xz: Update a comment in file_io.h.

This commit is contained in:
Lasse Collin 2020-01-26 13:37:08 +02:00
parent 15b55d5c63
commit f6d2424534
1 changed files with 4 additions and 1 deletions

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@ -20,7 +20,10 @@
/// is_sparse() accesses the buffer as uint64_t for maximum speed. /// is_sparse() accesses the buffer as uint64_t for maximum speed.
/// Use an union to make sure that the buffer is properly aligned. /// The u32 and u64 members must only be access through this union
/// to avoid strict aliasing violations. Taking a pointer of u8
/// should be fine as long as uint8_t maps to unsigned char which
/// can alias anything.
typedef union { typedef union {
uint8_t u8[IO_BUFFER_SIZE]; uint8_t u8[IO_BUFFER_SIZE];
uint32_t u32[IO_BUFFER_SIZE / sizeof(uint32_t)]; uint32_t u32[IO_BUFFER_SIZE / sizeof(uint32_t)];