Improved deserializeMsgPack() speed by reading several bytes at once

src/ArduinoJson/Deserialization/ArduinoStreamReader.hpp

@@ -23,6 +23,10 @@ struct ArduinoStreamReader {
     char c;
     return _stream.readBytes(&c, 1) ? c : -1;
   }
+
+  size_t readBytes(char* buffer, size_t length) {
+    return _stream.readBytes(buffer, length);
+  }
 };
 
 inline ArduinoStreamReader makeReader(Stream& input) {

src/ArduinoJson/Deserialization/CharPointerReader.hpp

@@ -4,6 +4,7 @@
 
 #pragma once
 
+#include <ArduinoJson/Deserialization/IteratorReader.hpp>
 #include <ArduinoJson/Namespace.hpp>
 
 namespace ARDUINOJSON_NAMESPACE {
@@ -28,22 +29,17 @@ class UnsafeCharPointerReader {
   int read() {
     return static_cast<unsigned char>(*_ptr++);
   }
+
+  size_t readBytes(char* buffer, size_t length) {
+    for (size_t i = 0; i < length; i++) buffer[i] = *_ptr++;
+    return length;
+  }
 };
 
-class SafeCharPointerReader {
-  const char* _ptr;
-  const char* _end;
-
+class SafeCharPointerReader : public IteratorReader<const char*> {
  public:
   explicit SafeCharPointerReader(const char* ptr, size_t len)
-      : _ptr(ptr ? ptr : reinterpret_cast<const char*>("")), _end(_ptr + len) {}
-
-  int read() {
-    if (_ptr < _end)
-      return static_cast<unsigned char>(*_ptr++);
-    else
-      return -1;
-  }
+      : IteratorReader<const char*>(ptr, ptr + len) {}
 };
 
 template <typename TChar>

src/ArduinoJson/Deserialization/FlashStringReader.hpp

@@ -19,6 +19,12 @@ class UnsafeFlashStringReader {
   int read() {
     return pgm_read_byte(_ptr++);
   }
+
+  size_t readBytes(char* buffer, size_t length) {
+    memcpy_P(buffer, _ptr, length);
+    _ptr += length;
+    return length;
+  }
 };
 
 class SafeFlashStringReader {
@@ -35,6 +41,14 @@ class SafeFlashStringReader {
     else
       return -1;
   }
+
+  size_t readBytes(char* buffer, size_t length) {
+    size_t available = static_cast<size_t>(_end - _ptr);
+    if (available < length) length = available;
+    memcpy_P(buffer, _ptr, length);
+    _ptr += length;
+    return length;
+  }
 };
 
 inline UnsafeFlashStringReader makeReader(const __FlashStringHelper* input) {

src/ArduinoJson/Deserialization/IteratorReader.hpp

@@ -22,6 +22,12 @@ class IteratorReader {
     else
       return -1;
   }
+
+  size_t readBytes(char* buffer, size_t length) {
+    size_t i = 0;
+    while (i < length && _ptr < _end) buffer[i++] = *_ptr++;
+    return i;
+  }
 };
 
 template <typename TInput>

src/ArduinoJson/Deserialization/StdStreamReader.hpp

@@ -24,6 +24,11 @@ class StdStreamReader {
     return _stream.get();
   }
 
+  size_t readBytes(char* buffer, size_t length) {
+    _stream.read(buffer, static_cast<std::streamsize>(length));
+    return static_cast<size_t>(_stream.gcount());
+  }
+
  private:
   StdStreamReader& operator=(const StdStreamReader&);  // Visual Studio C4512
 };

src/ArduinoJson/MsgPack/MsgPackDeserializer.hpp

@@ -142,10 +142,7 @@ class MsgPackDeserializer {
   }
 
   bool readBytes(uint8_t *p, size_t n) {
-    for (size_t i = 0; i < n; i++) {
-      if (!readByte(p[i])) return false;
-    }
-    return true;
+    return _reader.readBytes(reinterpret_cast<char *>(p), n) == n;
   }
 
   template <typename T>