pyfec: add precondition checks on the values of k and m to constructors

diff --git a/pyfec/fec/fecmodule.c b/pyfec/fec/fecmodule.c
index 8e0d776d1b24a1ecc5f63b8b4fd1fc33df709ec4..87aa1926f58984ebaa44663fe8d66e8b1fed1597 100644 (file)
--- a/pyfec/fec/fecmodule.c
+++ b/pyfec/fec/fecmodule.c
@@ -96,11 +96,23 @@ Encoder_init(Encoder *self, PyObject *args, PyObject *kwdict) {
     if (!PyArg_ParseTupleAndKeywords(args, kwdict, "ii", kwlist, &self->kk, &self->mm))
         return -1;
 
-    self->fec_matrix = fec_new(self->kk, self->mm);
-    if(self->fec_matrix == NULL) {
-        py_raise_fec_error(fec_error); /* xyz */
-        return -1;
+    if (self->kk < 1) {
+        py_raise_fec_error("Precondition violation: first argument is required to be greater than or equal to 1, but it was %d", self->kk);
+       return -1;
+    }
+    if (self->mm < 1) {
+        py_raise_fec_error("Precondition violation: second argument is required to be greater than or equal to 1, but it was %d", self->mm);
+       return -1;
+    }
+    if (self->mm > 255) {
+        py_raise_fec_error("Precondition violation: second argument is required to be less than or equal to 255, but it was %d", self->mm);
+       return -1;
     }
+    if (self->kk > self->mm) {
+        py_raise_fec_error("Precondition violation: first argument is required to be less than or equal to the second argument, but they were %d and %d respectively", self->kk, self->mm);
+       return -1;
+    }
+    self->fec_matrix = fec_new(self->kk, self->mm);
 
     return 0;
 }
@@ -333,14 +345,27 @@ Decoder_init(Encoder *self, PyObject *args, PyObject *kwdict) {
         "m",
         NULL
     };
+
     if (!PyArg_ParseTupleAndKeywords(args, kwdict, "ii", kwlist, &self->kk, &self->mm))
         return -1;
 
-    self->fec_matrix = fec_new(self->kk, self->mm);
-    if(self->fec_matrix == NULL) {
-        py_raise_fec_error(fec_error); /* xyz */
-        return -1;
+    if (self->kk < 1) {
+        py_raise_fec_error("Precondition violation: first argument is required to be greater than or equal to 1, but it was %d", self->kk);
+       return -1;
+    }
+    if (self->mm < 1) {
+        py_raise_fec_error("Precondition violation: second argument is required to be greater than or equal to 1, but it was %d", self->mm);
+       return -1;
     }
+    if (self->mm > 255) {
+        py_raise_fec_error("Precondition violation: second argument is required to be less than or equal to 255, but it was %d", self->mm);
+       return -1;
+    }
+    if (self->kk > self->mm) {
+        py_raise_fec_error("Precondition violation: first argument is required to be less than or equal to the second argument, but they were %d and %d respectively", self->kk, self->mm);
+       return -1;
+    }
+    self->fec_matrix = fec_new(self->kk, self->mm);
 
     return 0;
 }