Merge Python scripting support from Vasiliy Chernov

12 files changed, 556 insertions, 45 deletions

diff --git a/pcilib/config.h.in b/pcilib/config.h.in
index bdd9ec3..cd8033c 100644
--- a/pcilib/config.h.in
+++ b/pcilib/config.h.in
@@ -3,3 +3,4 @@
 #cmakedefine PCILIB_MODEL_DIR "${PCILIB_MODEL_DIR}"
 #cmakedefine PCILIB_DEBUG_DIR "${PCILIB_DEBUG_DIR}"
 #cmakedefine HAVE_STDATOMIC_H @HAVE_STDATOMIC_H@
+#cmakedefine HAVE_PYTHON
diff --git a/pcilib/error.c b/pcilib/error.c
index 06af292..ae8bacb 100644
--- a/pcilib/error.c
+++ b/pcilib/error.c
@@ -76,3 +76,15 @@ int pcilib_set_logger(pcilib_log_priority_t min_prio, pcilib_logger_t logger, vo
 
     return 0;
 }
+
+pcilib_logger_t pcilib_get_logger() {
+    return pcilib_logger;
+}
+
+pcilib_log_priority_t pcilib_get_log_level() {
+    return pcilib_logger_min_prio;
+}
+
+void* pcilib_get_logger_context() {
+    return pcilib_logger_argument;
+}
diff --git a/pcilib/error.h b/pcilib/error.h
index a9f4c0b..051ecd8 100644
--- a/pcilib/error.h
+++ b/pcilib/error.h
@@ -40,6 +40,20 @@ extern "C" {
 void pcilib_log_message(const char *file, int line, pcilib_log_flags_t flags, pcilib_log_priority_t prio, const char *msg, ...);
 void pcilib_log_vmessage(const char *file, int line, pcilib_log_flags_t flags, pcilib_log_priority_t prio, const char *msg, va_list va);
 
+/**
+ * Gets current logger function.
+ */
+pcilib_logger_t pcilib_get_logger();
+
+/**
+ * Gets current logger min priority.
+ */
+pcilib_log_priority_t pcilib_get_log_level();
+
+/**
+ * Gets current logger argument.
+ */
+void* pcilib_get_logger_context();
 
 #ifdef __cplusplus
 }
diff --git a/pcilib/pci.c b/pcilib/pci.c
index eaf41ac..19165ba 100644
--- a/pcilib/pci.c
+++ b/pcilib/pci.c
@@ -191,6 +191,14 @@ pcilib_t *pcilib_open(const char *device, const char *model) {
 
 	if (!ctx->model)
 	    ctx->model = strdup(model?model:"pci");
+	    
+	err = pcilib_py_add_script_dir(ctx, NULL);
+	if (err) {
+	    pcilib_error("Error (%i) add script path to python path", err);
+	    pcilib_close(ctx);
+	    return NULL;
+	}
+	
 	
 	xmlerr = pcilib_init_xml(ctx, ctx->model);
 	if ((xmlerr)&&(xmlerr != PCILIB_ERROR_NOTFOUND)) {
@@ -198,6 +206,7 @@ pcilib_t *pcilib_open(const char *device, const char *model) {
 	    pcilib_close(ctx);
 	    return NULL;
 	}
+	
 
 	    // We have found neither standard model nor XML
 	if ((err)&&(xmlerr)) {
@@ -219,7 +228,6 @@ pcilib_t *pcilib_open(const char *device, const char *model) {
 	    pcilib_close(ctx);
 	    return NULL;
 	}
-	
 	err = pcilib_init_event_engine(ctx);
 	if (err) {
 	    pcilib_error("Error (%i) initializing event engine\n", err);
@@ -305,8 +313,6 @@ void pcilib_close(pcilib_t *ctx) {
 
 	if (ctx->event_plugin)
 	    pcilib_plugin_close(ctx->event_plugin);
-	
-        pcilib_free_py(ctx);
 
 	if (ctx->locks.kmem)
 	    pcilib_free_locking(ctx);
@@ -348,11 +354,12 @@ void pcilib_close(pcilib_t *ctx) {
 
 	if (ctx->registers)
 	    free(ctx->registers);
-	
+	    
 	if (ctx->model)
 	    free(ctx->model);
 
 	pcilib_free_xml(ctx);
+	pcilib_free_py(ctx);
 
