bloat-buster/bootstrap/std/virtual_buffer.c

89 lines
2.6 KiB
C

#pragma once
fn void vb_generic_ensure_capacity(VirtualBuffer(u8)* vb, u32 item_size, u32 item_count)
{
u32 old_capacity = vb->capacity;
u32 wanted_capacity = vb->length + item_count;
if (old_capacity < wanted_capacity)
{
if (old_capacity == 0)
{
vb->pointer = os_reserve(0, item_size * UINT32_MAX, (OSReserveProtectionFlags) {}, (OSReserveMapFlags) { .priv = 1, .anon = 1, .noreserve = 1 });
}
let_cast(u32, old_page_capacity, align_forward_u64(old_capacity * item_size, minimum_granularity));
let_cast(u32, new_page_capacity, align_forward_u64(wanted_capacity * item_size, minimum_granularity));
let(commit_size, new_page_capacity - old_page_capacity);
void* commit_pointer = vb->pointer + old_page_capacity;
os_commit(commit_pointer, commit_size);
let(new_capacity, new_page_capacity / item_size);
vb->capacity = new_capacity;
}
}
fn u8* vb_generic_add_assume_capacity(VirtualBuffer(u8)* vb, u32 item_size, u32 item_count)
{
u32 index = vb->length;
assert(vb->capacity >= index + item_count);
vb->length = index + item_count;
return vb->pointer + (index * item_size);
}
fn u8* vb_generic_add(VirtualBuffer(u8)* vb, u32 item_size, u32 item_count)
{
vb_generic_ensure_capacity(vb, item_size, item_count);
return vb_generic_add_assume_capacity(vb, item_size, item_count);
}
fn u8* vb_append_bytes(VirtualBuffer(u8*) vb, Slice(u8) bytes)
{
let_cast(u32, len, bytes.length);
vb_generic_ensure_capacity(vb, sizeof(u8), len);
let(pointer, vb_generic_add_assume_capacity(vb, sizeof(u8), len));
memcpy(pointer, bytes.pointer, len);
return pointer;
}
fn u32 vb_copy_string(VirtualBuffer(u8)* buffer, String string)
{
let(offset, buffer->length);
let_cast(u32, length, string.length);
let(pointer, vb_add(buffer, length));
memcpy(pointer, string.pointer, length);
return offset;
}
fn u64 vb_copy_string_zero_terminated(VirtualBuffer(u8)* buffer, String string)
{
assert(string.pointer[string.length] == 0);
string.length += 1;
vb_copy_string(buffer, string);
return string.length;
}
fn void vb_copy_byte_repeatedly(VirtualBuffer(u8)* buffer, u8 byte, u32 times)
{
u8* ptr = vb_generic_add(buffer, 1, times);
memset(ptr, byte, times);
}
fn u64 vb_format(VirtualBuffer(u8)* vb, const char* format, ...)
{
u8 buffer[4096];
va_list args;
va_start(args, format);
let(result, format_string_va((String)array_to_slice(buffer), format, args));
va_end(args);
assert(result.length <= array_length(buffer));
vb_copy_string(vb, result);
return result.length;
}