It's starting to "properly" reply...

The ACSL coverage is far behind though.

10 files changed, 304 insertions, 94 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;
+}
diff --git a/src/knowledge/knowledge.h b/src/knowledge/knowledge.h
index e97d84e..876dbe4 100644
--- a/src/knowledge/knowledge.h
+++ b/src/knowledge/knowledge.h
@@ -4,20 +4,20 @@
 #include "../core/char_types.h"
 #include "../core/index_types.h"
 
-#include "../pipe/pipe_types.h"
+#include "../error/error.h"
 
 #include "knowledge_types.h"
 
 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]
 );
 
 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]
 );
 
 int ZoO_knowledge_initialize (struct ZoO_knowledge k [const restrict static 1]);
@@ -40,7 +40,7 @@ int ZoO_knowledge_learn_word
    const ZoO_char word [const restrict static 1],
    const size_t word_length,
    ZoO_index result [const restrict static 1],
-   const struct ZoO_pipe io [const restrict static 1]
+   FILE io [const restrict static 1]
 );
 
 int ZoO_knowledge_learn_sequence
@@ -49,7 +49,7 @@ int ZoO_knowledge_learn_sequence
    const ZoO_index sequence [const restrict static 1],
    const size_t sequence_length,
    const ZoO_index markov_order,
-   const struct ZoO_pipe io [const restrict static 1]
+   FILE io [const restrict static 1]
 );
 
 int ZoO_knowledge_learn_markov_sequence
@@ -58,7 +58,7 @@ int ZoO_knowledge_learn_markov_sequence
    const ZoO_index sequence [const restrict static 1],
    const ZoO_index markov_order, /* Pre (> markov_order 1) */
    ZoO_index sequence_id [const restrict static 1],
-   const struct ZoO_pipe io [const restrict static 1]
+   FILE io [const restrict static 1]
 );
 
 void ZoO_knowledge_get_word
@@ -95,6 +95,14 @@ int ZoO_knowledge_find_sequence
    ZoO_index sequence_id [const restrict static 1]
 );
 
+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]
+);
+
 int ZoO_knowledge_find_markov_sequence
 (
    const ZoO_index sequence_id,
@@ -131,7 +139,7 @@ int ZoO_knowledge_copy_random_swt_sequence
    ZoO_index sequence [const restrict static 1],
    const ZoO_index word_id,
    const ZoO_index markov_order,
-   const struct ZoO_pipe io [const restrict static 1]
+   FILE io [const restrict static 1]
 );
 
 int ZoO_knowledge_strengthen_swt
@@ -140,7 +148,7 @@ int ZoO_knowledge_strengthen_swt
    const ZoO_index sequence_id,
    const ZoO_index word_id,
    const ZoO_index target_id,
-   const struct ZoO_pipe io [const restrict static 1]
+   FILE io [const restrict static 1]
 );
 
 int ZoO_knowledge_strengthen_tws
@@ -149,7 +157,7 @@ int ZoO_knowledge_strengthen_tws
    const ZoO_index target_id,
    const ZoO_index word_id,
    const ZoO_index sequence_id,
-   const struct ZoO_pipe io [const restrict static 1]
+   FILE io [const restrict static 1]
 );
 
 /*
@@ -162,7 +170,7 @@ int ZoO_knowledge_weaken_swt
    const ZoO_index sequence_id,
    const ZoO_index word_id,
    const ZoO_index target_id,
-   const struct ZoO_pipe io [const restrict static 1]
+   FILE io [const restrict static 1]
 );
 
 int ZoO_knowledge_weaken_tws
@@ -171,7 +179,7 @@ int ZoO_knowledge_weaken_tws
    const ZoO_index target_id,
    const ZoO_index word_id,
    const ZoO_index sequence_id,
-   const struct ZoO_pipe io [const restrict static 1]
+   FILE io [const restrict static 1]
 );
 */
 #endif
diff --git a/src/knowledge/knowledge_finalize.c b/src/knowledge/knowledge_finalize.c
index 6c249f0..37548d4 100644
--- a/src/knowledge/knowledge_finalize.c
+++ b/src/knowledge/knowledge_finalize.c
@@ -2,7 +2,6 @@
 
 #include "knowledge.h"
 
