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33 lines
912 B
C++
33 lines
912 B
C++
#include "c4/memory_util.hpp"
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#include "c4/error.hpp"
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namespace c4 {
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/** Fills 'dest' with the first 'pattern_size' bytes at 'pattern', 'num_times'. */
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void mem_repeat(void* dest, void const* pattern, size_t pattern_size, size_t num_times)
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{
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if(C4_UNLIKELY(num_times == 0))
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return;
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C4_ASSERT( ! mem_overlaps(dest, pattern, num_times*pattern_size, pattern_size));
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char *begin = static_cast<char*>(dest);
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char *end = begin + num_times * pattern_size;
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// copy the pattern once
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::memcpy(begin, pattern, pattern_size);
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// now copy from dest to itself, doubling up every time
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size_t n = pattern_size;
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while(begin + 2*n < end)
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{
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::memcpy(begin + n, begin, n);
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n <<= 1; // double n
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}
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// copy the missing part
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if(begin + n < end)
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{
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::memcpy(begin + n, begin, static_cast<size_t>(end - (begin + n)));
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}
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}
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} // namespace c4
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