 	if (ctx->handle >= 0)
 	    close(ctx->handle);
diff --git a/pcilib/pcilib.h b/pcilib/pcilib.h
index 3e7cf2b..8ab8e9e 100644
--- a/pcilib/pcilib.h
+++ b/pcilib/pcilib.h
@@ -43,7 +43,8 @@ typedef enum {
 typedef enum {
     PCILIB_ACCESS_R = 1,			/**< getting property is allowed */
     PCILIB_ACCESS_W = 2,			/**< setting property is allowed */
-    PCILIB_ACCESS_RW = 3
+    PCILIB_ACCESS_RW = 3,
+    PCILIB_ACCESS_INCONSISTENT = 0x10000	/**< inconsistent access, one will not read that one has written */
 } pcilib_access_mode_t;
 
 typedef enum {
@@ -54,6 +55,7 @@ typedef enum {
     PCILIB_REGISTER_RW1C = 5,
     PCILIB_REGISTER_W1I = 8,			/**< writting 1 inversts the bit, writting 0 keeps the value */
     PCILIB_REGISTER_RW1I = 9,
+    PCILIB_REGISTER_INCONSISTENT = 0x10000	/**< inconsistent register, writting and reading does not match */
 } pcilib_register_mode_t;
 
 typedef enum {
@@ -1256,6 +1258,16 @@ int pcilib_set_value_from_register_value(pcilib_t *ctx, pcilib_value_t *val, pci
 int pcilib_set_value_from_static_string(pcilib_t *ctx, pcilib_value_t *val, const char *str);
 
 /**
+ * Initializes the polymorphic value from the string. The string is copied.
+ * If `val` already contains the value, cleans it first. Therefore, before first usage the value should be always initialized to 0.
+ * @param[in] ctx	- pcilib context
+ * @param[in,out] val	- initialized polymorphic value
+ * @param[in] str	- initializer
+ * @return		- 0 on success or memory error
+ */
+int pcilib_set_value_from_string(pcilib_t *ctx, pcilib_value_t *value, const char *str);
+
+/**
  * Get the floating point value from the polymorphic type. May inmply impliced type conversion,
  * for isntance parsing the number from the string. Will return 0. and report an error if
  * conversion failed.
diff --git a/pcilib/property.c b/pcilib/property.c
index a7d1a61..dfab9a6 100644
--- a/pcilib/property.c
+++ b/pcilib/property.c
@@ -165,7 +165,6 @@ pcilib_property_info_t *pcilib_get_property_list(pcilib_t *ctx, const char *bran
                 continue;
             }
 
-
             dir = (struct dir_hash_s*)malloc(sizeof(struct dir_hash_s));
             if (!dir) {
                 err = PCILIB_ERROR_MEMORY;
@@ -226,6 +225,10 @@ pcilib_property_info_t *pcilib_get_property_list(pcilib_t *ctx, const char *bran
         };
     }
 
+    HASH_ITER(hh, dir_hash, dir, dir_tmp) {
+	HASH_DEL(dir_hash, dir);
+	free(dir);
+    }
     HASH_CLEAR(hh, dir_hash);
 
     memset(&info[pos], 0, sizeof(pcilib_property_info_t));
diff --git a/pcilib/py.c b/pcilib/py.c
index 4256afc..9254df7 100644
--- a/pcilib/py.c
+++ b/pcilib/py.c
@@ -1,66 +1,333 @@
-#include <Python.h>
-
+#define _GNU_SOURCE
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <strings.h>
-
+#include <alloca.h>
 
 #include "pci.h"
 #include "debug.h"
 #include "pcilib.h"
 #include "py.h"
 #include "error.h"
+#include "config.h"
+
+#ifdef HAVE_PYTHON
+# include <Python.h>
+#endif /* HAVE_PYTHON */
+
+#ifdef HAVE_PYTHON
+typedef struct pcilib_script_s pcilib_script_t;
+
+struct pcilib_script_s {
+    const char *name;			/**< Script name */
+    PyObject *module;			/**< PyModule object, contains script enviroment */	
+    UT_hash_handle hh;			/**< hash */
+};
 
