base/bif/strings.bif.bro

GLOBAL

Definitions of built-in functions related to string processing and manipulation.

Namespace:GLOBAL Source File:/scripts/base/bif/strings.bif.bro

Summary

Functions

cat_string_array: function &deprecated	Concatenates all elements in an array of strings.
cat_string_array_n: function &deprecated	Concatenates a specific range of elements in an array of strings.
clean: function	Replaces non-printable characters in a string with escaped sequences.
edit: function	Returns an edited version of a string that applies a special “backspace character” (usually \x08 for backspace or \x7f for DEL).
escape_string: function	Replaces non-printable characters in a string with escaped sequences.
find_all: function	Finds all occurrences of a pattern in a string.
find_last: function	Finds the last occurrence of a pattern in a string.
gsub: function	Substitutes a given replacement string for all occurrences of a pattern in a given string.
hexdump: function	Returns a hex dump for given input data.
is_ascii: function	Determines whether a given string contains only ASCII characters.
join_string_array: function &deprecated	Joins all values in the given array of strings with a separator placed between each element.
join_string_vec: function	Joins all values in the given vector of strings with a separator placed between each element.
levenshtein_distance: function	Calculates the Levenshtein distance between the two strings.
reverse: function	Returns a reversed copy of the string
sort_string_array: function &deprecated	Sorts an array of strings.
split: function &deprecated	Splits a string into an array of strings according to a pattern.
split1: function &deprecated	Splits a string once into a two-element array of strings according to a pattern.
split_all: function &deprecated	Splits a string into an array of strings according to a pattern.
split_n: function &deprecated	Splits a string a given number of times into an array of strings according to a pattern.
split_string: function	Splits a string into an array of strings according to a pattern.
split_string1: function	Splits a string once into a two-element array of strings according to a pattern.
split_string_all: function	Splits a string into an array of strings according to a pattern.
split_string_n: function	Splits a string a given number of times into an array of strings according to a pattern.
str_shell_escape: function	Takes a string and escapes characters that would allow execution of commands at the shell level.
str_smith_waterman: function	Uses the Smith-Waterman algorithm to find similar/overlapping substrings.
str_split: function	Splits a string into substrings with the help of an index vector of cutting points.
strcmp: function	Lexicographically compares two strings.
string_cat: function	Concatenates all arguments into a single string.
string_fill: function	Generates a string of a given size and fills it with repetitions of a source string.
string_to_ascii_hex: function	Returns an ASCII hexadecimal representation of a string.
strip: function	Strips whitespace at both ends of a string.
strstr: function	Locates the first occurrence of one string in another.
sub: function	Substitutes a given replacement string for the first occurrence of a pattern in a given string.
sub_bytes: function	Get a substring from a string, given a starting position and length.
subst_string: function	Substitutes each (non-overlapping) appearance of a string in another.
to_lower: function	Replaces all uppercase letters in a string with their lowercase counterpart.
to_string_literal: function	Replaces non-printable characters in a string with escaped sequences.
to_upper: function	Replaces all lowercase letters in a string with their uppercase counterpart.

Detailed Interface

Functions

cat_string_array

Type:function (a: string_array) : string Attributes:&deprecated

Concatenates all elements in an array of strings.

A:The string_array (table[count] of string). Returns:The concatenation of all elements in a.

See also: cat, cat_sep, string_cat, cat_string_array_n, fmt, join_string_vec, join_string_array

cat_string_array_n

Type:function (a: string_array, start: count, end: count) : string Attributes:&deprecated

Concatenates a specific range of elements in an array of strings.

A:The string_array (table[count] of string). Start:The array index of the first element of the range. End:The array index of the last element of the range. Returns:The concatenation of the range [start, end] in a.

See also: cat, string_cat, cat_string_array, fmt, join_string_vec, join_string_array

clean

Type:function (str: string) : string

Replaces non-printable characters in a string with escaped sequences. The mappings are:

• values not in [32, 126] to \xXX

If the string does not yet have a trailing NUL, one is added internally.

In contrast to escape_string, this encoding is not fully reversible.`

Str:The string to escape. Returns:The escaped string.

