2020-12-19 00:29:37 (UTC-03:00)

Marcel Rodrigues <marcelgmr@gmail.com>

edit: add edit stack and basic operations

diff --git a/edit.c b/edit.c
new file mode 100644
index 0000000..0a5553a
--- /dev/null
+++ b/edit.c
@@ -0,0 +1,145 @@
+#include "seqt.h"
+
+#define NOPS    0x2000
+#define M1      (NOPS - 1)
+#define M2      ((NOPS << 1) - 1)
+
+typedef enum OpCode {DUR, PIT, INS, DEL} OpCode;
+
+static uint32_t stack[NOPS];
+static int p, q, r;
+
+static uint32_t
+track_index(unsigned track, unsigned index)
+{
+    return (track << 16) | (index << 4);
+}
+
+uint32_t
+op_dur(unsigned track, unsigned index, unsigned delta)
+{
+    uint32_t op = track_index(track, index) | DUR;
+    return op | (delta << 20);
+}
+
+uint32_t
+op_pit(unsigned track, unsigned index, unsigned voice, unsigned delta)
+{
+    uint32_t op = track_index(track, index) | PIT;
+    return op | (voice << 28) | (delta << 20);
+}
+
+uint32_t
+op_ins(unsigned track, unsigned index, unsigned nrows)
+{
+    uint32_t op = track_index(track, index) | INS;
+    return op | (nrows << 20);
+}
+
+uint32_t
+op_del(unsigned track, unsigned index, unsigned nrows)
+{
+    uint32_t op = track_index(track, index) | DEL;
+    return op | (nrows << 20);
+}
+
+#define inc(i)      (((i) + 1) & M2)
+#define dec(i)      (((i) - 1) & M2)
+#define isempty     (p == q)
+#define isfull      (p == (q ^ NOPS))
+
+static void
+push(uint32_t op)
+{
+    r = 0;
+    stack[q & M1] = op;
+    q = inc(q);
+}
+
+static uint32_t
+pop()
+{
+    r++;
+    q = dec(q);
+    return stack[q & M1];
+}
+
+static uint32_t
+unpop()
+{
+    r--;
+    q = inc(q);
+    return stack[q & M1];
+}
+
+static void
+apply(Matrix matrix, uint32_t op, int reverse)
+{
+    unsigned int track, index, delta, voice, nrows;
+    unsigned int args = op >> 20;
+    unsigned char duration, cell;
+    track = (op >> 16) & 0xF;
+    index = (op >>  4) & 0xFFF;
+    switch ((OpCode) (op & 3)) {
+        case DUR:
+            delta = args;
+            duration = matrix[index][0][track >> 1];
+            duration = track & 1 ? duration & 0x0F : duration >> 4;
+            if (reverse)
+                duration = (duration - delta) & 0x0F;
+            else
+                duration = (duration + delta) & 0x0F;
+            matrix[index][0][track >> 1] |= duration << ((~track & 1) << 2);
+            break;
+        case PIT:
+            voice = args >> 8;
+            delta = args & 0xFF;
+            cell = matrix[index][track][voice];
+            if (reverse)
+                cell = (cell - delta) & 0xFF;
+            else
+                cell = (cell + delta) & 0xFF;
+            matrix[index][track][voice] = cell;
+            break;
+        case INS:
+            /* TODO */
+            (void) nrows;
+            break;
+        case DEL:
+            /* TODO */
+            (void) nrows;
+    }
+}
+
+void
+doop(Matrix matrix, uint32_t op, int mark)
+{
+    apply(matrix, op, 0);
+    push(op | (((unsigned) mark) << 2));
+}
+
+void
+undo(Matrix matrix)
+{
+    uint32_t op;
+    while (!isempty) {
+        op = pop();
+        apply(matrix, op, 1);
+        if (op & 4)
+            break;
+    }
+}
+
+void
+redo(Matrix matrix)
+{
+    uint32_t op;
+    while (!isfull) {
+        op = unpop();
+        if (op & 4) {
+            (void) pop();
+            break;
+        }
+        apply(matrix, op, 0);
+    }
+}

diff --git a/seqt.c b/seqt.c
index 9a75de7..93b8faf 100644
--- a/seqt.c
+++ b/seqt.c
@@ -5,7 +5,7 @@
 
 int ntracks;
 char map[MAPSIZE][RECSIZE];
-unsigned char matrix[MAXINDEX][MAXTRACK][MAXVOICE];
+Matrix matrix;
 
 void
 print_blank()

diff --git a/seqt.h b/seqt.h
index 21d21e8..ff332d8 100644
--- a/seqt.h
+++ b/seqt.h
@@ -3,6 +3,7 @@
 
 #define _POSIX_C_SOURCE 200809L
 
+#include <stdint.h>
 #include <stdio.h>
 #include <fcntl.h>
 #include <sys/ioctl.h>
@@ -13,11 +14,23 @@
 #define MAXINDEX    0x1000
 #define MAXTRACK    0x0010
 #define MAXVOICE    0x0008
-extern unsigned char matrix[MAXINDEX][MAXTRACK][MAXVOICE];
+typedef unsigned char Matrix[MAXINDEX][MAXTRACK][MAXVOICE];
+extern Matrix matrix;
 
 #define REST    0
 #define CONT    1
 
+/* ============================== Edit ============================== */
+
+uint32_t op_dur(unsigned track, unsigned index, unsigned delta);
+uint32_t op_pit(unsigned track, unsigned index, unsigned voice, unsigned delta);
+uint32_t op_ins(unsigned track, unsigned index, unsigned nrows);
+uint32_t op_del(unsigned track, unsigned index, unsigned nrows);
+
+void doop(Matrix matrix, uint32_t op, int mark);
+void undo(Matrix matrix);
+void redo(Matrix matrix);
+
 /* =============================== Map ============================== */
 
 #define RECSIZE     0x20