 struct pcilib_py_s {
-    PyObject *main_module;
-    PyObject *global_dict;
+    int finalyze; 			/**< Indicates, that we are initialized from wrapper and should not destroy Python resources in destructor */
+    PyObject *main_module;		/**< Main interpreter */
+    PyObject *global_dict;		/**< Dictionary of main interpreter */
+    PyObject *pcilib_pywrap;		/**< pcilib wrapper module */
+    pcilib_script_t *script_hash;	/**< Hash with loaded scripts */
 };
+#endif /* HAVE_PYTHON */
+
+void pcilib_log_python_error(const char *file, int line, pcilib_log_flags_t flags, pcilib_log_priority_t prio, const char *msg, ...) {
+    va_list va;
+    const char *type = NULL;
+    const char *val = NULL;
+
+#ifdef HAVE_PYTHON
+    PyObject *pytype = NULL;
+    PyObject *pyval = NULL;
+    PyObject *pytraceback = NULL;
+
+    PyErr_Fetch(&pytype, &pyval, &pytraceback);
+    type = PyString_AsString(pytype);
+    val = PyString_AsString(pyval);
+#endif /* HAVE_PYTHON */
+    
+    va_start(va, msg);
+    if (type) {
+	char *str;
+	size_t len = 32;
+
+	if (msg) len += strlen(msg);
+	if (type) len += strlen(type);
+	if (val) len += strlen(val);
+	    
+	str = alloca(len * sizeof(char));
+	if (str) {
+	    if (msg&&val)
+		sprintf(str, "%s <%s: %s>", msg, type, val);
+	    else if (msg)
+		sprintf(str, "%s <%s>", msg, type);
+	    else if (val)
+		sprintf(str, "Python error %s: %s", type, val);
+	    else
+		sprintf(str, "Python error %s", type);
+	    
+	    pcilib_log_vmessage(file, line, flags, prio, str, va);
+	}
+    } else  {
+	pcilib_log_vmessage(file, line, flags, prio, msg, va);
+    }
+    va_end(va);
+
+#ifdef HAVE_PYTHON
+    Py_XDECREF(pytype);
+    Py_XDECREF(pyval);
+    Py_XDECREF(pytraceback);
+#endif /* HAVE_PYTHON */
+}
+
+
 
 int pcilib_init_py(pcilib_t *ctx) {
+#ifdef HAVE_PYTHON
     ctx->py = (pcilib_py_t*)malloc(sizeof(pcilib_py_t));
     if (!ctx->py) return PCILIB_ERROR_MEMORY;
 
-    Py_Initialize();
+    memset(ctx->py, 0, sizeof(pcilib_py_t));
 
+    if(Py_IsInitialized())
+	ctx->py->finalyze = 1;
+    else {
+        Py_Initialize();
+        
+    	    // Since python is being initializing from c programm, it needs to initialize threads to work properly with c threads
+        PyEval_InitThreads();
+        PyEval_ReleaseLock();
+    }
+		
     ctx->py->main_module = PyImport_AddModule("__parser__");
-    if (!ctx->py->main_module)
+    if (!ctx->py->main_module) {
+	pcilib_python_error("Error importing python parser");
         return PCILIB_ERROR_FAILED;
+    }
 
     ctx->py->global_dict = PyModule_GetDict(ctx->py->main_module);
-    if (!ctx->py->global_dict)
+    if (!ctx->py->global_dict) {
+	pcilib_python_error("Error locating global python dictionary");
+        return PCILIB_ERROR_FAILED;
+    }
+
+    PyObject *pywrap = PyImport_ImportModule("pcipywrap");
+    if (!pywrap) {
+	pcilib_python_error("Error importing pcilib python wrapper");
+	return PCILIB_ERROR_FAILED;
+    }
+	
+    PyObject *mod_name = PyString_FromString("Pcipywrap");
+    ctx->py->pcilib_pywrap = PyObject_CallMethodObjArgs(pywrap, mod_name, PyCObject_FromVoidPtr(ctx, NULL), NULL);
+    Py_XDECREF(mod_name);
+	
+    if (!ctx->py->pcilib_pywrap) {
+	pcilib_python_error("Error initializing python wrapper");
         return PCILIB_ERROR_FAILED;
+    }
+#endif /* HAVE_PYTHON */
+
+    return 0;
+}
+
+int pcilib_py_add_script_dir(pcilib_t *ctx, const char *dir) {
+#ifdef HAVE_PYTHON
+    PyObject* pypath;
+    char *script_dir;
+
+    const char *model_dir = getenv("PCILIB_MODEL_DIR");
+    if (!model_dir) model_dir = PCILIB_MODEL_DIR;
+
+    if (!dir) dir = ctx->model;
+
+    if (*dir == '/') {
+	script_dir = (char*)dir;
+    } else {
+	script_dir = alloca(strlen(model_dir) + strlen(dir) + 2);
+	if (!script_dir) return PCILIB_ERROR_MEMORY;
+	sprintf(script_dir, "%s/%s", model_dir, dir);
+    }
+
+    pypath = PySys_GetObject("path");
+    if (!pypath) {
+	pcilib_python_error("Can't get python path");
+	return PCILIB_ERROR_FAILED;
+    }
+
+	// Shall we check if the directory already in the path?
+    if(PyList_Append(pypath, PyString_FromString(script_dir)) == -1) {
+	pcilib_python_error("Can't add directory (%s) to python path", script_dir);
+	return PCILIB_ERROR_FAILED;
+    }
+#endif /* HAVE_PYTHON */
 
