Optimization: Use constant folding for divisions not a power of two (#…

…9609)

frontend/apps/filemanager/filemanagermenu.lua

@@ -889,10 +889,10 @@ function FileManagerMenu:_getTabIndexFromLocation(ges)
     if not ges then
         return last_tab_index
     -- if the start position is far right
-    elseif ges.pos.x > 2 * Screen:getWidth() / 3 then
+    elseif ges.pos.x > Screen:getWidth() * (2/3) then
         return BD.mirroredUILayout() and 1 or #self.tab_item_table
     -- if the start position is far left
-    elseif ges.pos.x < Screen:getWidth() / 3 then
+    elseif ges.pos.x < Screen:getWidth() * (1/3) then
         return BD.mirroredUILayout() and #self.tab_item_table or 1
     -- if center return the last index
     else

frontend/apps/reader/modules/readerdevicestatus.lua

@@ -64,7 +64,7 @@ function ReaderDeviceStatus:init()
             if statm then
                 local dummy, rss = statm:read("*number", "*number")
                 statm:close()
-                rss = math.floor(rss * 4096 / 1024 / 1024)
+                rss = math.floor(rss * (4096 / 1024 / 1024))
                 if rss >= self.memory_threshold then
                     if self.memory_confirm_box then
                         UIManager:close(self.memory_confirm_box)

frontend/apps/reader/modules/readerdogear.lua

@@ -17,8 +17,8 @@ function ReaderDogear:init()
     -- to not overwrite the book text.
     -- For other documents, there is no easy way to know if valuable content
     -- may be hidden by the icon (kopt's page_margin is quite obscure).
-    self.dogear_min_size = math.ceil(math.min(Screen:getWidth(), Screen:getHeight()) / 40)
-    self.dogear_max_size = math.ceil(math.min(Screen:getWidth(), Screen:getHeight()) / 32)
+    self.dogear_min_size = math.ceil(math.min(Screen:getWidth(), Screen:getHeight()) * (1/40))
+    self.dogear_max_size = math.ceil(math.min(Screen:getWidth(), Screen:getHeight()) * (1/32))
     self.dogear_size = nil
     self.dogear_y_offset = 0
     self.top_pad = nil

frontend/apps/reader/modules/readerfooter.lua

@@ -352,7 +352,7 @@ local footerTextGeneratorMap = {
             local dummy, rss = statm:read("*number", "*number")
             statm:close()
             -- we got the nb of 4Kb-pages used, that we convert to MiB
-            rss = math.floor(rss * 4096 / 1024 / 1024)
+            rss = math.floor(rss * (4096 / 1024 / 1024))
             return (prefix .. " %d"):format(rss)
         end
         return ""
@@ -390,7 +390,7 @@ local footerTextGeneratorMap = {
             local title = doc_info.title:gsub(" ", "\xC2\xA0") -- replace space with no-break-space
             local title_widget = TextWidget:new{
                 text = title,
-                max_width = footer._saved_screen_width * footer.settings.book_title_max_width_pct / 100,
+                max_width = footer._saved_screen_width * footer.settings.book_title_max_width_pct * (1/100),
                 face = Font:getFace(footer.text_font_face, footer.settings.text_font_size),
                 bold = footer.settings.text_font_bold,
             }
@@ -410,7 +410,7 @@ local footerTextGeneratorMap = {
             chapter_title = chapter_title:gsub(" ", "\xC2\xA0") -- replace space with no-break-space
             local chapter_widget = TextWidget:new{
                 text = chapter_title,
-                max_width = footer._saved_screen_width * footer.settings.book_chapter_max_width_pct / 100,
+                max_width = footer._saved_screen_width * footer.settings.book_chapter_max_width_pct * (1/100),
                 face = Font:getFace(footer.text_font_face, footer.settings.text_font_size),
                 bold = footer.settings.text_font_bold,
             }
@@ -2168,7 +2168,7 @@ function ReaderFooter:_updateFooterText(force_repaint, force_recompute)
             self.footer_text.height = 0
         else
             -- Alongside a progress bar, it's the bar's width plus whatever's left.
-            local text_max_available_ratio = (100 - self.settings.progress_bar_min_width_pct) / 100
+            local text_max_available_ratio = (100 - self.settings.progress_bar_min_width_pct) * (1/100)
             self.footer_text:setMaxWidth(math.floor(text_max_available_ratio * self._saved_screen_width - 2 * self.settings.progress_margin_width - self.horizontal_margin))
             -- Add some spacing between the text and the bar
             self.text_width = self.footer_text:getSize().w + self.horizontal_margin

