python/Modules/mmapmodule.c at master · charleson/python · GitHub

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/ Author: Sam Rushing <rushing@nightmare.com>

/ Hacked for Unix by AMK

/ $Id$

/ Modified to support mmap with offset - to map a 'window' of a file

/ Author: Yotam Medini yotamm@mellanox.co.il

/ mmapmodule.cpp -- map a view of a file into memory

/ todo: need permission flags, perhaps a 'chsize' analog

/ not all functions check range yet!!!

/ This version of mmapmodule.c has been changed significantly

/ from the original mmapfile.c on which it was based.

/ The original version of mmapfile is maintained by Sam at

/ ftp://squirl.nightmare.com/pub/python/python-ext.

#define PY_SSIZE_T_CLEAN

#include <Python.h>

#ifndef MS_WINDOWS

#define UNIX

#endif

#ifdef MS_WINDOWS

#include <windows.h>

static int

my_getpagesize(void)

{

SYSTEM_INFO si;

GetSystemInfo(&si);

return si.dwPageSize;

}

static int

my_getallocationgranularity (void)

{

SYSTEM_INFO si;

GetSystemInfo(&si);

return si.dwAllocationGranularity;

}

#endif

#ifdef UNIX

#include <sys/mman.h>

#include <sys/stat.h>

#if defined(HAVE_SYSCONF) && defined(_SC_PAGESIZE)

static int

my_getpagesize(void)

{

return sysconf(_SC_PAGESIZE);

}

#define my_getallocationgranularity my_getpagesize

#else

#define my_getpagesize getpagesize

#endif

#endif /* UNIX */

#include <string.h>

#ifdef HAVE_SYS_TYPES_H

#include <sys/types.h>

#endif /* HAVE_SYS_TYPES_H */

/* Prefer MAP_ANONYMOUS since MAP_ANON is deprecated according to man page. */

#if !defined(MAP_ANONYMOUS) && defined(MAP_ANON)

# define MAP_ANONYMOUS MAP_ANON

#endif

static PyObject *mmap_module_error;

typedef enum

{

ACCESS_DEFAULT,

ACCESS_READ,

ACCESS_WRITE,

ACCESS_COPY

} access_mode;

typedef struct {

PyObject_HEAD

char * data;

size_t size;

size_t pos; /* relative to offset */

size_t offset;

#ifdef MS_WINDOWS

HANDLE map_handle;

HANDLE file_handle;

char * tagname;

#endif

#ifdef UNIX

int fd;

#endif

access_mode access;

} mmap_object;

static void

mmap_object_dealloc(mmap_object *m_obj)

{

#ifdef MS_WINDOWS

if (m_obj->data != NULL)

UnmapViewOfFile (m_obj->data);

if (m_obj->map_handle != INVALID_HANDLE_VALUE)

CloseHandle (m_obj->map_handle);

if (m_obj->file_handle != INVALID_HANDLE_VALUE)

CloseHandle (m_obj->file_handle);

if (m_obj->tagname)

PyMem_Free(m_obj->tagname);

#endif /* MS_WINDOWS */

#ifdef UNIX

if (m_obj->fd >= 0)

(void) close(m_obj->fd);

if (m_obj->data!=NULL) {

msync(m_obj->data, m_obj->size, MS_SYNC);

munmap(m_obj->data, m_obj->size);

}

#endif /* UNIX */

Py_TYPE(m_obj)->tp_free((PyObject*)m_obj);

}

static PyObject *

mmap_close_method(mmap_object *self, PyObject *unused)

{

#ifdef MS_WINDOWS

/* For each resource we maintain, we need to check

the value is valid, and if so, free the resource

and set the member value to an invalid value so

the dealloc does not attempt to resource clearing

again.

