--

-- Licensed to the Apache Software Foundation (ASF) under one or more

-- contributor license agreements. See the NOTICE file distributed with

-- this work for additional information regarding copyright ownership.

-- The ASF licenses this file to You under the Apache License, Version 2.0

-- (the "License"); you may not use this file except in compliance with

-- the License. You may obtain a copy of the License at

--

-- http://www.apache.org/licenses/LICENSE-2.0

--

-- Unless required by applicable law or agreed to in writing, software

-- distributed under the License is distributed on an "AS IS" BASIS,

-- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

-- See the License for the specific language governing permissions and

-- limitations under the License.

--

--- Wrapped string module.

--

-- @module core.string

local error = error

local type = type

local str_byte = string.byte

local str_find = string.find

local ffi = require("ffi")

local C = ffi.C

local ffi_cast = ffi.cast

local ngx = ngx

local ngx_decode_args = ngx.decode_args

local ngx_encode_args = ngx.encode_args

ffi.cdef[[

int memcmp(const void *s1, const void *s2, size_t n);

]]

local _M = {

version = 0.1,

}

setmetatable(_M, {__index = string})

-- find a needle from a haystack in the plain text way

-- note: Make sure that the haystack is 'string' type, otherwise an exception will be thrown.

function _M.find(haystack, needle, from)

return str_find(haystack, needle, from or 1, true)

end

---

-- Tests whether the string s begins with prefix.

--

-- @function core.string.has_prefix

-- @tparam string s The string being tested.

-- @tparam string prefix Specify the prefix.

-- @treturn boolean Test result, true means the string s begins with prefix.

-- @usage

-- local res = core.string.has_prefix("/apisix/admin/routes", "/apisix/") -- true

function _M.has_prefix(s, prefix)

if type(s) ~= "string" or type(prefix) ~= "string" then

error("unexpected type: s:" .. type(s) .. ", prefix:" .. type(prefix))

end

if #s < #prefix then

return false

end

local rc = C.memcmp(s, prefix, #prefix)

return rc == 0

end

function _M.has_suffix(s, suffix)

if type(s) ~= "string" or type(suffix) ~= "string" then

error("unexpected type: s:" .. type(s) .. ", suffix:" .. type(suffix))

end

if #s < #suffix then

return false

end

local rc = C.memcmp(ffi_cast("char *", s) + #s - #suffix, suffix, #suffix)

return rc == 0

end

function _M.rfind_char(s, ch, idx)

local b = str_byte(ch)

for i = idx or #s, 1, -1 do

if str_byte(s, i, i) == b then

return i

end

end

return nil

end

-- reduce network consumption by compressing string indentation

-- this method should be used with caution

-- it will remove the spaces at the beginning of each line

-- and remove the spaces after `,` character

function _M.compress_script(s)

s = ngx.re.gsub(s, [[^\s+]], "", "mjo")

s = ngx.re.gsub(s, [[,\s+]], ",", "mjo")

return s

end

---

-- Decodes a URI encoded query-string into a Lua table.

-- All request arguments received will be decoded by default.

--

-- @function core.string.decode_args

-- @tparam string args A URI encoded query-string.

-- @treturn table the value of decoded query-string.

-- @usage

-- local args, err = core.string.decode_args("a=1&b=2") -- {a=1, b=2}

function _M.decode_args(args)

-- use 0 to avoid truncated result and keep the behavior as the

-- same as other platforms

return ngx_decode_args(args, 0)

end

---

-- Encode the Lua table to a query args string according to the URI encoded rules.

--

-- @function core.string.encode_args

-- @tparam table args The query args Lua table.

-- @treturn string the value of query args string.

-- @usage

-- local str = core.string.encode_args({a=1, b=2}) -- "a=1&b=2"

function _M.encode_args(args)

return ngx_encode_args(args)

end

return _M