Merge #20429: refactor: replace (sizeof(a)/sizeof(a[0])) with C++17 std::size

e829c9afbf75e930db6c3fe77a269b0af5e7a3ad refactor: replace sizeof(a)/sizeof(a[0]) by std::size (C++17) (Sebastian Falbesoner)
365539c84691d470b44d35df374d8c049f8c1192 refactor: init vectors via std::{begin,end} to avoid pointer arithmetic (Sebastian Falbesoner)
63d4ee1968144cc3d115f92baef95785abf813ac refactor: iterate arrays via C++11 range-based for loops if idx is not needed (Sebastian Falbesoner)

Pull request description:

  This refactoring PR picks up the idea of #19626 and replaces all occurences of `sizeof(x)/sizeof(x[0])` (or `sizeof(x)/sizeof(*x)`, respectively) with the now-available C++17 [`std::size`](https://en.cppreference.com/w/cpp/iterator/size)  (as [suggested by sipa](https://github.com/bitcoin/bitcoin/pull/19626#issuecomment-666487228)), making the macro `ARRAYLEN` obsolete.

  As preparation for this, two other changes are done to eliminate `sizeof(x)/sizeof(x[0])` usage:
  * all places where arrays are iterated via an index are changed to use C++11 range-based for loops If the index' only purpose is to access the array element (as [suggested by MarcoFalke](https://github.com/bitcoin/bitcoin/pull/19626#discussion_r463404541)).
  * `std::vector` initializations are done via `std::begin` and `std::end` rather than using pointer arithmetic to calculate the end (also [suggested by MarcoFalke](https://github.com/bitcoin/bitcoin/pull/20429#discussion_r567418821)).

ACKs for top commit:
  practicalswift:
    cr ACK e829c9afbf75e930db6c3fe77a269b0af5e7a3ad: patch looks correct
  fanquake:
    ACK e829c9afbf75e930db6c3fe77a269b0af5e7a3ad
  MarcoFalke:
    review ACK e829c9afbf75e930db6c3fe77a269b0af5e7a3ad 🌩

Tree-SHA512: b01d32c04b9e04d562b7717cae00a651ec9a718645047a90761be6959e0cc2adbd67494e058fe894641076711bb09c3b47a047d0275c736f0b2218e1ce0d193d

1 files changed, 11 insertions, 9 deletions

diff --git a/src/rest.cpp b/src/rest.cpp
index f872f6e59d..71426a4dc4 100644
--- a/src/rest.cpp
+++ b/src/rest.cpp
@@ -19,7 +19,6 @@
 #include <txmempool.h>
 #include <util/check.h>
 #include <util/ref.h>
-#include <util/strencodings.h>
 #include <validation.h>
 #include <version.h>
 
@@ -117,9 +116,10 @@ static RetFormat ParseDataFormat(std::string& param, const std::string& strReq)
     param = strReq.substr(0, pos);
     const std::string suff(strReq, pos + 1);
 
-    for (unsigned int i = 0; i < ARRAYLEN(rf_names); i++)
-        if (suff == rf_names[i].name)
-            return rf_names[i].rf;
+    for (const auto& rf_name : rf_names) {
+        if (suff == rf_name.name)
+            return rf_name.rf;
+    }
 
     /* If no suffix is found, return original string.  */
     param = strReq;
@@ -129,12 +129,13 @@ static RetFormat ParseDataFormat(std::string& param, const std::string& strReq)
 static std::string AvailableDataFormatsString()
 {
     std::string formats;
-    for (unsigned int i = 0; i < ARRAYLEN(rf_names); i++)
-        if (strlen(rf_names[i].name) > 0) {
+    for (const auto& rf_name : rf_names) {
+        if (strlen(rf_name.name) > 0) {
             formats.append(".");
-            formats.append(rf_names[i].name);
+            formats.append(rf_name.name);
             formats.append(", ");
         }
+    }
 
     if (formats.length() > 0)
         return formats.substr(0, formats.length() - 2);
@@ -695,6 +696,7 @@ void InterruptREST()
 
 void StopREST()
 {
-    for (unsigned int i = 0; i < ARRAYLEN(uri_prefixes); i++)
-        UnregisterHTTPHandler(uri_prefixes[i].prefix, false);
+    for (const auto& up : uri_prefixes) {
+        UnregisterHTTPHandler(up.prefix, false);
+    }
 }