frontend/apps/reader/modules/readerhighlight.lua

@@ -2022,8 +2022,8 @@ end
 function ReaderHighlight:onMoveHighlightIndicator(args)
     if self.view.visible_area and self._current_indicator_pos then
         local dx, dy, quick_move = unpack(args)
-        local quick_move_distance_dx = self.view.visible_area.w / 5 -- quick move distance: fifth of visible_area
-        local quick_move_distance_dy = self.view.visible_area.h / 5
+        local quick_move_distance_dx = self.view.visible_area.w * (1/5) -- quick move distance: fifth of visible_area
+        local quick_move_distance_dy = self.view.visible_area.h * (1/5)
         -- single move distance, small and capable to move on word with small font size and narrow line height
         local move_distance = Size.item.height_default / 4
         local rect = self._current_indicator_pos:copy()

frontend/apps/reader/modules/readermenu.lua

@@ -433,10 +433,10 @@ function ReaderMenu:_getTabIndexFromLocation(ges)
     if not ges then
         return self.last_tab_index
     -- if the start position is far right
-    elseif ges.pos.x > 2 * Screen:getWidth() / 3 then
+    elseif ges.pos.x > Screen:getWidth() * (2/3) then
         return BD.mirroredUILayout() and 1 or #self.tab_item_table
     -- if the start position is far left
-    elseif ges.pos.x < Screen:getWidth() / 3 then
+    elseif ges.pos.x < Screen:getWidth() * (1/3) then
         return BD.mirroredUILayout() and #self.tab_item_table or 1
     -- if center return the last index
     else

frontend/apps/reader/modules/readerpaging.lua

@@ -542,7 +542,7 @@ end
 
 function ReaderPaging:onGotoPercent(percent)
     logger.dbg("goto document offset in percent:", percent)
-    local dest = math.floor(self.number_of_pages * percent / 100)
+    local dest = math.floor(self.number_of_pages * percent * (1/100))
     if dest < 1 then dest = 1 end
     if dest > self.number_of_pages then
         dest = self.number_of_pages
@@ -908,8 +908,8 @@ function ReaderPaging:onGotoPageRel(diff)
     local x_pan_off, y_pan_off = 0, 0
     local right_to_left = self.ui.document.configurable.writing_direction and self.ui.document.configurable.writing_direction > 0
     local bottom_to_top = self.ui.zooming.zoom_bottom_to_top
-    local h_progress = 1 - self.ui.zooming.zoom_overlap_h / 100
-    local v_progress = 1 - self.ui.zooming.zoom_overlap_v / 100
+    local h_progress = 1 - self.ui.zooming.zoom_overlap_h * (1/100)
+    local v_progress = 1 - self.ui.zooming.zoom_overlap_v * (1/100)
     local old_va = self.visible_area
     local old_page = self.current_page
     local x, y, w, h = "x", "y", "w", "h"

frontend/apps/reader/modules/readerpanning.lua

@@ -40,8 +40,8 @@ function ReaderPanning:onPanning(args, _)
     local dx, dy = unpack(args)
     -- for now, bounds checking/calculation is done in the view
     self.view:PanningUpdate(
-        dx * self.panning_steps.normal * self.dimen.w / 100,
-        dy * self.panning_steps.normal * self.dimen.h / 100)
+        dx * self.panning_steps.normal * self.dimen.w * (1/100),
+        dy * self.panning_steps.normal * self.dimen.h * (1/100))
     return true
 end
 

frontend/apps/reader/modules/readerrolling.lua

@@ -696,7 +696,7 @@ function ReaderRolling:onGotoXPointer(xp, marker_xp)
         -- where xpointer target is (and remove if after 1s)
         local screen_y, screen_x = self.ui.document:getScreenPositionFromXPointer(marker_xp)
         local doc_margins = self.ui.document:getPageMargins()
-        local marker_h = Screen:scaleBySize(self.ui.font.font_size * 1.1 * self.ui.font.line_space_percent/100.0)
+        local marker_h = Screen:scaleBySize(self.ui.font.font_size * 1.1 * self.ui.font.line_space_percent * (1/100))
         -- Make it 4/5 of left margin wide (and bigger when huge margin)
         local marker_w = math.floor(math.max(doc_margins["left"] - Screen:scaleBySize(5), doc_margins["left"] * 4/5))
 