     return 0;
 }
 
 void pcilib_free_py(pcilib_t *ctx) {
-    if (ctx->py) {
-	    // Dict and module references are borrowed
+#ifdef HAVE_PYTHON
+    int finalyze = 0;
+	
+    if (ctx->py) {		
+	if(ctx->py->finalyze) finalyze = 1;
+
+	if (ctx->py->script_hash) {
+	    pcilib_script_t *script, *script_tmp;
+
+	    HASH_ITER(hh, ctx->py->script_hash, script, script_tmp) {
+		HASH_DEL(ctx->py->script_hash, script);
+		free(script);
+	    }
+	    ctx->py->script_hash = NULL;
+	}
+
         free(ctx->py);
         ctx->py = NULL;
     }
+    
+    if (finalyze)
+	Py_Finalize();
+#endif /* HAVE_PYTHON */
+}
+
+int pcilib_py_load_script(pcilib_t *ctx, const char *script_name) {
+#ifdef HAVE_PYTHON
+    PyObject* pymodule;
+    pcilib_script_t *module = NULL;
+
+
+    char *module_name = strdupa(script_name);
+    if (!module_name) return PCILIB_ERROR_MEMORY;
+
+    char *py = strrchr(module_name, '.');
+    if ((!py)||(strcasecmp(py, ".py"))) {
+	pcilib_error("Invalid script name (%s) is specified", script_name);
+	return PCILIB_ERROR_INVALID_ARGUMENT;
+    }
+    *py = 0;
+
+    HASH_FIND_STR(ctx->py->script_hash, script_name, module);
+    if (module) return 0;
+
+    pymodule = PyImport_ImportModule(module_name);
+    if (!pymodule) {
+	pcilib_python_error("Error importing script (%s)", script_name);
+	return PCILIB_ERROR_FAILED;
+    }
+
+    module = (pcilib_script_t*)malloc(sizeof(pcilib_script_t));
+    if (!module) return PCILIB_ERROR_MEMORY;
 
-    Py_Finalize();
+    module->module = pymodule;
+    module->name = script_name;
+    HASH_ADD_KEYPTR(hh, ctx->py->script_hash, module->name, strlen(module->name), module);
+#endif /* HAVE_PYTHON */
+    return 0;
 }
 
-/*
-static int pcilib_py_realloc_string(pcilib_t *ctx, size_t required, size_t *size, char **str) {
-    char *ptr;
-    size_t cur = *size;
+int pcilib_py_get_transform_script_properties(pcilib_t *ctx, const char *script_name, pcilib_access_mode_t *mode_ret) {
+    pcilib_access_mode_t mode = 0;
+
+#ifdef HAVE_PYTHON
+    PyObject *dict;
+    PyObject *pystr;
+    pcilib_script_t *module;
+	
+    HASH_FIND_STR(ctx->py->script_hash, script_name, module);
+
+    if(!module) {
+	pcilib_error("Script (%s) is not loaded yet", script_name);
+	return PCILIB_ERROR_NOTFOUND;
+    }
+	
+    dict = PyModule_GetDict(module->module);
+    if (!dict) {
+	pcilib_python_error("Error getting dictionary for script (%s)", script_name);
+	return PCILIB_ERROR_FAILED;
+    }
     
-    if ((required + 1) > cur) {
-        while (cur < required) cur *= 2;
-        ptr = (char*)realloc(*str, cur);
-        if (!ptr) return PCILIB_ERROR_MEMORY;
-        *size = cur;
-        *str = ptr;
-    }
-    ]
+    pystr = PyString_FromString("read_from_register");
+    if (pystr) {
+	if (PyDict_Contains(dict, pystr)) mode |= PCILIB_ACCESS_R;
+	Py_XDECREF(pystr);
+    }
+
+    pystr = PyString_FromString("write_to_register");
+    if (pystr) {
+	if (PyDict_Contains(dict, pystr)) mode |= PCILIB_ACCESS_W;
+	Py_XDECREF(pystr);
+    }
+#endif /* HAVE_PYTHON */
+
+    if (mode_ret) *mode_ret = mode;
     return 0;
 }
-*/
 
