From e68a454fd85ef33f821ee1b2142f1f2f3ea6246e Mon Sep 17 00:00:00 2001
From: Dobrohotov Alexei <alexdobrohotov@yandex.ru>
Date: Sun, 23 May 2021 16:02:05 +0300
Subject: [PATCH] More ESM cleanup

---
 components/esm/esmreader.cpp | 32 +++++++++++++-------------------
 components/esm/esmreader.hpp |  4 ----
 components/esm/loadland.cpp  |  4 +++-
 components/esm/loadregn.cpp  |  2 +-
 4 files changed, 17 insertions(+), 25 deletions(-)

diff --git a/components/esm/esmreader.cpp b/components/esm/esmreader.cpp
index 30c38d739c..899dc745fb 100644
--- a/components/esm/esmreader.cpp
+++ b/components/esm/esmreader.cpp
@@ -119,13 +119,13 @@ std::string ESMReader::getHString()
     // them. For some reason, they break the rules, and contain a byte
     // (value 0) even if the header says there is no data. If
     // Morrowind accepts it, so should we.
-    if (mCtx.leftSub == 0 && !mEsm->peek())
+    if (mCtx.leftSub == 0 && hasMoreSubs() && !mEsm->peek())
     {
         // Skip the following zero byte
         mCtx.leftRec--;
         char c;
-        getExact(&c, 1);
-        return "";
+        getT(c);
+        return std::string();
     }
 
     return getString(mCtx.leftSub);
@@ -155,14 +155,12 @@ void ESMReader::getSubNameIs(const char* name)
 {
     getSubName();
     if (mCtx.subName != name)
-        fail(
-                "Expected subrecord " + std::string(name) + " but got "
-                        + mCtx.subName.toString());
+        fail("Expected subrecord " + std::string(name) + " but got " + mCtx.subName.toString());
 }
 
 bool ESMReader::isNextSub(const char* name)
 {
-    if (!mCtx.leftRec)
+    if (!hasMoreSubs())
         return false;
 
     getSubName();
@@ -177,7 +175,7 @@ bool ESMReader::isNextSub(const char* name)
 
 bool ESMReader::peekNextSub(const char *name)
 {
-    if (!mCtx.leftRec)
+    if (!hasMoreSubs())
         return false;
 
     getSubName();
@@ -234,21 +232,17 @@ void ESMReader::skipHSubUntil(const char *name)
 
 void ESMReader::getSubHeader()
 {
-    if (mCtx.leftRec < 4)
+    if (mCtx.leftRec < sizeof(mCtx.leftSub))
         fail("End of record while reading sub-record header");
 
     // Get subrecord size
     getT(mCtx.leftSub);
+    mCtx.leftRec -= sizeof(mCtx.leftSub);
 
     // Adjust number of record bytes left
-    mCtx.leftRec -= mCtx.leftSub + 4;
-}
-
-void ESMReader::getSubHeaderIs(int size)
-{
-    getSubHeader();
-    if (size != static_cast<int> (mCtx.leftSub))
-        fail("getSubHeaderIs(): Sub header mismatch");
+    if (mCtx.leftRec < mCtx.leftSub)
+        fail("Record size is larger than rest of file");
+    mCtx.leftRec -= mCtx.leftSub;
 }
 
 NAME ESMReader::getRecName()
@@ -276,7 +270,7 @@ void ESMReader::skipRecord()
 void ESMReader::getRecHeader(uint32_t &flags)
 {
     // General error checking
-    if (mCtx.leftFile < 12)
+    if (mCtx.leftFile < 3 * sizeof(uint32_t))
         fail("End of file while reading record header");
     if (mCtx.leftRec)
         fail("Previous record contains unread bytes");
@@ -284,7 +278,7 @@ void ESMReader::getRecHeader(uint32_t &flags)
     getUint(mCtx.leftRec);
     getUint(flags);// This header entry is always zero
     getUint(flags);
-    mCtx.leftFile -= 12;
+    mCtx.leftFile -= 3 * sizeof(uint32_t);
 
     // Check that sizes add up
     if (mCtx.leftFile < mCtx.leftRec)
diff --git a/components/esm/esmreader.hpp b/components/esm/esmreader.hpp
index 503bb637d7..32adf8561e 100644
--- a/components/esm/esmreader.hpp
+++ b/components/esm/esmreader.hpp
@@ -206,10 +206,6 @@ public:
   */
   void getSubHeader();
 
-  /** Get sub header and check the size
-   */
-  void getSubHeaderIs(int size);
-
   /*************************************************************************
    *
    *  Low level record methods
diff --git a/components/esm/loadland.cpp b/components/esm/loadland.cpp
index 38596628f2..d23452d76e 100644
--- a/components/esm/loadland.cpp
+++ b/components/esm/loadland.cpp
@@ -50,7 +50,9 @@ namespace ESM
             switch (esm.retSubName().intval)
             {
                 case ESM::FourCC<'I','N','T','V'>::value:
-                    esm.getSubHeaderIs(8);
+                    esm.getSubHeader();
+                    if (esm.getSubSize() != 8)
+                        esm.fail("Subrecord size is not equal to 8");
                     esm.getT<int>(mX);
                     esm.getT<int>(mY);
                     hasLocation = true;
diff --git a/components/esm/loadregn.cpp b/components/esm/loadregn.cpp
index a56b9f2474..ada33dc3f8 100644
--- a/components/esm/loadregn.cpp
+++ b/components/esm/loadregn.cpp
@@ -39,7 +39,7 @@ namespace ESM
                         // May include the additional two bytes (but not necessarily)
                         if (esm.getSubSize() == sizeof(mData))
                         {
-                            esm.getExact(&mData, sizeof(mData));
+                            esm.getT(mData);
                         }
                         else
                         {