Pillow/src/map.c
Axel Huebl f79379ed7c Imaging.h: confusion with system
The file `libImaging/Imaging.h` gets installed flat on
Ubuntus into the public Python includes.

When building a newer version of Pillow from source and
hinting the Python includes "too early" in includes, e.g.
in package managers, this can confuse the two files and
pick up the external file over the internal one. With
different versions, this mismatch can lead to build errors,
e.g. undefined macros.

The most robust way to avoid this is to pre-fix the internal
include accordingly, so that the relative path to the including
file has to match as well.
2020-09-17 18:06:45 +10:00

413 lines
10 KiB
C

/*
* The Python Imaging Library.
*
* standard memory mapping interface for the Imaging library
*
* history:
* 1998-03-05 fl added Win32 read mapping
* 1999-02-06 fl added "I;16" support
* 2003-04-21 fl added PyImaging_MapBuffer primitive
*
* Copyright (c) 1998-2003 by Secret Labs AB.
* Copyright (c) 2003 by Fredrik Lundh.
*
* See the README file for information on usage and redistribution.
*/
/*
* FIXME: should move the memory mapping primitives into libImaging!
*/
#include "Python.h"
#include "libImaging/Imaging.h"
/* compatibility wrappers (defined in _imaging.c) */
extern int PyImaging_CheckBuffer(PyObject* buffer);
extern int PyImaging_GetBuffer(PyObject* buffer, Py_buffer *view);
/* -------------------------------------------------------------------- */
/* Standard mapper */
typedef struct {
PyObject_HEAD
char* base;
int size;
int offset;
#ifdef _WIN32
HANDLE hFile;
HANDLE hMap;
#endif
} ImagingMapperObject;
static PyTypeObject ImagingMapperType;
ImagingMapperObject*
PyImaging_MapperNew(const char* filename, int readonly)
{
ImagingMapperObject *mapper;
if (PyType_Ready(&ImagingMapperType) < 0) {
return NULL;
}
mapper = PyObject_New(ImagingMapperObject, &ImagingMapperType);
if (mapper == NULL) {
return NULL;
}
mapper->base = NULL;
mapper->size = mapper->offset = 0;
#ifdef _WIN32
mapper->hFile = (HANDLE)-1;
mapper->hMap = (HANDLE)-1;
/* FIXME: currently supports readonly mappings only */
mapper->hFile = CreateFile(
filename,
GENERIC_READ,
FILE_SHARE_READ,
NULL, OPEN_EXISTING,
FILE_ATTRIBUTE_NORMAL,
NULL);
if (mapper->hFile == (HANDLE)-1) {
PyErr_SetString(PyExc_OSError, "cannot open file");
Py_DECREF(mapper);
return NULL;
}
mapper->hMap = CreateFileMapping(
mapper->hFile, NULL,
PAGE_READONLY,
0, 0, NULL);
if (mapper->hMap == (HANDLE)-1) {
CloseHandle(mapper->hFile);
PyErr_SetString(PyExc_OSError, "cannot map file");
Py_DECREF(mapper);
return NULL;
}
mapper->base = (char*) MapViewOfFile(
mapper->hMap,
FILE_MAP_READ,
0, 0, 0);
mapper->size = GetFileSize(mapper->hFile, 0);
#endif
return mapper;
}
static void
mapping_dealloc(ImagingMapperObject* mapper)
{
#ifdef _WIN32
if (mapper->base != 0) {
UnmapViewOfFile(mapper->base);
}
if (mapper->hMap != (HANDLE)-1) {
CloseHandle(mapper->hMap);
}
if (mapper->hFile != (HANDLE)-1) {
CloseHandle(mapper->hFile);
}
mapper->base = 0;
mapper->hMap = mapper->hFile = (HANDLE)-1;
#endif
PyObject_Del(mapper);
}
/* -------------------------------------------------------------------- */
/* standard file operations */
static PyObject*
mapping_read(ImagingMapperObject* mapper, PyObject* args)
{
PyObject* buf;
int size = -1;
if (!PyArg_ParseTuple(args, "|i", &size)) {
return NULL;
}
/* check size */
if (size < 0 || mapper->offset + size > mapper->size) {
size = mapper->size - mapper->offset;
}
if (size < 0) {
size = 0;
}
buf = PyBytes_FromStringAndSize(NULL, size);
if (!buf) {
return NULL;
}
if (size > 0) {
memcpy(PyBytes_AsString(buf), mapper->base + mapper->offset, size);
mapper->offset += size;
}
return buf;
}
static PyObject*
mapping_seek(ImagingMapperObject* mapper, PyObject* args)
{
int offset;
int whence = 0;
if (!PyArg_ParseTuple(args, "i|i", &offset, &whence)) {
return NULL;
}
switch (whence) {
case 0: /* SEEK_SET */
mapper->offset = offset;
break;
case 1: /* SEEK_CUR */
mapper->offset += offset;
break;
case 2: /* SEEK_END */
mapper->offset = mapper->size + offset;
break;
default:
/* FIXME: raise ValueError? */
break;
}
Py_INCREF(Py_None);
return Py_None;
}
/* -------------------------------------------------------------------- */
/* map entire image */
extern PyObject*PyImagingNew(Imaging im);
static void
ImagingDestroyMap(Imaging im)
