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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-28 07:33:12 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-28 07:33:12 +0000
commit36082a2fe36ecd800d784ae44c14f1f18c66a7e9 (patch)
tree6c68e0c0097987aff85a01dabddd34b862309a7c /doc/examples/tlsproxy/buffer.c
parentInitial commit. (diff)
downloadgnutls28-upstream.tar.xz
gnutls28-upstream.zip
Adding upstream version 3.7.9.upstream/3.7.9upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'doc/examples/tlsproxy/buffer.c')
-rw-r--r--doc/examples/tlsproxy/buffer.c228
1 files changed, 228 insertions, 0 deletions
diff --git a/doc/examples/tlsproxy/buffer.c b/doc/examples/tlsproxy/buffer.c
new file mode 100644
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--- /dev/null
+++ b/doc/examples/tlsproxy/buffer.c
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+/*
+
+The MIT License (MIT)
+
+Copyright (c) 2016 Wrymouth Innovation Ltd
+
+Permission is hereby granted, free of charge, to any person obtaining a
+copy of this software and associated documentation files (the "Software"),
+to deal in the Software without restriction, including without limitation
+the rights to use, copy, modify, merge, publish, distribute, sublicense,
+and/or sell copies of the Software, and to permit persons to whom the
+Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included
+in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
+OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+OTHER DEALINGS IN THE SOFTWARE.
+
+*/
+
+#include "config.h"
+#include <sys/types.h>
+
+#include "buffer.h"
+
+struct buffer
+{
+ char *buf;
+ ssize_t size;
+ ssize_t hwm;
+ ssize_t ridx;
+ ssize_t widx;
+ int empty;
+};
+
+/* the buffer is organised internally as follows:
+ *
+ * * There are b->size bytes in the buffer.
+ *
+ * * Bytes are at offsets 0 to b->size-1
+ *
+ * * b->ridx points to the first readable byte
+ *
+ * * b->widx points to the first empty space
+ *
+ * * b->ridx < b->widx indicates a non-wrapped buffer:
+ *
+ * 0 ridx widx size
+ * | | | |
+ * V V V V
+ * ........XXXXXXXXX................
+ *
+ * * b->ridx > b->widx indicates a wrapped buffer:
+ *
+ * 0 widx ridx size
+ * | | | |
+ * V V V V
+ * XXXXXXXX.........XXXXXXXXXXXXXXXX
+ *
+ * * b->ridx == b->widx indicates a FULL buffer:
+ *
+ * * b->ridx == b->widx indicates a wrapped buffer:
+ *
+ * 0 widx == ridx size
+ * | | |
+ * V V V
+ * XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
+ *
+ * An empty buffer is indicated by empty=1
+ *
+ */
+
+buffer_t *
+bufNew (ssize_t size, ssize_t hwm)
+{
+ buffer_t *b = calloc (1, sizeof (buffer_t));
+ if (!b) return NULL;
+
+ b->buf = calloc (1, size);
+ b->size = size;
+ b->hwm = hwm;
+ b->empty = 1;
+ return b;
+}
+
+
+void
+bufFree (buffer_t * b)
+{
+ free (b->buf);
+ free (b);
+}
+
+/* get a maximal span to read. Returns 0 if buffer
+ * is empty
+ */
+ssize_t
+bufGetReadSpan (buffer_t * b, void **addr)
+{
+ if (b->empty)
+ {
+ *addr = NULL;
+ return 0;
+ }
+ *addr = &(b->buf[b->ridx]);
+ ssize_t len = b->widx - b->ridx;
+ if (len <= 0)
+ len = b->size - b->ridx;
+ return len;
+}
+
+/* get a maximal span to write. Returns 0 id buffer is full
+ */
+ssize_t
+bufGetWriteSpan (buffer_t * b, void **addr)
+{
+ if (b->empty)
+ {
+ *addr = b->buf;
+ b->ridx = 0;
+ b->widx = 0;
+ return b->size;
+ }
+ if (b->ridx == b->widx)
+ {
+ *addr = NULL;
+ return 0;
+ }
+ *addr = &(b->buf[b->widx]);
+ ssize_t len = b->ridx - b->widx;
+ if (len <= 0)
+ len = b->size - b->widx;
+ return len;
+}
+
+/* mark size bytes as read */
+void
+bufDoneRead (buffer_t * b, ssize_t size)
+{
+ while (!b->empty && (size > 0))
+ {
+ /* empty can't occur here, so equal pointers means full */
+ ssize_t len = b->widx - b->ridx;
+ if (len <= 0)
+ len = b->size - b->ridx;
+
+ /* len is the number of bytes in one read span */
+ if (len > size)
+ len = size;
+
+ b->ridx += len;
+ if (b->ridx >= b->size)
+ b->ridx = 0;
+
+ if (b->ridx == b->widx)
+ {
+ b->ridx = 0;
+ b->widx = 0;
+ b->empty = 1;
+ }
+
+ size -= len;
+ }
+}
+
+/* mark size bytes as written */
+void
+bufDoneWrite (buffer_t * b, ssize_t size)
+{
+ while ((b->empty || (b->ridx != b->widx)) && (size > 0))
+ {
+ /* full can't occur here, so equal pointers means empty */
+ ssize_t len = b->ridx - b->widx;
+ if (len <= 0)
+ len = b->size - b->widx;
+
+ /* len is the number of bytes in one write span */
+ if (len > size)
+ len = size;
+
+ b->widx += len;
+ if (b->widx >= b->size)
+ b->widx = 0;
+
+ /* it can't be empty as we've written at least one byte */
+ b->empty = 0;
+
+ size -= len;
+ }
+}
+
+int
+bufIsEmpty (buffer_t * b)
+{
+ return b->empty;
+}
+
+int
+bufIsFull (buffer_t * b)
+{
+ return !b->empty && (b->ridx == b->widx);
+}
+
+int
+bufIsOverHWM (buffer_t * b)
+{
+ return bufGetCount (b) > b->hwm;
+}
+
+ssize_t
+bufGetFree (buffer_t * b)
+{
+ return b->size - bufGetCount (b);
+}
+
+ssize_t
+bufGetCount (buffer_t * b)
+{
+ if (b->empty)
+ return 0;
+ return b->widx - b->ridx + ((b->ridx < b->widx) ? 0 : b->size);
+}