perf(luaJIT): use LuaJIT stringbuffers, if present. Fixes #67

Author: kikito

inspect.lua

@@ -1,4 +1,4 @@
-local _tl_compat; if (tonumber((_VERSION or ''):match('[%d.]*$')) or 0) < 5.3 then local p, m = pcall(require, 'compat53.module'); if p then _tl_compat = m end end; local math = _tl_compat and _tl_compat.math or math; local string = _tl_compat and _tl_compat.string or string; local table = _tl_compat and _tl_compat.table or table; local type = type
+local _tl_compat; if (tonumber((_VERSION or ''):match('[%d.]*$')) or 0) < 5.3 then local p, m = pcall(require, 'compat53.module'); if p then _tl_compat = m end end; local math = _tl_compat and _tl_compat.math or math; local pcall = _tl_compat and _tl_compat.pcall or pcall; local string = _tl_compat and _tl_compat.string or string; local table = _tl_compat and _tl_compat.table or table; local type = type
 local inspect = { Options = {} }
 
 
@@ -54,6 +54,33 @@ local char = string.char
 local gsub = string.gsub
 local fmt = string.format
 
+
+local sbexist, stringbuffer = pcall(require, "string.buffer")
+local sbnew
+local sbput
+local sbto_s
+
+if sbexist then
+   sbnew = stringbuffer.new
+   sbput = function(buf, str)
+      buf:put(str)
+   end
+   sbto_s = function(buf)
+      return buf:get()
+   end
+else
+   sbnew = function()
+      return { n = 0 }
+   end
+   sbput = function(buf, str)
+      buf.n = buf.n + 1
+      buf[buf.n] = str
+   end
+   sbto_s = function(buf)
+      return table.concat(buf)
+   end
+end
+
 local _rawget
 if rawget then
    _rawget = rawget
@@ -212,8 +239,7 @@ local function processRecursive(process,
 end
 
 local function puts(buf, str)
-   buf.n = buf.n + 1
-   buf[buf.n] = str
+   sbput(buf, str)
 end
 
 
@@ -332,7 +358,7 @@ function inspect.inspect(root, options)
    countCycles(root, cycles, depth)
 
    local inspector = setmetatable({
-      buf = { n = 0 },
+      buf = sbnew(),
       ids = {},
       cycles = cycles,
       depth = depth,
@@ -343,7 +369,7 @@ function inspect.inspect(root, options)
 
    inspector:putValue(root)
 
-   return table.concat(inspector.buf)
+   return sbto_s(inspector.buf)
 end
 
 setmetatable(inspect, {

inspect.tl

@@ -54,6 +54,33 @@ local char = string.char
 local gsub = string.gsub
 local fmt = string.format
 
+-- String buffer support (LuaJIT optimization)
+local sbexist, stringbuffer = pcall(require, "string.buffer")
+local sbnew: function(): table
+local sbput: function(table, string)
+local sbto_s: function(table): string
+
+if sbexist then
+  sbnew = stringbuffer.new
+  sbput = function(buf: table, str: string)
+    buf:put(str)
+  end
+  sbto_s = function(buf: table): string
+    return buf:get()
+  end
+else
+  sbnew = function(): table
+    return { n = 0 }
+  end
+  sbput = function(buf: table, str: string)
+    buf.n = buf.n as integer + 1
+    buf[buf.n as integer] = str
+  end
+  sbto_s = function(buf: table): string
+    return table.concat(buf as {string})
+  end
+end
+
 local _rawget: function(table, any): any
 if rawget then
    _rawget = rawget
@@ -212,8 +239,7 @@ local function processRecursive(process: inspect.ProcessFunction,
 end
 
 local function puts(buf: table, str:string): nil
-   buf.n = buf.n as integer + 1
-   buf[buf.n as integer] = str
+   sbput(buf, str)
 end
 
 -------------------------------------------------------------------
@@ -332,7 +358,7 @@ function inspect.inspect(root: any, options: inspect.Options): string
    countCycles(root, cycles, depth)
 
    local inspector = setmetatable({
-      buf              = { n = 0 },
+      buf              = sbnew(),
       ids              = {},
       cycles           = cycles,
       depth            = depth,
@@ -343,7 +369,7 @@ function inspect.inspect(root: any, options: inspect.Options): string
 
    inspector:putValue(root)
 
-   return table.concat(inspector.buf as {string})
+   return sbto_s(inspector.buf)
 end
 
 setmetatable(inspect, {