TODO - should we check for errors in the close operations???

if (self->data != NULL) {

UnmapViewOfFile(self->data);

self->data = NULL;

}

if (self->map_handle != INVALID_HANDLE_VALUE) {

CloseHandle(self->map_handle);

self->map_handle = INVALID_HANDLE_VALUE;

}

if (self->file_handle != INVALID_HANDLE_VALUE) {

CloseHandle(self->file_handle);

self->file_handle = INVALID_HANDLE_VALUE;

}

#endif /* MS_WINDOWS */

#ifdef UNIX

(void) close(self->fd);

self->fd = -1;

if (self->data != NULL) {

munmap(self->data, self->size);

self->data = NULL;

}

#endif

Py_INCREF(Py_None);

return Py_None;

}

#ifdef MS_WINDOWS

#define CHECK_VALID(err) \

do { \

if (self->map_handle == INVALID_HANDLE_VALUE) { \

PyErr_SetString(PyExc_ValueError, "mmap closed or invalid"); \

return err; \

} \

} while (0)

#endif /* MS_WINDOWS */

#ifdef UNIX

#define CHECK_VALID(err) \

do { \

if (self->data == NULL) { \

PyErr_SetString(PyExc_ValueError, "mmap closed or invalid"); \

return err; \

} \

} while (0)

#endif /* UNIX */

static PyObject *

mmap_read_byte_method(mmap_object *self,

PyObject *unused)

{

CHECK_VALID(NULL);

if (self->pos < self->size) {

char value = self->data[self->pos];

self->pos += 1;

return Py_BuildValue("c", value);

} else {

PyErr_SetString(PyExc_ValueError, "read byte out of range");

return NULL;

}

static PyObject *

mmap_read_line_method(mmap_object *self,

PyObject *unused)

{

char *start = self->data+self->pos;

char *eof = self->data+self->size;

char *eol;

PyObject *result;

CHECK_VALID(NULL);

eol = memchr(start, '\n', self->size - self->pos);

if (!eol)

eol = eof;

else

++eol; /* we're interested in the position after the

newline. */

result = PyString_FromStringAndSize(start, (eol - start));

self->pos += (eol - start);

return result;

}

static PyObject *

mmap_read_method(mmap_object *self,

PyObject *args)

{

Py_ssize_t num_bytes;

PyObject *result;

CHECK_VALID(NULL);

if (!PyArg_ParseTuple(args, "n:read", &num_bytes))

return(NULL);

/* silently 'adjust' out-of-range requests */

if (num_bytes > self->size - self->pos) {

num_bytes -= (self->pos+num_bytes) - self->size;

}

result = Py_BuildValue("s#", self->data+self->pos, num_bytes);

self->pos += num_bytes;

return result;

}

static PyObject *

mmap_gfind(mmap_object *self,

PyObject *args,

int reverse)

{

Py_ssize_t start = self->pos;

Py_ssize_t end = self->size;

const char *needle;

Py_ssize_t len;

CHECK_VALID(NULL);

if (!PyArg_ParseTuple(args, reverse ? "s#|nn:rfind" : "s#|nn:find",

&needle, &len, &start, &end)) {

return NULL;

} else {

const char *p, *start_p, *end_p;

int sign = reverse ? -1 : 1;

if (start < 0)

start += self->size;

if (start < 0)

start = 0;

else if ((size_t)start > self->size)

start = self->size;

if (end < 0)

end += self->size;

if (end < 0)

end = 0;

else if ((size_t)end > self->size)

end = self->size;

start_p = self->data + start;

end_p = self->data + end;

for (p = (reverse ? end_p - len : start_p);

(p >= start_p) && (p + len <= end_p); p += sign) {

Py_ssize_t i;

for (i = 0; i < len && needle[i] == p[i]; ++i)

/* nothing */;

if (i == len) {

return PyInt_FromSsize_t(p - self->data);

}

return PyInt_FromLong(-1);

}

static PyObject *

mmap_find_method(mmap_object *self,

PyObject *args)

{

return mmap_gfind(self, args, 0);

}

static PyObject *

mmap_rfind_method(mmap_object *self,

PyObject *args)

{

return mmap_gfind(self, args, 1);

}

static int

is_writeable(mmap_object *self)

{

if (self->access != ACCESS_READ)

return 1;

PyErr_Format(PyExc_TypeError, "mmap can't modify a readonly memory map.");

return 0;

