Function str_gsub

src/Chain/libraries/glua/lstrlib.cpp:845–881

static int str_gsub(lua_State *L) {
    size_t srcl, lp;
    const char *src = luaL_checklstring(L, 1, &srcl);
    const char *p = luaL_checklstring(L, 2, &lp);
    int tr = lua_type(L, 3);
    lua_Integer max_s = luaL_optinteger(L, 4, srcl + 1);
    int anchor = (*p == '^');
    lua_Integer n = 0;
    MatchState ms;
    luaL_Buffer b;
    luaL_argcheck(L, tr == LUA_TNUMBER || tr == LUA_TSTRING ||
        tr == LUA_TFUNCTION || tr == LUA_TTABLE, 3,
        "string/function/table expected");
    luaL_buffinit(L, &b);
    if (anchor) {
        p++; lp--;  /* skip anchor character */
    }
    prepstate(&ms, L, src, srcl, p, lp);
    while (n < max_s) {
        const char *e;
        reprepstate(&ms);
        if ((e = match(&ms, src, p)) != nullptr) {
            n++;
            add_value(&ms, &b, src, e, tr);
        }
        if (e && e > src) /* non empty match? */
            src = e;  /* skip it */
        else if (src < ms.src_end)
            luaL_addchar(&b, *src++);
        else break;
        if (anchor) break;
    }
    luaL_addlstring(&b, src, ms.src_end - src);
    luaL_pushresult(&b);
    lua_pushinteger(L, n);  /* number of substitutions */
    return 2;
}

/* }====================================================== */