Fix high octave numbers (8+) to not be interpreted as 0.

[scherzo] / pitch.h

diff --git a/pitch.h b/pitch.h
index 657e8fe07f8f291f1a4846c4cf0e596f1f2cdf7d..683d72772650138fa224e7b209af35e19c1f71e0 100644 (file)
--- a/pitch.h
+++ b/pitch.h
@@ -32,7 +32,7 @@ typedef uint32_t pitch_t;
 #define PITCH_NAME_MASK                (0x07 << PITCH_NAME_SHIFT)
 
 #define PITCH_OCTAVE_SHIFT     (6)
-#define PITCH_OCTAVE_MASK      (0x07 << PITCH_OCTAVE_SHIFT)
+#define PITCH_OCTAVE_MASK      (0x0F << PITCH_OCTAVE_SHIFT)
 
 #define PITCH_ACCIDENTAL(pitch)        \
     (((pitch) & PITCH_ACCIDENTAL_MASK) >> PITCH_ACCIDENTAL_SHIFT)
@@ -54,6 +54,14 @@ typedef uint32_t pitch_t;
 #define PITCH_NATURAL(literal_name, octave) \
     PITCH_LITERAL(literal_name, NATURAL, octave)
 
+/* PITCH_CLASS is useful for comparing pitches while ignoring any octave. */
+#define PITCH_CLASS(pitch) PITCH(PITCH_NAME(pitch), PITCH_ACCIDENTAL(pitch), 0)
+
+#define PITCH_CLASS_LITERAL(literal_name, literal_accidental) \
+    PITCH_LITERAL(literal_name, literal_accidental, 0)
+
+#define PITCH_NOT_A_PITCH ((pitch_t) -1)
+
 typedef enum pitch_accidental
 {
     PITCH_ACCIDENTAL_DOUBLE_FLAT,
@@ -78,4 +86,58 @@ typedef enum pitch_name
  * middle C to the B above middle C).
  */
 
+/* Get a string representation of a pitch_t value.
+ *
+ * Note: The returned value is static to the pithc_string function and
+ * may be modified by future calls to pitch_string. So the caller
+ * should copy the value if needed. */
+const char *
+pitch_string (pitch_t pitch);
+
+/* Return a new pitch, a number of octaves above 'pitch'
+ *
+ * Note: Maximum octave value is 8. A pitch with octave 8 will not be
+ * raised.
+ */
+pitch_t
+pitch_raise_by_octaves (pitch_t pitch, int octaves);
+
+/* Return a new pitch, a number of octaves below 'pitch'
+ *
+ * Note: Minimum octave value is 9. A pitch with octave 8 will not be
+ * lowered.
+ */
+pitch_t
+pitch_lower_by_octaves (pitch_t pitch, int octaves);
+
+/* Number of half steps from 'root' up to 'pitch' (that is, counting
+ * the steps up a chromatic scale), within the same octave. */
+int
+pitch_from_root_in_half_steps (pitch_t pitch, pitch_t root);
+
+/* Respell 'pitch' to have a name that matches the (diatonic) scale
+ * 'degree' from 'root'.
+ *
+ * If the pitch is too distant from the specified degree to be
+ * respelled, the original pitch will be returned unmodified.
+ */
+pitch_t
+pitch_spell_as_degree (pitch_t pitch, pitch_t root, int degree);
+
+/* Return a MIDI note value corresponding to 'pitch' */
+unsigned char
+pitch_to_midi (pitch_t pitch);
+
+/* Return the pitch_t value corresponding to the given MIDI note value. */
+pitch_t
+pitch_from_midi (unsigned char midi_note);
+
+/* Return true if 'a' and 'b' sound identical, (even if spelled differently)
+ *
+ * This comparison considers octaves as significant. So Bb and A# in
+ * the same octave are considered enharmonic, but Bb and A# in
+ * different octaves are not. */
+int
+pitch_enharmonic_to (pitch_t a, pitch_t b);
+
 #endif /* PITCH_H */