/********************************************************************

 import_nt.c 

  Win32 specific import code.

*/

#include "Python.h"

#include "osdefs.h"

#include <windows.h>

#include "importdl.h"

#include "malloc.h" /* for alloca */

/* a string loaded from the DLL at startup */

extern const char *PyWin_DLLVersionString;

FILE *PyWin_FindRegisteredModule(const char *moduleName,

				 struct filedescr **ppFileDesc,

				 char *pathBuf,

				 Py_ssize_t pathLen)

{

	char *moduleKey;

	const char keyPrefix[] = "Software\\Python\\PythonCore\\";

	const char keySuffix[] = "\\Modules\\";

#ifdef _DEBUG

	/* In debugging builds, we _must_ have the debug version

	 * registered.

	 */

	const char debugString[] = "\\Debug";

#else

	const char debugString[] = "";

#endif

	struct filedescr *fdp = NULL;

	FILE *fp;

	HKEY keyBase = HKEY_CURRENT_USER;

	int modNameSize;

	long regStat;

	/* Calculate the size for the sprintf buffer.

	 * Get the size of the chars only, plus 1 NULL.

	 */

	size_t bufSize = sizeof(keyPrefix)-1 +

	                 strlen(PyWin_DLLVersionString) +

	                 sizeof(keySuffix) +

	                 strlen(moduleName) +

	                 sizeof(debugString) - 1;

	/* alloca == no free required, but memory only local to fn,

	 * also no heap fragmentation!

	 */

	moduleKey = alloca(bufSize); 

	PyOS_snprintf(moduleKey, bufSize,

		      "Software\\Python\\PythonCore\\%s\\Modules\\%s%s",

		      PyWin_DLLVersionString, moduleName, debugString);

	assert(pathLen < INT_MAX);

	modNameSize = (int)pathLen;

	regStat = RegQueryValue(keyBase, moduleKey, pathBuf, &modNameSize);

	if (regStat != ERROR_SUCCESS) {

		/* No user setting - lookup in machine settings */

		keyBase = HKEY_LOCAL_MACHINE;

		/* be anal - failure may have reset size param */

		modNameSize = (int)pathLen;

		regStat = RegQueryValue(keyBase, moduleKey, 

		                        pathBuf, &modNameSize);

		if (regStat != ERROR_SUCCESS)

			return NULL;

	}

	/* use the file extension to locate the type entry. */

	for (fdp = _PyImport_Filetab; fdp->suffix != NULL; fdp++) {

		size_t extLen = strlen(fdp->suffix);

		assert(modNameSize >= 0); /* else cast to size_t is wrong */

		if ((size_t)modNameSize > extLen &&

		    strnicmp(pathBuf + ((size_t)modNameSize-extLen-1),

		             fdp->suffix,

		             extLen) == 0)

			break;

	}

	if (fdp->suffix == NULL)

		return NULL;

	fp = fopen(pathBuf, fdp->mode);

	if (fp != NULL)

		*ppFileDesc = fdp;

	return fp;

}