-
 static void knowledge_sequence_data_finalize
 (
    struct ZoO_knowledge_sequence_data sd [const restrict static 1]
diff --git a/src/knowledge/knowledge_get_random_sequence.c b/src/knowledge/knowledge_get_random_sequence.c
index 9055d31..92800a4 100644
--- a/src/knowledge/knowledge_get_random_sequence.c
+++ b/src/knowledge/knowledge_get_random_sequence.c
@@ -2,9 +2,10 @@
 
 #include "../core/char.h"
 #include "../core/index.h"
+
 #include "../sequence/sequence.h"
 
-#include "../pipe/pipe.h"
+#include "../error/error.h"
 
 #include "knowledge.h"
 
@@ -52,7 +53,7 @@ int ZoO_knowledge_copy_random_swt_sequence
    ZoO_index sequence [const restrict static 1],
    const ZoO_index word_id,
    const ZoO_index markov_order,
-   const struct ZoO_pipe io [const restrict static 1]
+   FILE io [const restrict static 1]
 )
 {
    ZoO_index sequence_id;
diff --git a/src/knowledge/knowledge_get_random_target.c b/src/knowledge/knowledge_get_random_target.c
index d9bf8a9..99fbc9b 100644
--- a/src/knowledge/knowledge_get_random_target.c
+++ b/src/knowledge/knowledge_get_random_target.c
@@ -2,9 +2,10 @@
 
 #include "../core/char.h"
 #include "../core/index.h"
-#include "../sequence/sequence.h"
 
-#include "../pipe/pipe.h"
+#include "../error/error.h"
+
+#include "../sequence/sequence.h"
 
 #include "knowledge.h"
 
diff --git a/src/knowledge/knowledge_learn_markov_sequence.c b/src/knowledge/knowledge_learn_markov_sequence.c
index 35cc123..54357c0 100644
--- a/src/knowledge/knowledge_learn_markov_sequence.c
+++ b/src/knowledge/knowledge_learn_markov_sequence.c
@@ -4,7 +4,7 @@
 
 #include "../sequence/sequence.h"
 
-#include "../pipe/pipe.h"
+#include "../error/error.h"
 
 #include "knowledge.h"
 
@@ -40,12 +40,12 @@ static void set_nth_sequence
 static int reallocate_sequences_list
 (
    struct ZoO_knowledge k [const restrict static 1],
-   const struct ZoO_pipe io [const restrict static 1]
+   FILE io [const restrict static 1]
 )
 {
    ZoO_index ** new_sequences;
 
-   if ((SIZE_MAX / sizeof(ZoO_index *)) > (size_t) k->sequences_length)
+   if ((SIZE_MAX / sizeof(ZoO_index *)) < (size_t) k->sequences_length)
    {
       ZoO_S_ERROR
       (
@@ -83,12 +83,12 @@ static int reallocate_sequences_list
 static int reallocate_sequences_sorted_list
 (
    struct ZoO_knowledge k [const restrict static 1],
-   const struct ZoO_pipe io [const restrict static 1]
+   FILE io [const restrict static 1]
 )
 {
    ZoO_index * new_sequences_sorted;
 
-   if ((SIZE_MAX / sizeof(ZoO_index)) > (size_t) k->sequences_length)
+   if ((SIZE_MAX / sizeof(ZoO_index)) < (size_t) k->sequences_length)
    {
       ZoO_S_ERROR
       (
@@ -104,7 +104,7 @@ static int reallocate_sequences_sorted_list
       (ZoO_index *) realloc
       (
          (void *) k->sequences_sorted,
-         ((size_t) k->sequences_length) * sizeof(ZoO_index)
+         (((size_t) k->sequences_length) * sizeof(ZoO_index))
       );
 
    if (new_sequences_sorted == (ZoO_index *) NULL)
@@ -144,7 +144,7 @@ static ZoO_index * copy_sequence
 (
    const ZoO_index base [const restrict static 1],
    const ZoO_index destination_length,
-   const struct ZoO_pipe io [const restrict static 1]
+   FILE io [const restrict static 1]
 )
 {
    ZoO_index i, diff;
@@ -189,7 +189,7 @@ static int add_sequence
    const ZoO_index markov_order, /* Pre (> markov_order 1) */
    const ZoO_index sequence_id,
    const ZoO_index sorted_sequence_id,
-   const struct ZoO_pipe io [const restrict static 1]
+   FILE io [const restrict static 1]
 )
 {
    ZoO_index * stored_sequence;
@@ -213,6 +213,30 @@ static int add_sequence
       return -1;
    }
 
