1 files changed, 122 insertions, 0 deletions
diff --git a/txt.c b/txt.c
new file mode 100644
index 0000000..b71bba3
--- /dev/null
+++ b/txt.c
@@ -0,0 +1,122 @@
+#include <stdint.h>
+#include <stddef.h>
+
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+
+#include "wrmr.h"
+#include "dynarr.h"
+#include "txt.h"
+
+void txt_insert_piece(Txt *b, u32 pi, TxtBufIdx buf, u32 ofs, u32 n) { 
+	DA_FIT(&b->ptbl, b->ptbl.n + 1);
+	MOVE(&b->ptbl.v[pi+1], &b->ptbl.v[pi], b->ptbl.n - pi);
+	b->ptbl.v[pi] = (TxtPiece) { buf, ofs, n };
+	b->ptbl.n++;
+}
+
+void txt_remove_piece(Txt *b, u32 pi) {
+	if (pi + 1 < b->ptbl.n) {
+		MOVE(&b->ptbl.v[pi], &b->ptbl.v[pi+1], b->ptbl.n - (pi + 1));
+	}
+	b->ptbl.n--;
+}
+
+u32 txt_split_piece(Txt *b, u32 pi, u32 i) {
+	TxtPiece *p = &b->ptbl.v[pi];
+	if (i == 0) return pi;
+	if (i == p->n) return pi + 1;
+	txt_insert_piece(b, pi + 1, p->buf, p->ofs + i, p->n - i);
+	b->ptbl.v[pi].n = i;
+	return pi + 1;
+}
+
+TxtLoc txt_at(Txt *b, u32 cur) {
+	for (u32 i = 0; i < b->ptbl.n; i++) {
+		if (cur <= b->ptbl.v[i].n) {
+			return (TxtLoc) { i, cur };
+		}
+		cur -= b->ptbl.v[i].n;
+	}
+	return (TxtLoc) { 0, 0 };
+}
+
+void txt_buf_append(Txt *b, TxtBufIdx bi, const char *s, u32 n) {
+	TxtBuf *buf = &b->buf[bi];
+	if (buf->n + n > buf->c) {
+		buf->c = stdc_bit_ceil(buf->n + n);
+		buf->s = realloc(buf->s, buf->c);
+		if (!buf->s) FAIL_WITH_MSG("realloc failure");
+	}
+	memcpy(&buf->s[buf->n], s, n);
+	buf->n += n;
+}
+
+u32 txt_insert(Txt *b, u32 cur, const char *s, u32 n) {
+	TxtLoc l = txt_at(b, cur);
+	if (l.p < b->ptbl.n) {
+		TxtPiece *p = &b->ptbl.v[l.p];
+		int mid = p->ofs + l.i < b->buf[p->buf].n;
+		if (p->buf == TXT_SRC || mid) {
+			l.p = txt_split_piece(b, l.p, l.i);
+			txt_insert_piece(b, l.p, TXT_ADD, b->buf[TXT_ADD].n, 0);
+		}
+	} else {
+		txt_insert_piece(b, l.p, TXT_ADD, b->buf[TXT_ADD].n, 0);
+	}
+	TxtPiece *p = &b->ptbl.v[l.p];
+	txt_buf_append(b, p->buf, s, n);
+	p->n += n;
+	b->len += n;
+	return cur + n;
+}
+
+u32 txt_insert_c(Txt *b, u32 cur, char ch) {
+	/* TODO: utf-8 char */
+	return txt_insert(b, cur, &ch, 1);
+}
+
+u32 txt_delete(Txt *b, u32 cur, u32 n) {
+	TxtLoc l = txt_at(b, cur);
+	txt_split_piece(b, l.p, l.i);
+	TxtPiece *p = &b->ptbl.v[l.p];
+	if (n > cur) n = cur;
+	cur -= n;
+	b->len -= n;
+	while (n > p->n) {
+		n -= p->n;
+		if (l.p + 1 < b->ptbl.n) txt_remove_piece(b, l.p);
+		b->ptbl.n--;
+		if (!l.p) return cur;
+		l.p--;
+		p = &b->ptbl.v[l.p];
+	}
+	p->n -= n;
+	if (p->n == 0) txt_remove_piece(b, l.p);
+	return cur;
+}
+
+int txt_open(Txt *b, const char *path) {
+	struct stat sb;
+	int fd = open(path, O_RDONLY);
+	if (fd == -1) return -1;
+	if (fstat(fd, &sb)) {
+		close(fd);
+		return -1;
+	}
+	void *m = mmap(0, sb.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
+	if (m == MAP_FAILED) {
+		close(fd);
+		return -1;
+	}
+	memset(b, 0, sizeof(TxtBuf));
+	b->buf[TXT_SRC].s = m;
+	b->buf[TXT_SRC].n = sb.st_size;
+	b->buf[TXT_SRC].c = sb.st_size;
+	b->len = sb.st_size;
+	close(fd);
+	txt_insert_piece(b, 0, TXT_SRC, 0, b->len);
+	return 0;
+}