See also: to_string_literal, escape_string

edit

Type:function (arg_s: string, arg_edit_char: string) : string

Returns an edited version of a string that applies a special “backspace character” (usually \x08 for backspace or \x7f for DEL). For example, edit("hello there", "e") returns "llo t".

Arg_s:The string to edit. Arg_edit_char:A string of exactly one character that represents the “backspace character”. If it is longer than one character Bro generates a run-time error and uses the first character in the string. Returns:An edited version of arg_s where arg_edit_char triggers the deletion of the last character.

See also: clean, to_string_literal, escape_string, strip

escape_string

Type:function (s: string) : string

Replaces non-printable characters in a string with escaped sequences. The mappings are:

• values not in [32, 126] to \xXX
• \ to \\

In contrast to clean, this encoding is fully reversible.`

Str:The string to escape. Returns:The escaped string.

See also: clean, to_string_literal

find_all

Type:function (str: string, re: pattern) : string_set

Finds all occurrences of a pattern in a string.

Str:The string to inspect. Re:The pattern to look for in str. Returns:The set of strings in str that match re, or the empty set.

find_last

Type:function (str: string, re: pattern) : string

Finds the last occurrence of a pattern in a string. This function returns the match that starts at the largest index in the string, which is not necessarily the longest match. For example, a pattern of /.*/ will return the final character in the string.

Str:The string to inspect. Re:The pattern to look for in str. Returns:The last string in str that matches re, or the empty string.

gsub

Type:function (str: string, re: pattern, repl: string) : string

Substitutes a given replacement string for all occurrences of a pattern in a given string.

Str:The string to perform the substitution in. Re:The pattern being replaced with repl. Repl:The string that replaces re. Returns:A copy of str with all occurrences of re replaced with repl.

See also: sub, subst_string

hexdump

Type:function (data_str: string) : string

Returns a hex dump for given input data. The hex dump renders 16 bytes per line, with hex on the left and ASCII (where printable) on the right.

Data_str:The string to dump in hex format. Returns:The hex dump of the given string.

See also: string_to_ascii_hex, bytestring_to_hexstr

Note

Based on Netdude’s hex editor code.

is_ascii

Type:function (str: string) : bool

Determines whether a given string contains only ASCII characters.

Str:The string to examine. Returns:False if any byte value of str is greater than 127, and true otherwise.

See also: to_upper, to_lower

join_string_array

Type:function (sep: string, a: string_array) : string Attributes:&deprecated

Joins all values in the given array of strings with a separator placed between each element.

Sep:The separator to place between each element. A:The string_array (table[count] of string). Returns:The concatenation of all elements in a, with sep placed between each element.

See also: cat, cat_sep, string_cat, cat_string_array, cat_string_array_n, fmt, join_string_vec

join_string_vec

Type:function (vec: string_vec, sep: string) : string

Joins all values in the given vector of strings with a separator placed between each element.

Sep:The separator to place between each element. Vec:The string_vec (vector of string). Returns:The concatenation of all elements in vec, with sep placed between each element.

See also: cat, cat_sep, string_cat, cat_string_array, cat_string_array_n, fmt, join_string_array

levenshtein_distance

Type:function (s1: string, s2: string) : count

Calculates the Levenshtein distance between the two strings. See Wikipedia for more information.

S1:The first string. S2:The second string. Returns:The Levenshtein distance of two strings as a count.

reverse

Type:function (str: string) : string

Returns a reversed copy of the string

Str:The string to reverse. Returns:A reversed copy of str

sort_string_array

Type:function (a: string_array) : string_array Attributes:&deprecated

Sorts an array of strings.

A:The string_array (table[count] of string). Returns:A sorted copy of a.

See also: sort

split

Type:function (str: string, re: pattern) : string_array Attributes:&deprecated

Splits a string into an array of strings according to a pattern.

Str:The string to split. Re:The pattern describing the element separator in str. Returns:An array of strings where each element corresponds to a substring in str separated by re.

