Include entropy (expressed in bits or bytes) into the Python API.

1 files changed, 119 insertions, 0 deletions

diff --git a/plugins/pychrysalide/common/entropy.c b/plugins/pychrysalide/common/entropy.c
new file mode 100644
index 0000000..2817747
--- /dev/null
+++ b/plugins/pychrysalide/common/entropy.c
@@ -0,0 +1,119 @@
+
+/* Chrysalide - Outil d'analyse de fichiers binaires
+ * entropy.c - équivalent Python du fichier "common/entropy.c"
+ *
+ * Copyright (C) 2024 Cyrille Bagard
+ *
+ *  This file is part of Chrysalide.
+ *
+ *  Chrysalide is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  Chrysalide is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+
+#include "entropy.h"
+
+
+#include <common/entropy.h>
+
+
+#include "../access.h"
+#include "../helpers.h"
+
+
+
+/* Détermine l'entropie d'un contenu binaire. */
+static PyObject *py_entropy_compute_entropy(PyObject *, PyObject *);
+
+
+
+/******************************************************************************
+*                                                                             *
+*  Paramètres  : self = NULL car méthode statique.                            *
+*                args = arguments fournis lors de l'appel à la fonction.      *
+*                                                                             *
+*  Description : Détermine l'entropie d'un contenu binaire.                   *
+*                                                                             *
+*  Retour      : Valeur d'entropie du contenu fourni.                         *
+*                                                                             *
+*  Remarques   : -                                                            *
+*                                                                             *
+******************************************************************************/
+
+static PyObject *py_entropy_compute_entropy(PyObject *self, PyObject *args)
+{
+    PyObject *result;                       /* Instance à retourner        */
+    const bin_t *data;                      /* Données à traiter           */
+    int bits;                               /* Choix de référentiel        */
+    size_t len;                             /* Quantité de ces données     */
+    int ret;                                /* Bilan de lecture des args.  */
+    double entropy;                         /* Valeur d'entropie déterminée*/
+
+#define COMPUTE_ENTROPY_METHOD PYTHON_METHOD_DEF        \
+(                                                       \
+    compute_entropy, "data, /, bits=False",             \
+    METH_VARARGS, py_entropy,                           \
+    "Compute the entropy of provided data.\n"           \
+    "\n"                                                \
+    "The *data* to process can be a string or bytes."   \
+    " The optional *bits* argument defines if the"      \
+    " computed value is expressed in bits (log base 2)" \
+    " or in bytes (log base 256).\n"                    \
+    "\n"                                                \
+    "The result is a float value."                      \
+)
+
+    bits = 0;
+
+    ret = PyArg_ParseTuple(args, "s#|p", &data, &len, &bits);
+    if (!ret) return NULL;
+
+    entropy = compute_entropy((const bin_t *)data, len, bits);
+
+    result = PyFloat_FromDouble(entropy);
+
+    return result;
+
+}
+
+
+/******************************************************************************
+*                                                                             *
+*  Paramètres  : -                                                            *
+*                                                                             *
+*  Description : Définit une extension du module 'common' à compléter.        *
+*                                                                             *
+*  Retour      : Bilan de l'opération.                                        *
+*                                                                             *
+*  Remarques   : -                                                            *
+*                                                                             *
+******************************************************************************/
+
+bool populate_common_module_with_entropy(void)
+{
+    bool result;                            /* Bilan à retourner           */
+    PyObject *module;                       /* Module à recompléter        */
+
+    static PyMethodDef py_entropy_methods[] = {
+        COMPUTE_ENTROPY_METHOD,
+        { NULL }
+    };
+
+    module = get_access_to_python_module("pychrysalide.common");
+
+    result = register_python_module_methods(module, py_entropy_methods);
+
+    return result;
+
+}