1 files changed, 180 insertions, 0 deletions
diff --git a/src/knowledge/knowledge.c b/src/knowledge/knowledge.c
new file mode 100644
index 0000000..93351da
--- /dev/null
+++ b/src/knowledge/knowledge.c
@@ -0,0 +1,180 @@
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <stdint.h> /* defines SIZE_MAX */
+
+#include "../error/error.h"
+
+#include "knowledge.h"
+
+/** Basic functions of the JH_knowledge structure ****************************/
+
+/* See: "knowledge.h" */
+int JH_knowledge_initialize (struct JH_knowledge k [const restrict static 1])
+{
+   int error;
+   JH_index reserved_word_id;
+
+   k->words = (struct JH_knowledge_word *) NULL;
+   k->words_length = 0;
+   k->words_sorted = (JH_index *) NULL;
+
+   k->sequences = (JH_index **) NULL;
+   k->sequences_length = 0;
+   k->sequences_sorted = (JH_index *) NULL;
+
+#ifndef JH_RUNNING_FRAMA_C
+   error = pthread_mutex_init(&(k->mutex), (const pthread_mutexattr_t *) NULL);
+#else
+   k->mutex = 1;
+   error = 0;
+#endif
+
+   if (error != 0)
+   {
+      JH_FATAL
+      (
+         stderr,
+         "Unable to initialize knowledge mutex: %s.",
+         strerror(error)
+      );
+
+      return -1;
+   }
+
+   if
+   (
+      (
+         JH_knowledge_learn_word
+         (
+            k,
+            "[SoS]",
+            5,
+            &reserved_word_id,
+            stderr
+         ) < 0
+      )
+      ||
+      (
+         JH_knowledge_learn_word
+         (
+            k,
+            "[EoS]",
+            5,
+            &reserved_word_id,
+            stderr
+         ) < 0
+      )
+   )
+   {
+      JH_S_FATAL(stderr, "Unable to learn reserved words.");
+
+      return -1;
+   }
+
+   return 0;
+}
+
+int JH_knowledge_lock_access
+(
+   struct JH_knowledge k [const restrict static 1],
+   FILE io [const restrict static 1]
+)
+{
+   int err;
+
+#ifndef JH_RUNNING_FRAMA_C
+   err = pthread_mutex_lock(&(k->mutex));
+#else
+   /*@ assert (k->mutex == 1); @*/
+   k->mutex = 0;
+   err = 0;
+#endif
+
+   if (err != 0)
+   {
+      JH_ERROR
+      (
+         io,
+         "Unable to get exclusive access to knowledge: %s",
+         strerror(err)
+      );
+
+      return -1;
+   }
+
+   return 0;
+}
+
+void JH_knowledge_unlock_access
+(
+   struct JH_knowledge k [const restrict static 1],
+   FILE io [const restrict static 1]
+)
+{
+   int err;
+
+#ifndef JH_RUNNING_FRAMA_C
+   err = pthread_mutex_unlock(&(k->mutex));
+#else
+   /*@ assert (k->mutex == 0); @*/
+   k->mutex = 1;
+   err = 0;
+#endif
+
+   if (err != 0)
+   {
+      JH_ERROR
+      (
+         io,
+         "Unable to release exclusive access to knowledge: %s",
+         strerror(err)
+      );
+   }
+}
+
+void JH_knowledge_get_word
+(
+   const struct JH_knowledge k [const static 1],
+   const JH_index word_ref,
+   const JH_char * word [const restrict static 1],
+   JH_index word_length [const restrict static 1]
+)
+{
+   *word = k->words[word_ref].word;
+   *word_length = k->words[word_ref].word_length;
+}
+
+int JH_knowledge_rarest_word
+(
+   const struct JH_knowledge k [const static 1],
+   const JH_index sequence [const restrict static 1],
+   const size_t sequence_length,
+   JH_index word_id [const restrict static 1]
+)
+{
+   JH_index current_max_score;
+   size_t i;
+   int success;
+
+   current_max_score = JH_INDEX_MAX;
+
+   success = -1;
+
+   for (i = 0; i < sequence_length; ++i)
+   {
+      if
+      (
+         (k->words[sequence[i]].occurrences <= current_max_score)
+         /* Otherwise we might just have learned it, or it must not be used. */
+         && (k->words[sequence[i]].occurrences > 1)
+      )
+      {
+         current_max_score = k->words[sequence[i]].occurrences;
+         *word_id = sequence[i];
+         success = 0;
+      }
+   }
+
+   return success;
+}