WString.h

/*
 WString.h - String library for Wiring & Arduino
 ...mostly rewritten by Paul Stoffregen...
 Copyright (c) 2009-10 Hernando Barragan.  All right reserved.
 Copyright 2011, Paul Stoffregen, paul@pjrc.com

 This library is free software; you can redistribute it and/or
 modify it under the terms of the GNU Lesser General Public
 License as published by the Free Software Foundation; either
 version 2.1 of the License, or (at your option) any later version.

 This library is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 Lesser General Public License for more details.

 You should have received a copy of the GNU Lesser General Public
 License along with this library; if not, write to the Free Software
 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

#ifndef String_class_h
#define String_class_h
#ifdef __cplusplus

#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <pgmspace.h>

// An inherited class for holding the result of a concatenation.  These
// result objects are assumed to be writable by subsequent concatenations.
class StringSumHelper;

// an abstract class used as a means to proide a unique pointer type
// but really has no body
class __FlashStringHelper;
#define FPSTR(pstr_pointer) (reinterpret_cast<const __FlashStringHelper *>(pstr_pointer))
#define F(string_literal) (FPSTR(PSTR(string_literal)))

// The string class
class String {
        // use a function pointer to allow for "if (s)" without the
        // complications of an operator bool(). for more information, see:
        // http://www.artima.com/cppsource/safebool.html
        typedef void (String::*StringIfHelperType)() const;
        void StringIfHelper() const {
        }

    public:
        // constructors
        // creates a copy of the initial value.
        // if the initial value is null or invalid, or if memory allocation
        // fails, the string will be marked as invalid (i.e. "if (s)" will
        // be false).
        String(const char *cstr = "");
        String(const String &str);
        String(const __FlashStringHelper *str);
#ifdef __GXX_EXPERIMENTAL_CXX0X__
        String(String &&rval);
        String(StringSumHelper &&rval);
#endif
        explicit String(char c);
        explicit String(unsigned char, unsigned char base = 10);
        explicit String(int, unsigned char base = 10);
        explicit String(unsigned int, unsigned char base = 10);
        explicit String(long, unsigned char base = 10);
        explicit String(unsigned long, unsigned char base = 10);
        explicit String(float, unsigned char decimalPlaces = 2);
        explicit String(double, unsigned char decimalPlaces = 2);
        ~String(void);

        // memory management
        // return true on success, false on failure (in which case, the string
        // is left unchanged).  reserve(0), if successful, will validate an
        // invalid string (i.e., "if (s)" will be true afterwards)
        unsigned char reserve(unsigned int size);
        inline unsigned int length(void) const {
            if(buffer()) {
                return len();
            } else {
                return 0;
            }
        }

        // creates a copy of the assigned value.  if the value is null or
        // invalid, or if the memory allocation fails, the string will be
        // marked as invalid ("if (s)" will be false).
        String & operator =(const String &rhs);
        String & operator =(const char *cstr);
        String & operator = (const __FlashStringHelper *str);
#ifdef __GXX_EXPERIMENTAL_CXX0X__
        String & operator =(String &&rval);
        String & operator =(StringSumHelper &&rval);
#endif

        // concatenate (works w/ built-in types)

        // returns true on success, false on failure (in which case, the string
        // is left unchanged).  if the argument is null or invalid, the
        // concatenation is considered unsucessful.
        unsigned char concat(const String &str);
        unsigned char concat(const char *cstr);
        unsigned char concat(char c);
        unsigned char concat(unsigned char c);
        unsigned char concat(int num);
        unsigned char concat(unsigned int num);
        unsigned char concat(long num);
        unsigned char concat(unsigned long num);
        unsigned char concat(float num);
        unsigned char concat(double num);
        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)
        String & operator +=(const String &rhs) {
            concat(rhs);
            return (*this);
        }
        String & operator +=(const char *cstr) {
            concat(cstr);
            return (*this);
        }
        String & operator +=(char c) {
            concat(c);
            return (*this);
        }
        String & operator +=(unsigned char num) {
            concat(num);
            return (*this);
        }
        String & operator +=(int num) {
            concat(num);
            return (*this);
        }
        String & operator +=(unsigned int num) {
            concat(num);
            return (*this);
        }
        String & operator +=(long num) {
            concat(num);
            return (*this);
        }
        String & operator +=(unsigned long num) {
            concat(num);
            return (*this);
        }
        String & operator +=(float num) {
            concat(num);
            return (*this);
        }
        String & operator +=(double num) {
            concat(num);
            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);
        friend StringSumHelper & operator +(const StringSumHelper &lhs, char c);
        friend StringSumHelper & operator +(const StringSumHelper &lhs, unsigned char num);
        friend StringSumHelper & operator +(const StringSumHelper &lhs, int num);
        friend StringSumHelper & operator +(const StringSumHelper &lhs, unsigned int num);
        friend StringSumHelper & operator +(const StringSumHelper &lhs, long num);
        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);