+pcilib_py_object *pcilib_get_value_as_pyobject(pcilib_t* ctx, pcilib_value_t *val, int *ret) {
+#ifdef HAVE_PYTHON	
+    int err = 0;
+    PyObject *res = NULL;
+
+    long ival;
+    double fval;
+	
+    switch(val->type) {
+     case PCILIB_TYPE_LONG:
+	ival = pcilib_get_value_as_int(ctx, val, &err);
+	if (!err) res = (PyObject*)PyInt_FromLong(ival);
+	break;
+     case PCILIB_TYPE_DOUBLE:
+	fval = pcilib_get_value_as_float(ctx, val, &err);
+	if (!err) res = (PyObject*)PyFloat_FromDouble(fval);
+	break;	
+     default:
+	err = PCILIB_ERROR_NOTSUPPORTED;
+	pcilib_error("Can't convert pcilib value of type (%lu) to PyObject", val->type);
+    }
+
+    if (err) {
+	if (ret) *ret = err;
+	return NULL;
+    } else if (!res) {
+	if (ret) *ret = PCILIB_ERROR_MEMORY;
+	return res;
+    } 
+
+    if (ret) *ret = 0;
+    return res;
+#else /* HAVE_PYTHON */
+    pcilib_error("Python is not supported");
+    return NULL;
+#endif /* HAVE_PYTHON */
+}
+
+int pcilib_set_value_from_pyobject(pcilib_t* ctx, pcilib_value_t *val, pcilib_py_object *pval) {
+#ifdef HAVE_PYTHON
+    int err = 0;
+    PyObject *pyval = (PyObject*)pval;
+	
+    if (PyInt_Check(pyval)) {
+        err = pcilib_set_value_from_int(ctx, val, PyInt_AsLong(pyval));
+    } else if (PyFloat_Check(pyval)) {
+        err = pcilib_set_value_from_float(ctx, val, PyFloat_AsDouble(pyval));
+    } else if (PyString_Check(pyval)) {
+        err = pcilib_set_value_from_string(ctx, val, PyString_AsString(pyval));
+    } else {
+        pcilib_error("Can't convert PyObject to polymorphic pcilib value");
+	err = PCILIB_ERROR_NOTSUPPORTED;
+    }
+    
+    return err;
+#else /* HAVE_PYTHON */
+    pcilib_error("Python is not supported");
+    return PCILIB_ERROR_NOTSUPPORTED;
+#endif /* HAVE_PYTHON */
+}
+
+#ifdef HAVE_PYTHON
 static char *pcilib_py_parse_string(pcilib_t *ctx, const char *codestr, pcilib_value_t *value) {
     int i;
     int err = 0;
@@ -166,8 +433,10 @@ static char *pcilib_py_parse_string(pcilib_t *ctx, const char *codestr, pcilib_v
 
     return dst;
 }
+#endif /* HAVE_PYTHON */
 
 int pcilib_py_eval_string(pcilib_t *ctx, const char *codestr, pcilib_value_t *value) {
+#ifdef HAVE_PYTHON
     PyGILState_STATE gstate;
     char *code;
     PyObject* obj;
@@ -189,4 +458,57 @@ int pcilib_py_eval_string(pcilib_t *ctx, const char *codestr, pcilib_value_t *va
 
     pcilib_debug(VIEWS, "Evaluating a Python string \'%s\' to %lf=\'%s\'", codestr, PyFloat_AsDouble(obj), code);
     return pcilib_set_value_from_float(ctx, value, PyFloat_AsDouble(obj));
+#else /* HAVE_PYTHON */
+	pcilib_error("Current build not support python.");
+    return PCILIB_ERROR_NOTAVAILABLE;
+#endif /* HAVE_PYTHON */
+}
+
+int pcilib_py_eval_func(pcilib_t *ctx, const char *script_name, const char *func_name, pcilib_value_t *val) {
+#ifdef HAVE_PYTHON
+    int err = 0;
+    PyObject *pyfunc;
+    PyObject *pyval = NULL, *pyret;
+    pcilib_script_t *module = NULL;
+
+    HASH_FIND_STR(ctx->py->script_hash, script_name, module);
+
+    if (!module) {
+	pcilib_error("Script (%s) is not loaded", script_name);
+	return PCILIB_ERROR_NOTFOUND;
+    }
+
+    if (val) {
+	pyval = pcilib_get_value_as_pyobject(ctx, val, &err);
+	if (err) return err;
+    }
+
+    pyfunc = PyUnicode_FromString(func_name);
+    if (!pyfunc) {
+	if (pyval) Py_XDECREF(pyval);
+	return PCILIB_ERROR_MEMORY;
+    }
+
+    PyGILState_STATE gstate = PyGILState_Ensure();
+    pyret = PyObject_CallMethodObjArgs(module->module, pyfunc, ctx->py->pcilib_pywrap, pyval, NULL);
+    PyGILState_Release(gstate);
+
+    Py_XDECREF(pyfunc);
+    Py_XDECREF(pyval);
+	
+    if (!pyret) {
+	pcilib_python_error("Error executing function (%s) of python script (%s)", func_name, script_name);
+	return PCILIB_ERROR_FAILED;
+    }
+
+    if ((val)&&(pyret != Py_None))
+	err = pcilib_set_value_from_pyobject(ctx, val, pyret);
+
+    Py_XDECREF(pyret);
+
+    return err;
+#else /* HAVE_PYTHON */
+    pcilib_error("Python is not supported");
+    return PCILIB_ERROR_NOTSUPPORTED;
+#endif /* HAVE_PYTHON */
 }
diff --git a/pcilib/py.h b/pcilib/py.h
index 21c31e9..c372a09 100644
--- a/pcilib/py.h
+++ b/pcilib/py.h
@@ -1,16 +1,123 @@
 #ifndef _PCILIB_PY_H
 #define _PCILIB_PY_H
 
