pygdioctx.c

Welcome to MS4W, the no fuss installer for setting up MapServer on Microsoft Windows platforms. The

/******************************************************************************
 * $Id: pygdioctx.c,v 1.6 2005/02/18 20:10:01 sean Exp $
 *
 * Project:  MapServer
 * Purpose:  Interface Python file-like objects with GD through IOCtx
 * Author:   Sean Gillies, [e-mail]
 *
 ******************************************************************************
 * The PyFileIfaceObj_IOCtx API is
 * 
 * Copyright 1995 Richard Jones, Bureau of Meteorology Australia.
 * [e-mail]
 *
 * Current maintainer is 
 * Chris Gonnerman <[e-mail]>
 * Please direct all questions and problems to me.
 *
 ******************************************************************************
 * GDMODULE LICENSE:
 * gdmodule - Python GD module Copyright (c) 1995 Richard Jones All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 * Redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in
 * the documentation and/or other materials provided with the
 * distribution.  Neither the name of the Bureau of Meteorology
 * Australia nor the names of its contributors may be used to endorse
 * or promote products derived from this software without specific
 * prior written permission. 
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 * ***************************************************************************/

#include "pygdioctx.h"

int PyFileIfaceObj_IOCtx_GetC(gdIOCtx *ctx)
{
    struct PyFileIfaceObj_gdIOCtx *pctx = (struct PyFileIfaceObj_gdIOCtx *)ctx;
    if (pctx->strObj) {
        Py_DECREF(pctx->strObj);
        pctx->strObj = NULL;
    }
    pctx->strObj = PyObject_CallMethod(pctx->fileIfaceObj, "read", "i", 1);
    if (!pctx->strObj || !PyString_Check(pctx->strObj)) {
        return EOF;
    }
    if (PyString_GET_SIZE(pctx->strObj) == 1) {
        return (int)(unsigned char)PyString_AS_STRING(pctx->strObj)[0];
    }
    return EOF;
}

int PyFileIfaceObj_IOCtx_GetBuf(gdIOCtx *ctx, void *data, int size)
{
    int err;
    char *value;
    struct PyFileIfaceObj_gdIOCtx *pctx = (struct PyFileIfaceObj_gdIOCtx *)ctx;
    if (pctx->strObj) {
        Py_DECREF(pctx->strObj);
        pctx->strObj = NULL;
    }
    pctx->strObj = PyObject_CallMethod(pctx->fileIfaceObj, "read", "i", size);
    if (!pctx->strObj) {
        return 0;
    }
    err = PyString_AsStringAndSize(pctx->strObj, &value, &size);
    if (err < 0) {
        /* this throws away the python exception since the gd library
         * won't pass it up properly.  gdmodule should create its own
         * since the "file" couldn't be read properly.  */
        PyErr_Clear();
        return 0;
    }
    memcpy(data, value, size);
    return size;
}

void PyFileIfaceObj_IOCtx_Free(gdIOCtx *ctx)
{
    struct PyFileIfaceObj_gdIOCtx *pctx = (struct PyFileIfaceObj_gdIOCtx *)ctx;
    if (pctx->strObj) {
        Py_DECREF(pctx->strObj);
        pctx->strObj = NULL;
    }
    if (pctx->fileIfaceObj) {
        Py_DECREF(pctx->fileIfaceObj);
        pctx->fileIfaceObj = NULL;
    }
    /* NOTE: we leave deallocation of the ctx structure itself to outside
     * code for memory allocation symmetry.  This function is safe to
     * call multiple times (gd should call it + we call it to be safe). */
}

struct PyFileIfaceObj_gdIOCtx * alloc_PyFileIfaceObj_IOCtx(PyObject *fileIfaceObj)
{
    struct PyFileIfaceObj_gdIOCtx *pctx;
    pctx = calloc(1, sizeof(struct PyFileIfaceObj_gdIOCtx));
    if (!pctx)
        return NULL;
    pctx->ctx.getC = PyFileIfaceObj_IOCtx_GetC; 
    pctx->ctx.getBuf = PyFileIfaceObj_IOCtx_GetBuf;
    pctx->ctx.gd_free = PyFileIfaceObj_IOCtx_Free;
    Py_INCREF(fileIfaceObj);
    pctx->fileIfaceObj = fileIfaceObj;
    return pctx;
}

void free_PyFileIfaceObj_IOCtx(struct PyFileIfaceObj_gdIOCtx *pctx)
{
    if (!pctx)
        return;
    assert(pctx->ctx.gd_free != NULL);
    pctx->ctx.gd_free((gdIOCtxPtr)pctx);
    free(pctx);
}

/* ===========================================================================
 * Mapserver function createImageObjFromPyFile by Sean Gillies,
 * <[e-mail]>
 * ======================================================================== */

imageObj *createImageObjFromPyFile(PyObject *file, const char *driver)
    {
    imageObj *image=NULL;
    struct PyFileIfaceObj_gdIOCtx *pctx;

    if (file == Py_None) 
    {
        msSetError(MS_IMGERR, "NULL file object",
                   "createImageObjFromPyFile()");
        return NULL;
    }
    else if (!driver) 
    {
        msSetError(MS_IMGERR, "NULL or invalid driver string",
                   "createImageObjFromPyFile()");
        return NULL;
    }
    else
    {
        pctx = alloc_PyFileIfaceObj_IOCtx(file);
        image = msImageLoadGDCtx((gdIOCtx *) pctx, driver);
        free_PyFileIfaceObj_IOCtx(pctx);
        return image;
    }
}