Adding upstream version 1:9.11.5.P4+dfsg.upstream/1%9.11.5.P4+dfsgupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 356 insertions, 0 deletions

diff --git a/lib/lwres/lwbuffer.c b/lib/lwres/lwbuffer.c
new file mode 100644
index 0000000..9cdf5ed
--- /dev/null
+++ b/lib/lwres/lwbuffer.c
@@ -0,0 +1,356 @@
+/*
+ * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * See the COPYRIGHT file distributed with this work for additional
+ * information regarding copyright ownership.
+ */
+
+/* $Id: lwbuffer.c,v 1.15 2007/06/19 23:47:22 tbox Exp $ */
+
+/*! \file */
+
+/**
+ *    These functions provide bounds checked access to a region of memory
+ *    where data is being read or written. They are based on, and similar
+ *    to, the isc_buffer_ functions in the ISC library.
+ *
+ *    A buffer is a region of memory, together with a set of related
+ *    subregions. The used region and the available region are disjoint, and
+ *    their union is the buffer's region. The used region extends from the
+ *    beginning of the buffer region to the last used byte. The available
+ *    region extends from one byte greater than the last used byte to the
+ *    end of the buffer's region. The size of the used region can be changed
+ *    using various buffer commands. Initially, the used region is empty.
+ *
+ *    The used region is further subdivided into two disjoint regions: the
+ *    consumed region and the remaining region. The union of these two
+ *    regions is the used region. The consumed region extends from the
+ *    beginning of the used region to the byte before the current offset (if
+ *    any). The remaining region the current pointer to the end of the used
+ *    region. The size of the consumed region can be changed using various
+ *    buffer commands. Initially, the consumed region is empty.
+ *
+ *    The active region is an (optional) subregion of the remaining region.
+ *    It extends from the current offset to an offset in the remaining
+ *    region. Initially, the active region is empty. If the current offset
+ *    advances beyond the chosen offset, the active region will also be
+ *    empty.
+ *
+ *
+ * \verbatim
+ *    /------------entire length---------------\\
+ *    /----- used region -----\\/-- available --\\
+ *    +----------------------------------------+
+ *    | consumed  | remaining |                |
+ *    +----------------------------------------+
+ *    a           b     c     d                e
+ *
+ *   a == base of buffer.
+ *   b == current pointer.  Can be anywhere between a and d.
+ *   c == active pointer.  Meaningful between b and d.
+ *   d == used pointer.
+ *   e == length of buffer.
+ *
+ *   a-e == entire length of buffer.
+ *   a-d == used region.
+ *   a-b == consumed region.
+ *   b-d == remaining region.
+ *   b-c == optional active region.
+ * \endverbatim
+ *
+ *    lwres_buffer_init() initializes the lwres_buffer_t *b and assocates it
+ *    with the memory region of size length bytes starting at location base.
+ *
+ *    lwres_buffer_invalidate() marks the buffer *b as invalid. Invalidating
+ *    a buffer after use is not required, but makes it possible to catch its
+ *    possible accidental use.
+ *
+ *    The functions lwres_buffer_add() and lwres_buffer_subtract()
+ *    respectively increase and decrease the used space in buffer *b by n
+ *    bytes. lwres_buffer_add() checks for buffer overflow and
+ *    lwres_buffer_subtract() checks for underflow. These functions do not
+ *    allocate or deallocate memory. They just change the value of used.
+ *
+ *    A buffer is re-initialised by lwres_buffer_clear(). The function sets
+ *    used , current and active to zero.
+ *
+ *    lwres_buffer_first() makes the consumed region of buffer *p empty by
+ *    setting current to zero (the start of the buffer).
+ *
+ *    lwres_buffer_forward() increases the consumed region of buffer *b by n
+ *    bytes, checking for overflow. Similarly, lwres_buffer_back() decreases
+ *    buffer b's consumed region by n bytes and checks for underflow.
+ *
+ *    lwres_buffer_getuint8() reads an unsigned 8-bit integer from *b and
+ *    returns it. lwres_buffer_putuint8() writes the unsigned 8-bit integer
+ *    val to buffer *b.
