From ff7bc85a8fd64efa27175ccec386ee22cc68aa28 Mon Sep 17 00:00:00 2001
From: terrafrost <terrafrost@php.net>
Date: Sat, 10 Sep 2016 15:50:34 -0700
Subject: [PATCH] SFTP: backport "parallel" upload code from master branch

---
 phpseclib/Net/SFTP.php | 80 ++++++++++++++++++++++++++++--------------
 1 file changed, 54 insertions(+), 26 deletions(-)

diff --git a/phpseclib/Net/SFTP.php b/phpseclib/Net/SFTP.php
index b1e60cbc..a279bdfb 100644
--- a/phpseclib/Net/SFTP.php
+++ b/phpseclib/Net/SFTP.php
@@ -2137,40 +2137,68 @@ class Net_SFTP extends Net_SSH2
         $fclose_check = $local_file !== false && !is_resource($local_file);
 
         $start = $offset;
-        $size = $this->max_sftp_packet < $length || $length < 0 ? $this->max_sftp_packet : $length;
+        $read = 0;
         while (true) {
-            $packet = pack('Na*N3', strlen($handle), $handle, $offset / 4294967296, $offset, $size);
-            if (!$this->_send_sftp_packet(NET_SFTP_READ, $packet)) {
-                if ($fclose_check) {
-                    fclose($fp);
-                }
-                return false;
-            }
+            $i = 0;
 
-            $response = $this->_get_sftp_packet();
-            switch ($this->packet_type) {
-                case NET_SFTP_DATA:
-                    $temp = substr($response, 4);
-                    $offset+= strlen($temp);
-                    if ($local_file === false) {
-                        $content.= $temp;
-                    } else {
-                        fputs($fp, $temp);
-                    }
-                    break;
-                case NET_SFTP_STATUS:
-                    // could, in theory, return false if !strlen($content) but we'll hold off for the time being
-                    $this->_logError($response);
-                    break 2;
-                default:
-                    user_error('Expected SSH_FXP_DATA or SSH_FXP_STATUS');
+            while ($i < NET_SFTP_QUEUE_SIZE && ($length < 0 || $read < $length)) {
+                $tempoffset = $start + $read;
+
+                $packet_size = $length > 0 ? min($this->max_sftp_packet, $length - $read) : $this->max_sftp_packet;
+
+                $packet = pack('Na*N3', strlen($handle), $handle, $tempoffset / 4294967296, $tempoffset, $packet_size);
+                if (!$this->_send_sftp_packet(NET_SFTP_READ, $packet)) {
                     if ($fclose_check) {
                         fclose($fp);
                     }
                     return false;
+                }
+                $packet = null;
+                $read+= $packet_size;
+                $i++;
             }
 
-            if ($length > 0 && $length <= $offset - $start) {
+            if (!$i) {
+                break;
+            }
+
+            $clear_responses = false;
+            while ($i > 0) {
+                $i--;
+
+                if ($clear_responses) {
+                    $this->_get_sftp_packet();
+                    continue;
+                } else {
+                    $response = $this->_get_sftp_packet();
+                }
+
+                switch ($this->packet_type) {
+                    case NET_SFTP_DATA:
+                        $temp = substr($response, 4);
+                        $offset+= strlen($temp);
+                        if ($local_file === false) {
+                            $content.= $temp;
+                        } else {
+                            fputs($fp, $temp);
+                        }
+                        $temp = null;
+                        break;
+                    case NET_SFTP_STATUS:
+                        // could, in theory, return false if !strlen($content) but we'll hold off for the time being
+                        $this->_logError($response);
+                        $clear_responses = true; // don't break out of the loop yet, so we can read the remaining responses
+                        break;
+                    default:
+                        if ($fclose_check) {
+                            fclose($fp);
+                        }
+                        user_error('Expected SSH_FX_DATA or SSH_FXP_STATUS');
+                }
+                $response = null;
+            }
+
+            if ($clear_responses) {
                 break;
             }
         }