mirror of
https://github.com/python-pillow/Pillow.git
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396 lines
10 KiB
C
396 lines
10 KiB
C
/*
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* The Python Imaging Library.
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*
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* standard memory mapping interface for the Imaging library
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*
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* history:
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* 1998-03-05 fl added Win32 read mapping
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* 1999-02-06 fl added "I;16" support
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* 2003-04-21 fl added PyImaging_MapBuffer primitive
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*
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* Copyright (c) 1998-2003 by Secret Labs AB.
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* Copyright (c) 2003 by Fredrik Lundh.
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*
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* See the README file for information on usage and redistribution.
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*/
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/*
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* FIXME: should move the memory mapping primitives into libImaging!
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*/
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#include "Python.h"
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#include "Imaging.h"
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#include "py3.h"
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/* compatibility wrappers (defined in _imaging.c) */
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extern int PyImaging_CheckBuffer(PyObject* buffer);
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extern int PyImaging_GetBuffer(PyObject* buffer, Py_buffer *view);
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/* -------------------------------------------------------------------- */
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/* Standard mapper */
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typedef struct {
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PyObject_HEAD
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char* base;
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int size;
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int offset;
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#ifdef _WIN32
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HANDLE hFile;
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HANDLE hMap;
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#endif
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} ImagingMapperObject;
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static PyTypeObject ImagingMapperType;
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ImagingMapperObject*
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PyImaging_MapperNew(const char* filename, int readonly)
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{
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ImagingMapperObject *mapper;
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if (PyType_Ready(&ImagingMapperType) < 0)
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return NULL;
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mapper = PyObject_New(ImagingMapperObject, &ImagingMapperType);
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if (mapper == NULL)
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return NULL;
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mapper->base = NULL;
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mapper->size = mapper->offset = 0;
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#ifdef _WIN32
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mapper->hFile = (HANDLE)-1;
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mapper->hMap = (HANDLE)-1;
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/* FIXME: currently supports readonly mappings only */
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mapper->hFile = CreateFile(
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filename,
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GENERIC_READ,
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FILE_SHARE_READ,
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NULL, OPEN_EXISTING,
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FILE_ATTRIBUTE_NORMAL,
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NULL);
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if (mapper->hFile == (HANDLE)-1) {
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PyErr_SetString(PyExc_IOError, "cannot open file");
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Py_DECREF(mapper);
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return NULL;
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}
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mapper->hMap = CreateFileMapping(
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mapper->hFile, NULL,
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PAGE_READONLY,
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0, 0, NULL);
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if (mapper->hMap == (HANDLE)-1) {
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CloseHandle(mapper->hFile);
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PyErr_SetString(PyExc_IOError, "cannot map file");
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Py_DECREF(mapper);
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return NULL;
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}
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mapper->base = (char*) MapViewOfFile(
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mapper->hMap,
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FILE_MAP_READ,
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0, 0, 0);
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mapper->size = GetFileSize(mapper->hFile, 0);
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#endif
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return mapper;
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}
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static void
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mapping_dealloc(ImagingMapperObject* mapper)
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{
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#ifdef _WIN32
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if (mapper->base != 0)
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UnmapViewOfFile(mapper->base);
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if (mapper->hMap != (HANDLE)-1)
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CloseHandle(mapper->hMap);
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if (mapper->hFile != (HANDLE)-1)
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CloseHandle(mapper->hFile);
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mapper->base = 0;
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mapper->hMap = mapper->hFile = (HANDLE)-1;
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#endif
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PyObject_Del(mapper);
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}
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/* -------------------------------------------------------------------- */
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/* standard file operations */
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static PyObject*
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mapping_read(ImagingMapperObject* mapper, PyObject* args)
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{
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PyObject* buf;
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int size = -1;
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if (!PyArg_ParseTuple(args, "|i", &size))
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return NULL;
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/* check size */
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if (size < 0 || mapper->offset + size > mapper->size)
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size = mapper->size - mapper->offset;
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if (size < 0)
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size = 0;
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buf = PyBytes_FromStringAndSize(NULL, size);
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if (!buf)
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return NULL;
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if (size > 0) {
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memcpy(PyBytes_AsString(buf), mapper->base + mapper->offset, size);
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mapper->offset += size;
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}
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return buf;
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}
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static PyObject*
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mapping_seek(ImagingMapperObject* mapper, PyObject* args)
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{
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int offset;
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int whence = 0;
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if (!PyArg_ParseTuple(args, "i|i", &offset, &whence))
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return NULL;
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switch (whence) {
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case 0: /* SEEK_SET */
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mapper->offset = offset;
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break;
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case 1: /* SEEK_CUR */
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mapper->offset += offset;
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break;
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case 2: /* SEEK_END */
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mapper->offset = mapper->size + offset;
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break;
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default:
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/* FIXME: raise ValueError? */
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break;
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}
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Py_INCREF(Py_None);
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return Py_None;
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}
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/* -------------------------------------------------------------------- */
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/* map entire image */
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extern PyObject*PyImagingNew(Imaging im);
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static void
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ImagingDestroyMap(Imaging im)
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{
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return; /* nothing to do! */
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}
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static PyObject*
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mapping_readimage(ImagingMapperObject* mapper, PyObject* args)
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{
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int y, size;
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Imaging im;
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char* mode;
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int xsize;
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int ysize;
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int stride;
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int orientation;
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if (!PyArg_ParseTuple(args, "s(ii)ii", &mode, &xsize, &ysize,
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&stride, &orientation))
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return NULL;