See also: split1, split_all, split_n, str_split, split_string1, split_string_all, split_string_n, str_split

Note

The returned table starts at index 1. Note that conceptually the return value is meant to be a vector and this might change in the future.

split1

Type:function (str: string, re: pattern) : string_array Attributes:&deprecated

Splits a string once into a two-element array of strings according to a pattern. This function is the same as split, but str is only split once (if possible) at the earliest position and an array of two strings is returned.

Str:The string to split. Re:The pattern describing the separator to split str in two pieces. Returns:An array of strings with two elements in which the first represents the substring in str up to the first occurence of re, and the second everything after re. An array of one string is returned when s cannot be split.

See also: split, split_all, split_n, str_split, split_string, split_string_all, split_string_n, str_split

split_all

Type:function (str: string, re: pattern) : string_array Attributes:&deprecated

Splits a string into an array of strings according to a pattern. This function is the same as split, except that the separators are returned as well. For example, split_all("a-b--cd", /(\-)+/) returns {"a", "-", "b", "--", "cd"}: odd-indexed elements do not match the pattern and even-indexed ones do.

Str:The string to split. Re:The pattern describing the element separator in str. Returns:An array of strings where each two successive elements correspond to a substring in str of the part not matching re (odd-indexed) and the part that matches re (even-indexed).

See also: split, split1, split_n, str_split, split_string, split_string1, split_string_n, str_split

split_n

Type:function (str: string, re: pattern, incl_sep: bool, max_num_sep: count) : string_array Attributes:&deprecated

Splits a string a given number of times into an array of strings according to a pattern. This function is similar to split1 and split_all, but with customizable behavior with respect to including separators in the result and the number of times to split.

Str:The string to split. Re:The pattern describing the element separator in str. Incl_sep:A flag indicating whether to include the separator matches in the result (as in split_all). Max_num_sep:The number of times to split str. Returns:An array of strings where, if incl_sep is true, each two successive elements correspond to a substring in str of the part not matching re (odd-indexed) and the part that matches re (even-indexed).

See also: split, split1, split_all, str_split, split_string, split_string1, split_string_all, str_split

split_string

Type:function (str: string, re: pattern) : string_vec

Splits a string into an array of strings according to a pattern.

Str:The string to split. Re:The pattern describing the element separator in str. Returns:An array of strings where each element corresponds to a substring in str separated by re.

See also: split_string1, split_string_all, split_string_n, str_split

split_string1

Type:function (str: string, re: pattern) : string_vec

Splits a string once into a two-element array of strings according to a pattern. This function is the same as split_string, but str is only split once (if possible) at the earliest position and an array of two strings is returned.

Str:The string to split. Re:The pattern describing the separator to split str in two pieces. Returns:An array of strings with two elements in which the first represents the substring in str up to the first occurence of re, and the second everything after re. An array of one string is returned when s cannot be split.

See also: split_string, split_string_all, split_string_n, str_split

split_string_all

Type:function (str: string, re: pattern) : string_vec

Splits a string into an array of strings according to a pattern. This function is the same as split_string, except that the separators are returned as well. For example, split_string_all("a-b--cd", /(\-)+/) returns {"a", "-", "b", "--", "cd"}: odd-indexed elements do match the pattern and even-indexed ones do not.

Str:The string to split. Re:The pattern describing the element separator in str. Returns:An array of strings where each two successive elements correspond to a substring in str of the part not matching re (even-indexed) and the part that matches re (odd-indexed).

See also: split_string, split_string1, split_string_n, str_split

split_string_n

Type:function (str: string, re: pattern, incl_sep: bool, max_num_sep: count) : string_vec

Splits a string a given number of times into an array of strings according to a pattern. This function is similar to split_string1 and split_string_all, but with customizable behavior with respect to including separators in the result and the number of times to split.

Str:The string to split. Re:The pattern describing the element separator in str. Incl_sep:A flag indicating whether to include the separator matches in the result (as in split_string_all). Max_num_sep:The number of times to split str. Returns:An array of strings where, if incl_sep is true, each two successive elements correspond to a substring in str of the part not matching re (even-indexed) and the part that matches re (odd-indexed).

See also: split_string, split_string1, split_string_all, str_split

str_shell_escape

Type:function (source: string) : string

Takes a string and escapes characters that would allow execution of commands at the shell level. Must be used before including strings in system or similar calls.

