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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.
94 lines
3.6 KiB
C
94 lines
3.6 KiB
C
/*
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* virendian.h: aid for reading endian-specific data
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*
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* Copyright (C) 2013 Red Hat, Inc.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library. If not, see
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* <http://www.gnu.org/licenses/>.
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*
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*/
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#ifndef __VIR_ENDIAN_H__
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# define __VIR_ENDIAN_H__
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# include "internal.h"
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/* The interfaces in this file are provided as macros for speed. */
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/**
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* virReadBufInt64BE:
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* @buf: byte to start reading at (can be 'char*' or 'unsigned char*');
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* evaluating buf must not have any side effects
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*
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* Read 8 bytes at BUF as a big-endian 64-bit number. Caller is
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* responsible to avoid reading beyond array bounds.
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*/
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# define virReadBufInt64BE(buf) \
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(((uint64_t)(uint8_t)((buf)[0]) << 56) | \
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((uint64_t)(uint8_t)((buf)[1]) << 48) | \
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((uint64_t)(uint8_t)((buf)[2]) << 40) | \
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((uint64_t)(uint8_t)((buf)[3]) << 32) | \
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((uint64_t)(uint8_t)((buf)[4]) << 24) | \
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((uint64_t)(uint8_t)((buf)[5]) << 16) | \
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((uint64_t)(uint8_t)((buf)[6]) << 8) | \
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(uint64_t)(uint8_t)((buf)[7]))
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/**
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* virReadBufInt64LE:
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* @buf: byte to start reading at (can be 'char*' or 'unsigned char*');
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* evaluating buf must not have any side effects
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*
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* Read 8 bytes at BUF as a little-endian 64-bit number. Caller is
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* responsible to avoid reading beyond array bounds.
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*/
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# define virReadBufInt64LE(buf) \
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((uint64_t)(uint8_t)((buf)[0]) | \
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((uint64_t)(uint8_t)((buf)[1]) << 8) | \
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((uint64_t)(uint8_t)((buf)[2]) << 16) | \
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((uint64_t)(uint8_t)((buf)[3]) << 24) | \
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((uint64_t)(uint8_t)((buf)[4]) << 32) | \
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((uint64_t)(uint8_t)((buf)[5]) << 40) | \
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((uint64_t)(uint8_t)((buf)[6]) << 48) | \
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((uint64_t)(uint8_t)((buf)[7]) << 56))
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/**
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* virReadBufInt32BE:
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* @buf: byte to start reading at (can be 'char*' or 'unsigned char*');
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* evaluating buf must not have any side effects
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*
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* Read 4 bytes at BUF as a big-endian 32-bit number. Caller is
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* responsible to avoid reading beyond array bounds.
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*/
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# define virReadBufInt32BE(buf) \
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(((uint32_t)(uint8_t)((buf)[0]) << 24) | \
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((uint32_t)(uint8_t)((buf)[1]) << 16) | \
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((uint32_t)(uint8_t)((buf)[2]) << 8) | \
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(uint32_t)(uint8_t)((buf)[3]))
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/**
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* virReadBufInt32LE:
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* @buf: byte to start reading at (can be 'char*' or 'unsigned char*');
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* evaluating buf must not have any side effects
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*
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* Read 4 bytes at BUF as a little-endian 32-bit number. Caller is
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* responsible to avoid reading beyond array bounds.
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*/
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# define virReadBufInt32LE(buf) \
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((uint32_t)(uint8_t)((buf)[0]) | \
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((uint32_t)(uint8_t)((buf)[1]) << 8) | \
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((uint32_t)(uint8_t)((buf)[2]) << 16) | \
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((uint32_t)(uint8_t)((buf)[3]) << 24))
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#endif /* __VIR_ENDIAN_H__ */
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