+#include <pcilib.h>
+#include <pcilib/error.h>
+
+#define pcilib_python_error(...)	pcilib_log_python_error(__FILE__, __LINE__, PCILIB_LOG_DEFAULT, PCILIB_LOG_ERROR, __VA_ARGS__)
+
 typedef struct pcilib_py_s pcilib_py_t;
+typedef void pcilib_py_object;
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
+void pcilib_log_python_error(const char *file, int line, pcilib_log_flags_t flags, pcilib_log_priority_t prio, const char *msg, ...);
+
+/** Initializes Python engine 
+ *
+ * This function will return success if Python support is disabled. Only functions
+ * executing python call, like pcilib_py_eval_string(), return errors. Either way,
+ * no script directories are configured. The pcilib_add_script_dir() call is used
+ * for this purpose.
+ * 
+ * @param[in,out] ctx 	- pcilib context
+ * @return 		- error or 0 on success
+ */
 int pcilib_init_py(pcilib_t *ctx);
-int pcilib_py_eval_string(pcilib_t *ctx, const char *codestr, pcilib_value_t *value);
+
+/** Cleans up memory used by various python structures 
+ * and finalyzes python environment if pcilib is not started from python script
+ *
+ * @param[in] ctx 	- the pcilib_t context
+ */
 void pcilib_free_py(pcilib_t *ctx);
 
+/** Add an additional path to look for python scripts
+ *
+ * The default location for python files is /usr/local/share/pcilib/models/@b{model}.
+ * This can be altered using CMake PCILIB_MODEL_DIR variable while building or using 
+ * PCILIB_MODEL_DIR environmental variable dynamicly. The default location is added
+ * with @b{location} = NULL. Additional directories can be added as well either 
+ * by specifying relative path from the default directory or absolute path in the 
+ * system.
+ *
+ * @param[in,out] ctx 	- pcilib context
+ * @param[in] location 	- NULL or path to additional scripts
+ * @return 		- error or 0 on success
+ */
+int pcilib_py_add_script_dir(pcilib_t *ctx, const char *location);
+
+/** Loads the specified python script
+ *
+ * Once loaded the script is available until pcilib context is destryoed.
+ * 
+ * @param[in,out] ctx 	- pcilib context
+ * @param[in] name	- script name, the passed variable is referenced and, hence, should have static duration
+ * @return 		- error or 0 on success
+ */
+int pcilib_py_load_script(pcilib_t *ctx, const char *name);
+
+/** Check if the specified script can be used as transform view and detects transform configuration
+ *
+ * @param[in,out] ctx 	- pcilib context
+ * @param[in] name	- script name
+ * @param[out] mode	- supported access mode (read/write/read-write)
+ * @return 		- error or 0 on success
+ */
+int pcilib_py_get_transform_script_properties(pcilib_t *ctx, const char *name, pcilib_access_mode_t *mode);
+
+/**
+ * Get the PyObject from the polymorphic type. The returned value should be cleaned with Py_XDECREF()
+ * @param[in] ctx	- pcilib context
+ * @param[in] val	- initialized polymorphic value of arbitrary type
+ * @param[out] err	- error code or 0 on sccuess
+ * @return		- valid PyObject or NULL in the case of error
+ */
+pcilib_py_object *pcilib_get_value_as_pyobject(pcilib_t* ctx, pcilib_value_t *val, int *err);
+
+/**
+ * Initializes the polymorphic value from PyObject. If `val` already contains the value, cleans it first. 
+ * Therefore, before first usage the value should be always initialized to 0.
+ * @param[in] ctx       - pcilib context
+ * @param[in,out] val   - initialized polymorphic value
+ * @param[in] pyval     - valid PyObject* containing PyInt, PyFloat, or PyString
+ * @return              - 0 on success or memory error
+ */
+int pcilib_set_value_from_pyobject(pcilib_t* ctx, pcilib_value_t *val, pcilib_py_object *pyval);
+
+/** Evaluates the specified python code and returns result in @b{val}
+ *
+ * The python code may include special variables which will be substituted by pcitool before executing Python interpreter
+ * @b{$value} 		- will be replaced by the current value of the @b{val} parameter
+ * @b{$reg}		- will be replaced by the current value of the specified register @b{reg}
+ * @b{${/prop/temp}}	- will be replaced by the current value of the specified property @b{/prop/temp} 
+ * @b{${/prop/temp:C}}	- will be replaced by the current value of the specified property @b{/prop/temp} in the given units
+
+ * @param[in,out] ctx 	- pcilib context
+ * @param[in] codestr	- python code to evaluate
+ * @param[in,out] val	- Should contain the value which will be substituted in place of @b{$value} and on 
+ * 			successful execution will contain the computed value
+ * @return 		- error or 0 on success
+ */
+int pcilib_py_eval_string(pcilib_t *ctx, const char *codestr, pcilib_value_t *val);
+
+/** Execute the specified function in the Python script which was loaded with pcilib_py_load_script() call
+ *
+ * The function is expected to accept two paramters. The first parameter is pcipywrap context and the @b{val}
+ * is passed as the second parameter. The return value of the script will be returned in the @b{val} as well.
+ * If function returns Py_None, the value of @b{val} will be unchanged.
+ *
+ * @param[in,out] ctx 	- pcilib context
+ * @param[in] script	- script name
+ * @param[in] func	- function name
+ * @param[in,out] val	- Should contain the value of second parameter of the function before call and on 
+ * 			successful return will contain the returned value
+ * @return 		- error or 0 on success
+ */
+int pcilib_py_eval_func(pcilib_t *ctx, const char *script, const char *func, pcilib_value_t *val);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/pcilib/value.c b/pcilib/value.c
index 6e65307..e8268e9 100644
--- a/pcilib/value.c
+++ b/pcilib/value.c
@@ -1,3 +1,4 @@
+#define _POSIX_C_SOURCE 200809L
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -71,6 +72,27 @@ int pcilib_set_value_from_static_string(pcilib_t *ctx, pcilib_value_t *value, co
     return 0;
 }
 
