try/catch in C [PHP interpreter]

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Abstract PHP interpreter is written in C, but uses try/catch construct known from other popular languages. This approach is different from everyday C-like error handling, where it's done by using function return value or by modifying error variable passed as an argument to a function. zend_try...

Access to object's fields by using pointer arithmetic

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Normally a method uses its object's field by using their name. It's presented below, where we want to get value of description field from getDescription method. class Car { std::string getDescription() { return description; // <- we return value of this field } std::string description; }; The...

Images hardcoded in a source code [PHP interpreter]

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Abstract Recently I presented a simple way to protect an image against saving, today I will show how PHP interpreter protect some of its images against changing. Image may be hardcoded in a regular array, where each field contains corresponding value of a byte in the original image file. You may imagine...

Smarter strings in C

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In C, strings are usually stored in variables with char* type, it's just container for characters, there isn't stored other data/metadata. This can be tedious, e.g. if we want to iterate thought string we need to obtain its length (e.g by invoke strlen() function on it) or carry its length in some additional...

How to replace modulo operator by using bitwise AND operator?

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Modulo operation on a and b returns a reminder from dividing a by b. It can be implemented by using bitwise AND operator if b is a power of two. Following samples in C and Python illustrate it. #include <stdio.h> int main() { // 8(dec) = 1000(bin) // 7(dec) = 111(bin) printf("19...
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