From 1293973a1bda202a692bf5f30d6f44a2a5b75be5 Mon Sep 17 00:00:00 2001
From: bt3gl <1130416+bt3gl@users.noreply.github.com>
Date: Thu, 29 Sep 2022 05:03:11 -0700
Subject: [PATCH] =?UTF-8?q?=F0=9F=8D=AB=20add=20ABI=20encoding?=
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 solidity/abi_encoding.md | 24 ++++++++++++++++++++++++
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+## ABI encoding
+
+* the solidity built-in function `abi.encode` encodes solidity types into raw bytes, that can be interpreted directly by the EVM.
+
+
+```
+contract StringEncoding {
+    bytes public encodedString = abi.encode("hacking");
+}
+```
+
+* this is what happens:
+     1. 1st (32 bytes) word = offset → indicates at which bytes index the string starts. If you count 32 from the beginning (= index 32), you will reach the starting point of where the actual encoded string starts.
+     2. 2nd (32 bytes) word = string length → in the case of the string, this indicates how many characters (including whitespaces) are included in the string. 
+     3. 3rd (32 bytes) word = the actual utf8 encoded string → each individual bytes corresponds to hex notation of a letter / character encoded in utf8. 
+
+<br>
+
+#### other ABI Encodings
+
+* address payable -> address
+* contract -> address
+* enum -> uint8
+* struct -> tuple of elementry types