f391d9dc93
Rename tab-complete.c to tab-complete.in.c, create the preprocessor script gen_tabcomplete.pl, and install Makefile/meson.build rules to create tab-complete.c from tab-complete.in.c. The preprocessor converts match_previous_words' else-if chain into a switch and populates tcpatterns[] with the data needed by the driver loop. The initial HeadMatches/TailMatches/Matches test in each else-if arm is now performed in a table-driven loop. Where we get a match, the corresponding switch case is invoked to see if the match succeeds. (It might not, if there were additional conditions in the original else-if test.) The total number of string comparisons done is just about the same as it was in the previous coding; however, now that we have table-driven logic underlying the handmade rules, there is room to improve that. For now I haven't bothered because tab completion is still plenty fast enough for human use. If the number of rules keeps increasing, we might someday need to do more in that area. The immediate benefit of all this thrashing is that C compilers frequently don't deal well with long else-if chains. On gcc 8.5.0, this reduces the compile time of tab-complete.c by about a factor of four, while MSVC is reported to crash outright with the previous coding. Discussion: https://postgr.es/m/2208466.1720729502@sss.pgh.pa.us
PostgreSQL Database Management System
This directory contains the source code distribution of the PostgreSQL database management system.
PostgreSQL is an advanced object-relational database management system that supports an extended subset of the SQL standard, including transactions, foreign keys, subqueries, triggers, user-defined types and functions. This distribution also contains C language bindings.
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