LuaSrcDiet工具介绍（lua源码处理软件）

Diet

Food

• Diet (nutrition), the sum of the food consumed by an organism or group
• Dieting, the deliberate selection of food to control body weight or nutrient intake
  • Diet food, foods that aid in creating a diet for weight loss

https://en.wikipedia.org/wiki/Diet

• 节食；进行规定饮食
• n.日常饮食；日常食物；规定饮食（为健康或减肥等目的）；规定饮食的时期
• Web食性；食谱；膳食

https://www.bing.com/dict/search?q=diet&FORM=BDVSP2&qpvt=diet

Diet 结合工具的使用， 应该是节食的含义， 即使用规定的饮食，达到减肥的目的。

luaSrcDiet

知道了英文的意思， 这里luasrcdiet == lua source code diet， 即 对lua源代码进行瘦身。

http://luasrcdiet.luaforge.net/

LuaSrcDiet reduces the size of Lua 5.1.x source files by aggressively removing all unnecessary whitespace and comments, optimizing constant tokens, and renaming local variables to shorter names.

LuaSrcDiet squeezes its own (heavily commented) sources from 121KB down to 28KB. Further compression (bzip2 or lzma) brings the size down to under 10KB, representing a 12X reduction in size.

Sample Output

The following is the result of processing llex.lua from LuaSrcDiet 0.11.0
using various optimization options:

LuaSrcDiet Option	Size (bytes)	Link to Sample File
Original	12,421	llex.lua.txt
Empty lines only	12,395	llex_emptylines.lua.txt
Whitespace only	9,372	llex_whitespace.lua.txt
Local rename only	11,794	llex_locals.lua.txt
--basic (token optimizations only)	3,835	llex_basic.lua.txt
Program default	3,208	llex_default.lua.txt
--maximum	3,130	llex_maximum.lua.txt

功能

LuaSrcDiet features include the following:

• Predefined default, --basic
  (token-only) and --maximum
  settings.
• Avoid deleting a block comment with a certain message with --keep; this is for copyright or
  license texts.
• Special handling for #! (shbang) lines and in functions, "self"
  implicit parameters.
• Dumping of raw information: lexer
  tokens and local variable name
  tracking information
• Plugin interface (experimental!) with HTML and SLOC plugins.
• HTML plugin: outputs files that highlights globals and locals
  (useful for eliminating globals), sample: html_sample.html.
  -----
  这个挺好@！！！！！
• SLOC plugin: counts
  significant lines of Lua code, like SLOCCount.

List of optimizations:

• Line endings are always normalized to LF, except those embedded
  in comments or strings.
• --opt-comments: Removal
  of comments and comment blocks.
• --opt-whitespace:
  Removal of whitespace, excluding end-of-line characters.
• --opt-emptylines:
  Removal of empty lines.
• --opt-eols: Removal of
  unnecessary end-of-line characters.
• --opt-strings: Rewrite
  strings and long strings. Sample: Before and After
• --opt-numbers: Rewrite
  numbers. Sample: Before and After
• --opt-locals: Rename
  local variable names. Does not rename field or method names.
• --opt-entropy: Tries to
  improve symbol entropy when renaming locals by calculating actual
  letter frequencies.

与其他工具对比

File sizes of LuaSrcDiet 0.11.0 main files in various forms:

Source File	Original Size (bytes)	luac normal (bytes)	luac stripped (bytes)	LuaSrcDiet --basic (bytes)	LuaSrcDiet --maximum (bytes)
LuaSrcDiet.lua	21,961	20,952	11,000	11,005	8,159
llex.lua	12,421	8,613	4,247	3,835	3,130
lparser.lua	41,757	27,215	12,506	11,755	7,666
optlex.lua	31,009	16,992	8,021	9,129	6,858
optparser.lua	16,511	9,021	3,520	5,087	2,999
Total	123,659	82,793	39,294	40,811	28,812

		Null loop	Stripped binary chunk	Original Sources	Squeezed Sources
Total Size	(bytes)	0	39,294	123,640	28,793
Iterations		312,155	9,680	1306	1,592
Duration	(sec)	10	10	10	10
Time/iteration	(msec)	0.032	1.033	7.657	6.281
Time/iteration, adjusted for null	(msec)	-	1.001	7.625	6.249
Load rate	(MB/sec)	-	37.44	15.46	4.39
Load time per byte	(ns)	-	25.5	61.7	217.0
Load time per token	(ns)	-	-	682	559
Source time vs binary chunk time ratio		-	1.00	7.62	6.24
Binary chunk rate vs. source rate ratio		-	1.00	2.42	8.53

The LuaSrcDiet 0.11.0 files (original, squeezed with --maximum and stripped binary chunks versions) are loaded into memory first before a loop runs to repeatedly load the script files for 10 seconds. A null loop is also performed (processing empty strings) and the time taken per null iteration is subtracted as a form of null adjustment. Then, various performance parameters are calculated. Note that LuaSrcDiet.lua was slightly modified (#! line removed) to let the loadstring function run. The results below were obtained with a Lua 5.1.3 executable compiled using "make generic" on Cygwin/Windows XP SP2 on a Sempron 3000+ (1.8GHz). The LuaSrcDiet 0.11.0 source files have 11,180 'real' tokens in total.

		Null loop	Stripped binary chunk	Original Sources	Squeezed Sources
Total Size	(bytes)	0	39,294	123,640	28,793
Iterations		312,155	9,680	1306	1,592
Duration	(sec)	10	10	10	10
Time/iteration	(msec)	0.032	1.033	7.657	6.281
Time/iteration, adjusted for null	(msec)	-	1.001	7.625	6.249
Load rate	(MB/sec)	-	37.44	15.46	4.39
Load time per byte	(ns)	-	25.5	61.7	217.0
Load time per token	(ns)	-	-	682	559
Source time vs binary chunk time ratio		-	1.00	7.62	6.24
Binary chunk rate vs. source rate ratio		-	1.00	2.42	8.53

The above shows that stripped binary chunks is still, in many ways,
the highest-performance form of fixed Lua scripts. On a very average
machine, scripts load at over 37MB/sec (in memory). This is very
comparable to the burst speeds of common desktop hard disks of 2008. If
instant response is paramount, stripped binary chunks has little
competition.