+int pcilib_set_value_from_string(pcilib_t *ctx, pcilib_value_t *value, const char *str) {
+    size_t len;
+
+    pcilib_clean_value(ctx, value);
+
+    len = strlen(str) + 1;
+    if (len < sizeof(value->str)) {
+	memcpy(value->str, str, len);
+	value->sval = value->str;
+    } else {
+        value->data = (void*)strdup(str);
+        if (!value->data) return PCILIB_ERROR_MEMORY;
+
+	value->size = strlen(str) + 1;
+	value->sval = value->data;
+    }
+    value->type = PCILIB_TYPE_STRING;
+
+    return 0;
+}
+
 double pcilib_get_value_as_float(pcilib_t *ctx, const pcilib_value_t *val, int *ret) {
     int err;
     double res;
diff --git a/pcilib/view.c b/pcilib/view.c
index e31fdba..985c1b2 100644
--- a/pcilib/view.c
+++ b/pcilib/view.c
@@ -69,8 +69,11 @@ int pcilib_add_views_custom(pcilib_t *ctx, size_t n, const pcilib_view_descripti
             return PCILIB_ERROR_MEMORY;
         }
 
+        memcpy(cur, v, v->api->description_size);
+        ctx->views[ctx->num_views + i] = cur;
+
         if (v->api->init) 
-            view_ctx = v->api->init(ctx);
+            view_ctx = v->api->init(ctx, ctx->num_views + i);
         else {
             view_ctx = (pcilib_view_context_t*)malloc(sizeof(pcilib_view_context_t));
             if (view_ctx) memset(view_ctx, 0, sizeof(pcilib_view_context_t));
@@ -83,14 +86,12 @@ int pcilib_add_views_custom(pcilib_t *ctx, size_t n, const pcilib_view_descripti
             return PCILIB_ERROR_FAILED;
         }
 
-        memcpy(cur, v, v->api->description_size);
-        view_ctx->view = ctx->num_views + i;
+	view_ctx->view = ctx->num_views + i;
         view_ctx->name = v->name;
 
-        if (refs) refs[i] = view_ctx;
-
         HASH_ADD_KEYPTR(hh, ctx->view_hash, view_ctx->name, strlen(view_ctx->name), view_ctx);
-        ctx->views[ctx->num_views + i] = cur;
+
+        if (refs) refs[i] = view_ctx;
 
