Add non-blocking HardwareSerial::read(buffer, size) extension (ESP8266 portability)

Author: dok-net

Diff for: cores/esp32/HardwareSerial.cpp

@@ -131,6 +131,24 @@ int HardwareSerial::read(void)
     return -1;
 }
 
+// read characters into buffer
+// terminates if size characters have been read, or no further are pending
+// returns the number of characters placed in the buffer
+// the buffer is NOT null terminated.
+size_t HardwareSerial::read(uint8_t *buffer, size_t size)
+{
+    size_t count = 0;
+    while(count < size) {
+        int c = read();
+        if(c < 0) {
+            break;
+        }
+        *buffer++ = (char) c;
+        count++;
+    }
+    return count;
+}
+
 void HardwareSerial::flush(void)
 {
     uartFlush(_uart);

Diff for: cores/esp32/HardwareSerial.h

@@ -62,6 +62,11 @@ class HardwareSerial: public Stream
     int availableForWrite(void);
     int peek(void);
     int read(void);
+    size_t read(uint8_t *buffer, size_t size);
+    inline size_t read(char * buffer, size_t size)
+    {
+        return read((uint8_t*) buffer, size);
+    }
     void flush(void);
     void flush( bool txOnly);
     size_t write(uint8_t);
@@ -70,7 +75,6 @@ class HardwareSerial: public Stream
     {
         return write((uint8_t*) buffer, size);
     }
-
     inline size_t write(const char * s)
     {
         return write((uint8_t*) s, strlen(s));