MemoryFunctions.cpp

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#include "stdafx.h"
#include "MemoryFunctions.h"

#include <stdio.h>
#include <stdlib.h>


// fill array
void fillarray( void* p, void* value, size_t size, size_t n ) {
    // void* -> char* (because void* doesn't have the size of element)
    char* cp = (char*)p;
    char* cv = (char*)value;

    // fill
    for( unsigned int i = 0; i < n; i++ ) {
        char* p_i = cp + ( size * i );
        for( unsigned int j = 0; j < size; j++ ) {
            p_i[ j ] = cv[ j ];
        }
    }
}

// fill 0
void fillzero( void* p, size_t n ) {
    unsigned char zero = 0;

    fillarray( p, &zero, 1, n );
}

// is big endian
bool isbigendian() {
    // create 2 bytes data
    short num = 1;  // (Big: 00 01,  Little: 01 00)

    // get first byte
    char* c = (char*)&num;

    return ( *c == 0 );
}

// is little endian
bool islittleendian() {
    return !isbigendian();
}

// memory reverse
void memreverse( void* p, size_t n ) {
    // check parameters
    if( p == NULL || n == 0 ) {
        return;
    }

    // create buffer
    char* buffer = new char[ n ];

    // copy to buffer
    memcpy( buffer, p, n );

    // reverse
    char* cp = (char*)p;
    for( unsigned int i = 0; i < n; i++ ) {
        cp[ i ] = buffer[ n - 1 - i ];
    }

    // delete
    delete[] buffer;
}

// memory swap
void memswap( void* p0, void* p1, size_t n ) {
    // check parameters
    if( p0 == NULL || p1 == NULL || n == 0 ) {
        return;
    }

    // create buffer
    void* tmp = malloc( n );

    // copy
    memcpy( tmp, p0, n );
    memcpy( p0, p1, n );
    memcpy( p1, tmp, n );

    // free
    free( tmp );
}