38 lines
881 B
C
38 lines
881 B
C
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#pragma once
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#include <cstddef>
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#include <cstdint>
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#include <cstring>
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#include <span>
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template <size_t N>
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class prepend_buffer {
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uint8_t m_buf[N];
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size_t m_start = N / 2;
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size_t m_end = N / 2;
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public:
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template <typename T>
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T* prepend() {
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m_start -= sizeof(T);
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return reinterpret_cast<T*>(m_buf + m_start);
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}
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uint8_t* append(size_t len) {
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uint8_t* p = m_buf + m_end;
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m_end += len;
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return p;
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}
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void append_copy(std::span<const uint8_t> data) {
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memcpy(append(data.size()), data.data(), data.size());
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}
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uint8_t* payload_ptr() { return m_buf + m_end; }
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uint8_t* data() { return m_buf + m_start; }
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const uint8_t* data() const { return m_buf + m_start; }
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size_t size() const { return m_end - m_start; }
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std::span<const uint8_t> span() const { return {data(), size()}; }
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};
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