amp

commit c4bc171cdd9705e0ffc0b38130c2c85583caae6e
parent a8e7ed87318a9b388a7866741175b89d00776f48
Author: Pavel Renev <an2qzavok@gmail.com>
Date:   Fri, 16 Feb 2024 01:29:30 +0000

fs: add code for reading "cut" file

Diffstat:
M
fs.c
 | 
23
++++++++++++++++-------
M
pages.h
 | 
2
+-

2 files changed, 17 insertions(+), 8 deletions(-)
diff --git a/fs.c b/fs.c
@@ -15,7 +15,7 @@ PBuf pg;
 struct {
 	int min;
 	int max;
-	char str[32];
+	char str[12*3+1]; // see update_selstr
 } sel;
 
 void fs_read(Req *r);
@@ -67,7 +67,15 @@ fs_read(Req *r)
 		  r->ifcall.count, r->ifcall.offset);
 		respond(r, nil);
 	} else if (r->fid->file == fcut) {
-		respond(r, "fcut nope");
+		vlong min = sel.min * FrameSize;
+		vlong max = sel.max * FrameSize;
+		r->ifcall.offset += min;
+		if (r->ifcall.offset + r->ifcall.count > max)
+			r->ifcall.count = max - r->ifcall.offset;
+		if (r->ifcall.offset > max) r->ifcall.count = 0;
+		r->ofcall.count = pbread(&pg, r->ofcall.data,
+		  r->ifcall.count, r->ifcall.offset);
+		respond(r, nil);
 	} else if (r->fid->file == fctl) {
 		readstr(r, sel.str);
 		respond(r, nil);
@@ -118,16 +126,17 @@ fs_write(Req *r)
 void
 normalize_sel(void)
 {
+	vlong bufmax = pg.count / FrameSize;
 	if (sel.min > sel.max) {
 		int x = sel.max;
-		sel.max = sel.min;
-		sel.min = x;
-	};
-	// TODO: should check max is not bigger than total buffer size
+		sel.max = (sel.min > bufmax) ? bufmax : sel.min;
+		sel.min = (x > bufmax) ? bufmax : x;
+	}
 }
 
 void
 update_selstr(void)
 {
-	snprint(sel.str, sizeof(sel.str), "%11d %11d ", sel.min, sel.max);
+	snprint(sel.str, sizeof(sel.str), "%11d %11d %11d \n",
+	  sel.min, sel.max, (int)(pg.count / FrameSize));
 }
diff --git a/pages.h b/pages.h
@@ -20,7 +20,7 @@ struct PBuf {
 	Page *end;
 	vlong size; // how many bytes were allocated in total
 	vlong count; // how many bytes are used for storage
-	//              count <= size
+	//              should be count ≤ size
 };
 
 long pbwrite(PBuf *pb, void *buf, long nbytes, vlong offset);