzerror, self->fp,

buffer+nfilled,

buffersize-nfilled, self);

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 (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 = PyString_FromStringAndSize(

NULL, buffersize);

if (big_buffer == NULL)

goto error;

buffer = PyString_AS_STRING(big_buffer);

memcpy(buffer, small_buffer, nfilled);

}

else {

/* Grow the big buffer */

_PyString_Resize(&big_buffer, buffersize);

buffer = PyString_AS_STRING(big_buffer);

}

continue;

}

end = buffer+nfilled+nread;

q = buffer;

do {

/* Process complete lines */

p++;

line = PyString_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);

} while (p != NULL);

/* 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 = PyString_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;

}

PyString_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;

char *buf;

int len;

int bzerror;

if (!PyArg_ParseTuple(args, "s#", &buf, &len))

return NULL;

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;;

}

PyFile_SoftSpace((PyObject*)self, 0);

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:

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);

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 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 (!PyString_Check(v)) {

const char *buffer;

int len;

if (PyObject_AsCharBuffer(v, &buffer, &len)) {

PyErr_SetString(PyExc_TypeError,

"writelines() "

"argument must be "

"a sequence of "

"strings");

goto error;

}

line = PyString_FromStringAndSize(buffer,

len);

if (line == NULL)

goto error;

Py_DECREF(v);

PyList_SET_ITEM(list, i, line);

}

}

PyFile_SoftSpace((PyObject*)self, 0);

/* 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 = PyString_GET_SIZE(line);

BZ2_bzWrite (&bzerror, self->fp,

PyString_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;

long offset;

char small_buffer[SMALLCHUNK];

char *buffer = small_buffer;

size_t buffersize = SMALLCHUNK;

int bytesread = 0;

int readsize;

int chunksize;

int bzerror;

int rewind = 0;

PyObject *func;

PyObject *ret = NULL;

if (!PyArg_ParseTuple(args, "l|i:seek", &offset, &where))

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 (offset < 0) {

if (where == 1) {

offset = self->pos + offset;

rewind = 1;

} else if (where == 2) {

if (self->size == -1) {

assert(self->mode != MODE_READ_EOF);

for (;;) {

Py_BEGIN_ALLOW_THREADS

chunksize = Util_UnivNewlineRead(

&bzerror, self->fp,

buffer, buffersize,

self);

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;

if (offset >= self->pos)

offset -= self->pos;