Don't bother looking at signatures that we know can't match

[scherzo] / scherzo.c

diff --git a/scherzo.c b/scherzo.c
index 676f5b459001412ad4ce7c4605dbc07e007cba8c..a1a279786b21339eec1d4dc3e597325f32e19e13 100644 (file)
--- a/scherzo.c
+++ b/scherzo.c
@@ -407,38 +407,34 @@ typedef struct analyzed_note {
 } analyzed_note_t;
 
 static int
-_compare_analyzed_note (const void *va, const void *vb)
+_compare_analyzed_note_by_midi_pitch (const void *va, const void *vb)
 {
     const analyzed_note_t *a = va, *b = vb;
 
     return a->midi_pitch - b->midi_pitch;
 }
 
+static int
+_compare_analyzed_note_by_relative_pitch (const void *va, const void *vb)
+{
+    const analyzed_note_t *a = va, *b = vb;
+
+    return a->relative_pitch - b->relative_pitch;
+}
+
 static int
 _chord_signature_matches (analyzed_note_t *notes,
                          int num_notes,
                          int *signature_pitches,
                          int num_signature_pitches)
 {
-    int n, s;
+    int i;
 
-    for (n = 0, s = 0; s < num_signature_pitches; s++) {
-       if (n >= num_notes)
-           return 0;
-       if (notes[n].relative_pitch != signature_pitches[s])
+    if (num_notes != num_signature_pitches)
            return 0;
-       n++;
-       /* Skip repeated notes in chord being tested. */
-       while (n < num_notes &&
-              notes[n].relative_pitch == signature_pitches[s])
-       {
-           n++;
-       }
-    }
 
-    /* If there are fewer notes in the signature than in the chord,
-     * then there is no match. */
-    if (n < num_notes)
+    for (i = 0; i < num_notes; i++)
+       if (notes[i].relative_pitch != signature_pitches[i])
            return 0;
 
     return 1;
@@ -450,7 +446,7 @@ scherzo_analyze_chord (scherzo_t *scherzo)
     void *local = talloc_new (NULL);
     analyzed_note_t *notes;
     note_group_t *note_group;
-    unsigned i, num_notes;
+    unsigned i, j, num_notes;
     int bass_pitch;
     const char *chord_name = NULL;
 
@@ -461,6 +457,10 @@ scherzo_analyze_chord (scherzo_t *scherzo)
 
     num_notes = note_group->num_notes;
 
+    struct { int pitches[1]; const char *name; } octaves[] = {
+       { {0}, "Octave"}
+    };
+
     struct { int pitches[2]; const char *name; } intervals[] = {
        { {0, 1}, "Minor 2nd"},
        { {0, 2}, "Major 2nd"},
@@ -484,14 +484,14 @@ scherzo_analyze_chord (scherzo_t *scherzo)
 
     struct { int pitches[4]; const char *name; } sevenths[] = {
        { {0, 4, 8, 11}, "Augmented/major 7" },
+       { {0, 4, 8, 10}, "Augmented 7" },
        { {0, 4, 7, 11}, "Major 7" },
        { {0, 4, 7, 10}, "Dominant 7" },
        { {0, 3, 7, 11}, "Minor/major 7" },
        { {0, 3, 7, 10}, "Minor 7" },
-       { {0, 3, 6, 10}, "Half-diminished 7" },
-       { {0, 3, 6, 9},  "Diminished 7" },
-       { {0, 4, 8, 10}, "Augmented 7" },
        { {0, 3, 6, 11}, "Diminished/major 7" },
+       { {0, 3, 6, 10}, "Half-diminished 7" },
+       { {0, 3, 6, 9},  "Diminished 7" }
     };
 
     if (scherzo->chord) {
@@ -515,27 +515,72 @@ scherzo_analyze_chord (scherzo_t *scherzo)
        notes[i].relative_pitch = 0;
     }
 
