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String::Make - new way how to create a small string fast [message #57545]

Sat, 18 September 2021 17:31

mirek
Messages: 13975
Registered: November 2005

Ultimate Member

While optimizing conversion routines, I have found a relative bottleneck when converting small char buffers to String. To solve that, there is now a new static method

template <class Maker> static String Make(int alloc, Maker m)

Optimized static method for creating Strings. This method creates internal buffer of at least alloc and then invokes lambda m passing the char * pointer to the internal buffer as lambda parameter. Lambda is then supposed to fill the characters to this buffer and return the length of string (which must be <= alloc). For the best performance, alloc should be constant.

Example:

String x = String::Make(12, [](char *t) { *t++ = 'X'; return 1; });

[Updated on: Sat, 26 February 2022 18:51]

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