Rework computer keyboard input to be mapped piano keyboard

[scherzo] / pitch.h

diff --git a/pitch.h b/pitch.h
index 525f14c8ae5038426bfe97c0c879ee8c67a3d637..3d1dd2e125b98cda6cc4c2ecfe150c54278258db 100644 (file)
--- a/pitch.h
+++ b/pitch.h
@@ -23,8 +23,44 @@
 #ifndef PITCH_H
 #define PITCH_H
 
-#define PITCH_ACCIDENTAL_MASK 0x07
-#define PITCH_ACCIDENTAL_SHIFT 0
+typedef uint32_t pitch_t;
+
+#define PITCH_ACCIDENTAL_SHIFT (0)
+#define PITCH_ACCIDENTAL_MASK  (0x07 << PITCH_ACCIDENTAL_SHIFT)
+
+#define PITCH_NAME_SHIFT       (3)
+#define PITCH_NAME_MASK                (0x07 << PITCH_NAME_SHIFT)
+
+#define PITCH_OCTAVE_SHIFT     (6)
+#define PITCH_OCTAVE_MASK      (0x07 << PITCH_OCTAVE_SHIFT)
+
+#define PITCH_ACCIDENTAL(pitch)        \
+    (((pitch) & PITCH_ACCIDENTAL_MASK) >> PITCH_ACCIDENTAL_SHIFT)
+#define PITCH_NAME(pitch)      \
+    (((pitch) & PITCH_NAME_MASK) >> PITCH_NAME_SHIFT)
+#define PITCH_OCTAVE(pitch)    \
+    (((pitch) & PITCH_OCTAVE_MASK) >> PITCH_OCTAVE_SHIFT)
+
+#define PITCH(name, accidental, octave)                  \
+    (((octave) << PITCH_OCTAVE_SHIFT)          | \
+     ((name) << PITCH_NAME_SHIFT)              | \
+     ((accidental) << PITCH_ACCIDENTAL_SHIFT))
+
+#define PITCH_LITERAL(literal_name, literal_accidental, octave)        \
+    PITCH(PITCH_NAME_##literal_name,                           \
+         PITCH_ACCIDENTAL_##literal_accidental,                \
+         octave)
+
+#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(name, accidental) PITCH(name, accidental, 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
 {
@@ -35,11 +71,6 @@ typedef enum pitch_accidental
     PITCH_ACCIDENTAL_DOUBLE_SHARP
 } pitch_accidental_t;
 
-#define PITCH_ACCIDENTAL(pitch) (((pitch) & PITCH_ACCIDENTAL_MASK) >> PITCH_ACCIDENTAL_SHIFT)
-
-#define PITCH_NAME_MASK 0x38
-#define PITCH_NAME_SHIFT 3
-
 typedef enum pitch_name
 {
     PITCH_NAME_C,
@@ -51,13 +82,32 @@ typedef enum pitch_name
     PITCH_NAME_B,
 } pitch_name_t;
 
-#define PITCH_NAME(pitch) (((pitch) & PITCH_NAME_MASK) >> PITCH_NAME_SHIFT)
+/* Octave numbers are ISO octave numbers [0:8], (so Octave 4 is from
+ * middle C to the B above middle C).
+ */
 
-#define PITCH(name, accidental) (((name) << PITCH_NAME_SHIFT) | (accidental))
+/* 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);
 
-#define PITCH_LITERAL(literal_name, literal_accidental) PITCH(PITCH_NAME_##literal_name, PITCH_ACCIDENTAL_##literal_accidental)
-#define PITCH_NATURAL(literal_name) PITCH_LITERAL(literal_name, NATURAL)
+/* 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);
 
-typedef uint32_t pitch_t;
+/* 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);
 
 #endif /* PITCH_H */