From b9503f8258656f6f5da9b214ce45aa5586fc7188 Mon Sep 17 00:00:00 2001
From: Andrew Noyes <andrew@weaselab.dev>
Date: Wed, 4 Sep 2024 12:19:53 -0700
Subject: [PATCH] Converting CheckRangeRightSide WIP

---
 ConflictSet.cpp | 129 ++++++++++++++++++++++++------------------------
 1 file changed, 64 insertions(+), 65 deletions(-)

diff --git a/ConflictSet.cpp b/ConflictSet.cpp
index 260a9d0..ca32d70 100644
--- a/ConflictSet.cpp
+++ b/ConflictSet.cpp
@@ -2627,72 +2627,73 @@ struct CheckRangeRightSide {
 
     assert(searchPathLen <= int(key.size()));
 
-    if (remaining.size() == 0) {
-      return downLeftSpine();
-    }
-
-    if (searchPathLen >= prefixLen) {
-      if (n->entryPresent && n->entry.pointVersion > readVersion) {
-        ok = false;
-        return true;
+    for (;; ++tls->range_read_iterations_accum) {
+      if (remaining.size() == 0) {
+        goto downLeftSpine;
       }
 
-      if (!checkMaxBetweenExclusive(n, -1, remaining[0], readVersion, tls)) {
-        ok = false;
-        return true;
-      }
-    }
+      if (searchPathLen >= prefixLen) {
+        if (n->entryPresent && n->entry.pointVersion > readVersion) {
+          ok = false;
+          return true;
+        }
 
-    if (searchPathLen > prefixLen && n->entryPresent &&
-        n->entry.rangeVersion > readVersion) {
-      ok = false;
-      return true;
-    }
-
-    auto *child = getChild(n, remaining[0]);
-    if (child == nullptr) {
-      auto c = getChildGeq(n, remaining[0]);
-      if (c != nullptr) {
-        n = c;
-        return downLeftSpine();
-      } else {
-        return backtrack();
-      }
-    }
-
-    n = child;
-    remaining = remaining.subspan(1, remaining.size() - 1);
-    ++searchPathLen;
-
-    if (n->partialKeyLen > 0) {
-      int commonLen = std::min<int>(n->partialKeyLen, remaining.size());
-      int i = longestCommonPrefix(n->partialKey(), remaining.data(), commonLen);
-      searchPathLen += i;
-      if (i < commonLen) {
-        ++searchPathLen;
-        auto c = n->partialKey()[i] <=> remaining[i];
-        if (c > 0) {
-          return downLeftSpine();
-        } else {
-          if (searchPathLen > prefixLen && n->entryPresent &&
-              n->entry.rangeVersion > readVersion) {
-            ok = false;
-            return true;
-          }
-          return backtrack();
+        if (!checkMaxBetweenExclusive(n, -1, remaining[0], readVersion, tls)) {
+          ok = false;
+          return true;
         }
       }
-      if (commonLen == n->partialKeyLen) {
-        // partial key matches
-        remaining = remaining.subspan(commonLen, remaining.size() - commonLen);
-      } else if (n->partialKeyLen > int(remaining.size())) {
-        return downLeftSpine();
+
+      if (searchPathLen > prefixLen && n->entryPresent &&
+          n->entry.rangeVersion > readVersion) {
+        ok = false;
+        return true;
+      }
+
+      auto *child = getChild(n, remaining[0]);
+      if (child == nullptr) {
+        auto c = getChildGeq(n, remaining[0]);
+        if (c != nullptr) {
+          n = c;
+          goto downLeftSpine;
+        } else {
+          goto backtrack;
+        }
+      }
+
+      n = child;
+      remaining = remaining.subspan(1, remaining.size() - 1);
+      ++searchPathLen;
+
+      if (n->partialKeyLen > 0) {
+        int commonLen = std::min<int>(n->partialKeyLen, remaining.size());
+        int i =
+            longestCommonPrefix(n->partialKey(), remaining.data(), commonLen);
+        searchPathLen += i;
+        if (i < commonLen) {
+          ++searchPathLen;
+          auto c = n->partialKey()[i] <=> remaining[i];
+          if (c > 0) {
+            goto downLeftSpine;
+          } else {
+            if (searchPathLen > prefixLen && n->entryPresent &&
+                n->entry.rangeVersion > readVersion) {
+              ok = false;
+              return true;
+            }
+            goto backtrack;
+          }
+        }
+        if (commonLen == n->partialKeyLen) {
+          // partial key matches
+          remaining =
+              remaining.subspan(commonLen, remaining.size() - commonLen);
+        } else if (n->partialKeyLen > int(remaining.size())) {
+          goto downLeftSpine;
+        }
       }
     }
-    return false;
-  }
-
-  bool backtrack() {
+  backtrack:
     for (;;) {
       // searchPathLen > prefixLen implies n is not the root
       if (searchPathLen > prefixLen && maxVersion(n) > readVersion) {
@@ -2711,12 +2712,10 @@ struct CheckRangeRightSide {
         searchPathLen -= n->partialKeyLen;
         n = next;
         searchPathLen += n->partialKeyLen;
-        return downLeftSpine();
+        goto downLeftSpine;
       }
     }
-  }
-
-  bool downLeftSpine() {
+  downLeftSpine:
     for (; !n->entryPresent; n = getFirstChildExists(n)) {
     }
     ok = n->entry.rangeVersion <= readVersion;
@@ -2786,7 +2785,7 @@ bool checkRangeRead(Node *n, std::span<const uint8_t> begin,
 
   if (lcp == int(begin.size())) {
     CheckRangeRightSide checkRangeRightSide{n, end, lcp, readVersion, tls};
-    for (; !checkRangeRightSide.step(); ++tls->range_read_iterations_accum)
+    for (; !checkRangeRightSide.step();)
       ;
     return checkRangeRightSide.ok;
   }
@@ -2801,7 +2800,7 @@ bool checkRangeRead(Node *n, std::span<const uint8_t> begin,
   assert(!(n->parent == nullptr && begin.size() == 0));
   bool lhsOk = checkRangeLeftSide(n, begin, lcp + 1, readVersion, tls);
   CheckRangeRightSide checkRangeRightSide{n, end, lcp + 1, readVersion, tls};
-  for (; !checkRangeRightSide.step(); ++tls->range_read_iterations_accum)
+  for (; !checkRangeRightSide.step();)
     ;
 
   return lhsOk && checkRangeRightSide.ok;