1 files changed, 98 insertions, 5 deletions

diff --git a/src/knowledge/knowledge.c b/src/knowledge/knowledge.c
index 5ce6917..e7d1cd9 100644
--- a/src/knowledge/knowledge.c
+++ b/src/knowledge/knowledge.c
@@ -3,7 +3,7 @@
 #include <stdio.h>
 #include <stdint.h> /* defines SIZE_MAX */
 
-#include "../pipe/pipe.h"
+#include "../error/error.h"
 
 #include "knowledge.h"
 
@@ -13,6 +13,7 @@
 int ZoO_knowledge_initialize (struct ZoO_knowledge k [const restrict static 1])
 {
    int error;
+   ZoO_index reserved_word_id;
 
    k->words = (struct ZoO_knowledge_word *) NULL;
    k->words_length = 0;
@@ -36,25 +37,83 @@ int ZoO_knowledge_initialize (struct ZoO_knowledge k [const restrict static 1])
       return -1;
    }
 
+   if
+   (
+      (
+         ZoO_knowledge_learn_word
+         (
+            k,
+            "[SoS]",
+            5,
+            &reserved_word_id,
+            stderr
+         ) < 0
+      )
+      ||
+      (
+         ZoO_knowledge_learn_word
+         (
+            k,
+            "[EoS]",
+            5,
+            &reserved_word_id,
+            stderr
+         ) < 0
+      )
+   )
+   {
+      ZoO_S_FATAL(stderr, "Unable to learn reserved words.");
+
+      return -1;
+   }
+
    return 0;
 }
 
 int ZoO_knowledge_lock_access
 (
    struct ZoO_knowledge k [const restrict static 1],
-   const struct ZoO_pipe io [const restrict static 1]
+   FILE io [const restrict static 1]
 )
 {
-   return pthread_mutex_lock(&(k->mutex));
+   int err;
+
+   err = pthread_mutex_lock(&(k->mutex));
+
+   if (err != 0)
+   {
+      ZoO_ERROR
+      (
+         io,
+         "Unable to get exclusive access to knowledge: %s",
+         strerror(err)
+      );
+
+      return -1;
+   }
+
+   return 0;
 }
 
 void ZoO_knowledge_unlock_access
 (
    struct ZoO_knowledge k [const restrict static 1],
-   const struct ZoO_pipe io [const restrict static 1]
+   FILE io [const restrict static 1]
 )
 {
-   pthread_mutex_unlock(&(k->mutex));
+   int err;
+
+   err = pthread_mutex_unlock(&(k->mutex));
+
+   if (err != 0)
+   {
+      ZoO_ERROR
+      (
+         io,
+         "Unable to release exclusive access to knowledge: %s",
+         strerror(err)
+      );
+   }
 }
 
 void ZoO_knowledge_get_word
@@ -68,3 +127,37 @@ void ZoO_knowledge_get_word
    *word = k->words[word_ref].word;
    *word_length = k->words[word_ref].word_length;
 }
+
+int ZoO_knowledge_rarest_word
+(
+   const struct ZoO_knowledge k [const static 1],
+   const ZoO_index sequence [const restrict static 1],
+   const size_t sequence_length,
+   ZoO_index word_id [const restrict static 1]
+)
+{
+   ZoO_index current_max_score;
+   size_t i;
+   int success;
+
+   current_max_score = ZoO_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;
+}