New files, implementing a bare-bones string

stream.

Rev: src/nettle/buffer.c:1.1
Rev: src/nettle/buffer.h:1.1

buffer.c

+/* buffer.c
+ *
+ * A bare-bones string stream.
+ */
+
+/* nettle, low-level cryptographics library
+ *
+ * Copyright (C) 2002 Niels Mller
+ *  
+ * The nettle 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.
+ * 
+ * The nettle 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 the nettle library; see the file COPYING.LIB.  If not, write to
+ * the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+ * MA 02111-1307, USA.
+ */
+
+#include "buffer.h"
+
+#include <stdlib.h>
+#include <string.h>
+
+static int
+grow_realloc(struct nettle_buffer *buffer,
+	     unsigned length)
+{
+  if (!length)
+    {
+      realloc(buffer->contents, 0);
+      buffer->contents = NULL;
+      buffer->alloc = 0;
+      buffer->size = 0;
+
+      return 1;
+    }
+  else
+    {
+      unsigned alloc = buffer->alloc * 2 + length + 100;
+      uint8_t *p = realloc(buffer->contents, alloc);
+      if (!p)
+	return 0;
+      
+      buffer->contents = p;
+      buffer->alloc = alloc;
+      
+      return 1;
+    }
+}
+
+void
+nettle_buffer_init(struct nettle_buffer *buffer)
+{
+  buffer->contents = NULL;
+  buffer->alloc = 0;
+  buffer->grow = grow_realloc;
+  buffer->size = 0;
+}
+
+void
+nettle_buffer_init_size(struct nettle_buffer *buffer,
+			unsigned length, uint8_t *space)
+{
+  buffer->contents = space;
+  buffer->alloc = length;
+  buffer->grow = NULL;
+  buffer->size = 0;
+}
+
+void
+nettle_buffer_clear(struct nettle_buffer *buffer)
+{
+  NETTLE_BUFFER_GROW(buffer, 0);
+}
+
+uint8_t *
+nettle_buffer_space(struct nettle_buffer *buffer,
+		    unsigned length)
+{
+  uint8_t *p;
+  if (buffer->size + length > buffer->alloc)
+    if (!NETTLE_BUFFER_GROW(buffer, length))
+      return NULL;
+
+  p = buffer->contents + buffer->size;
+  buffer->size += length;
+  return p;
+}
+     
+int
+nettle_buffer_write(struct nettle_buffer *buffer,
+		    unsigned length, const uint8_t *data)
+{
+  uint8_t *p = nettle_buffer_space(buffer, length);
+  if (p)
+    {
+      memcpy(p, data, length);
+      return 1;
+    }
+  else
+    return 0;
+}

buffer.h

+/* buffer.h
+ *
+ * A bare-bones string stream.
+ */
+
+/* nettle, low-level cryptographics library
+ *
+ * Copyright (C) 2002 Niels Möller
+ *  
+ * The nettle 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.
+ * 
+ * The nettle 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 the nettle library; see the file COPYING.LIB.  If not, write to
+ * the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+ * MA 02111-1307, USA.
+ */
+ 
+#ifndef NETTLE_BUFFER_H_INCLUDED
+#define NETTLE_BUFFER_H_INCLUDED
+
+#include <inttypes.h>
+
+struct nettle_buffer
+{
+  uint8_t *contents;
+  /* Allocated size */
+  unsigned alloc;
+  
+  /* If GROW is NULL, no reallocation is done. Otherwise, it should be
+   * a function that reallocates the contents to at least the size SIZE
+   * + LENGTH. It can return 0 if allocation fails. Furthermore, if
+   * GROW is called with LENGTH = 0, it should deallocate the buffer
+   * space. */
+  int (*grow)(struct nettle_buffer *buffer, unsigned length);
+
+  /* Current size */
+  unsigned size;
+};
+
+/* Initializes a buffer that uses plain realloc */
+void
+nettle_buffer_init(struct nettle_buffer *buffer);
+
+/* Initializes a buffer of fix size */
+void
+nettle_buffer_init_size(struct nettle_buffer *buffer,
+			unsigned length, uint8_t *space);
+
+void
+nettle_buffer_clear(struct nettle_buffer *buffer);
+
+#define NETTLE_BUFFER_GROW(o, l) ((o)->grow && (o)->grow((o), l))
+
+#define NETTLE_BUFFER_PUTC(buffer, c) \
+( (((buffer)->size < (buffer)->alloc) || NETTLE_BUFFER_GROW((buffer), 1)) \
+  && ((buffer)->contents[(buffer)->size++] = (c), 1) )
+
+int
+nettle_buffer_write(struct nettle_buffer *buffer,
+		    unsigned length, const uint8_t *data);
+
+/* Like nettle_buffer_write, but instead of copying data to the
+ * buffer, it returns a pointer to the area where the caller can copy
+ * the data. The pointer is valid only until the next call that can
+ * reallocate the buffer. */
+uint8_t *
+nettle_buffer_space(struct nettle_buffer *buffer,
+		    unsigned length);
+
+#endif /* NETTLE_BUFFER_H_INCLUDED */