forked from M-Labs/nac3
David Mak
b58c99369e
- Change CSlice to use `void*` for better pointer compatibility - Only include impl *.hpp files in irrt.cpp - Refactor typedef to using declaration - Add missing ``// namespace`
81 lines
4.1 KiB
C++
81 lines
4.1 KiB
C++
#pragma once
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#include "irrt/int_types.hpp"
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#include "irrt/math_util.hpp"
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extern "C" {
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// Handle list assignment and dropping part of the list when
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// both dest_step and src_step are +1.
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// - All the index must *not* be out-of-bound or negative,
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// - The end index is *inclusive*,
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// - The length of src and dest slice size should already
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// be checked: if dest.step == 1 then len(src) <= len(dest) else len(src) == len(dest)
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SliceIndex __nac3_list_slice_assign_var_size(SliceIndex dest_start,
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SliceIndex dest_end,
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SliceIndex dest_step,
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void* dest_arr,
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SliceIndex dest_arr_len,
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SliceIndex src_start,
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SliceIndex src_end,
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SliceIndex src_step,
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void* src_arr,
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SliceIndex src_arr_len,
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const SliceIndex size) {
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/* if dest_arr_len == 0, do nothing since we do not support extending list */
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if (dest_arr_len == 0)
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return dest_arr_len;
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/* if both step is 1, memmove directly, handle the dropping of the list, and shrink size */
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if (src_step == dest_step && dest_step == 1) {
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const SliceIndex src_len = (src_end >= src_start) ? (src_end - src_start + 1) : 0;
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const SliceIndex dest_len = (dest_end >= dest_start) ? (dest_end - dest_start + 1) : 0;
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if (src_len > 0) {
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__builtin_memmove(static_cast<uint8_t*>(dest_arr) + dest_start * size,
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static_cast<uint8_t*>(src_arr) + src_start * size, src_len * size);
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}
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if (dest_len > 0) {
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/* dropping */
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__builtin_memmove(static_cast<uint8_t*>(dest_arr) + (dest_start + src_len) * size,
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static_cast<uint8_t*>(dest_arr) + (dest_end + 1) * size,
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(dest_arr_len - dest_end - 1) * size);
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}
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/* shrink size */
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return dest_arr_len - (dest_len - src_len);
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}
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/* if two range overlaps, need alloca */
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uint8_t need_alloca = (dest_arr == src_arr)
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&& !(max(dest_start, dest_end) < min(src_start, src_end)
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|| max(src_start, src_end) < min(dest_start, dest_end));
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if (need_alloca) {
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void* tmp = __builtin_alloca(src_arr_len * size);
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__builtin_memcpy(tmp, src_arr, src_arr_len * size);
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src_arr = tmp;
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}
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SliceIndex src_ind = src_start;
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SliceIndex dest_ind = dest_start;
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for (; (src_step > 0) ? (src_ind <= src_end) : (src_ind >= src_end); src_ind += src_step, dest_ind += dest_step) {
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/* for constant optimization */
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if (size == 1) {
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__builtin_memcpy(static_cast<uint8_t*>(dest_arr) + dest_ind, static_cast<uint8_t*>(src_arr) + src_ind, 1);
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} else if (size == 4) {
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__builtin_memcpy(static_cast<uint8_t*>(dest_arr) + dest_ind * 4,
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static_cast<uint8_t*>(src_arr) + src_ind * 4, 4);
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} else if (size == 8) {
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__builtin_memcpy(static_cast<uint8_t*>(dest_arr) + dest_ind * 8,
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static_cast<uint8_t*>(src_arr) + src_ind * 8, 8);
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} else {
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/* memcpy for var size, cannot overlap after previous alloca */
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__builtin_memcpy(static_cast<uint8_t*>(dest_arr) + dest_ind * size,
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static_cast<uint8_t*>(src_arr) + src_ind * size, size);
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}
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}
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/* only dest_step == 1 can we shrink the dest list. */
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/* size should be ensured prior to calling this function */
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if (dest_step == 1 && dest_end >= dest_start) {
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__builtin_memmove(static_cast<uint8_t*>(dest_arr) + dest_ind * size,
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static_cast<uint8_t*>(dest_arr) + (dest_end + 1) * size,
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(dest_arr_len - dest_end - 1) * size);
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return dest_arr_len - (dest_end - dest_ind) - 1;
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}
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return dest_arr_len;
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}
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} // extern "C"
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