+   if (ZoO_DEBUG_KNOWLEDGE_LEARN_SEQUENCE)
+   {
+      ZoO_index i;
+
+      ZoO_S_DEBUG
+      (
+         io,
+         ZoO_DEBUG_KNOWLEDGE_LEARN_SEQUENCE,
+         "Learning new sequence."
+      );
+
+      for (i = 0; i < (markov_order - 1); ++i)
+      {
+         ZoO_DEBUG
+         (
+            io,
+            ZoO_DEBUG_KNOWLEDGE_LEARN_SEQUENCE,
+            "markov_sequence[%u]: %u",
+            i,
+            stored_sequence[i]
+         );
+      }
+   }
+
    k->sequences_length += 1;
 
    if (reallocate_sequences_list(k, io) < 0)
@@ -271,16 +295,15 @@ int ZoO_knowledge_find_sequence
    current_min = 0;
    current_max -= 1;
 
-   for (;;)
+   while (current_min <= current_max)
    {
       i = (current_min + ((current_max - current_min) / 2));
 
       cmp =
          ZoO_sequence_cmp
          (
-            k->sequences[k->sequences_sorted[i]],
-            markov_sequence_length,
             sequence,
+            k->sequences[k->sequences_sorted[i]],
             markov_sequence_length
          );
 
@@ -297,9 +320,9 @@ int ZoO_knowledge_find_sequence
       }
       else if (cmp < 0)
       {
-         if ((current_min > current_max) || (i == 0))
+         if ((current_min >= current_max) || (i == 0))
          {
-            *sequence_id = i;
+            *sequence_id = current_min;
 
             return -1;
          }
@@ -313,6 +336,10 @@ int ZoO_knowledge_find_sequence
          return 0;
       }
    }
+
+   *sequence_id = current_min;
+
+   return -1;
 }
 
 /******************************************************************************/
@@ -325,11 +352,35 @@ int ZoO_knowledge_learn_markov_sequence
    const ZoO_index sequence [const restrict static 1],
    const ZoO_index markov_order, /* Pre (> markov_order 1) */
    ZoO_index sequence_id [const restrict static 1],
-   const struct ZoO_pipe io [const restrict static 1]
+   FILE io [const restrict static 1]
 )
 {
    ZoO_index sorted_id;
 
+   if (ZoO_DEBUG_KNOWLEDGE_LEARN_SEQUENCE)
+   {
+      ZoO_index i;
+
+      ZoO_S_DEBUG
+      (
+         io,
+         ZoO_DEBUG_KNOWLEDGE_LEARN_SEQUENCE,
+         "Studying markov sequence..."
+      );
+
+      for (i = 0; i < (markov_order - 1); ++i)
+      {
+         ZoO_DEBUG
+         (
+            io,
+            ZoO_DEBUG_KNOWLEDGE_LEARN_SEQUENCE,
+            "markov_sequence[%u]: %u",
+            i,
+            sequence[i]
+         );
+      }
+   }
+
    if
    (
       ZoO_knowledge_find_sequence
@@ -341,6 +392,14 @@ int ZoO_knowledge_learn_markov_sequence
       ) == 0
    )
    {
+      ZoO_DEBUG
+      (
+         io,
+         ZoO_DEBUG_KNOWLEDGE_LEARN_SEQUENCE,
+         "Markov sequence is known. ID: %u",
+         *sequence_id
+      );
+
       return 0;
    }
 
diff --git a/src/knowledge/knowledge_learn_sequence.c b/src/knowledge/knowledge_learn_sequence.c
index 6a666bd..b127bfb 100644
--- a/src/knowledge/knowledge_learn_sequence.c
+++ b/src/knowledge/knowledge_learn_sequence.c
@@ -4,7 +4,7 @@
 
 #include "../sequence/sequence.h"
 
-#include "../pipe/pipe.h"
+#include "../error/error.h"
 
 #include "knowledge.h"
 
@@ -26,8 +26,6 @@ static void parse_swt_sequence
 
    for (j = 0; j < buffer_length; ++j)
    {
-      index_offset = (buffer_length - j);
-
       if (index >= index_offset)
       {
          buffer[j] = sequence[index - index_offset];
@@ -36,6 +34,8 @@ static void parse_swt_sequence
       {
          buffer[j] = ZoO_START_OF_SEQUENCE_ID;
       }
+
+      --index_offset;
    }
 }
 