}

static int

is_resizeable(mmap_object *self)

{

if ((self->access == ACCESS_WRITE) || (self->access == ACCESS_DEFAULT))

return 1;

PyErr_Format(PyExc_TypeError,

"mmap can't resize a readonly or copy-on-write memory map.");

return 0;

}

static PyObject *

mmap_write_method(mmap_object *self,

PyObject *args)

{

Py_ssize_t length;

char *data;

CHECK_VALID(NULL);

if (!PyArg_ParseTuple(args, "s#:write", &data, &length))

return(NULL);

if (!is_writeable(self))

return NULL;

if ((self->pos + length) > self->size) {

PyErr_SetString(PyExc_ValueError, "data out of range");

return NULL;

}

memcpy(self->data+self->pos, data, length);

self->pos = self->pos+length;

Py_INCREF(Py_None);

return Py_None;

}

static PyObject *

mmap_write_byte_method(mmap_object *self,

PyObject *args)

{

char value;

CHECK_VALID(NULL);

if (!PyArg_ParseTuple(args, "c:write_byte", &value))

return(NULL);

if (!is_writeable(self))

return NULL;

*(self->data+self->pos) = value;

self->pos += 1;

Py_INCREF(Py_None);

return Py_None;

}

static PyObject *

mmap_size_method(mmap_object *self,

PyObject *unused)

{

CHECK_VALID(NULL);

#ifdef MS_WINDOWS

if (self->file_handle != INVALID_HANDLE_VALUE) {

DWORD low,high;

PY_LONG_LONG size;

low = GetFileSize(self->file_handle, &high);

if (low == INVALID_FILE_SIZE) {

/* It might be that the function appears to have failed,

when indeed its size equals INVALID_FILE_SIZE */

DWORD error = GetLastError();

if (error != NO_ERROR)

return PyErr_SetFromWindowsErr(error);

}

if (!high && low < LONG_MAX)

return PyInt_FromLong((long)low);

size = (((PY_LONG_LONG)high)<<32) + low;

return PyLong_FromLongLong(size);

} else {

return PyInt_FromSsize_t(self->size);

}

#endif /* MS_WINDOWS */

#ifdef UNIX

{

struct stat buf;

if (-1 == fstat(self->fd, &buf)) {

PyErr_SetFromErrno(mmap_module_error);

return NULL;

}

return PyInt_FromSsize_t(buf.st_size);

}

#endif /* UNIX */

}

/* This assumes that you want the entire file mapped,

/ and when recreating the map will make the new file

/ have the new size

/ Is this really necessary? This could easily be done

/ from python by just closing and re-opening with the

/ new size?

static PyObject *

mmap_resize_method(mmap_object *self,

PyObject *args)

{

Py_ssize_t new_size;

CHECK_VALID(NULL);

if (!PyArg_ParseTuple(args, "n:resize", &new_size) ||

!is_resizeable(self)) {

return NULL;

#ifdef MS_WINDOWS

} else {

DWORD dwErrCode = 0;

DWORD off_hi, off_lo, newSizeLow, newSizeHigh;

/* First, unmap the file view */

UnmapViewOfFile(self->data);

/* Close the mapping object */

CloseHandle(self->map_handle);

/* Move to the desired EOF position */

#if SIZEOF_SIZE_T > 4

newSizeHigh = (DWORD)((self->offset + new_size) >> 32);

newSizeLow = (DWORD)((self->offset + new_size) & 0xFFFFFFFF);

off_hi = (DWORD)(self->offset >> 32);

off_lo = (DWORD)(self->offset & 0xFFFFFFFF);

#else

newSizeHigh = 0;

newSizeLow = (DWORD)new_size;

off_hi = 0;

off_lo = (DWORD)self->offset;

#endif

SetFilePointer(self->file_handle,

newSizeLow, &newSizeHigh, FILE_BEGIN);

/* Change the size of the file */

SetEndOfFile(self->file_handle);

