1 files changed, 136 insertions, 0 deletions
diff --git a/file_io/unix/seek.c b/file_io/unix/seek.c
new file mode 100644
index 0000000..2e97337
--- /dev/null
+++ b/file_io/unix/seek.c
@@ -0,0 +1,136 @@
+/* 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);
+}