         ptr += v->api->description_size;
     }
diff --git a/pcilib/view.h b/pcilib/view.h
index 33d4d96..8b1c07c 100644
--- a/pcilib/view.h
+++ b/pcilib/view.h
@@ -19,7 +19,7 @@ typedef enum {
 typedef struct {
     pcilib_version_t version;                                                                                                           /**< Version */
     size_t description_size;                                                                                                            /**< The actual size of the description */
-    pcilib_view_context_t *(*init)(pcilib_t *ctx);                                                                                      /**< Optional function which should allocated context used by read/write functions */
+    pcilib_view_context_t *(*init)(pcilib_t *ctx, pcilib_view_t view);									/**< Optional function which should allocated context used by read/write functions */
     void (*free)(pcilib_t *ctx, pcilib_view_context_t *view);                                                                           /**< Optional function which should clean context */
     void (*free_description)(pcilib_t *ctx, pcilib_view_description_t *view);                                                           /**< Optional function which shoud clean required parts of the extended description if non-static memory was used to initialize it */
     int (*read_from_reg)(pcilib_t *ctx, pcilib_view_context_t *view, pcilib_register_value_t regval, pcilib_value_t *val);              /**< Function which computes view value based on the passed the register value (view-based properties should not use register value) */
diff --git a/pcilib/xml.c b/pcilib/xml.c
index 50aaa35..fd12636 100644
--- a/pcilib/xml.c
+++ b/pcilib/xml.c
@@ -40,6 +40,7 @@
 #include "xml.h"
 #include "error.h"
 #include "view.h"
+#include "py.h"
 #include "views/enum.h"
 #include "views/transform.h"
 
@@ -48,11 +49,11 @@
 #define REGISTERS_PATH ((xmlChar*)"./register")		 			/**< all standard registers nodes */
 #define BIT_REGISTERS_PATH ((xmlChar*)"./field") 				/**< all bits registers nodes */
 #define REGISTER_VIEWS_PATH ((xmlChar*)"./view") 				/**< supported register & field views */
-#define TRANSFORM_VIEWS_PATH ((xmlChar*)"/model/transform")			/**< path to complete nodes of views */
+#define TRANSFORM_VIEWS_PATH ((xmlChar*)"/model/transform")		/**< path to complete nodes of views */
 #define ENUM_VIEWS_PATH ((xmlChar*)"/model/enum")	 			/**< path to complete nodes of views */
 #define ENUM_ELEMENTS_PATH ((xmlChar*)"./name") 				/**< all elements in the enum */
 #define UNITS_PATH ((xmlChar*)"/model/unit")	 				/**< path to complete nodes of units */
-#define UNIT_TRANSFORMS_PATH ((xmlChar*)"./transform") 				/**< all transforms of the unit */
+#define UNIT_TRANSFORMS_PATH ((xmlChar*)"./transform") 			/**< all transforms of the unit */
 
 
 
@@ -492,6 +493,8 @@ static int pcilib_xml_parse_view(pcilib_t *ctx, xmlXPathContextPtr xpath, xmlDoc
     xmlAttrPtr cur;
     const char *value, *name;
 
+    int inconsistent = (desc->mode & PCILIB_ACCESS_INCONSISTENT);
+
     for (cur = node->properties; cur != NULL; cur = cur->next) {
         if (!cur->children) continue;
         if (!xmlNodeIsText(cur->children)) continue;
@@ -537,8 +540,14 @@ static int pcilib_xml_parse_view(pcilib_t *ctx, xmlXPathContextPtr xpath, xmlDoc
                 pcilib_error("Invalid access mode (%s) is specified in the XML register description", value);
                 return PCILIB_ERROR_INVALID_DATA;
             }
-        }
+        } else if (!strcasecmp(name, "write_verification")) {
+	    if (strcmp(value, "0")) inconsistent = 0;
+	    else inconsistent = 1;
+	}
     }
+	
+    if (inconsistent) desc->mode |= PCILIB_ACCESS_INCONSISTENT;
+    else desc->mode &= ~PCILIB_ACCESS_INCONSISTENT;
 
     return 0;
 }
@@ -585,10 +594,12 @@ static int pcilib_xml_create_transform_view(pcilib_t *ctx, xmlXPathContextPtr xp
             }
             desc.write_to_reg = value;
             if ((value)&&(*value)) mode |= PCILIB_ACCESS_W;
-        } 
+        } else if (!strcasecmp(name, "script")) {
+	    desc.script = value;
+	    break;
+        }
     }
-
-    desc.base.mode &= mode;
+    desc.base.mode &= (~PCILIB_ACCESS_RW)|mode;
 
     err = pcilib_add_views_custom(ctx, 1, (pcilib_view_description_t*)&desc, &view_ctx);
     if (err) return err;
@@ -597,7 +608,6 @@ static int pcilib_xml_create_transform_view(pcilib_t *ctx, xmlXPathContextPtr xp
     return 0;
 }
 
-
 static int pcilib_xml_parse_value_name(pcilib_t *ctx, xmlXPathContextPtr xpath, xmlDocPtr doc, xmlNodePtr node, pcilib_register_value_name_t *desc) {
     xmlAttr *cur;
     char *value, *name;