/* Create another mapping object and remap the file view */

self->map_handle = CreateFileMapping(

self->file_handle,

NULL,

PAGE_READWRITE,

self->tagname);

if (self->map_handle != NULL) {

self->data = (char *) MapViewOfFile(self->map_handle,

FILE_MAP_WRITE,

off_hi,

off_lo,

new_size);

if (self->data != NULL) {

self->size = new_size;

Py_INCREF(Py_None);

return Py_None;

} else {

dwErrCode = GetLastError();

}

} else {

dwErrCode = GetLastError();

}

PyErr_SetFromWindowsErr(dwErrCode);

return NULL;

#endif /* MS_WINDOWS */

#ifdef UNIX

#ifndef HAVE_MREMAP

} else {

PyErr_SetString(PyExc_SystemError,

"mmap: resizing not available--no mremap()");

return NULL;

#else

} else {

void *newmap;

if (ftruncate(self->fd, new_size) == -1) {

PyErr_SetFromErrno(mmap_module_error);

return NULL;

}

#ifdef MREMAP_MAYMOVE

newmap = mremap(self->data, self->size, new_size, MREMAP_MAYMOVE);

#else

newmap = mremap(self->data, self->size, new_size, 0);

#endif

if (newmap == (void *)-1)

{

PyErr_SetFromErrno(mmap_module_error);

return NULL;

}

self->data = newmap;

self->size = new_size;

Py_INCREF(Py_None);

return Py_None;

#endif /* HAVE_MREMAP */

#endif /* UNIX */

}

static PyObject *

mmap_tell_method(mmap_object *self, PyObject *unused)

{

CHECK_VALID(NULL);

return PyInt_FromSize_t(self->pos);

}

static PyObject *

mmap_flush_method(mmap_object *self, PyObject *args)

{

Py_ssize_t offset = 0;

Py_ssize_t size = self->size;

CHECK_VALID(NULL);

if (!PyArg_ParseTuple(args, "|nn:flush", &offset, &size))

return NULL;

if ((size_t)(offset + size) > self->size) {

PyErr_SetString(PyExc_ValueError, "flush values out of range");

return NULL;

}

#ifdef MS_WINDOWS

return PyInt_FromLong((long) FlushViewOfFile(self->data+offset, size));

#elif defined(UNIX)

/* XXX semantics of return value? */

/* XXX flags for msync? */

if (-1 == msync(self->data + offset, size, MS_SYNC)) {

PyErr_SetFromErrno(mmap_module_error);

return NULL;

}

return PyInt_FromLong(0);

#else

PyErr_SetString(PyExc_ValueError, "flush not supported on this system");

return NULL;

#endif

}

static PyObject *

mmap_seek_method(mmap_object *self, PyObject *args)

{

Py_ssize_t dist;

int how=0;

CHECK_VALID(NULL);

if (!PyArg_ParseTuple(args, "n|i:seek", &dist, &how))

return NULL;

else {

size_t where;

switch (how) {

case 0: /* relative to start */

if (dist < 0)

goto onoutofrange;

where = dist;

break;

case 1: /* relative to current position */

if ((Py_ssize_t)self->pos + dist < 0)

goto onoutofrange;

where = self->pos + dist;

break;

case 2: /* relative to end */

if ((Py_ssize_t)self->size + dist < 0)

goto onoutofrange;

where = self->size + dist;

break;

default:

PyErr_SetString(PyExc_ValueError, "unknown seek type");

return NULL;

}

if (where > self->size)

goto onoutofrange;

self->pos = where;

Py_INCREF(Py_None);

return Py_None;

}

onoutofrange:

PyErr_SetString(PyExc_ValueError, "seek out of range");

return NULL;

}

static PyObject *

mmap_move_method(mmap_object *self, PyObject *args)

{

unsigned long dest, src, count;

CHECK_VALID(NULL);

if (!PyArg_ParseTuple(args, "kkk:move", &dest, &src, &count) ||

!is_writeable(self)) {

return NULL;

} else {

/* bounds check the values */

if (/* end of source after end of data?? */

((src+count) > self->size)

/* dest will fit? */

|| (dest+count > self->size)) {

PyErr_SetString(PyExc_ValueError,

"source or destination out of range");

return NULL;

