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"use strict";
const assert = require('assert');
const lua = require('./lua.js');
const lapi = require('./lapi.js');
const lauxlib = require('./lauxlib.js');
/* translate a relative string position: negative means back from end */
const posrelat = function(pos, len) {
if (pos >= 0) return pos;
else if (0 - pos > len) return 0;
else return len + pos + 1;
};
const str_len = function(L) {
lapi.lua_pushinteger(L, lauxlib.luaL_checkstring(L, 1).length);
return 1;
};
const str_char = function(L) {
let n = lapi.lua_gettop(L); /* number of arguments */
let p = "";
for (let i = 1; i <= n; i++) {
let c = lauxlib.luaL_checkinteger(L, i);
lauxlib.luaL_argcheck(L, c >= 0 && c <= 255, "value out of range"); // Strings are 8-bit clean
p += String.fromCharCode(c);
}
lapi.lua_pushstring(L, p);
return 1;
};
const str_reverse = function(L) {
lapi.lua_pushstring(L, lauxlib.luaL_checkstring(L, 1).split("").reverse().join(""));
return 1;
};
const str_lower = function(L) {
lapi.lua_pushstring(L, lauxlib.luaL_checkstring(L, 1).toLowerCase());
return 1;
};
const str_upper = function(L) {
lapi.lua_pushstring(L, lauxlib.luaL_checkstring(L, 1).toUpperCase());
return 1;
};
const str_rep = function(L) {
let s = lauxlib.luaL_checkstring(L, 1);
let n = lauxlib.luaL_checkinteger(L, 2);
let sep = lauxlib.luaL_optstring(L, 3, "");
lapi.lua_pushstring(L, (s + sep).repeat(n - 1) + s);
return 1;
};
const str_byte = function(L) {
let s = lauxlib.luaL_checkstring(L, 1);
s = L.stack[lapi.index2addr_(L, 1)].value;
let l = s.length;
let posi = posrelat(lauxlib.luaL_optinteger(L, 2, 1), l);
let pose = posrelat(lauxlib.luaL_optinteger(L, 3, posi), l);
if (posi < 1) posi = 1;
if (pose > l) pose = l;
if (posi > pose) return 0; /* empty interval; return no values */
if (pose - posi >= Number.MAX_SAFE_INTEGER) /* arithmetic overflow? */
return lauxlib.luaL_error(L, "string slice too long");
let n = (pose - posi) + 1;
lauxlib.luaL_checkstack(L, n, "string slice too long");
for (let i = 0; i < n; i++)
lapi.lua_pushinteger(L, s[posi + i - 1]);
return n;
};
const strlib = {
"byte": str_byte,
"char": str_char,
"len": str_len,
"lower": str_lower,
"rep": str_rep,
"reverse": str_reverse,
"upper": str_upper
};
const createmetatable = function(L) {
lapi.lua_createtable(L, 0, 1); /* table to be metatable for strings */
lapi.lua_pushliteral(L, ""); /* dummy string */
lapi.lua_pushvalue(L, -2); /* copy table */
lapi.lua_setmetatable(L, -2); /* set table as metatable for strings */
lapi.lua_pop(L, 1); /* pop dummy string */
lapi.lua_pushvalue(L, -2); /* get string library */
lapi.lua_setfield(L, -2, "__index"); /* metatable.__index = string */
lapi.lua_pop(L, 1); /* pop metatable */
};
const luaopen_string = function(L) {
lauxlib.luaL_newlib(L, strlib);
createmetatable(L);
return 1;
};
module.exports.luaopen_string = luaopen_string;
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