Other minor frontend.util cleanups (#5629)

* Resync fixUtf8 w/ upstream
* Fix lastIndexOf desc
* Drop unichar usage, it's a crappier unicodeCodepointToUtf8 ;).

frontend/apps/filemanager/filemanagersearch.lua

@@ -9,7 +9,8 @@ local Screen = require("device").screen
 local UIManager = require("ui/uimanager")
 local lfs = require("libs/libkoreader-lfs")
 local logger = require("logger")
-local util = require("ffi/util")
+local FFIUtil = require("ffi/util")
+local util = require("util")
 local _ = require("gettext")
 local T = require("ffi/util").template
 
@@ -255,7 +256,7 @@ function Search:find(option)
             s=string.sub(s, n, string.len(s)-j)
         end
 
-        s=string.gsub(s, "\\u([a-f0-9][a-f0-9][a-f0-9][a-f0-9])", function(w) return util.unichar(tonumber(w, 16)) end)
+        s=string.gsub(s, "\\u([a-f0-9][a-f0-9][a-f0-9][a-f0-9])", function(w) return util.unicodeCodepointToUtf8(tonumber(w, 16)) end)
 
         return s
     end
@@ -606,7 +607,7 @@ function Search:browse(option, run, chosen)
     if run == 1 then
         self.results = {}
         if option == "series" then
-            for v,n in util.orderedPairs(self.browse_series) do
+            for v,n in FFIUtil.orderedPairs(self.browse_series) do
                 dummy = v
                 if not SEARCH_CASESENSITIVE then dummy = string.upper(dummy) end
                 if string.find(dummy, upsearch, nil, true) then
@@ -619,7 +620,7 @@ function Search:browse(option, run, chosen)
                 end
            end
         else
-            for v,n in util.orderedPairs(self.browse_tags) do
+            for v,n in FFIUtil.orderedPairs(self.browse_tags) do
                 dummy = v
                 if not SEARCH_CASESENSITIVE then dummy = string.upper(dummy) end
                 if string.find(dummy, upsearch, nil, true) then

frontend/apps/reader/modules/readerdictionary.lua

@@ -567,7 +567,7 @@ function ReaderDictionary:cleanSelection(text)
     -- with plain ascii quote (for french words like "aujourd’hui")
     text = text:gsub("\xE2\x80\x99", "'") -- U+2019 (right single quotation mark)
     -- Strip punctuation characters around selection
-    text = util.stripePunctuations(text)
+    text = util.stripPunctuation(text)
     -- Strip some common english grammatical construct
     text = text:gsub("'s$", '') -- english possessive
     -- Strip some common french grammatical constructs

frontend/apps/reader/modules/readerhighlight.lua

@@ -1116,7 +1116,7 @@ function ReaderHighlight:onHighlightSearch()
     logger.dbg("search highlight")
     self:highlightFromHoldPos()
     if self.selected_text then
-        local text = require("util").stripePunctuations(self.selected_text.text)
+        local text = require("util").stripPunctuation(self.selected_text.text)
         self.ui:handleEvent(Event:new("ShowSearchDialog", text))
     end
 end

frontend/ui/data/keyboardlayouts/ko_KR_helper.lua

@@ -22,6 +22,7 @@
 --]]
 
 local BaseUtil = require("ffi/util")
+local util = require("util")
 local logger = require("logger")
 
 -- Hangul Syllables
@@ -82,8 +83,8 @@ end
 
 
 function HgSylbls:get_combined_char(initial, medial, final)
-    -- utf8.char()
-    return BaseUtil.unichar(HgSylbls:_get_combined_charcode(initial, medial, final))
+    -- utf8.char() (i.e., encode)
+    return util.unicodeCodepointToUtf8(HgSylbls:_get_combined_charcode(initial, medial, final))
 end
 function HgSylbls:_get_combined_charcode(initial, medial, final)
     local len_medial = #HgSylbls.CHARS_MEDIAL
@@ -145,7 +146,7 @@ function HgSylbls:in_vowel_char(char)
             HgSylbls.UNI_HG_COMPAT_VOWEL_BASE, HgSylbls.UNI_HG_COMPAT_VOWEL_UPPER)
 end
 function HgSylbls:_in_target_char_group(char, base, upper, compat_base, compat_upper)
-    local code = BaseUtil.utf8charcode(char) -- utf8.codepoint()
+    local code = BaseUtil.utf8charcode(char) -- utf8.codepoint() (i.e., decode)
 
     if code == nil then
         return false

frontend/ui/opdsparser.lua

@@ -3,7 +3,7 @@
 
     https://github.com/Wiladams/LAPHLibs
 --]]
-local util = require("ffi/util")
+local util = require("util")
 local luxl = require("luxl")
 local ffi = require("ffi")
 
@@ -23,7 +23,7 @@ local function unescape(str)
         if unescape_map[s] then
             return unescape_map[s]
         elseif n == "#" then  -- unescape unicode
-            return util.unichar(tonumber(s))
+            return util.unicodeCodepointToUtf8(tonumber(s))
         else
             return orig
         end

frontend/util.lua

@@ -7,19 +7,20 @@ local dbg = require("dbg")
 local _ = require("gettext")
 local T = BaseUtil.template
 
