libcw/cwMem.cpp

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2019-12-19 03:24:12 +00:00
#include "cwCommon.h"
#include "cwLog.h"
#include "cwCommonImpl.h"
#include "cwMem.h"
namespace cw
{
void* _memAlloc( void* p0, unsigned n, bool zeroFl )
{
void* p = nullptr; // ptr to new block
unsigned p0N = 0; // size of existing block
// if there is no existing block
if( p0 == nullptr )
n += sizeof(unsigned); // add space for the size of the block
else
{
p0N = ((unsigned*)p0)[-1]; // get size of existing block
// if the block is shrinking
if( p0N >= n )
return p0;
}
p = malloc(n); // allocate new memory
// if expanding then copy in data from existing block
if( p0 != nullptr )
{
memcpy(p,p0,p0N);
memFree(p0); // free the existing block
}
// if requested zero the block
if( zeroFl )
memset(((char*)p)+p0N,0,n-p0N);
// get pointer to base of new block
unsigned* p1 = static_cast<unsigned*>(p);
p1[0] = p0N + n; // set size of new block
// advance past the block size and return
return p1+1;
}
}
unsigned cw::memByteCount( const void* p )
{
return p==nullptr ? 0 : static_cast<const unsigned*>(p)[-1];
}
char* cw::memAllocStr( const char* s )
{
char* s1 = nullptr;
if( s != nullptr )
{
unsigned sn = strlen(s);
s1 = static_cast<char*>(_memAlloc(nullptr,sn+1,false));
memcpy(s1,s,sn);
s1[sn] = 0;
}
return s1;
}
void* cw::memAllocDupl( const void* p0, unsigned byteN )
{
if( p0 == nullptr || byteN == 0 )
return nullptr;
void* p1 = _memAlloc(nullptr,byteN,false);
memcpy(p1,p0,byteN);
return p1;
}
void* cw::memAllocDupl( const void* p )
{
return memAllocDupl(p,memByteCount(p));
}
void cw::memFree( void* p )
{
if( p != nullptr)
{
free(static_cast<unsigned*>(p)-1);
}
}