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util: add virendian.h macros

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We have several cases where we need to read endian-dependent
data regardless of host endianness; rather than open-coding
these call sites, it will be nicer to funnel things through
a macro.

The virendian.h file can be expanded to add writer functions,
and/or 16-bit access patterns, if needed.  Also, if we need
to turn things into a function to avoid multiple evaluations
of buf, that can be done later.  But for now, a macro worked.

* src/util/virendian.h: New file.
* src/Makefile.am (UTIL_SOURCES): Ship it.
* tests/virendiantest.c: New test.
* tests/Makefile.am (test_programs, virendiantest_SOURCES): Run
the test.
* .gitignore: Ignore built file.
This commit is contained in:
Eric Blake 2013-02-08 16:44:21 -07:00
parent d1c7b00b60
commit c6f1060ca7
5 changed files with 203 additions and 2 deletions
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1
.gitignore vendored
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@ -177,6 +177,7 @@
/tests/virbitmaptest
/tests/virbuftest
/tests/virdrivermoduletest
/tests/virendiantest
/tests/virhashtest
/tests/virkeyfiletest
/tests/virlockspacetest

1
src/Makefile.am
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@ -67,6 +67,7 @@ UTIL_SOURCES = \
util/virdbus.c util/virdbus.h \
util/virdnsmasq.c util/virdnsmasq.h \
util/virebtables.c util/virebtables.h \
util/virendian.h \
util/virerror.c util/virerror.h \
util/virevent.c util/virevent.h \
util/vireventpoll.c util/vireventpoll.h \

93
src/util/virendian.h Normal file
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@ -0,0 +1,93 @@
/*
* virendian.h: aid for reading endian-specific data
*
* Copyright (C) 2013 Red Hat, Inc.
*
* This 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.
*
* This 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 this library. If not, see
* <http://www.gnu.org/licenses/>.
*
*/
#ifndef __VIR_ENDIAN_H__
# define __VIR_ENDIAN_H__
# include "internal.h"
/* The interfaces in this file are provided as macros for speed. */
/**
* virReadBufInt64BE:
* @buf: byte to start reading at (can be 'char*' or 'unsigned char*');
* evaluating buf must not have any side effects
*
* Read 8 bytes at BUF as a big-endian 64-bit number. Caller is
* responsible to avoid reading beyond array bounds.
*/
# define virReadBufInt64BE(buf) \
(((uint64_t)(uint8_t)((buf)[0]) << 56) | \
((uint64_t)(uint8_t)((buf)[1]) << 48) | \
((uint64_t)(uint8_t)((buf)[2]) << 40) | \
((uint64_t)(uint8_t)((buf)[3]) << 32) | \
((uint64_t)(uint8_t)((buf)[4]) << 24) | \
((uint64_t)(uint8_t)((buf)[5]) << 16) | \
((uint64_t)(uint8_t)((buf)[6]) << 8) | \
(uint64_t)(uint8_t)((buf)[7]))
/**
* virReadBufInt64LE:
* @buf: byte to start reading at (can be 'char*' or 'unsigned char*');
* evaluating buf must not have any side effects
*
* Read 8 bytes at BUF as a little-endian 64-bit number. Caller is
* responsible to avoid reading beyond array bounds.
*/
# define virReadBufInt64LE(buf) \
((uint64_t)(uint8_t)((buf)[0]) | \
((uint64_t)(uint8_t)((buf)[1]) << 8) | \
((uint64_t)(uint8_t)((buf)[2]) << 16) | \
((uint64_t)(uint8_t)((buf)[3]) << 24) | \
((uint64_t)(uint8_t)((buf)[4]) << 32) | \
((uint64_t)(uint8_t)((buf)[5]) << 40) | \
((uint64_t)(uint8_t)((buf)[6]) << 48) | \
((uint64_t)(uint8_t)((buf)[7]) << 56))
/**
* virReadBufInt32BE:
* @buf: byte to start reading at (can be 'char*' or 'unsigned char*');
* evaluating buf must not have any side effects
*
* Read 4 bytes at BUF as a big-endian 32-bit number. Caller is
* responsible to avoid reading beyond array bounds.
*/
# define virReadBufInt32BE(buf) \
(((uint32_t)(uint8_t)((buf)[0]) << 24) | \
((uint32_t)(uint8_t)((buf)[1]) << 16) | \
((uint32_t)(uint8_t)((buf)[2]) << 8) | \
(uint32_t)(uint8_t)((buf)[3]))
/**
* virReadBufInt32LE:
* @buf: byte to start reading at (can be 'char*' or 'unsigned char*');
* evaluating buf must not have any side effects
*
* Read 4 bytes at BUF as a little-endian 32-bit number. Caller is
* responsible to avoid reading beyond array bounds.
*/
# define virReadBufInt32LE(buf) \
((uint32_t)(uint8_t)((buf)[0]) | \
((uint32_t)(uint8_t)((buf)[1]) << 8) | \
((uint32_t)(uint8_t)((buf)[2]) << 16) | \
((uint32_t)(uint8_t)((buf)[3]) << 24))
#endif /* __VIR_ENDIAN_H__ */

