From 4c5442ccd9428c4bb4e73939d3eff50911b574c0 Mon Sep 17 00:00:00 2001
From: WormHeamer
Date: Mon, 29 Dec 2025 02:29:53 -0500
Subject: various asserts

---
 txt.c | 65 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 59 insertions(+), 6 deletions(-)

(limited to 'txt.c')

diff --git a/txt.c b/txt.c
index 7092964..36af521 100644
--- a/txt.c
+++ b/txt.c
@@ -58,7 +58,7 @@ static void txt_buf_append(Txt *b, TxtBufIdx bi, const char *s, u32 n) {
 
 static isize txt_buf_dedup(Txt *b, TxtBufIdx bi, const char *s, u32 n) {
 	TxtBuf *buf = &b->buf[bi];
-	if (buf->n >= n && !memcmp(buf->s + (buf->n - n), s, n)) {
+	if (buf->n >= n && buf->s && !memcmp(buf->s + (buf->n - n), s, n)) {
 		return buf->n - n;
 	} else {
 		return -1;
@@ -128,6 +128,14 @@ static TxtLoc txt_join_or_kill(TxtLoc l) {
 	return l;
 }
 
+static inline TxtLoc resolve_loc(TxtLoc l) {
+	if (l.p + 1 < l.t->ptbl.n && l.i == l.t->ptbl.v[l.p].n) {
+		l.p++;
+		l.i = 0;
+	}
+	return l;
+}
+
 TxtLoc txt_insert(TxtLoc l, const char *s, u32 n) {
 	l = txt_add_piece(l.t, l);
 	TxtPiece *p = &l.t->ptbl.v[l.p];
@@ -142,7 +150,7 @@ TxtLoc txt_insert(TxtLoc l, const char *s, u32 n) {
 	l.i = p->n;
 	l = txt_join_or_kill(l);
 	l.i = l.t->ptbl.v[l.p].n;
-	return l;
+	return resolve_loc(l);
 }
 
 TxtLoc txt_insert_c(TxtLoc l, u32 ch) {
@@ -173,15 +181,28 @@ TxtLoc txt_delete(TxtLoc l, u32 n) {
 		}
 		l = txt_join_or_kill(l);
 	}
-	return txt_join_or_kill(l);
+	return resolve_loc(txt_join_or_kill(l));
+}
+
+u32 txt_range_len(TxtLoc lo, TxtLoc hi) {
+	u32 n = 0;
+	while (lo.p < hi.p) {
+		n += lo.t->ptbl.v[lo.p].n - lo.i;
+		lo.p++;
+		lo.i = 0;
+	}
+	n += hi.i - lo.i;
+	return n;
 }
 
 TxtLoc txt_delete_range(TxtLoc lo, TxtLoc hi) {
 	/* TODO: figure out nr. of chars, then delete all at once */
-	while (txt_before(lo, hi)) {
-		hi = txt_delete(hi, 1);
+	if (txt_before(hi, lo)) {
+		TxtLoc t = lo;
+		lo = hi;
+		hi = t;
 	}
-	return lo;
+	return txt_delete(hi, txt_range_len(lo, hi));
 }
 
 TxtLoc txt_delete_c(TxtLoc l) {
@@ -242,8 +263,28 @@ void txt_free(Txt *t) {
 	free(t->ptbl.v);
 }
 
+void txt_write_range(int fd, TxtLoc lo, TxtLoc hi) {
+	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);
+		lo.p++;
+		lo.i = 0;
+	}
+	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);
+	}
+}
+
 /* navigation */
 
+int txt_valid_loc(TxtLoc l) {
+	return l.p < l.t->ptbl.n
+	    && (l.i < l.t->ptbl.v[l.p].n
+		|| (l.p + 1 == l.t->ptbl.n
+			&& l.i <= l.t->ptbl.v[l.p].n));
+}
+
 TxtLoc txt_at(Txt *b, u32 ofs) {
 	for (u32 i = 0; i < b->ptbl.n; i++) {
 		if (ofs < b->ptbl.v[i].n) {
@@ -263,13 +304,25 @@ u32 txt_ofs(TxtLoc l) {
 }
 
 int txt_before(TxtLoc a, TxtLoc b) {
+	ASSERT(txt_valid_loc(a));
+	ASSERT(txt_valid_loc(b));
 	return a.p < b.p || (a.p == b.p && a.i < b.i);
 }
 
 int txt_after(TxtLoc a, TxtLoc b) {
+	ASSERT(txt_valid_loc(a));
+	ASSERT(txt_valid_loc(b));
 	return a.p > b.p || (a.p == b.p && a.i > b.i);
 }
 
+TxtLoc txt_start(Txt *t) {
+	return (TxtLoc) { t, 0, 0 };
+}
+
+TxtLoc txt_end(Txt *t) {
+	return (TxtLoc) { t, t->ptbl.n-1, t->ptbl.v[t->ptbl.n-1].n };
+}
+
 TxtLoc bnext(TxtLoc l) {
 	TxtPiece *p = &l.t->ptbl.v[l.p];
 	if (l.p + 1 < l.t->ptbl.n) {
-- 
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