@@ -48,7 +48,7 @@ static int add_swt_sequence
    const ZoO_index markov_order,
    ZoO_index buffer [const restrict static 1],
    const ZoO_index buffer_length,
-   const struct ZoO_pipe io [const restrict static 1]
+   FILE io [const restrict static 1]
 )
 {
    ZoO_index sequence_id;
@@ -64,7 +64,7 @@ static int add_swt_sequence
          (buffer_length + 1),
          &sequence_id,
          io
-      )
+      ) < 0
    )
    {
       return -1;
@@ -110,15 +110,14 @@ static void parse_tws_sequence
 {
    size_t j;
    size_t index_offset;
-   const size_t remaining_items = (sequence_length - index);
 
    for (j = 0; j < buffer_length; ++j)
    {
-      index_offset = (j + 1);
+      index_offset = (j + 1) + index;
 
-      if (remaining_items > index_offset)
+      if (sequence_length > index_offset)
       {
-         buffer[j] = sequence[index + index_offset];
+         buffer[j] = sequence[index_offset];
       }
       else
       {
@@ -136,7 +135,7 @@ static int add_tws_sequence
    const ZoO_index markov_order,
    ZoO_index buffer [const restrict static 1],
    const ZoO_index buffer_length,
-   const struct ZoO_pipe io [const restrict static 1]
+   FILE io [const restrict static 1]
 )
 {
    ZoO_index sequence_id;
@@ -152,7 +151,7 @@ static int add_tws_sequence
          (buffer_length + 1),
          &sequence_id,
          io
-      )
+      ) < 0
    )
    {
       return -1;
@@ -193,7 +192,7 @@ int ZoO_knowledge_learn_sequence
    const ZoO_index sequence [const restrict static 1],
    const size_t sequence_length,
    const ZoO_index markov_order,
-   const struct ZoO_pipe io [const restrict static 1]
+   FILE io [const restrict static 1]
 )
 {
    ZoO_index * buffer;
@@ -220,30 +219,43 @@ int ZoO_knowledge_learn_sequence
 
    for (i = 0; i < sequence_length; ++i)
    {
-      /* TODO: handle failure. */
-      add_tws_sequence
+      if
       (
-         k,
-         sequence,
-         i,
-         sequence_length,
-         markov_order,
-         buffer,
-         buffer_length,
-         io
-      );
+         add_swt_sequence
+         (
+            k,
+            sequence,
+            i,
+            sequence_length,
+            markov_order,
+            buffer,
+            buffer_length,
+            io
+         ) < 0
+      )
+      {
+         return -1;
+      }
 
-      add_swt_sequence
+      /* TODO: handle failure. */
+      if
       (
-         k,
-         sequence,
-         i,
-         sequence_length,
-         markov_order,
-         buffer,
-         buffer_length,
-         io
-      );
+         add_tws_sequence
+         (
+            k,
+            sequence,
+            i,
+            sequence_length,
+            markov_order,
+            buffer,
+            buffer_length,
+            io
+         ) < 0
+      )
+      {
+         return -1;
+      }
+
 
       k->words[sequence[i]].occurrences += 1;
    }
diff --git a/src/knowledge/knowledge_learn_word.c b/src/knowledge/knowledge_learn_word.c
index 8430bc0..605af8e 100644
--- a/src/knowledge/knowledge_learn_word.c
+++ b/src/knowledge/knowledge_learn_word.c
@@ -2,7 +2,7 @@
 #include <string.h>
 #include <stdint.h> /* defines SIZE_MAX */
 
-#include "../pipe/pipe.h"
+#include "../error/error.h"
 
 #include "knowledge.h"
 
@@ -40,7 +40,7 @@ static ZoO_char * copy_word
 (
    const ZoO_char original [const restrict static 1],
    const ZoO_index original_length,
-   const struct ZoO_pipe io [const restrict static 1]
+   FILE io [const restrict static 1]
 )
 {
    ZoO_char * result;
@@ -67,13 +67,13 @@ static ZoO_char * copy_word
       (((size_t) original_length) * sizeof(ZoO_char))
    );
 
