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Committer:
rillig
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Date:
2021-04-12 18:48:00 UTC
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Revision ID:
rillig-20210412184800-1pem5s72iyev92xo
make: reduce memory allocation and strlen calls in modifier ':from=to'
Previously, SysVMatch was quite verbose and felt like hand-optimized
assembler code, which made it difficult to discover the underlying idea
of the code.
All this code was replaced with two simple calls to Substring_HasPrefix
and Substring_HasSuffix. Now that the operands of that modifier are no
longer passed as C strings, there is no need to collect all information
in a single scan through the word and the pattern.
It was not necessary to call Var_Subst unconditionally. Calling it only
when the string contains a '$' saves another memory allocation and two
string copies (because of the Buf_DoneDataCompact).
No functional change.