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-rw-r--r--file_io/unix/seek.c136
1 files changed, 136 insertions, 0 deletions
diff --git a/file_io/unix/seek.c b/file_io/unix/seek.c
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+/* 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"
+
+static apr_status_t setptr(apr_file_t *thefile, apr_off_t pos )
+{
+ apr_off_t newbufpos;
+ apr_status_t rv;
+
+ if (thefile->direction == 1) {
+ rv = apr_file_flush_locked(thefile);
+ if (rv) {
+ return rv;
+ }
+ thefile->bufpos = thefile->direction = thefile->dataRead = 0;
+ }
+
+ newbufpos = pos - (thefile->filePtr - thefile->dataRead);
+ if (newbufpos >= 0 && newbufpos <= thefile->dataRead) {
+ thefile->bufpos = newbufpos;
+ rv = APR_SUCCESS;
+ }
+ else {
+ if (lseek(thefile->filedes, pos, SEEK_SET) != -1) {
+ thefile->bufpos = thefile->dataRead = 0;
+ thefile->filePtr = pos;
+ rv = APR_SUCCESS;
+ }
+ else {
+ rv = errno;
+ }
+ }
+
+ return rv;
+}
+
+
+APR_DECLARE(apr_status_t) apr_file_seek(apr_file_t *thefile, apr_seek_where_t where, apr_off_t *offset)
+{
+ apr_off_t rv;
+
+ thefile->eof_hit = 0;
+
+ if (thefile->buffered) {
+ int rc = EINVAL;
+ apr_finfo_t finfo;
+
+ file_lock(thefile);
+
+ 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_locked(&finfo, APR_FINFO_SIZE, thefile);
+ if (rc == APR_SUCCESS)
+ rc = setptr(thefile, finfo.size + *offset);
+ break;
+ }
+
+ *offset = thefile->filePtr - thefile->dataRead + thefile->bufpos;
+
+ file_unlock(thefile);
+
+ return rc;
+ }
+ else {
+ rv = lseek(thefile->filedes, *offset, where);
+ if (rv == -1) {
+ *offset = -1;
+ return errno;
+ }
+ else {
+ *offset = rv;
+ return APR_SUCCESS;
+ }
+ }
+}
+
+apr_status_t apr_file_trunc(apr_file_t *fp, apr_off_t offset)
+{
+ if (fp->buffered) {
+ int rc = 0;
+ file_lock(fp);
+ if (fp->direction == 1 && fp->bufpos != 0) {
+ apr_off_t len = fp->filePtr + fp->bufpos;
+ if (offset < len) {
+ /* New file end fall below our write buffer limit.
+ * Figure out if and what needs to be flushed.
+ */
+ apr_off_t off = len - offset;
+ if (off >= 0 && off <= fp->bufpos)
+ fp->bufpos = fp->bufpos - (size_t)off;
+ else
+ fp->bufpos = 0;
+ }
+ rc = apr_file_flush_locked(fp);
+ /* Reset buffer positions for write mode */
+ fp->bufpos = fp->direction = fp->dataRead = 0;
+ }
+ else if (fp->direction == 0) {
+ /* Discard the read buffer, as we are about to reposition
+ * ourselves to the end of file.
+ */
+ fp->bufpos = 0;
+ fp->dataRead = 0;
+ }
+ file_unlock(fp);
+ if (rc) {
+ return rc;
+ }
+ }
+ if (ftruncate(fp->filedes, offset) == -1) {
+ return errno;
+ }
+ return apr_file_seek(fp, APR_SET, &offset);
+}