{
return; /* nothing to do! */
}
static PyObject*
mapping_readimage(ImagingMapperObject* mapper, PyObject* args)
{
int y, size;
Imaging im;
char* mode;
int xsize;
int ysize;
int stride;
int orientation;
if (!PyArg_ParseTuple(args, "s(ii)ii", &mode, &xsize, &ysize,
&stride, &orientation)) {
return NULL;
}
if (stride <= 0) {
/* FIXME: maybe we should call ImagingNewPrologue instead */
if (!strcmp(mode, "L") || !strcmp(mode, "P")) {
stride = xsize;
} else if (!strcmp(mode, "I;16") || !strcmp(mode, "I;16B")) {
stride = xsize * 2;
} else {
stride = xsize * 4;
}
}
size = ysize * stride;
if (mapper->offset + size > mapper->size) {
PyErr_SetString(PyExc_OSError, "image file truncated");
return NULL;
}
im = ImagingNewPrologue(mode, xsize, ysize);
if (!im) {
return NULL;
}
/* setup file pointers */
if (orientation > 0) {
for (y = 0; y < ysize; y++) {
im->image[y] = mapper->base + mapper->offset + y * stride;
}
} else {
for (y = 0; y < ysize; y++) {
im->image[ysize-y-1] = mapper->base + mapper->offset + y * stride;
}
}
im->destroy = ImagingDestroyMap;
mapper->offset += size;
return PyImagingNew(im);
}
static struct PyMethodDef methods[] = {
/* standard file interface */
{"read", (PyCFunction)mapping_read, 1},
{"seek", (PyCFunction)mapping_seek, 1},
/* extensions */
{"readimage", (PyCFunction)mapping_readimage, 1},
{NULL, NULL} /* sentinel */
};
static PyTypeObject ImagingMapperType = {
PyVarObject_HEAD_INIT(NULL, 0)
"ImagingMapper", /*tp_name*/
sizeof(ImagingMapperObject), /*tp_size*/
0, /*tp_itemsize*/
/* methods */
(destructor)mapping_dealloc, /*tp_dealloc*/
0, /*tp_print*/
0, /*tp_getattr*/
0, /*tp_setattr*/
0, /*tp_compare*/
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*/
0, /*tp_doc*/
0, /*tp_traverse*/
0, /*tp_clear*/
0, /*tp_richcompare*/
0, /*tp_weaklistoffset*/
0, /*tp_iter*/
0, /*tp_iternext*/
methods, /*tp_methods*/
0, /*tp_members*/
0, /*tp_getset*/
};
PyObject*
PyImaging_Mapper(PyObject* self, PyObject* args)
{
char* filename;
if (!PyArg_ParseTuple(args, "s", &filename)) {
return NULL;
}
return (PyObject*) PyImaging_MapperNew(filename, 1);
}
/* -------------------------------------------------------------------- */
/* Buffer mapper */
typedef struct ImagingBufferInstance {
struct ImagingMemoryInstance im;
PyObject* target;
Py_buffer view;
} ImagingBufferInstance;
static void
mapping_destroy_buffer(Imaging im)
{
ImagingBufferInstance* buffer = (ImagingBufferInstance*) im;
PyBuffer_Release(&buffer->view);
Py_XDECREF(buffer->target);
}
PyObject*
PyImaging_MapBuffer(PyObject* self, PyObject* args)
{
Py_ssize_t y, size;
Imaging im;
PyObject* target;
Py_buffer view;
char* mode;
char* codec;
Py_ssize_t offset;
int xsize, ysize;
int stride;
int ystep;
if (!PyArg_ParseTuple(args, "O(ii)sn(sii)", &target, &xsize, &ysize,
&codec, &offset, &mode, &stride, &ystep)) {
return NULL;
}
if (!PyImaging_CheckBuffer(target)) {
PyErr_SetString(PyExc_TypeError, "expected string or buffer");
return NULL;
}
if (stride <= 0) {
if (!strcmp(mode, "L") || !strcmp(mode, "P")) {
stride = xsize;
} else if (!strncmp(mode, "I;16", 4)) {
stride = xsize * 2;
} else {
stride = xsize * 4;
}
}
if (stride > 0 && ysize > PY_SSIZE_T_MAX / stride) {
PyErr_SetString(PyExc_MemoryError, "Integer overflow in ysize");
return NULL;
}
size = (Py_ssize_t) ysize * stride;
if (offset > PY_SSIZE_T_MAX - size) {
PyErr_SetString(PyExc_MemoryError, "Integer overflow in offset");
return NULL;
}
/* check buffer size */
if (PyImaging_GetBuffer(target, &view) < 0) {
return NULL;
}
if (view.len < 0) {
PyErr_SetString(PyExc_ValueError, "buffer has negative size");
PyBuffer_Release(&view);
return NULL;
}
if (offset + size > view.len) {
PyErr_SetString(PyExc_ValueError, "buffer is not large enough");
PyBuffer_Release(&view);
return NULL;
}
im = ImagingNewPrologueSubtype(
mode, xsize, ysize, sizeof(ImagingBufferInstance));
if (!im) {
PyBuffer_Release(&view);
return NULL;
}
/* setup file pointers */
if (ystep > 0) {
for (y = 0; y < ysize; y++) {
im->image[y] = (char*)view.buf + offset + y * stride;
}
} else {
for (y = 0; y < ysize; y++) {
im->image[ysize-y-1] = (char*)view.buf + offset + y * stride;
}
}
im->destroy = mapping_destroy_buffer;
Py_INCREF(target);
((ImagingBufferInstance*) im)->target = target;
((ImagingBufferInstance*) im)->view = view;
return PyImagingNew(im);
}