-   return 0;
+   return result;
 }
 
 static int reallocate_words_list
 (
    struct ZoO_knowledge k [const restrict static 1],
-   const struct ZoO_pipe io [const restrict static 1]
+   FILE io [const restrict static 1]
 )
 {
    struct ZoO_knowledge_word * new_words;
@@ -81,7 +81,7 @@ static int reallocate_words_list
    if
    (
       (SIZE_MAX / sizeof(struct ZoO_knowledge_word))
-      > (size_t) k->words_length
+      < (size_t) k->words_length
    )
    {
       ZoO_S_ERROR
@@ -120,7 +120,7 @@ static int reallocate_words_list
 static int reallocate_words_sorted_list
 (
    struct ZoO_knowledge k [const restrict static 1],
-   const struct ZoO_pipe io [const restrict static 1]
+   FILE io [const restrict static 1]
 )
 {
    ZoO_index * new_words_sorted;
@@ -130,7 +130,7 @@ static int reallocate_words_sorted_list
     * whose size is bigger than a ZoO_index.
     * */
    /*
-   if ((SIZE_MAX / sizeof(ZoO_index)) > k->words_length)
+   if ((SIZE_MAX / sizeof(ZoO_index)) < k->words_length)
    {
       ZoO_S_ERROR
       (
@@ -197,7 +197,7 @@ static int add_word
    const ZoO_index word_length,
    const ZoO_index word_id,
    const ZoO_index sorted_word_id,
-   const struct ZoO_pipe io [const restrict static 1]
+   FILE io [const restrict static 1]
 )
 {
    ZoO_char * stored_word;
@@ -244,7 +244,7 @@ static int add_word
 
    set_nth_word(k, sorted_word_id, word_id);
 
-   return -1;
+   return 0;
 }
 
 /******************************************************************************/
@@ -257,7 +257,7 @@ int ZoO_knowledge_learn_word
    const ZoO_char word [const restrict static 1],
    const size_t word_length,
    ZoO_index word_id [const restrict static 1],
-   const struct ZoO_pipe io [const restrict static 1]
+   FILE io [const restrict static 1]
 )
 {
    ZoO_index sorted_id;
@@ -280,11 +280,30 @@ int ZoO_knowledge_learn_word
       ) == 0
    )
    {
+      ZoO_DEBUG
+      (
+         io,
+         ZoO_DEBUG_KNOWLEDGE_LEARN_WORD,
+         "Word of size %u is already known (id: %u).",
+         (ZoO_index) word_length,
+         *word_id
+      );
+
       return 0;
    }
 
    sorted_id = *word_id;
    *word_id = k->words_length;
 
+   ZoO_DEBUG
+   (
+      io,
+      ZoO_DEBUG_KNOWLEDGE_LEARN_WORD,
+      "Learning new word of size %u (id: %u, sorted_id: %u).",
+      (ZoO_index) word_length,
+      *word_id,
+      sorted_id
+   );
+
    return add_word(k, word, (ZoO_index) word_length, *word_id, sorted_id, io);
 }
diff --git a/src/knowledge/knowledge_search.c b/src/knowledge/knowledge_search.c
index cc1934e..1163f61 100644
--- a/src/knowledge/knowledge_search.c
+++ b/src/knowledge/knowledge_search.c
@@ -4,7 +4,7 @@
 #include "../core/index.h"
 #include "../sequence/sequence.h"
 
-#include "../pipe/pipe.h"
+#include "../error/error.h"
 
 #include "knowledge.h"
 
@@ -36,11 +36,18 @@ int ZoO_knowledge_find_word_id
    current_min = 0;
    current_max -= 1;
 
-   for (;;)
+   while (current_min <= current_max)
    {
       i = (current_min + ((current_max - current_min) / 2));
 
-      cmp = ZoO_word_cmp(word, word_length, k->words[k->words_sorted[i]].word);
+      cmp =
+         ZoO_word_cmp
+         (
+            word,
+            word_length,
+            k->words[k->words_sorted[i]].word,
+            k->words[k->words_sorted[i]].word_length
+         );
 
       if (cmp > 0)
       {
@@ -55,7 +62,7 @@ int ZoO_knowledge_find_word_id
       }
       else if (cmp < 0)
       {
-         if ((current_min > current_max) || (i == 0))
+         if ((current_min >= current_max) || (i == 0))
          {
             *result = current_min;
 
