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Fix a mis-parse of NPY v2.0 and 3.0 headers #77

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Fix a mis-parse of NPY v2.0 and 3.0 headers #77

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3392473
Fix a mis-parse of NPY v2.0 and 3.0 headers
nmcclatchey Aug 17, 2020
4f8c6e4
Bugfix: `header` string was oversized
nmcclatchey Sep 3, 2025
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9 changes: 7 additions & 2 deletions cnpy.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -63,8 +63,13 @@ void cnpy::parse_npy_header(unsigned char* buffer,size_t& word_size, std::vector
//std::string magic_string(buffer,6);
uint8_t major_version = *reinterpret_cast<uint8_t*>(buffer+6);
uint8_t minor_version = *reinterpret_cast<uint8_t*>(buffer+7);
uint16_t header_len = *reinterpret_cast<uint16_t*>(buffer+8);
std::string header(reinterpret_cast<char*>(buffer+9),header_len);
bool extended_header = (major_version > 1);
uint32_t header_len;
if (extended_header)
header_len = *reinterpret_cast<uint32_t*>(buffer+8);
else
header_len = *reinterpret_cast<uint16_t*>(buffer+8);
std::string header(reinterpret_cast<char*>(buffer+(extended_header ? 11 : 9)),header_len);

@s-trinh s-trinh Sep 2, 2025

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Since header_len is uint16_t, I think it should be?

Suggested change
std::string header(reinterpret_cast<char*>(buffer+(extended_header ? 11 : 9)),header_len);
std::string header(reinterpret_cast<char*>(buffer+(extended_header ? 12 : 10)),header_len);

@nmcclatchey nmcclatchey Sep 3, 2025

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I think you're right. It's been working because the only use of header has been based on relative locations discovered using find and similar, but we could improve performance (ever so slightly) by using the correct offset.

@nmcclatchey nmcclatchey Sep 3, 2025

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Fixed. Thanks for pointing this out.


size_t loc1, loc2;

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