IPv4 addresses are fundamentally 32‑bit integers that can be expressed in many notations—decimal, octal, hexadecimal, or combined forms—thanks to historic Unix parsing rules, and these flexible representations can lead to security bypasses and parsing inconsistencies across systems.
This article explains the relationships between bits, binary, hexadecimal, bytes and strings, shows how computers store and process data using binary, demonstrates hexadecimal and Base64 encodings, provides conversion tables and examples, and clarifies how UTF‑8 encodes characters.
An in‑depth examination of a long‑standing PHP bug where the expression 0x00+2 incorrectly evaluates to 4, tracing its origin to the switch from flex to re2c in the lexer of PHP 5.3, detailing affected versions, code behavior, and the eventual fix in PHP 5.3.11.
This article explains the concept of numeral bases, why hexadecimal became the standard in computing due to its compact mapping to binary, explores the theoretical possibility of higher bases like base‑20 or base‑32, and discusses their limited practical applications and inherent complexities.
The article explains that computers operate in binary, humans benefit from hexadecimal because each hex digit maps to four bits, while decimal lacks this direct mapping, making hex a more intuitive bridge between human readability and binary representation.
hexdec() is a PHP built‑in function that converts a hexadecimal string to its decimal value, ignoring any non‑hex characters, and returns the corresponding integer; the article explains its syntax, parameters, return value, and provides example code demonstrating conversions such as "See" and "a0".
The article explains PHP's dechex() function, detailing its purpose of converting a decimal integer to a hexadecimal string, describing the valid input range, parameter definition, return value, and providing example code with expected output.