8
tests/Makefile.am
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@ -1,6 +1,6 @@
## Process this file with automake to produce Makefile.in
## Copyright (C) 2005-2012 Red Hat, Inc.
## Copyright (C) 2005-2013 Red Hat, Inc.
## See COPYING.LIB for the License of this software
SHELL = $(PREFERABLY_POSIX_SHELL)
@ -95,7 +95,7 @@ test_programs = virshtest sockettest \
utiltest shunloadtest \
virtimetest viruritest virkeyfiletest \
virauthconfigtest \
virbitmaptest \
virbitmaptest virendiantest \
virlockspacetest \
virstringtest \
virportallocatortest \
@ -649,6 +649,10 @@ virbitmaptest_SOURCES = \
virbitmaptest.c testutils.h testutils.c
virbitmaptest_LDADD = $(LDADDS)
virendiantest_SOURCES = \
virendiantest.c testutils.h testutils.c
virendiantest_LDADD = $(LDADDS)
jsontest_SOURCES = \
jsontest.c testutils.h testutils.c
jsontest_LDADD = $(LDADDS)

102
tests/virendiantest.c Normal file
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@ -0,0 +1,102 @@
/*
* Copyright (C) 2013 Red Hat, Inc.
*
* This 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.
*
* This 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 this library. If not, see
* <http://www.gnu.org/licenses/>.
*
*/
#include <config.h>
#include "testutils.h"
#include "virendian.h"
static int
test1(const void *data ATTRIBUTE_UNUSED)
{
/* Regular char should work, even if signed, and even with
* unaligned access. */
char array[] = { 1, 2, 3, 4, 5, 6, 7, 8,
0x89, 0x8a, 0x8b, 0x8c, 0x8d };
int ret = -1;
if (virReadBufInt64BE(array) != 0x0102030405060708ULL)
goto cleanup;
if (virReadBufInt64BE(array + 5) != 0x060708898a8b8c8dULL)
goto cleanup;
if (virReadBufInt64LE(array) != 0x0807060504030201ULL)
goto cleanup;
if (virReadBufInt64LE(array + 5) != 0x8d8c8b8a89080706ULL)
goto cleanup;
if (virReadBufInt32BE(array) != 0x01020304U)
goto cleanup;
if (virReadBufInt32BE(array + 9) != 0x8a8b8c8dU)
goto cleanup;
if (virReadBufInt32LE(array) != 0x04030201U)
goto cleanup;
if (virReadBufInt32LE(array + 9) != 0x8d8c8b8aU)
goto cleanup;
ret = 0;
cleanup:
return ret;
}
static int
test2(const void *data ATTRIBUTE_UNUSED)
{
/* Unsigned char should work without cast, even if unaligned access. */
unsigned char array[] = { 1, 2, 3, 4, 5, 6, 7, 8,
0x89, 0x8a, 0x8b, 0x8c, 0x8d };
int ret = -1;
if (virReadBufInt64BE(array) != 0x0102030405060708ULL)
goto cleanup;
if (virReadBufInt64BE(array + 5) != 0x060708898a8b8c8dULL)
goto cleanup;
if (virReadBufInt64LE(array) != 0x0807060504030201ULL)
goto cleanup;
if (virReadBufInt64LE(array + 5) != 0x8d8c8b8a89080706ULL)
goto cleanup;
if (virReadBufInt32BE(array) != 0x01020304U)
goto cleanup;
if (virReadBufInt32BE(array + 9) != 0x8a8b8c8dU)
goto cleanup;
if (virReadBufInt32LE(array) != 0x04030201U)
goto cleanup;
if (virReadBufInt32LE(array + 9) != 0x8d8c8b8aU)
goto cleanup;
ret = 0;
cleanup:
return ret;
}
static int
mymain(void)
{
int ret = 0;
if (virtTestRun("test1", 1, test1, NULL) < 0)
ret = -1;
if (virtTestRun("test2", 1, test2, NULL) < 0)
ret = -1;
return ret;
}
VIRT_TEST_MAIN(mymain)