Question

I have a memory location a and I want to copy a certain amount of bytes to another location fast, how would I do this in D ?

For example how would i do this:

int main()
{
    void* src_data = 0x40001255;
    void* dst_data = 0x47F22000;
    u32 size = 0x200;
    memcpy(dst_data, src_data, size);
}

Also how would fill a struct fast:

struct data_struct
{
    u32 block1;
    u32 block2;
    u32 block3;
    u32 block4;
    u32 block5;
    u62 block6;
    u128 bigblock;
} data_struct_t;

int main()
{
    void* src_data = 0x40001255;
    struct data_struct_t dst_data; 
    u32 size = sizeof(data_struct);
    memcpy(dst_data, src_data, size);
}

Thanks!
Roel

Answer 1

Assigning to a slice will perform an array copy, which calls memcpy internally.

void main()
{
    void* src_data = 0x40001255;
    void* dst_data = 0x47F22000;
    uint size = 0x200;
    dst_data[0..size] = src_data[0..size];
}

For the second one:

struct data_struct
{
    uint block1, block2, block3, block4, block5;
    ulong block6;
    uint[4] bigblock;
}

void main()
{
    auto src_data = cast(data_struct*) 0x40001255; // unaligned, WTF?!
    auto dst_data = *src_data;
}