@@ -794,7 +794,7 @@ function ReaderRolling:onGotoViewRel(diff)
         local pan_diff = diff * page_visible_height
         if self.view.page_overlap_enable then
             local overlap_lines = G_reader_settings:readSetting("copt_overlap_lines") or 1
-            local overlap_h = Screen:scaleBySize(self.ui.font.font_size * 1.1 * self.ui.font.line_space_percent/100.0) * overlap_lines
+            local overlap_h = Screen:scaleBySize(self.ui.font.font_size * 1.1 * self.ui.font.line_space_percent * (1/100)) * overlap_lines
             if pan_diff > overlap_h then
                 pan_diff = pan_diff - overlap_h
             elseif pan_diff < -overlap_h then
@@ -1023,9 +1023,9 @@ end
 
 function ReaderRolling:_gotoPercent(new_percent)
     if self.view.view_mode == "page" then
-        self:_gotoPage(new_percent * self.ui.document:getPageCount() / 100)
+        self:_gotoPage(new_percent * self.ui.document:getPageCount() * (1/100))
     else
-        self:_gotoPos(new_percent * self.ui.document.info.doc_height / 100)
+        self:_gotoPos(new_percent * self.ui.document.info.doc_height * (1/100))
     end
 end
 
@@ -1151,24 +1151,24 @@ function ReaderRolling:handleEngineCallback(ev, ...)
         self:showEngineProgress(0) -- Start initial delay countdown
     elseif ev == "OnLoadFileProgress" then
         -- Initial load from file (step 1/2) or from cache (step 1/1)
-        self:showEngineProgress(args[1]/100/2)
+        self:showEngineProgress(args[1]*(1/100/2))
     elseif ev == "OnNodeStylesUpdateStart" then -- Start of re-rendering
         self:showEngineProgress(0) -- Start initial delay countdown
     elseif ev == "OnNodeStylesUpdateProgress" then
         -- Update node styles (step 1/2 on re-rendering)
-        self:showEngineProgress(args[1]/100/2)
+        self:showEngineProgress(args[1]*(1/100/2))
     elseif ev == "OnFormatStart" then -- Start of step 2/2
         self:showEngineProgress(1/2) -- 50%, in case of no OnFormatProgress
     elseif ev == "OnFormatProgress" then
         -- Paragraph formatting and page splitting (step 2/2 after load
         -- from file, step 2/2 on re-rendering)
-        self:showEngineProgress(1/2 + args[1]/100/2)
+        self:showEngineProgress(1/2 + args[1]*(1/100/2))
     elseif ev == "OnSaveCacheFileStart" then -- Start of cache file save
         self:showEngineProgress(1) -- Start initial delay countdown, fully filled
     elseif ev == "OnSaveCacheFileProgress" then
         -- Cache file save (when closing book after initial load from
         -- file or re-rendering)
-        self:showEngineProgress(1 - args[1]/100) -- unfill progress
+        self:showEngineProgress(1 - args[1]*(1/100)) -- unfill progress
     elseif ev == "OnDocumentReady" or ev == "OnSaveCacheFileEnd" then
         self:showEngineProgress() -- cleanup
     elseif ev == "OnLoadFileError" then
@@ -1214,7 +1214,7 @@ function ReaderRolling:showEngineProgress(percent)
             y = y + self.current_header_height
         end
 
