add txt_collect_range() and txt_read_chunk()

1 files changed, 35 insertions, 3 deletions

diff --git a/txt.c b/txt.c
index 054245d..038140d 100644
--- a/txt.c
+++ b/txt.c
@@ -7,9 +7,11 @@
 #include <sys/mman.h>
 
 #include "wrmr.h"
+#include "arena.h"
 #include "dynarr.h"
 #include "txt.h"
 #include "utf8.h"
+#include "str.h"
 
 void txt_replace_piece(Txt *b, u32 pi, TxtBufIdx buf, u32 ofs, u32 n) { 
 	b->ptbl.v[pi] = (TxtPiece) { buf, ofs, n };
@@ -277,18 +279,48 @@ void txt_free(Txt *t) {
 	free(t->ptbl.v);
 }
 
-void txt_write_range(int fd, TxtLoc lo, TxtLoc hi) {
+Str txt_collect_range(TxtLoc lo, TxtLoc hi, Arena *a) {
+	DYNARR(char) buf = { 0 };
 	while (lo.p < hi.p) {
 		TxtPiece *p = &lo.t->ptbl.v[lo.p];
-		write(fd, lo.t->buf[p->buf].s + p->ofs + lo.i, p->n - lo.i);
+		DA_APUSH_MULT(&buf, a, lo.t->buf[p->buf].s + p->ofs + lo.i, p->n - lo.i);
 		lo.p++;
 		lo.i = 0;
 	}
 	ASSERT(lo.p == hi.p);
 	if (hi.i > lo.i) {
 		TxtPiece *p = &lo.t->ptbl.v[lo.p];
-		write(fd, lo.t->buf[p->buf].s + p->ofs + lo.i, hi.i - lo.i);
+		DA_AGROW(&buf, a, hi.i - lo.i);
+		memcpy((&buf)->v + (&buf)->n, lo.t->buf[p->buf].s + p->ofs + lo.i, DA_ELEM(&buf, hi.i - lo.i));
+		(&buf)->n += (hi.i - lo.i);
+		//DA_APUSH_MULT(&buf, a, lo.t->buf[p->buf].s + p->ofs + lo.i, hi.i - lo.i);
 	}
+	return (Str) { buf.v, buf.n };
+}
+
+u32 txt_read_chunk(TxtLoc *lo, TxtLoc hi, char *buf, u32 sz) {
+	u32 n = 0;
+	TxtLoc l = *lo;
+	while (n < sz && l.p < hi.p) {
+		TxtPiece *p = &l.t->ptbl.v[l.p];
+		u32 copy_n = p->n - l.i;
+		if (copy_n > sz - n) copy_n = sz - n;
+		memcpy(buf + n, l.t->buf[p->buf].s + p->ofs + l.i, copy_n);
+		n += copy_n;
+		l.i += copy_n;
+		if (l.i >= p->n) {
+			l.p++;
+			l.i = 0;
+		}
+	}
+	if (n < sz && hi.i > l.i) {
+		TxtPiece *p = &l.t->ptbl.v[l.p];
+		u32 copy_n = hi.i - l.i;
+		if (copy_n > sz - n) copy_n = sz - n;
+		memcpy(buf + n, l.t->buf[p->buf].s + p->ofs + l.i, copy_n);
+	}
+	*lo = l;
+	return n;
 }
 
 /* navigation */