undo/redo

1 files changed, 21 insertions, 6 deletions

diff --git a/txt.h b/txt.h
index 5df33a7..148369e 100644
--- a/txt.h
+++ b/txt.h
@@ -5,6 +5,8 @@
 #include "arena.h"
 #include "str.h"
 
+#define TXT_HIST_MAX 32
+
 typedef enum : u8 {
 	TXT_SRC,
 	TXT_ADD
@@ -20,18 +22,27 @@ typedef struct {
 	u32 n, c;
 } TxtBuf;
 
+typedef DYNARR(TxtPiece)  TxtPieceTbl;
+
+typedef struct {
+	struct Txt *t;
+	u32 p, i;
+} TxtLoc;
+
 typedef struct {
-	DYNARR(TxtPiece) ptbl;
+	TxtPieceTbl v[TXT_HIST_MAX];
+	TxtLoc cur[TXT_HIST_MAX];
+	u32 i, n;
+} TxtHist;
+
+typedef struct Txt {
+	TxtPieceTbl ptbl;
+	TxtHist hist;
 	TxtBuf buf[2];
 	u32 len;
 	int dirty;
 } Txt;
 
-typedef struct {
-	Txt *t;
-	u32 p, i;
-} TxtLoc;
-
 /* text buffer manipulation */
 
 TxtLoc txt_split_piece(TxtLoc l);
@@ -43,6 +54,10 @@ int txt_load(Txt *b, const char *path);
 int txt_save(Txt *b, const char *path);
 void txt_free(Txt *b);
 
+void txt_hist_push(Txt *t, TxtLoc cur);
+int txt_hist_fwd(Txt *t, TxtLoc *cur);
+int txt_hist_back(Txt *t, TxtLoc *cur);
+
 Str txt_collect_range(TxtLoc lo, TxtLoc hi, Arena *a);
 u32 txt_read_chunk(TxtLoc *lo, TxtLoc hi, char *buf, u32 sz);
 Str txt_next_chunk(TxtLoc *l);