diff options
Diffstat (limited to 'file_io/win32/seek.c')
| -rw-r--r-- | file_io/win32/seek.c | 203 |
1 files changed, 203 insertions, 0 deletions
diff --git a/file_io/win32/seek.c b/file_io/win32/seek.c new file mode 100644 index 0000000..dfef577 --- /dev/null +++ b/file_io/win32/seek.c @@ -0,0 +1,203 @@ +/* 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. + */ + +#include "apr_arch_file_io.h" +#include "apr_file_io.h" +#include <errno.h> +#include <string.h> + +static apr_status_t setptr(apr_file_t *thefile, apr_off_t pos ) +{ + apr_off_t newbufpos; + apr_status_t rv; + DWORD rc; + + if (thefile->direction == 1) { + /* XXX: flush here is not mutex protected */ + rv = apr_file_flush(thefile); + if (rv != APR_SUCCESS) + return rv; + thefile->bufpos = thefile->dataRead = 0; + thefile->direction = 0; + } + + /* We may be truncating to size here. + * XXX: testing an 'unsigned' as >= 0 below indicates a bug + */ + newbufpos = pos - (thefile->filePtr - thefile->dataRead); + + if (newbufpos >= 0 && newbufpos <= (apr_off_t)thefile->dataRead) { + thefile->bufpos = (apr_size_t)newbufpos; + rv = APR_SUCCESS; + } else { + DWORD offlo = (DWORD)pos; + LONG offhi = (LONG)(pos >> 32); + rc = SetFilePointer(thefile->filehand, offlo, &offhi, FILE_BEGIN); + + if (rc == (DWORD)-1) + /* A legal value, perhaps? MSDN implies prior SetLastError isn't + * needed, googling for SetLastError SetFilePointer seems + * to confirm this. INVALID_SET_FILE_POINTER is too recently + * added for us to rely on it as a constant. + */ + rv = apr_get_os_error(); + else + rv = APR_SUCCESS; + + if (rv == APR_SUCCESS) { + rv = APR_SUCCESS; + thefile->eof_hit = 0; + thefile->bufpos = thefile->dataRead = 0; + thefile->filePtr = pos; + } + } + + return rv; +} + + +APR_DECLARE(apr_status_t) apr_file_seek(apr_file_t *thefile, apr_seek_where_t where, apr_off_t *offset) +{ + apr_finfo_t finfo; + apr_status_t rc = APR_SUCCESS; + + thefile->eof_hit = 0; + + if (thefile->buffered) { + switch (where) { + case APR_SET: + rc = setptr(thefile, *offset); + break; + + case APR_CUR: + rc = setptr(thefile, thefile->filePtr - thefile->dataRead + + thefile->bufpos + *offset); + break; + + case APR_END: + rc = apr_file_info_get(&finfo, APR_FINFO_SIZE, thefile); + if (rc == APR_SUCCESS) + rc = setptr(thefile, finfo.size + *offset); + break; + + default: + return APR_EINVAL; + } + + *offset = thefile->filePtr - thefile->dataRead + thefile->bufpos; + return rc; + } + /* A file opened with APR_FOPEN_XTHREAD has been opened for overlapped i/o. + * APR must explicitly track the file pointer in this case. + */ + else if (thefile->pOverlapped || thefile->flags & APR_FOPEN_XTHREAD) { + switch(where) { + case APR_SET: + thefile->filePtr = *offset; + break; + + case APR_CUR: + thefile->filePtr += *offset; + break; + + case APR_END: + rc = apr_file_info_get(&finfo, APR_FINFO_SIZE, thefile); + if (rc == APR_SUCCESS && finfo.size + *offset >= 0) + thefile->filePtr = finfo.size + *offset; + break; + + default: + return APR_EINVAL; + } + *offset = thefile->filePtr; + return rc; + } + else { + DWORD howmove; + DWORD offlo = (DWORD)*offset; + DWORD offhi = (DWORD)(*offset >> 32); + + switch(where) { + case APR_SET: + howmove = FILE_BEGIN; break; + case APR_CUR: + howmove = FILE_CURRENT; break; + case APR_END: + howmove = FILE_END; break; + default: + return APR_EINVAL; + } + offlo = SetFilePointer(thefile->filehand, (LONG)offlo, + (LONG*)&offhi, howmove); + if (offlo == 0xFFFFFFFF) + rc = apr_get_os_error(); + else + rc = APR_SUCCESS; + /* Since we can land at 0xffffffff we will measure our APR_SUCCESS */ + if (rc == APR_SUCCESS) + *offset = ((apr_off_t)offhi << 32) | offlo; + return rc; + } +} + + +APR_DECLARE(apr_status_t) apr_file_trunc(apr_file_t *thefile, apr_off_t offset) +{ + apr_status_t rv; + DWORD offlo = (DWORD)offset; + LONG offhi = (LONG)(offset >> 32); + DWORD rc; + + if (thefile->buffered) { + if (thefile->direction == 1) { + /* Figure out what needs to be flushed. Don't flush the part + * of the write buffer that will get truncated anyway. + */ + if (offset < thefile->filePtr) { + thefile->bufpos = 0; + } + else if (offset < thefile->filePtr + (apr_off_t)thefile->bufpos) { + thefile->bufpos = (apr_size_t)(offset - thefile->filePtr); + } + + if (thefile->bufpos != 0) { + rv = apr_file_flush(thefile); + if (rv != APR_SUCCESS) + return rv; + } + } + else if (thefile->direction == 0) { + /* Discard the read buffer, as we are about to reposition + * ourselves to the end of file. + */ + thefile->bufpos = 0; + thefile->dataRead = 0; + } + } + + rc = SetFilePointer(thefile->filehand, offlo, &offhi, FILE_BEGIN); + if (rc == 0xFFFFFFFF) + if ((rv = apr_get_os_error()) != APR_SUCCESS) + return rv; + thefile->filePtr = offset; + /* Don't report EOF until the next read. */ + thefile->eof_hit = 0; + + if (!SetEndOfFile(thefile->filehand)) + return apr_get_os_error(); + + return APR_SUCCESS; +} |