        // comparison (only works w/ Strings and "strings")
        operator StringIfHelperType() const {
            return buffer() ? &String::StringIfHelper : 0;
        }
        int compareTo(const String &s) const;
        unsigned char equals(const String &s) const;
        unsigned char equals(const char *cstr) 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 String &rhs) const {
            return !equals(rhs);
        }
        unsigned char operator !=(const char *cstr) const {
            return !equals(cstr);
        }
        unsigned char operator <(const String &rhs) const;
        unsigned char operator >(const String &rhs) const;
        unsigned char operator <=(const String &rhs) const;
        unsigned char operator >=(const String &rhs) const;
        unsigned char equalsIgnoreCase(const String &s) const;
        unsigned char equalsConstantTime(const String &s) const;
        unsigned char startsWith(const String &prefix) const;
        unsigned char startsWith(const String &prefix, unsigned int offset) const;
        unsigned char endsWith(const String &suffix) const;

        // character acccess
        char charAt(unsigned int index) const;
        void setCharAt(unsigned int index, char c);
        char operator [](unsigned int index) const;
        char& operator [](unsigned int index);
        void getBytes(unsigned char *buf, unsigned int bufsize, unsigned int index = 0) const;
        void toCharArray(char *buf, unsigned int bufsize, unsigned int index = 0) const {
            getBytes((unsigned char *) buf, bufsize, index);
        }
        const char* c_str() const { return buffer(); }
        char* begin() { return wbuffer(); }
        char* end() { return wbuffer() + length(); }
        const char* begin() const { return c_str(); }
        const char* end() const { return c_str() + length(); }

        // search
        int indexOf(char ch) const;
        int indexOf(char ch, unsigned int fromIndex) const;
        int indexOf(const String &str) const;
        int indexOf(const String &str, unsigned int fromIndex) const;
        int lastIndexOf(char ch) const;
        int lastIndexOf(char ch, unsigned int fromIndex) const;
        int lastIndexOf(const String &str) const;
        int lastIndexOf(const String &str, unsigned int fromIndex) const;
        String substring(unsigned int beginIndex) const {
            return substring(beginIndex, len());
        }
        ;
        String substring(unsigned int beginIndex, unsigned int endIndex) const;

        // modification
        void replace(char find, char replace);
        void replace(const String& find, const String& replace);
        void remove(unsigned int index);
        void remove(unsigned int index, unsigned int count);
        void toLowerCase(void);
        void toUpperCase(void);
        void trim(void);

        // parsing/conversion
        long toInt(void) const;
        float toFloat(void) const;

    protected:
        // Contains the string info when we're not in SSO mode
        struct _ptr { 
            char *   buff;
            uint16_t cap;
            uint16_t len;
        };

        // SSO is handled by checking the last byte of sso_buff.
        // When not in SSO mode, that byte is set to 0xff, while when in SSO mode it is always 0x00 (so it can serve as the string terminator as well as a flag)
        // This allows strings up up to 12 (11 + \0 termination) without any extra space.
        enum { SSOSIZE = sizeof(struct _ptr) + 4 }; // Characters to allocate space for SSO, must be 12 or more
        enum { CAPACITY_MAX = 65535 }; // If size of capacity changed, be sure to update this enum
        union {
            struct _ptr ptr;
            char sso_buf[SSOSIZE];
        };
        // Accessor functions
        inline bool sso() const { return sso_buf[SSOSIZE - 1] == 0; }
        inline unsigned int len() const { return sso() ? strlen(sso_buf) : ptr.len; }
        inline unsigned int capacity() const { return sso() ? SSOSIZE - 1 : ptr.cap; }
        inline void setSSO(bool sso) { sso_buf[SSOSIZE - 1] = sso ? 0x00 : 0xff; }
        inline void setLen(int len) { if (!sso()) ptr.len = len; }
        inline void setCapacity(int cap) { if (!sso()) ptr.cap = cap; }
	inline void setBuffer(char *buff) { if (!sso()) ptr.buff = buff; }
        // Buffer accessor functions
        inline const char *buffer() const { return (const char *)(sso() ? sso_buf : ptr.buff); }
        inline char *wbuffer() const { return sso() ? const_cast<char *>(sso_buf) : ptr.buff; } // Writable version of buffer

    protected:
        void init(void);
        void invalidate(void);
        unsigned char changeBuffer(unsigned int maxStrLen);
        unsigned char concat(const char *cstr, unsigned int length);

        // copy and move
        String & copy(const char *cstr, unsigned int length);
        String & copy(const __FlashStringHelper *pstr, unsigned int length);
#ifdef __GXX_EXPERIMENTAL_CXX0X__
        void move(String &rhs);
#endif
};

class StringSumHelper: public String {
    public:
        StringSumHelper(const String &s) :
                String(s) {
        }
        StringSumHelper(const char *p) :
                String(p) {
        }
        StringSumHelper(char c) :
                String(c) {
        }
        StringSumHelper(unsigned char num) :
                String(num) {
        }
        StringSumHelper(int num) :
                String(num) {
        }
        StringSumHelper(unsigned int num) :
                String(num) {
        }
        StringSumHelper(long num) :
                String(num) {
        }
        StringSumHelper(unsigned long num) :
                String(num) {
        }
        StringSumHelper(float num) :
                String(num) {
        }
        StringSumHelper(double num) :
                String(num) {
        }
};

extern const String emptyString;

#endif  // __cplusplus
#endif  // String_class_h