modes: starting to replace raw pointer arithmetic with std::span view.#5265
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modes: starting to replace raw pointer arithmetic with std::span view.#5265
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reneme
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Feb 3, 2026
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reneme
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reneme
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Some general suggestions. Note that this clashes with #4880 which has been open for a while. Perhaps let's revisit this once 3.11.0 is out the door, @randombit?
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| const secure_vector<uint8_t>& ad = ad_buf(); | ||
| BOTAN_ARG_CHECK(ad.size() % CCM_BS == 0, "AD is block size multiple"); | ||
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| const BlockCipher& E = cipher(); | ||
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| secure_vector<uint8_t> T(CCM_BS); | ||
| E.encrypt(format_b0(sz), T); | ||
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| for(size_t i = 0; i != ad.size(); i += CCM_BS) { | ||
| xor_buf(T.data(), &ad[i], CCM_BS); | ||
| xor_buf(std::span{T}.first(CCM_BS), std::span(&ad[i], CCM_BS)); | ||
| E.encrypt(T); | ||
| } |
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For the record: This could be simplified even further, along those lines:
Suggested change
| } | |
| BufferSlicer ad(ad_buf()); | |
| BOTAN_ARG_CHECK(ad.remaining() % CCM_BS == 0, "AD is block size multiple"); | |
| const BlockCipher& E = cipher(); | |
| secure_vector<uint8_t> T(CCM_BS); | |
| E.encrypt(format_b0(sz), T); | |
| while(!ad.empty()) { | |
| xor_buf(T, ad.take<CCM_BS>()); | |
| E.encrypt(T); | |
| } | |
| BOTAN_DEBUG_ASSERT(ad.empty()); |
... no need for the .first for T because T is allocated with exactly CCM_BS bytes anyway. Also, you might have to include stl_util.h for the BufferSlicer.
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| copy_mem(std::span{out}.first(k1.length()), k1.bits_of()); | ||
| xor_buf(std::span{out}.first(k2.length()), k2.bits_of()); | ||
| return OctetString(out); |
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While you're on it:
Suggested change
| copy_mem(std::span{out}.first(k1.length()), k1.bits_of()); | |
| xor_buf(std::span{out}.first(k2.length()), k2.bits_of()); | |
| return OctetString(out); | |
| copy_mem(std::span{out}.first(k1.length()), k1.bits_of()); | |
| xor_buf(std::span{out}.first(k2.length()), k2.bits_of()); | |
| return OctetString(std::move(out)); |
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| const secure_vector<uint8_t>& ad = ad_buf(); | ||
| BOTAN_ARG_CHECK(ad.size() % CCM_BS == 0, "AD is block size multiple"); | ||
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| const BlockCipher& E = cipher(); | ||
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| secure_vector<uint8_t> T(CCM_BS); | ||
| E.encrypt(format_b0(sz - tag_size()), T); | ||
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| for(size_t i = 0; i != ad.size(); i += CCM_BS) { | ||
| xor_buf(T.data(), &ad[i], CCM_BS); | ||
| xor_buf(std::span{T}.first(CCM_BS), std::span(&ad[i], CCM_BS)); | ||
| E.encrypt(T); | ||
| } |
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