-        local w = math.floor(Screen:getWidth() / 3)
+        local w = math.floor(Screen:getWidth() * (1/3))
         local h = Size.line.progress
         if self.engine_progress_widget then
             self.engine_progress_widget:setPercentage(percent)

frontend/apps/reader/modules/readerscrolling.lua

@@ -385,7 +385,7 @@ function ReaderScrolling:_setupAction()
         local dist = math.floor(self._velocity * self._inertial_scroll_interval)
         if math.abs(dist) < self.end_scroll_dist then
             -- Decrease it even more so scrolling stops sooner
-            self._velocity = self._velocity / 1.5
+            self._velocity = self._velocity * (2/3)
         end
         -- self._stats_scroll_iterations = self._stats_scroll_iterations + 1
         -- self._stats_scroll_distance = self._stats_scroll_distance + dist

frontend/apps/reader/modules/readerthumbnail.lua

@@ -123,7 +123,7 @@ function ReaderThumbnail:setupCache()
         local max_bytes = math.ceil(N * Screen:getWidth() * Screen:getHeight() * Blitbuffer.TYPE_TO_BPP[self.bb_type] / 8)
         -- We don't really care about limiting any number of slots, so allow
         -- for at least 5 pages of 10x10 tiles
-        local avg_itemsize = math.ceil(max_bytes / 500)
+        local avg_itemsize = math.ceil(max_bytes * (1/500))
         self.tile_cache = Cache:new{
             size = max_bytes,
             avg_itemsize = avg_itemsize, -- will make slots=500

frontend/apps/reader/modules/readerview.lua

@@ -32,7 +32,7 @@ local ReaderView = OverlapGroup:extend{
 
     -- single page state
     state = nil, -- table
-    outer_page_color = Blitbuffer.gray(G_defaults:readSetting("DOUTER_PAGE_COLOR") / 15),
+    outer_page_color = Blitbuffer.gray(G_defaults:readSetting("DOUTER_PAGE_COLOR") * (1/15)),
     -- highlight with "lighten" or "underscore" or "strikeout" or "invert"
     highlight = nil, -- table
     highlight_visible = true,
@@ -42,7 +42,7 @@ local ReaderView = OverlapGroup:extend{
     note_mark_pos_x2 = nil, -- page 2 in two-page mode
     -- PDF/DjVu continuous paging
     page_scroll = nil,
-    page_bgcolor = Blitbuffer.gray(G_defaults:readSetting("DBACKGROUND_COLOR") / 15),
+    page_bgcolor = Blitbuffer.gray(G_defaults:readSetting("DBACKGROUND_COLOR") * (1/15)),
     page_states = nil, -- table
     -- properties of the gap drawn between each page in scroll mode:
     page_gap = nil, -- table
@@ -95,7 +95,7 @@ function ReaderView:init()
     self.page_states = {}
     self.page_gap = {
         -- color (0 = white, 8 = gray, 15 = black)
-        color = Blitbuffer.gray((G_reader_settings:readSetting("page_gap_color") or 8) / 15),
+        color = Blitbuffer.gray((G_reader_settings:readSetting("page_gap_color") or 8) * (1/15)),
     }
     self.visible_area = Geom:new{x = 0, y = 0, w = 0, h = 0}
     self.page_area = Geom:new{x = 0, y = 0, w = 0, h = 0}

frontend/device/kindle/device.lua

@@ -322,7 +322,7 @@ function Kindle:outofScreenSaver()
                         -- The banner on a 1236x1648 PW5 is 1235x125; we refresh the bottom 10% of the screen to be safe.
                         local Geom = require("ui/geometry")
                         local screen_height = self.screen:getHeight()
-                        local refresh_height = math.ceil(screen_height / 10)
+                        local refresh_height = math.ceil(screen_height * (1/10))
                         local refresh_region = Geom:new{
                             x = 0,
                             y = screen_height - 1 - refresh_height,

