add WiFiClient::write_P to be used with PROGMEM

Author: martinayotte

libraries/ESP8266WiFi/src/WiFiClient.cpp

@@ -177,6 +177,38 @@ size_t WiFiClient::write(const uint8_t *buf, size_t size)
     return _client->write(reinterpret_cast<const char*>(buf), size);
 }
 
+size_t WiFiClient::write_P(PGM_P buf, size_t size)
+{
+    if (!_client || !size)
+    {
+        return 0;
+    }
+
+    char chunkUnit[WIFICLIENT_MAX_PACKET_SIZE + 1];
+    chunkUnit[WIFICLIENT_MAX_PACKET_SIZE] = '\0';
+    while (buf != NULL) 
+    {
+        size_t chunkUnitLen;
+        PGM_P chunkNext;
+        chunkNext = (PGM_P)memccpy_P((void*)chunkUnit, (PGM_VOID_P)buf, 0, WIFICLIENT_MAX_PACKET_SIZE);
+        if (chunkNext == NULL) 
+        {
+            // no terminator, more data available
+            buf += WIFICLIENT_MAX_PACKET_SIZE;
+            chunkUnitLen = WIFICLIENT_MAX_PACKET_SIZE;
+        }
+        else 
+        {
+            // reached terminator
+            chunkUnitLen = chunkNext - buf;
+            buf = NULL;
+        }
+        if (size < WIFICLIENT_MAX_PACKET_SIZE) chunkUnitLen = size;
+        _client->write((const char*)chunkUnit, chunkUnitLen);
+    }
+    return size;
+}
+
 int WiFiClient::available()
 {
     if (!_client)

libraries/ESP8266WiFi/src/WiFiClient.h

@@ -28,6 +28,8 @@
 #include <memory>
 #include "include/slist.h"
 
+#define WIFICLIENT_MAX_PACKET_SIZE 1460
+
 class ClientContext;
 class WiFiServer;
 
@@ -46,6 +48,7 @@ class WiFiClient : public Client, public SList<WiFiClient> {
   virtual int connect(const char *host, uint16_t port);
   virtual size_t write(uint8_t);
   virtual size_t write(const uint8_t *buf, size_t size);
+  size_t write_P(PGM_P buf, size_t size);
   template <typename T>
   size_t write(T& source, size_t unitSize);
 
@@ -65,16 +68,16 @@ class WiFiClient : public Client, public SList<WiFiClient> {
   static void setLocalPortStart(uint16_t port) { _localPort = port; }
 
   template<typename T> size_t write(T &src){
-    uint8_t obuf[1460];
+    uint8_t obuf[WIFICLIENT_MAX_PACKET_SIZE];
     size_t doneLen = 0;
     size_t sentLen;
     int i;
 
-    while (src.available() > 1460){
-      src.read(obuf, 1460);
-      sentLen = write(obuf, 1460);
+    while (src.available() > WIFICLIENT_MAX_PACKET_SIZE){
+      src.read(obuf, WIFICLIENT_MAX_PACKET_SIZE);
+      sentLen = write(obuf, WIFICLIENT_MAX_PACKET_SIZE);
       doneLen = doneLen + sentLen;
-      if(sentLen != 1460){
+      if(sentLen != WIFICLIENT_MAX_PACKET_SIZE){
         return doneLen;
       }
     }