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/*!A cross-platform build utility based on Lua
*
* Licensed 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.
*
* Copyright (C) 2015-present, Xmake Open Source Community.
*
* @author OpportunityLiu, ruki
* @file file_seek.c
*
*/
/* //////////////////////////////////////////////////////////////////////////////////////
* trace
*/
#define TB_TRACE_MODULE_NAME "file_seek"
#define TB_TRACE_MODULE_DEBUG (0)
/* //////////////////////////////////////////////////////////////////////////////////////
* includes
*/
#include "prefix.h"
/* //////////////////////////////////////////////////////////////////////////////////////
* implementation
*/
// io.file_seek(file, [whence [, offset]])
tb_int_t xm_io_file_seek(lua_State *lua) {
tb_assert_and_check_return_val(lua, 0);
// is user data?
if (!lua_isuserdata(lua, 1)) {
xm_io_return_error(lua, "seek(invalid file)!");
}
// get file
xm_io_file_t *file = (xm_io_file_t *)lua_touserdata(lua, 1);
tb_check_return_val(file, 0);
// get whence and offset
tb_char_t const *whence = luaL_optstring(lua, 2, "cur");
tb_hong_t offset = (tb_hong_t)luaL_optnumber(lua, 3, 0);
tb_assert_and_check_return_val(whence, 0);
// seek file
if (xm_io_file_is_file(file)) {
tb_assert(file->u.file_ref);
switch (*whence) {
case 's': // "set"
break;
case 'e': // "end"
{
tb_hong_t size = tb_stream_size(file->u.file_ref);
if (size > 0 && size + offset <= size) {
offset = size + offset;
} else {
xm_io_return_error(lua, "seek failed, invalid offset!");
}
} break;
default: // "cur"
offset = tb_stream_offset(file->u.file_ref) + offset;
break;
}
if (tb_stream_seek(file->u.file_ref, offset)) {
lua_pushnumber(lua, (lua_Number)offset);
return 1;
} else {
xm_io_return_error(lua, "seek failed!");
}
} else {
xm_io_return_error(lua, "seek is not supported on this file");
}
}
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