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Added __FlashStringhelper* comparison operators to String object #2264

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Added __FlashStringhelper* comparison operators to String object #2264

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c780997
Added __FlashStringhelper* comparison operators to String object
Aug 26, 2014
cb35772
Added a null terminator check
dvdfreitag Aug 27, 2014
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15 changes: 15 additions & 0 deletions hardware/arduino/cores/arduino/WString.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -453,6 +453,21 @@ unsigned char String::equals(const char *cstr) const
return strcmp(buffer, cstr) == 0;
}

unsigned char String::equals(const __FlashStringHelper *fstr) const
{
const char PROGMEM *p = (const char PROGMEM *)fstr;
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@Lauszus Lauszus Aug 27, 2014

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Shouldn't you be using reinterpret_cast here? Please see: #1770.

Note that PGM_P macro should be used for compatible with older version of avr-libc. Please see: 98777e8#diff-0 and ffddfc8.

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@cmaglie cmaglie Aug 27, 2014

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In this case PROGMEM/PGM_P is not needed at all, like in #1770.


for (int i = 0; i < len; i++)
{
if (pgm_read_byte(p) == 0) return 0;
if (buffer[i] != (char)pgm_read_byte(p++)) return 0;
}

if (pgm_read_byte(p) != 0) return 0;

return 1;
}

unsigned char String::operator<(const String &rhs) const
{
return compareTo(rhs) < 0;
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3 changes: 3 additions & 0 deletions hardware/arduino/cores/arduino/WString.h
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Expand Up @@ -139,10 +139,13 @@ class String
int compareTo(const String &s) const;
unsigned char equals(const String &s) const;
unsigned char equals(const char *cstr) const;
unsigned char equals(const __FlashStringHelper *fstr) const;
unsigned char operator == (const String &rhs) const {return equals(rhs);}
unsigned char operator == (const char *cstr) const {return equals(cstr);}
unsigned char operator == (const __FlashStringHelper *fstr) const {return equals(fstr);}
unsigned char operator != (const String &rhs) const {return !equals(rhs);}
unsigned char operator != (const char *cstr) const {return !equals(cstr);}
unsigned char operator != (const __FlashStringHelper *fstr) const {return !equals(fstr);}
unsigned char operator < (const String &rhs) const;
unsigned char operator > (const String &rhs) const;
unsigned char operator <= (const String &rhs) const;
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