luajit新推出了buffer接口，yyjson是简直就是最快json c库（不应用simd指令）
比拟yyjson与luajit buffer的性能。
测试json文件：应用rapidjson性能测试仓库中的测试文件：data目录下的三个文件： "./canada.json", "./twitter.json", "./citm_catalog.json"

测试机：Manjaro 21/5.10.60 linux内核，gcc-11.1.0, P50(Intel(R) Core(TM) i7-6700HQ CPU @ 2.60GHz, 8G)
测试论断：
Luajit的buffer编码性能是yyjson 2-3倍， 解码性能与yyjson相当， 然而luajit buffer解码进去是table十分不便查问， 且buffer还有元词典扩大性能未应用。json文本，buffer二进制格局。

luajit-2.1 buffer encode 4-5ms, decode 8-11ms-- yyjson 非insitu下yyjson-0.3.0-debug decode file 28ms, decode str 17ms, encode 24msyyjson-0.3.0-release decode file 13-14ms, decode str 8-12ms, encode 7-10ms-- yyjson insitu下yyjson-0.3.0-insitu-release decode file 14ms, decode str 10ms, encode 9ms其余lua库：[json.lua](https://github.com/rxi/json.lua): encode 211ms, decode 235ms[lua-cjson](https://github.com/openresty/lua-cjson.git)(应用resty执行):encode 49ms, decode 112ms

yyjson代码:
cmake -DBUILD_SHARED_LIBS=ON -DCMAKE_BUILD_TYPE=Release ..
cmake --build . --config Release

#include "yyjson.h"#include <stdio.h>#include <time.h>int main(){    struct timespec s = {0,0}, e = {0,0}, e2 = {0,0};    clock_gettime(CLOCK_MONOTONIC, &s);    yyjson_doc *doc1 = yyjson_read_file("./canada.json", 0, NULL, NULL);    yyjson_doc *doc2 = yyjson_read_file("./twitter.json", 0, NULL, NULL);    yyjson_doc *doc3 = yyjson_read_file("./citm_catalog.json", 0, NULL, NULL);    clock_gettime(CLOCK_MONOTONIC, &e);    printf("%d\n", ((e.tv_sec - s.tv_sec) * 10^9 + e.tv_nsec - s.tv_nsec)/1000000);    char *json1 = yyjson_write(doc1, 0, NULL);    char *json2 = yyjson_write(doc2, 0, NULL);    char *json3 = yyjson_write(doc3, 0, NULL);    clock_gettime(CLOCK_MONOTONIC, &s);    yyjson_doc *doc11 = yyjson_read(json1, strlen(json1), 0);    yyjson_doc *doc12 = yyjson_read(json2, strlen(json2), 0);    yyjson_doc *doc13 = yyjson_read(json3, strlen(json3), 0);    clock_gettime(CLOCK_MONOTONIC, &e);    printf("%d\n", ((e.tv_sec - s.tv_sec) * 10^9 + e.tv_nsec - s.tv_nsec)/1000000);    char *json11 = yyjson_write(doc11, 0, NULL);    char *json12 = yyjson_write(doc12, 0, NULL);    char *json13 = yyjson_write(doc13, 0, NULL);    clock_gettime(CLOCK_MONOTONIC, &e2);    printf("%d\n", ((e2.tv_sec - e.tv_sec) * 10^9 + e2.tv_nsec - e.tv_nsec)/1000000);    // free(json1);free(json2);free(json3);    // yyjson_doc_free(doc1);    // yyjson_doc_free(doc2);    // yyjson_doc_free(doc3);    return 0;}

luajit buffer 测试代码：

local buffer = require("string.buffer")local json = require("json")-- local json = require("cjson")-- json.encode_escape_forward_slash(false)local a = {"./canada.json", "./twitter.json", "./citm_catalog.json"}local file = {}for _, n in ipairs(a) do    local f = io.open(n)    file[#file + 1] = f:read("a")    f:close()endlocal s = os.clock()local decfile = {}for i, f in ipairs(file) do    decfile[i] = json.decode(f)endlocal e = os.clock()print("json decode:", e - s)local s = os.clock()for _, jt in ipairs(decfile) do    local b = json.encode(jt)endlocal e = os.clock()print("json encode:", e - s)local a = {}local s = os.clock()for i, jt in ipairs(decfile) do    a[i] = buffer.encode(jt)endlocal e = os.clock()print("luajit buffer encode:", e - s)-- print(#a[1])local b = {}local s = os.clock()for i, jt in ipairs(a) do    b[i] = buffer.decode(jt)endlocal e = os.clock()print("luajit buffer decode:", e - s)