+local lshift = bit.lshift
 local rshift = bit.rshift
 local band = bit.band
 local bor = bit.bor
 
 local util = {}
 
---- Strips all punctuation and spaces from a string.
+--- Strips all punctuation marks and spaces from a string.
 ---- @string text the string to be stripped
 ---- @treturn string stripped text
-function util.stripePunctuations(text)
+function util.stripPunctuation(text)
     if not text then return end
-    -- strip ASCII punctuation characters around text
-    -- and strip any generic punctuation (U+2000 - U+206F) in the text
+    -- strip ASCII punctuation marks around text
+    -- and strip any generic punctuation marks (U+2000 - U+206F) in the text
     return text:gsub("\226[\128-\131][\128-\191]", ''):gsub("^%p+", ''):gsub("%p+$", '')
 end
 
@@ -286,7 +287,7 @@ function util.tableMerge(t1, t2)
 end
 
 --[[--
-Gets last index of string in character
+Gets last index of character in string (i.e., strrchr)
 
 Returns the index within this string of the last occurrence of the specified character
 or -1 if the character does not occur.
@@ -348,7 +349,7 @@ function util.splitToChars(text)
                     hi_surrogate_uchar = uchar -- will be added if not followed by low surrogate
                 elseif hi_surrogate and charcode and charcode >= 0xDC00 and charcode <= 0xDFFF then
                     -- low surrogate following a high surrogate, good, let's make them a single char
-                    charcode = (hi_surrogate - 0xD800) * 0x400 + (charcode - 0xDC00) + 0x10000
+                    charcode = lshift((hi_surrogate - 0xD800), 10) + (charcode - 0xDC00) + 0x10000
                     table.insert(tab, util.unicodeCodepointToUtf8(charcode))
                     hi_surrogate = nil
                 else
@@ -379,13 +380,13 @@ function util.hasCJKChar(str)
     return string.match(str, "[\228-\234][\128-\191].") ~= nil
 end
 
---- Split texts into a list of words, spaces and punctuation.
+--- Split texts into a list of words, spaces and punctuation marks.
 ---- @string text text to split
----- @treturn table list of words, spaces and punctuation
+---- @treturn table list of words, spaces and punctuation marks
 function util.splitToWords(text)
     local wlist = {}
     for word in util.gsplit(text, "[%s%p]+", true) do
-        -- if space splitted word contains CJK characters
+        -- if space split word contains CJK characters
         if util.hasCJKChar(word) then
             -- split with CJK characters
             for char in util.gsplit(word, "[\228-\234\192-\255][\128-\191]+", true) do
@@ -399,11 +400,11 @@ function util.splitToWords(text)
 end
 
 -- We don't want to split on a space if it is followed by some
--- specific punctuation : e.g. "word :" or "word )"
--- (In french, there is a space before a colon, and it better
+-- specific punctuation marks : e.g. "word :" or "word )"
+-- (In French, there is a non-breaking space before a colon, and it better
 -- not be wrapped there.)
 local non_splittable_space_tailers = ":;,.!?)]}$%=-+*/|<>»”"
--- Same if a space has some specific other punctuation before it
+-- Same if a space has some specific other punctuation mark before it
 local non_splittable_space_leaders = "([{$=-+*/|<>«“"
 
 
@@ -460,20 +461,20 @@ function util.isSplittable(c, next_c, prev_c)
             return true
         end
     elseif c == " " then
-        -- we only split on a space (so punctuation sticks to prev word)
+        -- we only split on a space (so a punctuation mark sticks to prev word)
         -- if next_c or prev_c is provided, we can make a better decision
         if next_c and non_splittable_space_tailers:find(next_c, 1, true) then
-            -- this space is followed by some punctuation that is better kept with us
+            -- this space is followed by some punctuation mark that is better kept with us
             return false
         elseif prev_c and non_splittable_space_leaders:find(prev_c, 1, true) then
-            -- this space is lead by some punctuation that is better kept with us
+            -- this space is lead by some punctuation mark that is better kept with us
             return false
         else
             -- we can split on this space
             return true
         end
     end
-    -- otherwise, non splittable
+    -- otherwise, not splittable
     return false
 end
 
@@ -570,7 +571,7 @@ local function replaceSlashChar(str)
 end
 
 --[[--
-Replaces characters that are invalid filenames.
+Replaces characters that are invalid in filenames.
 
 Replaces the characters `\/:*?"<>|` with an `_` unless an optional path is provided. These characters are problematic on Windows filesystems. On Linux only the `/` poses a problem.
 
@@ -683,7 +684,7 @@ function util.getMenuText(item)
         text = item.text
     end
     if item.sub_item_table ~= nil or item.sub_item_table_func then
-        text = text .. " \226\150\184"
+        text = text .. " ▸"
     end
     return text
 end
@@ -692,6 +693,8 @@ end
 Replaces invalid UTF-8 characters with a replacement string.
 
