Move strbuf implementation to shared/

Just move the strbuf-like implementation to shared/. No renames were
made yet to avoid cluttering the diff. It will come in a separate patch.

2 files changed, 153 insertions, 0 deletions

diff --git a/shared/strbuf.c b/shared/strbuf.c
new file mode 100644
index 0000000..5974660
--- /dev/null
+++ b/shared/strbuf.c
@@ -0,0 +1,123 @@
+/*
+ * libkmod - interface to kernel module operations
+ *
+ * Copyright (C) 2011-2013  ProFUSION embedded systems
+ * Copyright (C) 2014  Intel Corporation. All rights reserved.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#include <assert.h>
+#include <stdbool.h>
+#include <stdlib.h>
+
+#include "util.h"
+#include "strbuf.h"
+
+#define BUF_STEP (2048)
+
+static bool buf_grow(struct buffer *buf, size_t newsize)
+{
+	void *tmp;
+	size_t sz;
+
+	if (newsize % BUF_STEP == 0)
+		sz = newsize;
+	else
+		sz = ((newsize / BUF_STEP) + 1) * BUF_STEP;
+
+	if (buf->size == sz)
+		return true;
+
+	tmp = realloc(buf->bytes, sz);
+	if (sz > 0 && tmp == NULL)
+		return false;
+	buf->bytes = tmp;
+	buf->size = sz;
+	return true;
+}
+
+void buf_init(struct buffer *buf)
+{
+	buf->bytes = NULL;
+	buf->size = 0;
+	buf->used = 0;
+}
+
+void buf_release(struct buffer *buf)
+{
+	free(buf->bytes);
+}
+
+char *buf_steal(struct buffer *buf)
+{
+	char *bytes;
+
+	bytes = realloc(buf->bytes, buf->used + 1);
+	if (!bytes) {
+		free(buf->bytes);
+		return NULL;
+	}
+	bytes[buf->used] = '\0';
+	return bytes;
+}
+
+const char *buf_str(struct buffer *buf)
+{
+	if (!buf_grow(buf, buf->used + 1))
+		return NULL;
+	buf->bytes[buf->used] = '\0';
+	return buf->bytes;
+}
+
+bool buf_pushchar(struct buffer *buf, char ch)
+{
+	if (!buf_grow(buf, buf->used + 1))
+		return false;
+	buf->bytes[buf->used] = ch;
+	buf->used++;
+	return true;
+}
+
+unsigned buf_pushchars(struct buffer *buf, const char *str)
+{
+	unsigned i = 0;
+	int ch;
+
+	while ((ch = str[i])) {
+		buf_pushchar(buf, ch);
+		i++;
+	}
+
+	return i;
+}
+
+void buf_popchar(struct buffer *buf)
+{
+	assert(buf->used > 0);
+	buf->used--;
+}
+
+void buf_popchars(struct buffer *buf, unsigned n)
+{
+	assert(buf->used >= n);
+	buf->used -= n;
+}
+
+void buf_clear(struct buffer *buf)
+{
+	buf->used = 0;
+}
+
diff --git a/shared/strbuf.h b/shared/strbuf.h
new file mode 100644
index 0000000..d3ac55b
--- /dev/null
+++ b/shared/strbuf.h
@@ -0,0 +1,30 @@
+#pragma once
+
+#include <stdbool.h>
+
+/*
+ * Buffer abstract data type
+ */
+struct buffer {
+	char *bytes;
+	unsigned size;
+	unsigned used;
+};
+
+void buf_init(struct buffer *buf);
+void buf_release(struct buffer *buf);
+void buf_clear(struct buffer *buf);
+
+/* Destroy buffer and return a copy as a C string */
+char *buf_steal(struct buffer *buf);
+
+/*
+ * Return a C string owned by the buffer invalidated if the buffer is
+ * changed).
+ */
+const char *buf_str(struct buffer *buf);
+
+bool buf_pushchar(struct buffer *buf, char ch);
+unsigned buf_pushchars(struct buffer *buf, const char *str);
+void buf_popchar(struct buffer *buf);
+void buf_popchars(struct buffer *buf, unsigned n);