} else {

memmove(self->data+dest, self->data+src, count);

Py_INCREF(Py_None);

return Py_None;

}

static struct PyMethodDef mmap_object_methods[] = {

{"close", (PyCFunction) mmap_close_method, METH_NOARGS},

{"find", (PyCFunction) mmap_find_method, METH_VARARGS},

{"rfind", (PyCFunction) mmap_rfind_method, METH_VARARGS},

{"flush", (PyCFunction) mmap_flush_method, METH_VARARGS},

{"move", (PyCFunction) mmap_move_method, METH_VARARGS},

{"read", (PyCFunction) mmap_read_method, METH_VARARGS},

{"read_byte", (PyCFunction) mmap_read_byte_method, METH_NOARGS},

{"readline", (PyCFunction) mmap_read_line_method, METH_NOARGS},

{"resize", (PyCFunction) mmap_resize_method, METH_VARARGS},

{"seek", (PyCFunction) mmap_seek_method, METH_VARARGS},

{"size", (PyCFunction) mmap_size_method, METH_NOARGS},

{"tell", (PyCFunction) mmap_tell_method, METH_NOARGS},

{"write", (PyCFunction) mmap_write_method, METH_VARARGS},

{"write_byte", (PyCFunction) mmap_write_byte_method, METH_VARARGS},

{NULL, NULL} /* sentinel */

};

/* Functions for treating an mmap'ed file as a buffer */

static Py_ssize_t

mmap_buffer_getreadbuf(mmap_object *self, Py_ssize_t index, const void **ptr)

{

CHECK_VALID(-1);

if (index != 0) {

PyErr_SetString(PyExc_SystemError,

"Accessing non-existent mmap segment");

return -1;

}

*ptr = self->data;

return self->size;

}

static Py_ssize_t

mmap_buffer_getwritebuf(mmap_object *self, Py_ssize_t index, const void **ptr)

{

CHECK_VALID(-1);

if (index != 0) {

PyErr_SetString(PyExc_SystemError,

"Accessing non-existent mmap segment");

return -1;

}

if (!is_writeable(self))

return -1;

*ptr = self->data;

return self->size;

}

static Py_ssize_t

mmap_buffer_getsegcount(mmap_object *self, Py_ssize_t *lenp)

{

CHECK_VALID(-1);

if (lenp)

*lenp = self->size;

return 1;

}

static Py_ssize_t

mmap_buffer_getcharbuffer(mmap_object *self, Py_ssize_t index, const void **ptr)

{

if (index != 0) {

PyErr_SetString(PyExc_SystemError,

"accessing non-existent buffer segment");

return -1;

}

*ptr = (const char *)self->data;

return self->size;

}

static Py_ssize_t

mmap_length(mmap_object *self)

{

CHECK_VALID(-1);

return self->size;

}

static PyObject *

mmap_item(mmap_object *self, Py_ssize_t i)

{

CHECK_VALID(NULL);

if (i < 0 || (size_t)i >= self->size) {

PyErr_SetString(PyExc_IndexError, "mmap index out of range");

return NULL;

}

return PyString_FromStringAndSize(self->data + i, 1);

}

static PyObject *

mmap_slice(mmap_object *self, Py_ssize_t ilow, Py_ssize_t ihigh)

{

CHECK_VALID(NULL);

if (ilow < 0)

ilow = 0;

else if ((size_t)ilow > self->size)

ilow = self->size;

if (ihigh < 0)

ihigh = 0;

if (ihigh < ilow)

ihigh = ilow;

else if ((size_t)ihigh > self->size)

ihigh = self->size;

return PyString_FromStringAndSize(self->data + ilow, ihigh-ilow);

}

static PyObject *

mmap_subscript(mmap_object *self, PyObject *item)

{

CHECK_VALID(NULL);

if (PyIndex_Check(item)) {

Py_ssize_t i = PyNumber_AsSsize_t(item, PyExc_IndexError);

if (i == -1 && PyErr_Occurred())

return NULL;

if (i < 0)

i += self->size;

if (i < 0 || (size_t)i > self->size) {

PyErr_SetString(PyExc_IndexError,

"mmap index out of range");

return NULL;

