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- /***************************************************************************
- * _ _ ____ _
- * Project ___| | | | _ \| |
- * / __| | | | |_) | |
- * | (__| |_| | _ <| |___
- * \___|\___/|_| \_\_____|
- *
- * Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
- *
- * This software is licensed as described in the file COPYING, which
- * you should have received as part of this distribution. The terms
- * are also available at https://curl.se/docs/copyright.html.
- *
- * You may opt to use, copy, modify, merge, publish, distribute and/or sell
- * copies of the Software, and permit persons to whom the Software is
- * furnished to do so, under the terms of the COPYING file.
- *
- * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
- * KIND, either express or implied.
- *
- * SPDX-License-Identifier: curl
- *
- ***************************************************************************/
- #include "tool_setup.h"
- #define ENABLE_CURLX_PRINTF
- /* use our own printf() functions */
- #include "curlx.h"
- #include "tool_cfgable.h"
- #include "tool_operate.h"
- #include "tool_cb_see.h"
- #include "memdebug.h" /* keep this as LAST include */
- /* OUR_MAX_SEEK_L has 'long' data type, OUR_MAX_SEEK_O has 'curl_off_t,
- both represent the same value. Maximum offset used here when we lseek
- using a 'long' data type offset */
- #define OUR_MAX_SEEK_L 2147483647L - 1L
- #define OUR_MAX_SEEK_O CURL_OFF_T_C(0x7FFFFFFF) - CURL_OFF_T_C(0x1)
- /*
- ** callback for CURLOPT_SEEKFUNCTION
- **
- ** Notice that this is not supposed to return the resulting offset. This
- ** shall only return CURL_SEEKFUNC_* return codes.
- */
- int tool_seek_cb(void *userdata, curl_off_t offset, int whence)
- {
- struct per_transfer *per = userdata;
- #if(SIZEOF_CURL_OFF_T > SIZEOF_OFF_T) && !defined(USE_WIN32_LARGE_FILES)
- /* The offset check following here is only interesting if curl_off_t is
- larger than off_t and we are not using the WIN32 large file support
- macros that provide the support to do 64bit seeks correctly */
- if(offset > OUR_MAX_SEEK_O) {
- /* Some precaution code to work around problems with different data sizes
- to allow seeking >32bit even if off_t is 32bit. Should be very rare and
- is really valid on weirdo-systems. */
- curl_off_t left = offset;
- if(whence != SEEK_SET)
- /* this code path doesn't support other types */
- return CURL_SEEKFUNC_FAIL;
- if(LSEEK_ERROR == lseek(per->infd, 0, SEEK_SET))
- /* couldn't rewind to beginning */
- return CURL_SEEKFUNC_FAIL;
- while(left) {
- long step = (left > OUR_MAX_SEEK_O) ? OUR_MAX_SEEK_L : (long)left;
- if(LSEEK_ERROR == lseek(per->infd, step, SEEK_CUR))
- /* couldn't seek forwards the desired amount */
- return CURL_SEEKFUNC_FAIL;
- left -= step;
- }
- return CURL_SEEKFUNC_OK;
- }
- #endif
- if(LSEEK_ERROR == lseek(per->infd, offset, whence))
- /* couldn't rewind, the reason is in errno but errno is just not portable
- enough and we don't actually care that much why we failed. We'll let
- libcurl know that it may try other means if it wants to. */
- return CURL_SEEKFUNC_CANTSEEK;
- return CURL_SEEKFUNC_OK;
- }
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