Source:The string to escape. Returns:A shell-escaped version of source.

See also: system

str_smith_waterman

Type:function (s1: string, s2: string, params: sw_params) : sw_substring_vec

Uses the Smith-Waterman algorithm to find similar/overlapping substrings. See Wikipedia.

S1:The first string. S2:The second string. Params:Parameters for the Smith-Waterman algorithm. Returns:The result of the Smith-Waterman algorithm calculation.

str_split

Type:function (s: string, idx: index_vec) : string_vec

Splits a string into substrings with the help of an index vector of cutting points.

S:The string to split. Idx:The index vector (vector of count) with the cutting points. Returns:A vector of strings.

See also: split, split1, split_all, split_n

strcmp

Type:function (s1: string, s2: string) : int

Lexicographically compares two strings.

S1:The first string. S2:The second string. Returns:An integer greater than, equal to, or less than 0 according as s1 is greater than, equal to, or less than s2.

string_cat

Type:function (va_args: any) : string

Concatenates all arguments into a single string. The function takes a variable number of arguments of type string and stitches them together.

Returns:The concatenation of all (string) arguments.

See also: cat, cat_sep, cat_string_array, cat_string_array_n, fmt, join_string_vec, join_string_array

string_fill

Type:function (len: int, source: string) : string

Generates a string of a given size and fills it with repetitions of a source string.

Len:The length of the output string. Source:The string to concatenate repeatedly until len has been reached. Returns:A string of length len filled with source.

string_to_ascii_hex

Type:function (s: string) : string

Returns an ASCII hexadecimal representation of a string.

S:The string to convert to hex. Returns:A copy of s where each byte is replaced with the corresponding hex nibble.

strip

Type:function (str: string) : string

Strips whitespace at both ends of a string.

Str:The string to strip the whitespace from. Returns:A copy of str with leading and trailing whitespace removed.

See also: sub, gsub

strstr

Type:function (big: string, little: string) : count

Locates the first occurrence of one string in another.

Big:The string to look in. Little:The (smaller) string to find inside big. Returns:The location of little in big, or 0 if little is not found in big.

See also: find_all, find_last

sub

Type:function (str: string, re: pattern, repl: string) : string

Substitutes a given replacement string for the first occurrence of a pattern in a given string.

Str:The string to perform the substitution in. Re:The pattern being replaced with repl. Repl:The string that replaces re. Returns:A copy of str with the first occurence of re replaced with repl.

See also: gsub, subst_string

sub_bytes

Type:function (s: string, start: count, n: int) : string

Get a substring from a string, given a starting position and length.

S:The string to obtain a substring from. Start:The starting position of the substring in s, where 1 is the first character. As a special case, 0 also represents the first character. N:The number of characters to extract, beginning at start. Returns:A substring of s of length n from position start.

subst_string

Type:function (s: string, from: string, to: string) : string

Substitutes each (non-overlapping) appearance of a string in another.

S:The string in which to perform the substitution. From:The string to look for which is replaced with to. To:The string that replaces all occurrences of from in s. Returns:A copy of s where each occurrence of from is replaced with to.

See also: sub, gsub

to_lower

Type:function (str: string) : string

Replaces all uppercase letters in a string with their lowercase counterpart.

Str:The string to convert to lowercase letters. Returns:A copy of the given string with the uppercase letters (as indicated by isascii and isupper) folded to lowercase (via tolower).

See also: to_upper, is_ascii

to_string_literal

Type:function (str: string) : string

Replaces non-printable characters in a string with escaped sequences. The mappings are:

• values not in [32, 126] to \xXX
• \ to \\
• ' and "" to \' and \", respectively.

Str:The string to escape. Returns:The escaped string.

See also: clean, escape_string

to_upper

Type:function (str: string) : string

Replaces all lowercase letters in a string with their uppercase counterpart.

Str:The string to convert to uppercase letters. Returns:A copy of the given string with the lowercase letters (as indicated by isascii and islower) folded to uppercase (via toupper).

See also: to_lower, is_ascii