+ *
+ *    lwres_buffer_getuint16() and lwres_buffer_getuint32() are identical to
+ *    lwres_buffer_putuint8() except that they respectively read an unsigned
+ *    16-bit or 32-bit integer in network byte order from b. Similarly,
+ *    lwres_buffer_putuint16() and lwres_buffer_putuint32() writes the
+ *    unsigned 16-bit or 32-bit integer val to buffer b, in network byte
+ *    order.
+ *
+ *    Arbitrary amounts of data are read or written from a lightweight
+ *    resolver buffer with lwres_buffer_getmem() and lwres_buffer_putmem()
+ *    respectively. lwres_buffer_putmem() copies length bytes of memory at
+ *    base to b. Conversely, lwres_buffer_getmem() copies length bytes of
+ *    memory from b to base.
+ */
+
+#include <config.h>
+
+#include <inttypes.h>
+#include <string.h>
+
+#include <lwres/lwbuffer.h>
+
+#include "assert_p.h"
+
+void
+lwres_buffer_init(lwres_buffer_t *b, void *base, unsigned int length)
+{
+	/*
+	 * Make 'b' refer to the 'length'-byte region starting at base.
+	 */
+
+	REQUIRE(b != NULL);
+
+	b->magic = LWRES_BUFFER_MAGIC;
+	b->base = base;
+	b->length = length;
+	b->used = 0;
+	b->current = 0;
+	b->active = 0;
+}
+
+/*  Make 'b' an invalid buffer. */
+void
+lwres_buffer_invalidate(lwres_buffer_t *b)
+{
+
+	REQUIRE(LWRES_BUFFER_VALID(b));
+
+	b->magic = 0;
+	b->base = NULL;
+	b->length = 0;
+	b->used = 0;
+	b->current = 0;
+	b->active = 0;
+}
+
+/* Increase the 'used' region of 'b' by 'n' bytes. */
+void
+lwres_buffer_add(lwres_buffer_t *b, unsigned int n)
+{
+
+	REQUIRE(LWRES_BUFFER_VALID(b));
+	REQUIRE(b->used + n <= b->length);
+
+	b->used += n;
+}
+
+/* Decrease the 'used' region of 'b' by 'n' bytes. */
+void
+lwres_buffer_subtract(lwres_buffer_t *b, unsigned int n)
+{
+
+	REQUIRE(LWRES_BUFFER_VALID(b));
+	REQUIRE(b->used >= n);
+
+	b->used -= n;
+	if (b->current > b->used)
+		b->current = b->used;
+	if (b->active > b->used)
+		b->active = b->used;
+}
+
+/* Make the used region empty. */
+void
+lwres_buffer_clear(lwres_buffer_t *b)
+{
+
+	REQUIRE(LWRES_BUFFER_VALID(b));
+
+	b->used = 0;
+	b->current = 0;
+	b->active = 0;
+}
+
+/* Make the consumed region empty. */
+void
+lwres_buffer_first(lwres_buffer_t *b)
+{
+
+	REQUIRE(LWRES_BUFFER_VALID(b));
+
+	b->current = 0;
+}
+
+/* Increase the 'consumed' region of 'b' by 'n' bytes. */
+void
+lwres_buffer_forward(lwres_buffer_t *b, unsigned int n)
+{
+
+	REQUIRE(LWRES_BUFFER_VALID(b));
+	REQUIRE(b->current + n <= b->used);
+
+	b->current += n;
+}
+
+/* Decrease the 'consumed' region of 'b' by 'n' bytes. */
+void
+lwres_buffer_back(lwres_buffer_t *b, unsigned int n)
+{
+
+	REQUIRE(LWRES_BUFFER_VALID(b));
+	REQUIRE(n <= b->current);
+
+	b->current -= n;
+}
+
+/* Read an unsigned 8-bit integer from 'b' and return it. */
+uint8_t
+lwres_buffer_getuint8(lwres_buffer_t *b)
+{
+	unsigned char *cp;
+	uint8_t result;
+
+
+	REQUIRE(LWRES_BUFFER_VALID(b));