}

return PyString_FromStringAndSize(self->data + i, 1);

}

else if (PySlice_Check(item)) {

Py_ssize_t start, stop, step, slicelen;

if (PySlice_GetIndicesEx((PySliceObject *)item, self->size,

&start, &stop, &step, &slicelen) < 0) {

return NULL;

}

if (slicelen <= 0)

return PyString_FromStringAndSize("", 0);

else if (step == 1)

return PyString_FromStringAndSize(self->data + start,

slicelen);

else {

char *result_buf = (char *)PyMem_Malloc(slicelen);

Py_ssize_t cur, i;

PyObject *result;

if (result_buf == NULL)

return PyErr_NoMemory();

for (cur = start, i = 0; i < slicelen;

cur += step, i++) {

result_buf[i] = self->data[cur];

}

result = PyString_FromStringAndSize(result_buf,

slicelen);

PyMem_Free(result_buf);

return result;

}

else {

PyErr_SetString(PyExc_TypeError,

"mmap indices must be integers");

return NULL;

}

static PyObject *

mmap_concat(mmap_object *self, PyObject *bb)

{

CHECK_VALID(NULL);

PyErr_SetString(PyExc_SystemError,

"mmaps don't support concatenation");

return NULL;

}

static PyObject *

mmap_repeat(mmap_object *self, Py_ssize_t n)

{

CHECK_VALID(NULL);

PyErr_SetString(PyExc_SystemError,

"mmaps don't support repeat operation");

return NULL;

}

static int

mmap_ass_slice(mmap_object *self, Py_ssize_t ilow, Py_ssize_t ihigh, PyObject *v)

{

const char *buf;

CHECK_VALID(-1);

if (ilow < 0)

ilow = 0;

else if ((size_t)ilow > self->size)

ilow = self->size;

if (ihigh < 0)

ihigh = 0;

if (ihigh < ilow)

ihigh = ilow;

else if ((size_t)ihigh > self->size)

ihigh = self->size;

if (v == NULL) {

PyErr_SetString(PyExc_TypeError,

"mmap object doesn't support slice deletion");

return -1;

}

if (! (PyString_Check(v)) ) {

PyErr_SetString(PyExc_IndexError,

"mmap slice assignment must be a string");

return -1;

}

if (PyString_Size(v) != (ihigh - ilow)) {

PyErr_SetString(PyExc_IndexError,

"mmap slice assignment is wrong size");

return -1;

}

if (!is_writeable(self))

return -1;

buf = PyString_AsString(v);

memcpy(self->data + ilow, buf, ihigh-ilow);

return 0;

}

static int

mmap_ass_item(mmap_object *self, Py_ssize_t i, PyObject *v)

{

const char *buf;

CHECK_VALID(-1);

if (i < 0 || (size_t)i >= self->size) {

PyErr_SetString(PyExc_IndexError, "mmap index out of range");

return -1;

}

if (v == NULL) {

PyErr_SetString(PyExc_TypeError,

"mmap object doesn't support item deletion");

return -1;

}

if (! (PyString_Check(v) && PyString_Size(v)==1) ) {

PyErr_SetString(PyExc_IndexError,

"mmap assignment must be single-character string");

return -1;

}

if (!is_writeable(self))

return -1;

buf = PyString_AsString(v);

self->data[i] = buf[0];

return 0;

}

static int

mmap_ass_subscript(mmap_object *self, PyObject *item, PyObject *value)

{

CHECK_VALID(-1);

if (PyIndex_Check(item)) {

Py_ssize_t i = PyNumber_AsSsize_t(item, PyExc_IndexError);

const char *buf;

if (i == -1 && PyErr_Occurred())

return -1;

if (i < 0)

i += self->size;

if (i < 0 || (size_t)i > self->size) {

PyErr_SetString(PyExc_IndexError,

"mmap index out of range");

return -1;

}

if (value == NULL) {

PyErr_SetString(PyExc_TypeError,

"mmap object doesn't support item deletion");

return -1;

