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PORealloc()/Resize an object in C++ for a string implementation
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  1. PORealloc()/Resize an object in C++ for a string implementation
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    copied!<p><strong>When they are represented in memory, are C++ objects the same as C structs?</strong></p> <p>For example, with C, I could do something like this:</p> <pre><code>struct myObj { int myInt; char myVarChar; }; int main() { myObj * testObj = (myObj *) malloc(sizeof(int)+5); testObj-&gt;myInt = 3; strcpy((char*)&amp;testObj-&gt;myVarChar, "test"); printf("String: %s", (char *) &amp;testObj-&gt;myVarChar); } </code></pre> <p>I don't think C++ allows overloading the <code>+</code> operator for the built-in <code>char *</code> type.</p> <p>So i'd like to create my own lightweight string class which has no extra overhead that <code>std::string</code> has. I think <code>std::string</code> is represented contiguously:</p> <pre><code>(int)length, (char[])data </code></pre> <p>I want exactly the same functionality but without prefixing the length (saving 8 bytes overhead).</p> <p>Here is the code i'm using to test, but it results in a segfault</p> <pre><code>#include &lt;iostream&gt; using namespace std; class pString { public: char c; pString * pString::operator=(const char *); }; pString * pString::operator=(const char * buff) { cout &lt;&lt; "Address of this: " &lt;&lt; (uint32_t) this &lt;&lt; endl; cout &lt;&lt; "Address of this-&gt;c: " &lt;&lt; (uint32_t) &amp;this-&gt;c &lt;&lt; endl; realloc(this, strlen(buff)+1); memcpy(this, buff, strlen(buff)); *(this+strlen(buff)) = '\0'; return this; }; struct myObj { int myInt; char myVarChar; }; int main() { pString * myString = (pString *) malloc(sizeof(pString)); *myString = "testing"; cout &lt;&lt; "'" &lt;&lt; (char *) myString &lt;&lt; "'"; } </code></pre> <hr> <p>Edit: nobody really understands what i want to do. Yes i know i can have a pointer to the string in the class but thats 8 bytes more expensive than a plain cstring, i wanted exactly the same internal representation. Thanks for trying though</p> <hr> <p>Edit: The end result of what i wanted to achieve was being able to use the + operator with NO extra memory usage compared to using strcat etc </p> <pre><code>const char * operator+(const char * first, const char * second); </code></pre>
 

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