1 files changed, 140 insertions, 0 deletions
diff --git a/nselib/stringaux.lua b/nselib/stringaux.lua
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+++ b/nselib/stringaux.lua
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+--- Auxiliary functions for string manipulation
+--
+-- @author Daniel Miller
+-- @copyright Same as Nmap--See https://nmap.org/book/man-legal.html
+-- @class module
+-- @name stringaux
+
+local assert = assert
+local type = type
+
+local string = require "string"
+local byte = string.byte
+local find = string.find
+local match = string.match
+local sub = string.sub
+local gsub = string.gsub
+local format = string.format
+local lower = string.lower
+local upper = string.upper
+
+local table = require "table"
+local concat = table.concat
+
+local _ENV = {}
+
+--- Join a list of strings with a separator string.
+--
+-- This is Lua's <code>table.concat</code> function with the parameters
+-- swapped for coherence.
+-- @usage
+-- stringaux.strjoin(", ", {"Anna", "Bob", "Charlie", "Dolores"})
+-- --> "Anna, Bob, Charlie, Dolores"
+-- @param delimiter String to delimit each element of the list.
+-- @param list Array of strings to concatenate.
+-- @return Concatenated string.
+function strjoin(delimiter, list)
+  assert(type(delimiter) == "string" or type(delimiter) == nil, "delimiter is of the wrong type! (did you get the parameters backward?)")
+
+  return concat(list, delimiter);
+end
+
+--- Split a string at a given delimiter, which may be a pattern.
+--
+-- If you want to loop over the resulting values, consider using string.gmatch instead.
+-- @usage
+-- stringaux.strsplit(",%s*", "Anna, Bob, Charlie, Dolores")
+-- --> { "Anna", "Bob", "Charlie", "Dolores" }
+-- @param pattern Pattern that separates the desired strings.
+-- @param text String to split.
+-- @return Array of substrings without the separating pattern.
+-- @see string.gmatch
+function strsplit(pattern, text)
+  local list, pos = {}, 1;
+
+  assert(pattern ~= "", "delimiter matches empty string!");
+
+  while true do
+    local first, last = find(text, pattern, pos);
+    if first then -- found?
+      list[#list+1] = sub(text, pos, first-1);
+      pos = last+1;
+    else
+      list[#list+1] = sub(text, pos);
+      break;
+    end
+  end
+  return list;
+end
+
+-- This pattern must match the percent sign '%' since it is used in
+-- escaping.
+local FILESYSTEM_UNSAFE = "[^a-zA-Z0-9._-]"
+local function _escape_helper (c)
+  return format("%%%02x", byte(c))
+end
+---
+-- Escape a string to remove bytes and strings that may have meaning to
+-- a filesystem, such as slashes.
+--
+-- All bytes are escaped, except for:
+-- * alphabetic <code>a</code>-<code>z</code> and <code>A</code>-<code>Z</code>
+-- * digits 0-9
+-- * <code>.</code> <code>_</code> <code>-</code>
+-- In addition, the strings <code>"."</code> and <code>".."</code> have
+-- their characters escaped.
+--
+-- Bytes are escaped by a percent sign followed by the two-digit
+-- hexadecimal representation of the byte value.
+-- * <code>filename_escape("filename.ext") --> "filename.ext"</code>
+-- * <code>filename_escape("input/output") --> "input%2foutput"</code>
+-- * <code>filename_escape(".") --> "%2e"</code>
+-- * <code>filename_escape("..") --> "%2e%2e"</code>
+-- This escaping is somewhat like that of JavaScript
+-- <code>encodeURIComponent</code>, except that fewer bytes are
+-- whitelisted, and it works on bytes, not Unicode characters or UTF-16
+-- code points.
+function filename_escape(s)
+  if s == "." then
+    return "%2e"
+  elseif s == ".." then
+    return "%2e%2e"
+  else
+    return (gsub(s, FILESYSTEM_UNSAFE, _escape_helper))
+  end
+end
+
+--- Returns the case insensitive pattern of given parameter
+--
+-- Useful while doing case insensitive pattern match using string library.
+-- https://stackoverflow.com/questions/11401890/case-insensitive-lua-pattern-matching/11402486#11402486
+--
+-- @usage stringaux.ipattern("user")
+-- --> "[uU][sS][eE][rR]"
+-- @param pattern The string
+-- @return A case insensitive patterned string
+function ipattern(pattern)
+  local in_brackets = false
+  -- Find an optional '%' (group 2) followed by any character (group 3)
+  local p = gsub(pattern, "(%%?)(.)", function(percent, letter)
+    if percent ~= "" then
+      -- It's a %-escape, return as-is
+      return nil
+    elseif not match(letter, "%a") then
+      -- It's not alpha. Update bracket status and return as-is
+      if letter == "[" then
+        in_brackets = true
+      elseif letter == "]" then
+        in_brackets = false
+      end
+      return nil
+    elseif not in_brackets then
+      -- Else, return a case-insensitive character class of the matched letter
+      return format("[%s%s]", lower(letter), upper(letter))
+    end
+  end)
+
+  return p
+end
+
+return _ENV