frontend/device/kobo/powerd.lua

@@ -42,7 +42,7 @@ function KoboPowerD:_syncKoboLightOnStart()
                     -- ColorSetting is stored as a color temperature scale in Kelvin,
                     -- from 1500 to 6400
                     -- so normalize this to [0, 100] on our end.
-                    new_warmth = (100 - Math.round((new_color - 1500) / 49))
+                    new_warmth = (100 - Math.round((new_color - 1500) * (1/49)))
                 end
             end
             if is_frontlight_on == nil then
@@ -303,7 +303,7 @@ function KoboPowerD:turnOffFrontlightHW()
     end
     ffiUtil.runInSubProcess(function()
         for i = 1,5 do
-            self:setIntensityHW(math.floor(self.fl_intensity - ((self.fl_intensity / 5) * i)))
+            self:setIntensityHW(math.floor(self.fl_intensity - ((self.fl_intensity * (1/5)) * i)))
             --- @note: Newer devices appear to block slightly longer on FL ioctls/sysfs, so only sleep on older devices,
             ---        otherwise we get a jump and not a ramp ;).
             if not self.device:hasNaturalLight() then
@@ -336,7 +336,7 @@ function KoboPowerD:turnOnFrontlightHW()
     end
     ffiUtil.runInSubProcess(function()
         for i = 1,5 do
-            self:setIntensityHW(math.ceil(self.fl_min + ((self.fl_intensity / 5) * i)))
+            self:setIntensityHW(math.ceil(self.fl_min + ((self.fl_intensity * (1/5)) * i)))
             --- @note: Newer devices appear to block slightly longer on FL ioctls/sysfs, so only sleep on older devices,
             ---        otherwise we get a jump and not a ramp ;).
             if not self.device:hasNaturalLight() then

frontend/ui/data/optionsutil.lua

@@ -25,7 +25,7 @@ local function convertSizeTo(px, format)
     local format_factor = 1 -- we are defaulting on mm
 
     if format == "pt" then
-        format_factor =  format_factor * 2660 / 1000 -- see https://www.wikiwand.com/en/Metric_typographic_units
+        format_factor =  format_factor * (2660 / 1000) -- see https://www.wikiwand.com/en/Metric_typographic_units
     elseif format == "in" then
         format_factor = 1 / 25.4
     end

frontend/ui/elements/page_turns.lua

@@ -46,7 +46,7 @@ table.insert(page_turns_tap_zones_sub_items, {
             value_max = 100,
             default_value = math.floor(G_defaults:readSetting("DTAP_ZONE_FORWARD").w * 100),
             callback = function(spin)
-                G_reader_settings:saveSetting("page_turns_tap_zone_forward_size_ratio", spin.value / 100)
+                G_reader_settings:saveSetting("page_turns_tap_zone_forward_size_ratio", spin.value * (1/100))
                 ReaderUI.instance.view:setupTouchZones()
                 if touchmenu_instance then touchmenu_instance:updateItems() end
             end,

frontend/ui/elements/timeout_android.lua

@@ -20,9 +20,9 @@ local timeout_custom6 = 25 * 60 * 1000
 local timeout_custom7 = 30 * 60 * 1000
 
 local function humanReadableTimeout(timeout)
-    local sec = timeout / 1000
+    local sec = timeout * (1/1000)
     if sec >= 60 then
-        return T(N_("1 minute", "%1 minutes", sec), sec / 60)
+        return T(N_("1 minute", "%1 minutes", sec), sec * (1/60))
     else
         return T(N_("1 second", "%1 seconds", sec), sec)
     end

frontend/ui/otamanager.lua

@@ -372,10 +372,10 @@ function OTAManager:_buildLocalPackage()
         -- Defaults to a sane-ish value as-of now, in case shit happens...
         local blocks = 6405
         if tarball_size then
-            blocks = tarball_size / (512 * 20)
+            blocks = tarball_size * (1/(512 * 20))
         end
         -- And since we want a percentage, devise the exact value we need for tar to spit out exactly 100 checkpoints ;).
-        local cpoints = blocks / 100
+        local cpoints = blocks * (1/100)
         return os.execute(string.format(
             "./tar --no-recursion -cf %s -C .. -T %s --checkpoint=%d --checkpoint-action=exec='./fbink -q -y -6 -P $(($TAR_CHECKPOINT/%d))'",
             self.installed_package, self.package_indexfile, cpoints, cpoints))

frontend/ui/time.lua

@@ -133,7 +133,7 @@ end
 --- Converts an fts time to a Lua (decimal) number (sec.usecs) (accurate to the ms, rounded to 4 decimal places)
 function time.to_number(time_fts)
     -- Round to 4 decimal places
-    return math.floor(time.to_s(time_fts) * 10000 + 0.5) / 10000
+    return math.floor(time.to_s(time_fts) * 10000 + 0.5) * (1/10000)
 end
 
 --- Converts an fts to a Lua (int) number (resolution: 1µs)