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63 lines
1.7 KiB
Text
63 lines
1.7 KiB
Text
##! Functions to assist with small string analysis and manipulation that can
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##! be implemented as Bro functions and don't need to be implemented as built-in
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##! functions.
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## Returns true if the given string is at least 25% composed of 8-bit
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## characters.
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function is_string_binary(s: string): bool
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{
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return |gsub(s, /[\x00-\x7f]/, "")| * 100 / |s| >= 25;
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}
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## Join a set of strings together, with elements delimited by a constant string.
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##
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## ss: a set of strings to join.
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##
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## j: the string used to join set elements.
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##
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## Returns: a string composed of all elements of the set, delimited by the
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## joining string.
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function join_string_set(ss: set[string], j: string): string
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{
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local output="";
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local i=0;
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for ( s in ss )
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{
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if ( i > 0 )
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output = cat(output, j);
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output = cat(output, s);
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++i;
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}
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return output;
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}
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## Given a string, returns an escaped version.
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##
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## s: a string to escape.
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##
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## chars: a string containing all the characters that need to be escaped.
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##
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## Returns: a string with all occurrences of any character in *chars* escaped
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## using ``\``, and any literal ``\`` characters likewise escaped.
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function string_escape(s: string, chars: string): string
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{
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s = subst_string(s, "\\", "\\\\");
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for ( c in chars )
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s = subst_string(s, c, cat("\\", c));
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return s;
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}
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## Cut a number of characters from the end of the given string.
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##
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## s: a string to trim.
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##
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## tail_len: the number of characters to remove from the end of the string.
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##
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## Returns: the given string with *tail_len* characters removed from the end.
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function cut_tail(s: string, tail_len: count): string
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{
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if ( tail_len > |s| )
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tail_len = |s|;
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return sub_bytes(s, 1, int_to_count(|s| - tail_len));
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}
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