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Slightly reorganize command line options help.

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Bruno Haible
2003-01-29 12:31:42 +00:00
parent f54d310530
commit 3aff1fd64f
4 changed files with 27 additions and 18 deletions
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7
ChangeLog
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@@ -1,3 +1,10 @@
2002-11-16 Bruno Haible <bruno@clisp.org>
* doc/gperf.texi: Move description of option -l from section
Algorithmic Details to section Output Details.
* src/options.cc (Options::long_usage): Likewise.
* tests/test-6.exp: Update.
2002-11-12 Bruno Haible <bruno@clisp.org>
* src/options.h (Output::get_output_file_name): New method.

22
doc/gperf.texi
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@@ -683,6 +683,17 @@ test like @samp{c >= 'A' && c <= 'Z'} guarantees this.) This was the
default in versions of @code{gperf} earlier than 2.7; now the default is
to support 8-bit and multibyte characters.
@item -l
@itemx --compare-strlen
Compare keyword lengths before trying a string comparison. This option
is mandatory for binary comparisons (@pxref{Binary Strings}). It also might
cut down on the number of string comparisons made during the lookup, since
keywords with different lengths are never compared via @code{strcmp}.
However, using @samp{-l} might greatly increase the size of the
generated C code if the lookup table range is large (which implies that
the switch option @samp{-S} is not enabled), since the length table
contains as many elements as there are entries in the lookup table.
@item -c
@itemx --compare-strncmp
Generates C code that uses the @code{strncmp} function to perform
@@ -767,17 +778,6 @@ with length less than the indicated byte positions work properly, since
selected byte positions exceeding the keyword length are simply not
referenced in the hash function.
@item -l
@itemx --compare-strlen
Compare keyword lengths before trying a string comparison. This might cut
down on the number of string comparisons made during the lookup, since
keywords with different lengths are never compared via @code{strcmp}.
However, using @samp{-l} might greatly increase the size of the
generated C code if the lookup table range is large (which implies that
the switch option @samp{-S} is not enabled), since the length table
contains as many elements as there are entries in the lookup table.
This option is mandatory for binary comparisons (@pxref{Binary Strings}).
@item -D
@itemx --duplicates
@cindex Duplicates

9
src/options.cc
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@@ -137,6 +137,11 @@ Options::long_usage (FILE * stream) const
" 'Perfect_Hash'.\n");
fprintf (stream,
" -7, --seven-bit Assume 7-bit characters.\n");
fprintf (stream,
" -l, --compare-strlen Compare key lengths before trying a string\n"
" comparison. This is necessary if the keywords\n"
" contain NUL bytes. It also helps cut down on the\n"
" number of string comparisons made during the lookup.\n");
fprintf (stream,
" -c, --compare-strncmp Generate comparison code using strncmp rather than\n"
" strcmp.\n");
@@ -187,10 +192,6 @@ Options::long_usage (FILE * stream) const
" indicates the \"final character\" of a key, e.g.,\n"
" $,1,2,4,6-10.\n",
Positions::MAX_KEY_POS);
fprintf (stream,
" -l, --compare-strlen Compare key lengths before trying a string\n"
" comparison. This helps cut down on the number of\n"
" string comparisons made during the lookup.\n");
fprintf (stream,
" -D, --duplicates Handle keywords that hash to duplicate values. This\n"
" is useful for certain highly redundant keyword sets.\n");

7
tests/test-6.exp
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@@ -42,6 +42,10 @@ Details in the output code:
-Z, --class-name=NAME Specify name of generated C++ class. Default name is
'Perfect_Hash'.
-7, --seven-bit Assume 7-bit characters.
-l, --compare-strlen Compare key lengths before trying a string
comparison. This is necessary if the keywords
contain NUL bytes. It also helps cut down on the
number of string comparisons made during the lookup.
-c, --compare-strncmp Generate comparison code using strncmp rather than
strcmp.
-C, --readonly-tables Make the contents of generated lookup tables
@@ -81,9 +85,6 @@ Algorithm employed by gperf:
hash function to consider ALL key positions, and $
indicates the "final character" of a key, e.g.,
$,1,2,4,6-10.
-l, --compare-strlen Compare key lengths before trying a string
comparison. This helps cut down on the number of
string comparisons made during the lookup.
-D, --duplicates Handle keywords that hash to duplicate values. This
is useful for certain highly redundant keyword sets.
-f, --fast=ITERATIONS Generate the gen-perf.hash function "fast". This