Fixes implementation of __FlashStringHelper (espressif#183)

Previous __FlashStringHelper implementation was defines as a char which brought problem in case the method with char* parameter used overloading with __FlashStringHelper* parameter (they was identical). Now __FlashStringHelper is defined as a class and all casts between char* and __FlashStringHelper* are made with reinterpret_cast sugar.

Author: arcao

cores/esp32/Print.cpp

@@ -68,19 +68,12 @@ size_t Print::printf(const char *format, ...)
  }
  return len;
 }
-/*
-size_t Print::print(const __FlashStringHelper *ifsh) {
- PGM_P p = reinterpret_cast<PGM_P>(ifsh);
 
- size_t n = 0;
- while (1) {
- uint8_t c = pgm_read_byte(p++);
- if (c == 0) break;
- n += write(c);
- }
- return n;
+size_t Print::print(const __FlashStringHelper *ifsh)
+{
+ return print(reinterpret_cast<const char *>(ifsh));
 }
-*/
+
 size_t Print::print(const String &s)
 {
  return write(s.c_str(), s.length());
@@ -140,14 +133,14 @@ size_t Print::print(double n, int digits)
 {
  return printFloat(n, digits);
 }
-/*
+
 size_t Print::println(const __FlashStringHelper *ifsh)
 {
  size_t n = print(ifsh);
  n += println();
  return n;
 }
-*/
+
 size_t Print::print(const Printable& x)
 {
  return x.printTo(*this);

cores/esp32/Print.h

@@ -72,7 +72,7 @@ class Print
  }
 
  size_t printf(const char * format, ...) __attribute__ ((format (printf, 2, 3)));
- //size_t print(const __FlashStringHelper *);
+ size_t print(const __FlashStringHelper *);
  size_t print(const String &);
  size_t print(const char[]);
  size_t print(char);
@@ -85,7 +85,7 @@ class Print
  size_t print(const Printable&);
  size_t print(struct tm * timeinfo, const char * format = NULL);
 
- //size_t println(const __FlashStringHelper *);
+ size_t println(const __FlashStringHelper *);
  size_t println(const String &s);
  size_t println(const char[]);
  size_t println(char);

cores/esp32/WString.cpp

@@ -44,12 +44,7 @@ String::String(const String &value)
  init();
  *this = value;
 }
-/*
-String::String(const __FlashStringHelper *pstr) {
- init();
- *this = pstr; // see operator =
-}
-*/
+
 #ifdef __GXX_EXPERIMENTAL_CXX0X__
 String::String(String &&rval)
 {
@@ -200,17 +195,12 @@ String & String::copy(const char *cstr, unsigned int length)
  strcpy(buffer, cstr);
  return *this;
 }
-/*
-String & String::copy(const __FlashStringHelper *pstr, unsigned int length) {
- if (!reserve(length)) {
- invalidate();
- return *this;
- }
- len = length;
- strcpy_P(buffer, (PGM_P)pstr);
- return *this;
+
+String & String::copy(const __FlashStringHelper *pstr, unsigned int length)
+{
+ return copy(reinterpret_cast<const char *>(pstr), length);
 }
-*/
+
 #ifdef __GXX_EXPERIMENTAL_CXX0X__
 void String::move(String &rhs)
 {
@@ -276,15 +266,15 @@ String & String::operator =(const char *cstr)
 
  return *this;
 }
-/*
+
 String & String::operator = (const __FlashStringHelper *pstr)
 {
  if (pstr) copy(pstr, strlen_P((PGM_P)pstr));
  else invalidate();
 
  return *this;
 }
-*/
+
 // /*********************************************/
 // /* concat */
 // /*********************************************/
@@ -375,18 +365,12 @@ unsigned char String::concat(double num)
  char* string = dtostrf(num, 4, 2, buf);
  return concat(string, strlen(string));
 }
-/*
-unsigned char String::concat(const __FlashStringHelper * str) {
- if (!str) return 0;
- int length = strlen_P((PGM_P)str);
- if (length == 0) return 1;
- unsigned int newlen = len + length;
- if (!reserve(newlen)) return 0;
- strcpy_P(buffer + len, (PGM_P)str);
- len = newlen;
- return 1;
+
+unsigned char String::concat(const __FlashStringHelper * str)
+{
+ return concat(reinterpret_cast<const char *>(str));
 }
-*/
+
 /*********************************************/
 /* Concatenate */
 /*********************************************/
@@ -480,14 +464,14 @@ StringSumHelper & operator +(const StringSumHelper &lhs, double num)
  }
  return a;
 }
-/*
+
 StringSumHelper & operator + (const StringSumHelper &lhs, const __FlashStringHelper *rhs)
 {
  StringSumHelper &a = const_cast<StringSumHelper&>(lhs);
  if (!a.concat(rhs))	a.invalidate();
  return a;
 }
-*/
+
 // /*********************************************/
 // /* Comparison */
 // /*********************************************/