}

if (!PyString_Check(value) || PyString_Size(value) != 1) {

PyErr_SetString(PyExc_IndexError,

"mmap assignment must be single-character string");

return -1;

}

if (!is_writeable(self))

return -1;

buf = PyString_AsString(value);

self->data[i] = buf[0];

return 0;

}

else if (PySlice_Check(item)) {

Py_ssize_t start, stop, step, slicelen;

if (PySlice_GetIndicesEx((PySliceObject *)item,

self->size, &start, &stop,

&step, &slicelen) < 0) {

return -1;

}

if (value == NULL) {

PyErr_SetString(PyExc_TypeError,

"mmap object doesn't support slice deletion");

return -1;

}

if (!PyString_Check(value)) {

PyErr_SetString(PyExc_IndexError,

"mmap slice assignment must be a string");

return -1;

}

if (PyString_Size(value) != slicelen) {

PyErr_SetString(PyExc_IndexError,

"mmap slice assignment is wrong size");

return -1;

}

if (!is_writeable(self))

return -1;

if (slicelen == 0)

return 0;

else if (step == 1) {

const char *buf = PyString_AsString(value);

if (buf == NULL)

return -1;

memcpy(self->data + start, buf, slicelen);

return 0;

}

else {

Py_ssize_t cur, i;

const char *buf = PyString_AsString(value);

if (buf == NULL)

return -1;

for (cur = start, i = 0; i < slicelen;

cur += step, i++) {

self->data[cur] = buf[i];

}

return 0;

}

else {

PyErr_SetString(PyExc_TypeError,

"mmap indices must be integer");

return -1;

}

static PySequenceMethods mmap_as_sequence = {

(lenfunc)mmap_length, /*sq_length*/

(binaryfunc)mmap_concat, /*sq_concat*/

(ssizeargfunc)mmap_repeat, /*sq_repeat*/

(ssizeargfunc)mmap_item, /*sq_item*/

(ssizessizeargfunc)mmap_slice, /*sq_slice*/

(ssizeobjargproc)mmap_ass_item, /*sq_ass_item*/

(ssizessizeobjargproc)mmap_ass_slice, /*sq_ass_slice*/

};

static PyMappingMethods mmap_as_mapping = {

(lenfunc)mmap_length,

(binaryfunc)mmap_subscript,

(objobjargproc)mmap_ass_subscript,

};

static PyBufferProcs mmap_as_buffer = {

(readbufferproc)mmap_buffer_getreadbuf,

(writebufferproc)mmap_buffer_getwritebuf,

(segcountproc)mmap_buffer_getsegcount,

(charbufferproc)mmap_buffer_getcharbuffer,

};

static PyObject *

new_mmap_object(PyTypeObject *type, PyObject *args, PyObject *kwdict);

PyDoc_STRVAR(mmap_doc,

"Windows: mmap(fileno, length[, tagname[, access[, offset]]])\n\

\n\

Maps length bytes from the file specified by the file handle fileno,\n\

and returns a mmap object. If length is larger than the current size\n\

of the file, the file is extended to contain length bytes. If length\n\

is 0, the maximum length of the map is the current size of the file,\n\

except that if the file is empty Windows raises an exception (you cannot\n\

create an empty mapping on Windows).\n\

\n\

Unix: mmap(fileno, length[, flags[, prot[, access[, offset]]]])\n\

\n\

Maps length bytes from the file specified by the file descriptor fileno,\n\

and returns a mmap object. If length is 0, the maximum length of the map\n\

will be the current size of the file when mmap is called.\n\

flags specifies the nature of the mapping. MAP_PRIVATE creates a\n\

private copy-on-write mapping, so changes to the contents of the mmap\n\

object will be private to this process, and MAP_SHARED creates a mapping\n\

that's shared with all other processes mapping the same areas of the file.\n\

The default value is MAP_SHARED.\n\

\n\

To map anonymous memory, pass -1 as the fileno (both versions).");

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python/Modules/mmapmodule.c at master · charleson/python · GitHub

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