1 files changed, 206 insertions, 0 deletions
diff --git a/wsutil/buffer.c b/wsutil/buffer.c
new file mode 100644
index 0000000..9533008
--- /dev/null
+++ b/wsutil/buffer.c
@@ -0,0 +1,206 @@
+/* buffer.c
+ *
+ * Wiretap Library
+ * Copyright (c) 1998 by Gilbert Ramirez <gram@alumni.rice.edu>
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+#include "config.h"
+#define WS_LOG_DOMAIN LOG_DOMAIN_WSUTIL
+#include "buffer.h"
+
+#include <stdlib.h>
+#include <string.h>
+
+#include <wsutil/ws_assert.h>
+#include <wsutil/wslog.h>
+
+#define SMALL_BUFFER_SIZE (2 * 1024) /* Everyone still uses 1500 byte frames, right? */
+static GPtrArray *small_buffers = NULL; /* Guaranteed to be at least SMALL_BUFFER_SIZE */
+/* XXX - Add medium and large buffers? */
+
+/* Initializes a buffer with a certain amount of allocated space */
+void
+ws_buffer_init(Buffer* buffer, size_t space)
+{
+	ws_assert(buffer);
+	if (G_UNLIKELY(!small_buffers)) small_buffers = g_ptr_array_sized_new(1024);
+
+	if (space <= SMALL_BUFFER_SIZE) {
+		if (small_buffers->len > 0) {
+			buffer->data = (uint8_t*) g_ptr_array_remove_index(small_buffers, small_buffers->len - 1);
+			ws_assert(buffer->data);
+		} else {
+			buffer->data = (uint8_t*)g_malloc(SMALL_BUFFER_SIZE);
+		}
+		buffer->allocated = SMALL_BUFFER_SIZE;
+	} else {
+		buffer->data = (uint8_t*)g_malloc(space);
+		buffer->allocated = space;
+	}
+	buffer->start = 0;
+	buffer->first_free = 0;
+}
+
+/* Frees the memory used by a buffer */
+void
+ws_buffer_free(Buffer* buffer)
+{
+	ws_assert(buffer);
+	if (buffer->allocated == SMALL_BUFFER_SIZE) {
+		ws_assert(buffer->data);
+		g_ptr_array_add(small_buffers, buffer->data);
+	} else {
+		g_free(buffer->data);
+	}
+	buffer->allocated = 0;
+	buffer->data = NULL;
+}
+
+/* Assures that there are 'space' bytes at the end of the used space
+	so that another routine can copy directly into the buffer space. After
+	doing that, the routine will also want to run
+	ws_buffer_increase_length(). */
+void
+ws_buffer_assure_space(Buffer* buffer, size_t space)
+{
+	ws_assert(buffer);
+	size_t available_at_end = buffer->allocated - buffer->first_free;
+	size_t space_used;
+	bool space_at_beginning;
+
+	/* If we've got the space already, good! */
+	if (space <= available_at_end) {
+		return;
+	}
+
+	/* Maybe we don't have the space available at the end, but we would
+		if we moved the used space back to the beginning of the
+		allocation. The buffer could have become fragmented through lots
+		of calls to ws_buffer_remove_start(). I'm using buffer->start as the
+		same as 'available_at_start' in this comparison. */
+
+	/* or maybe there's just no more room. */
+
+	space_at_beginning = buffer->start >= space;
+	if (space_at_beginning || buffer->start > 0) {
+		space_used = buffer->first_free - buffer->start;
+		/* this memory copy better be safe for overlapping memory regions! */
+		memmove(buffer->data, buffer->data + buffer->start, space_used);
+		buffer->start = 0;
+		buffer->first_free = space_used;
+	}
+	/*if (buffer->start >= space) {*/
+	if (space_at_beginning) {
+		return;
+	}
+
+	/* We'll allocate more space */
+	buffer->allocated += space + 1024;
+	buffer->data = (uint8_t*)g_realloc(buffer->data, buffer->allocated);
+}
+
+void
+ws_buffer_append(Buffer* buffer, uint8_t *from, size_t bytes)
+{
+	ws_assert(buffer);
+	ws_buffer_assure_space(buffer, bytes);
+	memcpy(buffer->data + buffer->first_free, from, bytes);
+	buffer->first_free += bytes;
+}
+
+void
+ws_buffer_remove_start(Buffer* buffer, size_t bytes)
+{
+	ws_assert(buffer);
+	if (buffer->start + bytes > buffer->first_free) {
+		ws_error("ws_buffer_remove_start trying to remove %" PRIu64 " bytes. s=%" PRIu64 " ff=%" PRIu64 "!\n",
+			(uint64_t)bytes, (uint64_t)buffer->start,
+			(uint64_t)buffer->first_free);
+		/** ws_error() does an abort() and thus never returns **/
+	}
+	buffer->start += bytes;
+
+	if (buffer->start == buffer->first_free) {
+		buffer->start = 0;
+		buffer->first_free = 0;
+	}
+}
+
+
+#ifndef SOME_FUNCTIONS_ARE_DEFINES
+void
+ws_buffer_clean(Buffer* buffer)
+{
+	ws_assert(buffer);
+	ws_buffer_remove_start(buffer, ws_buffer_length(buffer));
+}
+#endif
+
+#ifndef SOME_FUNCTIONS_ARE_DEFINES
+void
+ws_buffer_increase_length(Buffer* buffer, size_t bytes)
+{
+	ws_assert(buffer);
+	buffer->first_free += bytes;
+}
+#endif
+
+#ifndef SOME_FUNCTIONS_ARE_DEFINES
+size_t
+ws_buffer_length(Buffer* buffer)
+{
+	ws_assert(buffer);
+	return buffer->first_free - buffer->start;
+}
+#endif
+
+#ifndef SOME_FUNCTIONS_ARE_DEFINES
+uint8_t *
+ws_buffer_start_ptr(Buffer* buffer)
+{
+	ws_assert(buffer);
+	return buffer->data + buffer->start;
+}
+#endif
+
+#ifndef SOME_FUNCTIONS_ARE_DEFINES
+uint8_t *
+ws_buffer_end_ptr(Buffer* buffer)
+{
+	ws_assert(buffer);
+	return buffer->data + buffer->first_free;
+}
+#endif
+
+#ifndef SOME_FUNCTIONS_ARE_DEFINES
+void
+ws_buffer_append_buffer(Buffer* buffer, Buffer* src_buffer)
+{
+	ws_assert(buffer);
+	ws_buffer_append(buffer, ws_buffer_start_ptr(src_buffer), ws_buffer_length(src_buffer));
+}
+#endif
+
+void
+ws_buffer_cleanup(void)
+{
+	if (small_buffers) {
+		g_ptr_array_set_free_func(small_buffers, g_free);
+		g_ptr_array_free(small_buffers, true);
+		small_buffers = NULL;
+	}
+}
+
+/*
+ * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
+ *
+ * Local variables:
+ * c-basic-offset: 8
+ * tab-width: 8
+ * indent-tabs-mode: t
+ * End:
+ *
+ * vi: set shiftwidth=8 tabstop=8 noexpandtab:
+ * :indentSize=8:tabSize=8:noTabs=false:
+ */