增加sql的waf功能

resty/string.lua

@@ -0,0 +1,40 @@
+-- Copyright (C) by Yichun Zhang (agentzh)
+
+
+local ffi = require "ffi"
+local ffi_new = ffi.new
+local ffi_str = ffi.string
+local C = ffi.C
+--local setmetatable = setmetatable
+--local error = error
+local tonumber = tonumber
+
+
+local _M = { _VERSION = '0.14' }
+
+
+ffi.cdef[[
+typedef unsigned char u_char;
+
+u_char * ngx_hex_dump(u_char *dst, const u_char *src, size_t len);
+
+intptr_t ngx_atoi(const unsigned char *line, size_t n);
+]]
+
+local str_type = ffi.typeof("uint8_t[?]")
+
+
+function _M.to_hex(s)
+    local len = #s
+    local buf_len = len * 2
+    local buf = ffi_new(str_type, buf_len)
+    C.ngx_hex_dump(buf, s, len)
+    return ffi_str(buf, buf_len)
+end
+
+function _M.atoi(s)
+    return tonumber(C.ngx_atoi(s, #s))
+end
+
+
+return _M