A small C header to help with laying out and retrieving heterogeneous objects in contiguous memory.
const struct blayout lays[] = {{1, sizeof(double), alignof(double)},
{1, sizeof(int), alignof(int) }};
size_t size = blcalc(BL_ALIGNMENT, 0, 2, lays, 0);
assert(size != 0 && "`blcalc()` error");
void *block = malloc(size);
assert(block != NULL && "`malloc()` error");
double *d = blnext(block, 0, lays[0].align);
int *i = blnext( d, blsizeof(&lays[0]), lays[1].align);
*d = 3.14;
*i = 42;
printf("%f %d\n", *d, *i);
/*
* `BL_ALIGNMENT` is equal to `alignof(max_align_t)` but the header provides
* a portable alternative, because MSVC, while it claims C11 conformance,
* doesn't have `max_align_t`, even though the standard mandates it. See
* comment in the header for more information.
*/Only freestanding headers are required:
<assert.h>(optional)<stddef.h>NULLmax_align_t(optional)ptrdiff_tsize_t(overridable)
<stdint.h>SIZE_MAX(overridable)uintptr_t
Currently, the header targets C99 and later standards, due to the hard dependency on the existence of uintptr_t. Other than that, you should be able to compile the code with any C89/C90/ANSI compiler if you provide a suitable substitute for your platform.
The header may or may not compile and work under a C++ compiler.
See here.
MIT No Attribution
Copyright 2025 pan <pan_@disroot.org>
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