+	REQUIRE(b->used - b->current >= 1);
+
+	cp = b->base;
+	cp += b->current;
+	b->current += 1;
+	result = ((unsigned int)(cp[0]));
+
+	return (result);
+}
+
+/* Put an unsigned 8-bit integer */
+void
+lwres_buffer_putuint8(lwres_buffer_t *b, uint8_t val)
+{
+	unsigned char *cp;
+
+	REQUIRE(LWRES_BUFFER_VALID(b));
+	REQUIRE(b->used + 1 <= b->length);
+
+	cp = b->base;
+	cp += b->used;
+	b->used += 1;
+	cp[0] = (val & 0x00ff);
+}
+
+/*  Read an unsigned 16-bit integer in network byte order from 'b', convert it to host byte order, and return it. */
+uint16_t
+lwres_buffer_getuint16(lwres_buffer_t *b)
+{
+	unsigned char *cp;
+	uint16_t result;
+
+
+	REQUIRE(LWRES_BUFFER_VALID(b));
+	REQUIRE(b->used - b->current >= 2);
+
+	cp = b->base;
+	cp += b->current;
+	b->current += 2;
+	result = ((unsigned int)(cp[0])) << 8;
+	result |= ((unsigned int)(cp[1]));
+
+	return (result);
+}
+
+/* Put an unsigned 16-bit integer. */
+void
+lwres_buffer_putuint16(lwres_buffer_t *b, uint16_t val)
+{
+	unsigned char *cp;
+
+	REQUIRE(LWRES_BUFFER_VALID(b));
+	REQUIRE(b->used + 2 <= b->length);
+
+	cp = b->base;
+	cp += b->used;
+	b->used += 2;
+	cp[0] = (val & 0xff00) >> 8;
+	cp[1] = (val & 0x00ff);
+}
+
+/*  Read an unsigned 32-bit integer in network byte order from 'b', convert it to host byte order, and return it. */
+uint32_t
+lwres_buffer_getuint32(lwres_buffer_t *b)
+{
+	unsigned char *cp;
+	uint32_t result;
+
+	REQUIRE(LWRES_BUFFER_VALID(b));
+	REQUIRE(b->used - b->current >= 4);
+
+	cp = b->base;
+	cp += b->current;
+	b->current += 4;
+	result = ((unsigned int)(cp[0])) << 24;
+	result |= ((unsigned int)(cp[1])) << 16;
+	result |= ((unsigned int)(cp[2])) << 8;
+	result |= ((unsigned int)(cp[3]));
+
+	return (result);
+}
+
+/* Put an unsigned 32-bit integer. */
+void
+lwres_buffer_putuint32(lwres_buffer_t *b, uint32_t val)
+{
+	unsigned char *cp;
+
+	REQUIRE(LWRES_BUFFER_VALID(b));
+	REQUIRE(b->used + 4 <= b->length);
+
+	cp = b->base;
+	cp += b->used;
+	b->used += 4;
+	cp[0] = (unsigned char)((val & 0xff000000) >> 24);
+	cp[1] = (unsigned char)((val & 0x00ff0000) >> 16);
+	cp[2] = (unsigned char)((val & 0x0000ff00) >> 8);
+	cp[3] = (unsigned char)(val & 0x000000ff);
+}
+
+/* copies length bytes of memory at base to b */
+void
+lwres_buffer_putmem(lwres_buffer_t *b, const unsigned char *base,
+		    unsigned int length)
+{
+	unsigned char *cp;
+
+	REQUIRE(LWRES_BUFFER_VALID(b));
+	REQUIRE(b->used + length <= b->length);
+
+	cp = (unsigned char *)b->base + b->used;
+	memmove(cp, base, length);
+	b->used += length;
+}
+
+/* copies length bytes of memory at b to base */
+void
+lwres_buffer_getmem(lwres_buffer_t *b, unsigned char *base,
+		    unsigned int length)
+{
+	unsigned char *cp;
+
+	REQUIRE(LWRES_BUFFER_VALID(b));
+	REQUIRE(b->used - b->current >= length);
+
+	cp = b->base;
+	cp += b->current;
+	b->current += length;
+
+	memmove(base, cp, length);
+}