1 files changed, 103 insertions, 0 deletions
diff --git a/buffer.c b/buffer.c
new file mode 100644
index 0000000..9eb117f
--- /dev/null
+++ b/buffer.c
@@ -0,0 +1,103 @@
+/* Copyright (C) 2020  C. McEnroe <june@causal.agency>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * Additional permission under GNU GPL version 3 section 7:
+ *
+ * If you modify this Program, or any covered work, by linking or
+ * combining it with OpenSSL (or a modified version of that library),
+ * containing parts covered by the terms of the OpenSSL License and the
+ * original SSLeay license, the licensors of this Program grant you
+ * additional permission to convey the resulting work. Corresponding
+ * Source for a non-source form of such a combination shall include the
+ * source code for the parts of OpenSSL used as well as that of the
+ * covered work.
+ */
+
+#include <err.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sysexits.h>
+#include <time.h>
+
+#include "chat.h"
+
+struct Lines {
+	size_t len;
+	struct Line lines[BufferCap];
+};
+_Static_assert(!(BufferCap & (BufferCap - 1)), "BufferCap is power of two");
+
+struct Buffer {
+	struct Lines soft;
+	struct Lines hard;
+};
+
+struct Buffer *bufferAlloc(void) {
+	struct Buffer *buffer = calloc(1, sizeof(*buffer));
+	if (!buffer) err(EX_OSERR, "calloc");
+	return buffer;
+}
+
+void bufferFree(struct Buffer *buffer) {
+	for (size_t i = 0; i < BufferCap; ++i) {
+		free(buffer->soft.lines[i].str);
+		free(buffer->hard.lines[i].str);
+	}
+	free(buffer);
+}
+
+static const struct Line *linesLine(const struct Lines *lines, size_t i) {
+	const struct Line *line = &lines->lines[(lines->len + i) % BufferCap];
+	return (line->str ? line : NULL);
+}
+
+const struct Line *bufferSoft(const struct Buffer *buffer, size_t i) {
+	return linesLine(&buffer->soft, i);
+}
+
+const struct Line *bufferHard(const struct Buffer *buffer, size_t i) {
+	return linesLine(&buffer->hard, i);
+}
+
+static void flow(struct Lines *hard, int cols, const struct Line *soft) {
+	(void)hard;
+	(void)cols;
+	(void)soft;
+}
+
+void bufferPush(
+	struct Buffer *buffer, int cols,
+	enum Heat heat, time_t time, const char *str
+) {
+	struct Line *soft = &buffer->soft.lines[buffer->soft.len++ % BufferCap];
+	free(soft->str);
+	soft->heat = heat;
+	soft->time = time;
+	soft->str = strdup(str);
+	if (!soft->str) err(EX_OSERR, "strdup");
+	flow(&buffer->hard, cols, soft);
+}
+
+void bufferReflow(struct Buffer *buffer, int cols) {
+	buffer->hard.len = 0;
+	for (size_t i = 0; i < BufferCap; ++i) {
+		free(buffer->hard.lines[i].str);
+		buffer->hard.lines[i].str = NULL;
+	}
+	for (size_t i = 0; i < BufferCap; ++i) {
+		const struct Line *soft = bufferSoft(buffer, i);
+		if (soft) flow(&buffer->hard, cols, soft);
+	}
+}