timingsafe_memcmp for crypto

[rurban]

Excellent collection of extensions.
I'm just missing more crypto stuff from the BSD's.

And maybe better UTF-8 string support, instead of the dreaded wchar standard, which doesn't even know about normalization, thus cannot do string cmp, searching for strings in unicode.

[jart]

Cosmopolitan now includes timingsafe_memcmp. Enjoy!

Cosmopolitan uses the C locale with UTF-8. So I'm not quite sure what you're requesting w.r.t. collation and normalization, which is a task that's largely governed by policy table restrictions that might be more appropriately left to something like libicu.

One thing Cosmo does implement quite well, however, is support for East Asian Monospace Widths, since that frequently comes up in my work. For example, the printf() family of functions will actually take it into consideration if you were to do something like printf("%8s\n", "😀").

[rurban]

Thanks.

I disagree with bloatware libicu. String support needs to be in the standard IMHO, and is pretty simple. I do support wcsnorm and wcsfc in safeclib, but nobody should use wcs anymore.

The Asian width support also, as u8glen, btw. (Graphical length). For u8 I'm adding identifier support for restrictions to public names (usernames, paths, symbols, ...), with the u8i prefix.

[jart]

I feel the same way. You've got a nice library. Out of curiosity what's your view on ASAN?

cosmopolitan/libc/log/asan.c

Lines 39 to 66 in 1df1363

	* @fileoverview Cosmopolitan Address Sanitizer Runtime.
	*
	* Someone brilliant at Google figured out a way to improve upon memory
	* protection. Rather than invent another Java or Rust they changed GCC
	* so it can emit fast code, that checks the validity of each memory op
	* with byte granularity, by probing shadow memory.
	*
	* - AddressSanitizer dedicates one-eighth of the virtual address space
	* to its shadow memory and uses a direct mapping with a scale and
	* offset to translate an application address to its corresponding
	* shadow address. Given the application memory address Addr, the
	* address of the shadow byte is computed as (Addr>>3)+Offset."
	*
	* - We use the following encoding for each shadow byte: 0 means that
	* all 8 bytes of the corresponding application memory region are
	* addressable; k (1 ≤ k ≤ 7) means that the first k bytes are
	* addressible; any negative value indicates that the entire 8-byte
	* word is unaddressable. We use different negative values to
	* distinguish between different kinds of unaddressable memory (heap
	* redzones, stack redzones, global redzones, freed memory).
	*
	* Here's what the generated code looks like for 64-bit reads:
	*
	* movq %addr,%tmp
	* shrq $3,%tmp
	* cmpb $0,0x7fff8000(%tmp)
	* jnz abort
	* movq (%addr),%dst

[rurban]

Brilliant. I love Kosta