 Based on <http://notebook.kulchenko.com/programming/fixing-malformed-utf8-in-lua>.
+c.f.,    FixUTF8 @ <https://github.com/pkulchenko/ZeroBraneStudio/blob/master/src/util.lua>.
+
 @string str the string to be checked for invalid characters
 @string replacement the string to replace invalid characters with
 @treturn string valid UTF-8
@@ -700,15 +703,15 @@ function util.fixUtf8(str, replacement)
     local pos = 1
     local len = #str
     while pos <= len do
-        if     pos == str:find("[%z\1-\127]", pos) then pos = pos + 1
-        elseif pos == str:find("[\194-\223][\128-\191]", pos) then pos = pos + 2
-        elseif pos == str:find(       "\224[\160-\191][\128-\191]", pos)
-            or pos == str:find("[\225-\236][\128-\191][\128-\191]", pos)
-            or pos == str:find(       "\237[\128-\159][\128-\191]", pos)
-            or pos == str:find("[\238-\239][\128-\191][\128-\191]", pos) then pos = pos + 3
-        elseif pos == str:find(       "\240[\144-\191][\128-\191][\128-\191]", pos)
-            or pos == str:find("[\241-\243][\128-\191][\128-\191][\128-\191]", pos)
-            or pos == str:find(       "\244[\128-\143][\128-\191][\128-\191]", pos) then pos = pos + 4
+        if     str:find("^[%z\1-\127]", pos) then pos = pos + 1
+        elseif str:find("^[\194-\223][\128-\191]", pos) then pos = pos + 2
+        elseif str:find(       "^\224[\160-\191][\128-\191]", pos)
+            or str:find("^[\225-\236][\128-\191][\128-\191]", pos)
+            or str:find(       "^\237[\128-\159][\128-\191]", pos)
+            or str:find("^[\238-\239][\128-\191][\128-\191]", pos) then pos = pos + 3
+        elseif str:find(       "^\240[\144-\191][\128-\191][\128-\191]", pos)
+            or str:find("^[\241-\243][\128-\191][\128-\191][\128-\191]", pos)
+            or str:find(       "^\244[\128-\143][\128-\191][\128-\191]", pos) then pos = pos + 4
         else
             str = str:sub(1, pos - 1) .. replacement .. str:sub(pos + 1)
             pos = pos + #replacement
@@ -735,6 +738,7 @@ end
 --- Convert a Unicode codepoint (number) to UTF-8 char
 --- c.f., <https://stackoverflow.com/a/4609989>
 ---     & <https://stackoverflow.com/a/38492214>
+--- See utf8charcode in ffi/util for a decoder.
 --
 --- @int c Unicode codepoint
 --- @treturn string UTF-8 char
@@ -779,12 +783,12 @@ local HTML_ENTITIES_TO_UTF8 = {
     {"&amp;", "&"}, -- must be last
 }
 --[[--
-Replace HTML entities with their UTF8 equivalent in text.
+Replace HTML entities with their UTF-8 encoded equivalent in text.
 
 Supports only basic ones and those with numbers (no support for named entities like `&eacute;`).
 
 @int string text with HTML entities
-@treturn string UTF8 text
+@treturn string UTF-8 text
 ]]
 function util.htmlEntitiesToUtf8(text)
     for _, t in ipairs(HTML_ENTITIES_TO_UTF8) do
@@ -834,7 +838,7 @@ function util.htmlToPlainTextIfHtml(text)
         is_html = true
     else
         -- no <tag> found
-        -- but we may meet some text badly twicely encoded html containing "&lt;br&gt;"
+        -- but we may meet some text badly/twice encoded html containing "&lt;br&gt;"
         local nb_encoded_tags
         _, nb_encoded_tags = text:gsub("&lt;%a+&gt;", "")
         if nb_encoded_tags > 0 then

spec/unit/util_spec.lua

@@ -6,14 +6,14 @@ describe("util module", function()
         util = require("util")
     end)
 
-    it("should strip punctuations around word", function()
-        assert.is_equal("hello world", util.stripePunctuations("\"hello world\""))
-        assert.is_equal("hello world", util.stripePunctuations("\"hello world?\""))
-        assert.is_equal("hello, world", util.stripePunctuations("\"hello, world?\""))
-        assert.is_equal("你好", util.stripePunctuations("“你好“"))
-        assert.is_equal("你好", util.stripePunctuations("“你好?“"))
-        assert.is_equal("", util.stripePunctuations(""))
-        assert.is_nil(util.stripePunctuations(nil))
+    it("should strip punctuation marks around word", function()
+        assert.is_equal("hello world", util.stripPunctuation("\"hello world\""))
+        assert.is_equal("hello world", util.stripPunctuation("\"hello world?\""))
+        assert.is_equal("hello, world", util.stripPunctuation("\"hello, world?\""))
+        assert.is_equal("你好", util.stripPunctuation("“你好“"))
+        assert.is_equal("你好", util.stripPunctuation("“你好?“"))
+        assert.is_equal("", util.stripPunctuation(""))
+        assert.is_nil(util.stripPunctuation(nil))
     end)
 
     describe("gsplit()", function()