@@ -71,6 +78,10 @@ int ZoO_knowledge_find_word_id
          return 0;
       }
    }
+
+   *result = current_min;
+
+   return -1;
 }
 
 int ZoO_knowledge_find_markov_sequence
@@ -94,7 +105,7 @@ int ZoO_knowledge_find_markov_sequence
    current_min = 0;
    current_max = (sc->sequences_ref_length - 1);
 
-   for (;;)
+   while (current_min <= current_max)
    {
       i = (current_min + ((current_max - current_min) / 2));
 
@@ -118,7 +129,7 @@ int ZoO_knowledge_find_markov_sequence
       }
       else if (cmp < 0)
       {
-         if ((current_min > current_max) || (i == 0))
+         if ((current_min >= current_max) || (i == 0))
          {
             *result = current_min;
 
@@ -134,6 +145,10 @@ int ZoO_knowledge_find_markov_sequence
          return 0;
       }
    }
+
+   *result = current_min;
+
+   return -1;
 }
 
 int ZoO_knowledge_find_sequence_target
@@ -157,7 +172,7 @@ int ZoO_knowledge_find_sequence_target
    current_min = 0;
    current_max = (sd->targets_length - 1);
 
-   for (;;)
+   while (current_min <= current_max)
    {
       i = (current_min + ((current_max - current_min) / 2));
 
@@ -176,7 +191,7 @@ int ZoO_knowledge_find_sequence_target
       }
       else if (cmp < 0)
       {
-         if ((current_min > current_max) || (i == 0))
+         if ((current_min >= current_max) || (i == 0))
          {
             *result = current_min;
 
@@ -192,4 +207,8 @@ int ZoO_knowledge_find_sequence_target
          return 0;
       }
    }
+
+   *result = current_min;
+
+   return -1;
 }
diff --git a/src/knowledge/knowledge_swt_tws_modifications.c b/src/knowledge/knowledge_swt_tws_modifications.c
index 40e2e3b..1a8048d 100644
--- a/src/knowledge/knowledge_swt_tws_modifications.c
+++ b/src/knowledge/knowledge_swt_tws_modifications.c
@@ -2,7 +2,7 @@
 
 #include "../core/index.h"
 
-#include "../pipe/pipe.h"
+#include "../error/error.h"
 
 #include "knowledge.h"
 
@@ -12,7 +12,7 @@ static int add_target
    const ZoO_index target_id,
    const ZoO_index s_index,
    const ZoO_index t_index,
-   const struct ZoO_pipe io [const restrict static 1]
+   FILE io [const restrict static 1]
 )
 {
    struct ZoO_knowledge_target * new_p;
@@ -68,7 +68,7 @@ static int add_sequence
    struct ZoO_knowledge_sequence_collection sc [const restrict static 1],
    const ZoO_index sequence_id,
    ZoO_index s_index [const restrict static 1],
-   const struct ZoO_pipe io [const restrict static 1]
+   FILE io [const restrict static 1]
 )
 {
    struct ZoO_knowledge_sequence_data * new_p;
@@ -149,7 +149,7 @@ static int add_sequence
    sc->sequences_ref[*s_index].targets = (struct ZoO_knowledge_target *) NULL;
    sc->sequences_ref[*s_index].targets_length = 0;
 
-   return -1;
+   return 0;
 }
 
 int ZoO_knowledge_strengthen_swt
@@ -158,7 +158,7 @@ int ZoO_knowledge_strengthen_swt
    const ZoO_index sequence_id,
    const ZoO_index word_id,
    const ZoO_index target_id,
-   const struct ZoO_pipe io [const restrict static 1]
+   FILE io [const restrict static 1]
 )
 {
    ZoO_index s_index, t_index;
@@ -248,7 +248,7 @@ int ZoO_knowledge_strengthen_tws
    const ZoO_index target_id,
    const ZoO_index word_id,
    const ZoO_index sequence_id,
-   const struct ZoO_pipe io [const restrict static 1]
+   FILE io [const restrict static 1]
 )
 {
    ZoO_index s_index, t_index;
@@ -278,7 +278,6 @@ int ZoO_knowledge_strengthen_tws
       }
    }
 
-
    if
    (
       ZoO_knowledge_find_sequence_target
@@ -330,5 +329,5 @@ int ZoO_knowledge_strengthen_tws
    k->words[word_id].tws.sequences_ref[s_index].occurrences += 1;
    k->words[word_id].tws.sequences_ref[s_index].targets[t_index].occurrences += 1;
 
-   return -1;
+   return 0;
 }