Mesh Oriented datABase
(version 5.5.1)
An array-based unstructured mesh library
SysUtil.hpp
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#ifndef MB_SYS_UTIL_HPP
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#define MB_SYS_UTIL_HPP
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#include <cstring>
// for size_t
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#include <cstdio>
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#include <iosfwd>
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namespace
moab
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{
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namespace
SysUtil
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{
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/**\brief Similar to memset, but accepts values larger than 1 char
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*
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* Set block of memory to repeating copies of a sequene of bytes.
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*\param mem Pointer to start of memory block to initialize
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*\param value Byte sequence to initialize mem with
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*\param value_size Size of 'value'
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*\param num_elem Size of 'mem' as a multiple of value_size (the number of
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* copies of 'value' to write into 'mem'.)
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*/
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void
setmem
(
void
* mem,
const
void
* value,
unsigned
value_size,
size_t
num_elem );
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/**\brief Get size of file (if it is a regular file)
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*
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* Get size of regular file.
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*\return - file size if known
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* - -1 if file size cannot be determined (e.g. a pipe)
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* - -2 if an unexpected failure occured (may indicate change
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* in file position.)
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*/
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long
filesize
( FILE* filp );
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/**\brief Get size of file (if it is a regular file)
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*
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* Get size of regular file.
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*\return - file size if known
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* - -1 if file size cannot be determined (e.g. a pipe)
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* - -2 if an unexpected failure occured (may indicate change
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* in file position.)
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*/
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long
filesize
( std::ifstream& str );
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/**\brief Check if platform is little-endian
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*
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* Check if platform is little-endian (least significant
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* byte at highest memory address.)
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*/
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inline
bool
little_endian
()
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{
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const
unsigned
one = 1;
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return
!*( (
char
*)&one );
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}
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/**\brief Check if platform is big-endian
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*
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* Check if platform is big-endian (least significant
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* byte at lowest memory address.)
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*/
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inline
bool
big_endian
()
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{
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const
unsigned
one = 1;
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return
!( ( (
char
*)&one )[
sizeof
( unsigned ) - 1] );
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}
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/**\brief Swap byte order (e.g. change from big-endian to little-endian)
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*
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* Reverse byte order or array of values.
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*\param data Pointer to beginning of memory block to modify
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*\param values_size Size of one value
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*\param num_elem Number of values of size 'value_size' in 'data'
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*/
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void
byteswap
(
void
* data,
unsigned
value_size,
size_t
num_elem );
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/**\brief Alternate byteswap optimized for 2-byte values */
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void
byteswap2
(
void
* data,
size_t
num_elem );
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/**\brief Alternate byteswap optimized for 4-byte values */
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void
byteswap4
(
void
* data,
size_t
num_elem );
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/**\brief Alternate byteswap optimized for 8-byte values */
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void
byteswap8
(
void
* data,
size_t
num_elem );
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/**\brief Type-specific byte swap */
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template
<
typename
T >
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inline
void
byteswap
( T* data,
size_t
num_elem )
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{
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switch
(
sizeof
( T ) )
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{
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case
1:
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break
;
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case
2:
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byteswap2
( data, num_elem );
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break
;
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case
4:
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byteswap4
( data, num_elem );
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break
;
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case
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byteswap8
( data, num_elem );
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break
;
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default
:
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byteswap
( data,
sizeof
( T ), num_elem );
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break
;
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}
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}
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}
// namespace SysUtil
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}
// namespace moab
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#endif
src
SysUtil.hpp
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