cores/esp32/WString.h

@@ -34,7 +34,8 @@ class StringSumHelper;
 
 // an abstract class used as a means to proide a unique pointer type
 // but really has no body
-//class __FlashStringHelper;
+class __FlashStringHelper;
+#define F(string_literal) (reinterpret_cast<const __FlashStringHelper *>(PSTR(string_literal)))
 
 // The string class
 class String
@@ -55,7 +56,7 @@ class String
  // be false).
  String(const char *cstr = "");
  String(const String &str);
- //String(const __FlashStringHelper *str);
+ String(const __FlashStringHelper *str) : String(reinterpret_cast<const char *>(str)) {};
 #ifdef __GXX_EXPERIMENTAL_CXX0X__
  String(String &&rval);
  String(StringSumHelper &&rval);
@@ -89,7 +90,7 @@ class String
  // marked as invalid ("if (s)" will be false).
  String & operator =(const String &rhs);
  String & operator =(const char *cstr);
- //String & operator = (const __FlashStringHelper *str);
+ String & operator = (const __FlashStringHelper *str);
 #ifdef __GXX_EXPERIMENTAL_CXX0X__
  String & operator =(String &&rval);
  String & operator =(StringSumHelper &&rval);
@@ -110,7 +111,7 @@ class String
  unsigned char concat(unsigned long num);
  unsigned char concat(float num);
  unsigned char concat(double num);
- //unsigned char concat(const __FlashStringHelper * str);
+ unsigned char concat(const __FlashStringHelper * str);
 
  // if there's not enough memory for the concatenated value, the string
  // will be left unchanged (but this isn't signalled in any way)
@@ -164,10 +165,11 @@ class String
  concat(num);
  return (*this);
  }
- //String & operator += (const __FlashStringHelper *str){
- // concat(str);
- // return (*this);
- //}
+ String & operator += (const __FlashStringHelper *str)
+ {
+ concat(str);
+ return (*this);
+ }
 
  friend StringSumHelper & operator +(const StringSumHelper &lhs, const String &rhs);
  friend StringSumHelper & operator +(const StringSumHelper &lhs, const char *cstr);
@@ -179,7 +181,7 @@ class String
  friend StringSumHelper & operator +(const StringSumHelper &lhs, unsigned long num);
  friend StringSumHelper & operator +(const StringSumHelper &lhs, float num);
  friend StringSumHelper & operator +(const StringSumHelper &lhs, double num);
- //friend StringSumHelper & operator +(const StringSumHelper &lhs, const __FlashStringHelper *rhs);
+ friend StringSumHelper & operator +(const StringSumHelper &lhs, const __FlashStringHelper *rhs);
 
  // comparison (only works w/ Strings and "strings")
  operator StringIfHelperType() const
@@ -270,7 +272,7 @@ class String
 
  // copy and move
  String & copy(const char *cstr, unsigned int length);
- //String & copy(const __FlashStringHelper *pstr, unsigned int length);
+ String & copy(const __FlashStringHelper *pstr, unsigned int length);
 #ifdef __GXX_EXPERIMENTAL_CXX0X__
  void move(String &rhs);
 #endif

cores/esp32/pgmspace.h

@@ -29,16 +29,13 @@ typedef unsigned short prog_uint16_t;
 typedef long prog_int32_t;
 typedef unsigned long prog_uint32_t;
 
-typedef char __FlashStringHelper;
-
 #define SIZE_IRRELEVANT 0x7fffffff
 
 #define PROGMEM
 #define PGM_P const char *
 #define PGM_VOID_P const void *
 #define FPSTR(p) ((const char *)(p))
 #define PSTR(s) (s)
-#define F(s) (s)
 #define _SFR_BYTE(n) (n)
 
 #define pgm_read_byte(addr) (*(const unsigned char *)(addr))