Curl_range: commonize FTP and FILE range handling

Closes #2205

1 files changed, 90 insertions, 0 deletions

diff --git a/lib/curl_range.c b/lib/curl_range.c
new file mode 100644
index 000000000..e24215f4d
--- /dev/null
+++ b/lib/curl_range.c
@@ -0,0 +1,90 @@
+/***************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 1998 - 2018, 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.haxx.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.
+ *
+ ***************************************************************************/
+
+#include "curl_setup.h"
+#include <curl/curl.h>
+#include "curl_range.h"
+#include "sendf.h"
+#include "strtoofft.h"
+
+/* Only include this function if one or more of FTP, FILE are enabled. */
+#if !defined(CURL_DISABLE_FTP) && !defined(CURL_DISABLE_FILE)
+
+ /*
+  Check if this is a range download, and if so, set the internal variables
+  properly.
+ */
+CURLcode Curl_range(struct connectdata *conn)
+{
+  curl_off_t from, to;
+  curl_off_t totalsize = -1;
+  char *ptr;
+  char *ptr2;
+  struct Curl_easy *data = conn->data;
+
+  if(data->state.use_range && data->state.range) {
+    CURLofft from_t;
+    CURLofft to_t;
+    from_t = curlx_strtoofft(data->state.range, &ptr, 0, &from);
+    if(from_t == CURL_OFFT_FLOW)
+      return CURLE_RANGE_ERROR;
+    while(*ptr && (ISSPACE(*ptr) || (*ptr == '-')))
+      ptr++;
+    to_t = curlx_strtoofft(ptr, &ptr2, 0, &to);
+    if(to_t == CURL_OFFT_FLOW)
+      return CURLE_RANGE_ERROR;
+    if((to_t == CURL_OFFT_INVAL) && !from_t) {
+      /* X - */
+      data->state.resume_from = from;
+      DEBUGF(infof(data, "RANGE %" CURL_FORMAT_CURL_OFF_T " to end of file\n",
+                   from));
+    }
+    else if((from_t == CURL_OFFT_INVAL) && !to_t) {
+      /* -Y */
+      data->req.maxdownload = to;
+      data->state.resume_from = -to;
+      DEBUGF(infof(data, "RANGE the last %" CURL_FORMAT_CURL_OFF_T " bytes\n",
+                   to));
+    }
+    else {
+      /* X-Y */
+      totalsize = to-from;
+      if(totalsize == CURL_OFF_T_MAX)
+        /* this is too big to increase, so bail out */
+        return CURLE_RANGE_ERROR;
+      data->req.maxdownload = totalsize + 1; /* include last byte */
+      data->state.resume_from = from;
+      DEBUGF(infof(data, "RANGE from %" CURL_FORMAT_CURL_OFF_T
+                   " getting %" CURL_FORMAT_CURL_OFF_T " bytes\n",
+                   from, data->req.maxdownload));
+    }
+    DEBUGF(infof(data, "range-download from %" CURL_FORMAT_CURL_OFF_T
+                 " to %" CURL_FORMAT_CURL_OFF_T ", totally %"
+                 CURL_FORMAT_CURL_OFF_T " bytes\n",
+                 from, to, data->req.maxdownload));
+  }
+  else
+    data->req.maxdownload = -1;
+  return CURLE_OK;
+}
+
+#endif