From d4a8b7e34dd619a4debf9a206c81db26d1402ea6 Mon Sep 17 00:00:00 2001
From: Damien Miller <djm@mindrot.org>
Date: Wed, 27 Oct 1999 13:42:43 +1000
Subject: Initial revision

---
 buffer.c | 150 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 150 insertions(+)
 create mode 100644 buffer.c

(limited to 'buffer.c')

diff --git a/buffer.c b/buffer.c
new file mode 100644
index 00000000..e183d101
--- /dev/null
+++ b/buffer.c
@@ -0,0 +1,150 @@
+/*
+
+buffer.c
+
+Author: Tatu Ylonen <ylo@cs.hut.fi>
+
+Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
+                   All rights reserved
+
+Created: Sat Mar 18 04:15:33 1995 ylo
+
+Functions for manipulating fifo buffers (that can grow if needed).
+
+*/
+
+#include "includes.h"
+RCSID("$Id: buffer.c,v 1.1 1999/10/27 03:42:43 damien Exp $");
+
+#include "xmalloc.h"
+#include "buffer.h"
+#include "ssh.h"
+
+/* Initializes the buffer structure. */
+
+void buffer_init(Buffer *buffer)
+{
+  buffer->alloc = 4096;
+  buffer->buf = xmalloc(buffer->alloc);
+  buffer->offset = 0;
+  buffer->end = 0;
+}
+
+/* Frees any memory used for the buffer. */
+
+void buffer_free(Buffer *buffer)
+{
+  memset(buffer->buf, 0, buffer->alloc);
+  xfree(buffer->buf);
+}
+
+/* Clears any data from the buffer, making it empty.  This does not actually
+   zero the memory. */
+
+void buffer_clear(Buffer *buffer)
+{
+  buffer->offset = 0;
+  buffer->end = 0;
+}
+
+/* Appends data to the buffer, expanding it if necessary. */
+
+void buffer_append(Buffer *buffer, const char *data, unsigned int len)
+{
+  char *cp;
+  buffer_append_space(buffer, &cp, len);
+  memcpy(cp, data, len);
+}
+
+/* Appends space to the buffer, expanding the buffer if necessary.
+   This does not actually copy the data into the buffer, but instead
+   returns a pointer to the allocated region. */
+
+void buffer_append_space(Buffer *buffer, char **datap, unsigned int len)
+{
+  /* If the buffer is empty, start using it from the beginning. */
+  if (buffer->offset == buffer->end)
+    {
+      buffer->offset = 0;
+      buffer->end = 0;
+    }
+
+ restart:
+  /* If there is enough space to store all data, store it now. */
+  if (buffer->end + len < buffer->alloc)
+    {
+      *datap = buffer->buf + buffer->end;
+      buffer->end += len;
+      return;
+    }
+
+  /* If the buffer is quite empty, but all data is at the end, move the
+     data to the beginning and retry. */
+  if (buffer->offset > buffer->alloc / 2)
+    {
+      memmove(buffer->buf, buffer->buf + buffer->offset,
+	      buffer->end - buffer->offset);
+      buffer->end -= buffer->offset;
+      buffer->offset = 0;
+      goto restart;
+    }
+
+  /* Increase the size of the buffer and retry. */
+  buffer->alloc += len + 32768;
+  buffer->buf = xrealloc(buffer->buf, buffer->alloc);
+  goto restart;
+}
+
+/* Returns the number of bytes of data in the buffer. */
+
+unsigned int buffer_len(Buffer *buffer)
+{
+  return buffer->end - buffer->offset;
+}
+
+/* Gets data from the beginning of the buffer. */
+
+void buffer_get(Buffer *buffer, char *buf, unsigned int len)
+{
+  if (len > buffer->end - buffer->offset)
+    fatal("buffer_get trying to get more bytes than in buffer");
+  memcpy(buf, buffer->buf + buffer->offset, len);
+  buffer->offset += len;
+}
+
+/* Consumes the given number of bytes from the beginning of the buffer. */
+
+void buffer_consume(Buffer *buffer, unsigned int bytes)
+{
+  if (bytes > buffer->end - buffer->offset)
+    fatal("buffer_get trying to get more bytes than in buffer");
+  buffer->offset += bytes;
+}  
+
+/* Consumes the given number of bytes from the end of the buffer. */
+
+void buffer_consume_end(Buffer *buffer, unsigned int bytes)
+{
+  if (bytes > buffer->end - buffer->offset)
+    fatal("buffer_get trying to get more bytes than in buffer");
+  buffer->end -= bytes;
+}  
+
+/* Returns a pointer to the first used byte in the buffer. */
+
+char *buffer_ptr(Buffer *buffer)
+{
+  return buffer->buf + buffer->offset;
+}
+
+/* Dumps the contents of the buffer to stderr. */
+
+void buffer_dump(Buffer *buffer)
+{
+  int i;
+  unsigned char *ucp = (unsigned char *)buffer->buf;
+  
+  for (i = buffer->offset; i < buffer->end; i++)
+    fprintf(stderr, " %02x", ucp[i]);
+  fprintf(stderr, "\n");
+}
-- 
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