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if (stride <= 0) {
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/* FIXME: maybe we should call ImagingNewPrologue instead */
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if (!strcmp(mode, "L") || !strcmp(mode, "P"))
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stride = xsize;
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else if (!strcmp(mode, "I;16") || !strcmp(mode, "I;16B"))
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stride = xsize * 2;
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else
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stride = xsize * 4;
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}
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size = ysize * stride;
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if (mapper->offset + size > mapper->size) {
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PyErr_SetString(PyExc_IOError, "image file truncated");
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return NULL;
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}
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im = ImagingNewPrologue(mode, xsize, ysize);
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if (!im)
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return NULL;
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/* setup file pointers */
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if (orientation > 0)
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for (y = 0; y < ysize; y++)
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im->image[y] = mapper->base + mapper->offset + y * stride;
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else
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for (y = 0; y < ysize; y++)
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im->image[ysize-y-1] = mapper->base + mapper->offset + y * stride;
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im->destroy = ImagingDestroyMap;
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if (!ImagingNewEpilogue(im))
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return NULL;
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mapper->offset += size;
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return PyImagingNew(im);
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}
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static struct PyMethodDef methods[] = {
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/* standard file interface */
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{"read", (PyCFunction)mapping_read, 1},
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{"seek", (PyCFunction)mapping_seek, 1},
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/* extensions */
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{"readimage", (PyCFunction)mapping_readimage, 1},
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{NULL, NULL} /* sentinel */
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};
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static PyTypeObject ImagingMapperType = {
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PyVarObject_HEAD_INIT(NULL, 0)
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"ImagingMapper", /*tp_name*/
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sizeof(ImagingMapperObject), /*tp_size*/
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0, /*tp_itemsize*/
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/* methods */
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(destructor)mapping_dealloc, /*tp_dealloc*/
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0, /*tp_print*/
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0, /*tp_getattr*/
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0, /*tp_setattr*/
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0, /*tp_compare*/
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0, /*tp_repr*/
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0, /*tp_as_number */
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0, /*tp_as_sequence */
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0, /*tp_as_mapping */
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0, /*tp_hash*/
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0, /*tp_call*/
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0, /*tp_str*/
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0, /*tp_getattro*/
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0, /*tp_setattro*/
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0, /*tp_as_buffer*/
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Py_TPFLAGS_DEFAULT, /*tp_flags*/
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0, /*tp_doc*/
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0, /*tp_traverse*/
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0, /*tp_clear*/
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0, /*tp_richcompare*/
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0, /*tp_weaklistoffset*/
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0, /*tp_iter*/
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0, /*tp_iternext*/
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methods, /*tp_methods*/
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0, /*tp_members*/
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0, /*tp_getset*/
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};
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PyObject*
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PyImaging_Mapper(PyObject* self, PyObject* args)
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{
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char* filename;
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if (!PyArg_ParseTuple(args, "s", &filename))
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return NULL;
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return (PyObject*) PyImaging_MapperNew(filename, 1);
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}
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/* -------------------------------------------------------------------- */
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/* Buffer mapper */
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typedef struct ImagingBufferInstance {
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struct ImagingMemoryInstance im;
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PyObject* target;
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Py_buffer view;
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} ImagingBufferInstance;
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static void
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mapping_destroy_buffer(Imaging im)
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{
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ImagingBufferInstance* buffer = (ImagingBufferInstance*) im;
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PyBuffer_Release(&buffer->view);
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Py_XDECREF(buffer->target);
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}
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PyObject*
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PyImaging_MapBuffer(PyObject* self, PyObject* args)
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{
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Py_ssize_t y, size;
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Imaging im;
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PyObject* target;
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Py_buffer view;
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char* mode;
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char* codec;
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PyObject* bbox;
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Py_ssize_t offset;
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int xsize, ysize;
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int stride;
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int ystep;
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if (!PyArg_ParseTuple(args, "O(ii)sOn(sii)", &target, &xsize, &ysize,
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&codec, &bbox, &offset, &mode, &stride, &ystep))
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return NULL;
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if (!PyImaging_CheckBuffer(target)) {
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PyErr_SetString(PyExc_TypeError, "expected string or buffer");
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return NULL;
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}
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if (stride <= 0) {
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if (!strcmp(mode, "L") || !strcmp(mode, "P"))
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stride = xsize;
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else if (!strncmp(mode, "I;16", 4))
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stride = xsize * 2;
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else
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stride = xsize * 4;
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}
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if (ysize > INT_MAX / stride) {
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PyErr_SetString(PyExc_MemoryError, "Integer overflow in ysize");
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return NULL;
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}
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size = (Py_ssize_t) ysize * stride;
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if (offset > SIZE_MAX - size) {
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PyErr_SetString(PyExc_MemoryError, "Integer overflow in offset");
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return NULL;
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}
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/* check buffer size */
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if (PyImaging_GetBuffer(target, &view) < 0)
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return NULL;
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if (view.len < 0) {
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PyErr_SetString(PyExc_ValueError, "buffer has negative size");
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return NULL;
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}
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if (offset + size > view.len) {
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PyErr_SetString(PyExc_ValueError, "buffer is not large enough");
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return NULL;
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}
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im = ImagingNewPrologueSubtype(
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mode, xsize, ysize, sizeof(ImagingBufferInstance)
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);
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if (!im)
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return NULL;
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/* setup file pointers */
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if (ystep > 0)
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for (y = 0; y < ysize; y++)
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im->image[y] = (char*)view.buf + offset + y * stride;
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else
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for (y = 0; y < ysize; y++)
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im->image[ysize-y-1] = (char*)view.buf + offset + y * stride;
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im->destroy = mapping_destroy_buffer;
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Py_INCREF(target);
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((ImagingBufferInstance*) im)->target = target;
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((ImagingBufferInstance*) im)->view = view;
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if (!ImagingNewEpilogue(im))
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return NULL;
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return PyImagingNew(im);
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}
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