68 lines
2.1 KiB
C
68 lines
2.1 KiB
C
#include <std/virtual_buffer.h>
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#include <std/os.h>
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fn void vb_generic_ensure_capacity(VirtualBuffer(u8)* vb, u32 item_size, u32 item_count)
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{
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u32 old_capacity = vb->capacity;
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u32 wanted_capacity = vb->length + item_count;
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if (old_capacity < wanted_capacity)
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{
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if (old_capacity == 0)
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{
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vb->pointer = os_reserve(0, item_size * UINT32_MAX, (OSReserveProtectionFlags) {}, (OSReserveMapFlags) { .priv = 1, .anon = 1, .noreserve = 1 });
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}
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let_cast(u32, old_page_capacity, align_forward(old_capacity * item_size, minimum_granularity));
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let_cast(u32, new_page_capacity, align_forward(wanted_capacity * item_size, minimum_granularity));
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let(commit_size, new_page_capacity - old_page_capacity);
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void* commit_pointer = vb->pointer + old_page_capacity;
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os_commit(commit_pointer, commit_size);
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let(new_capacity, new_page_capacity / item_size);
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vb->capacity = new_capacity;
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}
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}
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fn u8* vb_generic_add_assume_capacity(VirtualBuffer(u8)* vb, u32 item_size, u32 item_count)
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{
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u32 index = vb->length;
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assert(vb->capacity >= index + item_count);
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vb->length = index + item_count;
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return vb->pointer + (index * item_size);
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}
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fn u8* vb_generic_add(VirtualBuffer(u8)* vb, u32 item_size, u32 item_count)
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{
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vb_generic_ensure_capacity(vb, item_size, item_count);
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return vb_generic_add_assume_capacity(vb, item_size, item_count);
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}
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fn u8* vb_append_bytes(VirtualBuffer(u8*) vb, Slice(u8) bytes)
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{
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let_cast(u32, len, bytes.length);
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vb_generic_ensure_capacity(vb, sizeof(u8), len);
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let(pointer, vb_generic_add_assume_capacity(vb, sizeof(u8), len));
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memcpy(pointer, bytes.pointer, len);
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return pointer;
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}
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fn void vb_copy_string(VirtualBuffer(u8)* buffer, String string)
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{
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let_cast(u32, length, string.length);
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let(pointer, vb_add(buffer, length));
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memcpy(pointer, string.pointer, length);
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}
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fn u64 vb_copy_string_zero_terminated(VirtualBuffer(u8)* buffer, String string)
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{
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assert(string.pointer[string.length] == 0);
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string.length += 1;
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vb_copy_string(buffer, string);
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return string.length;
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}
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