-    qsort (notes, num_notes, sizeof (analyzed_note_t), _compare_analyzed_note);
+    /* First, sort by midi pitch to find the bass note. */
+    qsort (notes, num_notes, sizeof (analyzed_note_t),
+          _compare_analyzed_note_by_midi_pitch);
     
     bass_pitch = notes[0].midi_pitch;
 
+    /* With the bass note identified, we can find all relative pitches. */
     for (i = 0; i < num_notes; i++) {
        notes[i].relative_pitch = notes[i].midi_pitch - bass_pitch;
+       while (notes[i].relative_pitch >= 12)
+           notes[i].relative_pitch -= 12;
     }
 
-    for (i = 0; i < ARRAY_SIZE (intervals); i++) {
-       if (_chord_signature_matches (notes, num_notes, intervals[i].pitches, 2))
-           chord_name = intervals[i].name;
-    }
-
-    for (i = 0; i < ARRAY_SIZE (triads); i++) {
-       if (_chord_signature_matches (notes, num_notes, triads[i].pitches, 3))
-           chord_name = triads[i].name;
+    /* Now, sort again by relative pitch. */
+    qsort (notes, num_notes, sizeof (analyzed_note_t),
+          _compare_analyzed_note_by_relative_pitch);
+
+    /* Finally, eliminate all duplicate notes. */
+    for (i = 0; i < num_notes - 1; i++) {
+           if (notes[i+1].relative_pitch == notes[i].relative_pitch) {
+                   j = i+1;
+                   while (j < num_notes &&
+                          notes[j].relative_pitch == notes[i].relative_pitch)
+                   {
+                           j++;
+                   }
+                   /* The loop incremented j one past the last
+                    * duplicate. Decrement so that it points to the
+                    * last duplicate (and is guaranteed to not exceed
+                    * the array bounds).*/
+                   j--;
+
+                   if (j < num_notes - 1) {
+                           memmove (&notes[i+1], &notes[j+1],
+                                    (num_notes - j) * sizeof (analyzed_note_t));
+                   }
+
+                   num_notes -= (j - i);
+           }
     }
 
-    for (i = 0; i < ARRAY_SIZE(sevenths); i++) {
-       if (_chord_signature_matches (notes, num_notes, sevenths[i].pitches, 4))
-           chord_name = sevenths[i].name;
+    switch (num_notes) {
+    case 1:
+       for (i = 0; i < ARRAY_SIZE (octaves); i++) {
+           if (_chord_signature_matches (notes, num_notes, octaves[i].pitches, 1))
+               chord_name = octaves[i].name;
+       }
+       break;
+    case 2:
+       for (i = 0; i < ARRAY_SIZE (intervals); i++) {
+           if (_chord_signature_matches (notes, num_notes, intervals[i].pitches, 2))
+               chord_name = intervals[i].name;
+       }
+       break;
+    case 3:
+       for (i = 0; i < ARRAY_SIZE (triads); i++) {
+           if (_chord_signature_matches (notes, num_notes, triads[i].pitches, 3))
+               chord_name = triads[i].name;
+       }
+       break;
+    case 4:
+       for (i = 0; i < ARRAY_SIZE(sevenths); i++) {
+           if (_chord_signature_matches (notes, num_notes, sevenths[i].pitches, 4))
+               chord_name = sevenths[i].name;
+       }
+       break;
     }
 
     if (chord_name)
@@ -559,6 +604,17 @@ note_group_init (void *ctx, note_group_t *group)
 static void
 note_group_add_note (note_group_t *group, score_note_t *note)
 {
+    int i;
+
+    /* Do nothing if note is already in group. */
+    for (i = 0; i < group->num_notes; i++) {
+       if (group->notes[i]->pitch == note->pitch &&
+           group->notes[i]->octave == note->octave)
+       {
+           return;
+       }
+    }
+
     group->num_notes++;
 
     if (group->num_notes > group->size) {