Started porting ESM reader

esm/.gitignore

@@ -0,0 +1,4 @@
+old
+*.esm
+*.esp
+reader

esm/Makefile

@@ -0,0 +1 @@
+all: reader

esm/reader.cpp

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+#include <iostream>
+#include <string>
+#include <stdint.h>
+#include <assert.h>
+using namespace std;
+
+#include "../mangle/stream/stream.h"
+#include "../mangle/stream/servers/file_stream.h"
+#include "../mangle/tools/str_exception.h"
+
+/* A structure used for holding fixed-length strings. In the case of
+   LEN=4, it can be more efficient to match the string as a 32 bit
+   number, therefore the struct is implemented as a union with an int.
+ */
+template <int LEN>
+union NAME_T
+{
+  char name[LEN];
+  int32_t val;
+
+  bool operator==(const char *str)
+  {
+    for(int i=0; i<LEN; i++)
+      if(name[i] != str[i]) return false;
+      else if(name[i] == 0) return true;
+    return str[LEN] == 0;
+  }
+  bool operator!=(const char *str) { return !((*this)==str); }
+
+  bool operator==(const string &str)
+  {
+    return (*this) == str.c_str();
+  }
+  bool operator!=(const string &str) { return !((*this)==str); }
+
+  bool operator==(int v) { return v == val; }
+  bool operator!=(int v) { return v != val; }
+};
+
+typedef NAME_T<4> NAME;
+typedef NAME_T<32> NAME32;
+typedef NAME_T<256> NAME256;
+
+class ESMReader
+{
+  Mangle::Stream::StreamPtr esm;
+  size_t leftFile;
+  uint32_t leftRec;
+  string filename;
+
+  NAME recName, subName;
+
+public:
+  void open(Mangle::Stream::StreamPtr _esm, const string &name)
+  {
+    esm = _esm;
+    filename = name;
+    leftFile = esm->size();
+    leftRec = 0;
+    recName.val = 0;
+    subName.val = 0;
+
+    cout << "left: " << leftFile << endl;
+    if(getRecName() != "TES3")
+      fail("Not a valid Morrowind file");
+    cout << "left: " << leftFile << endl;
+
+    // The flags are always zero
+    uint32_t flags;
+    getRecHeader(flags);
+  }
+
+  void open(const string &file)
+  {
+    using namespace Mangle::Stream;
+    open(StreamPtr(new FileStream(file)), file);
+  }
+
+  /*************************************************************************
+   *
+   *  Low level reading methods
+   *
+   *************************************************************************/
+
+  NAME getRecName()
+  {
+    if(!hasMoreRecs())
+      fail("No more records, getRecName() failed");
+    getName(recName);
+    leftFile -= 4;
+    return recName;
+  }
+
+  /* Read record header. This updatesleftFile BEYOND the data that
+     follows the header, ie beyond the entire record. You should use
+     leftRec to orient yourself inside the record itself.
+  */
+  void getRecHeader(uint32_t &flags)
+    {
+      // General error checking
+      if(leftFile < 12)
+	fail("End of file while reading record header");
+      if(leftRec)
+	fail("Previous record contains unread bytes");
+
+      getUint(leftRec);
+      getUint(flags);// This header entry is always zero
+      getUint(flags);
+      leftFile -= 12;
+
+      // Check that sizes add up
+      if(leftFile < leftRec)
+	fail("Record size is larger than rest of file");
+
+      // Adjust number of bytes left in file
+      leftFile -= leftRec;
+    }
+
+  bool hasMoreRecs() { return leftFile > 0; }
+
+  void getName(NAME &name) { esm->read(&name,4); }
+  void getUint(uint32_t &u) { esm->read(&u,4); }
+
+  /// Used for error handling
+  void fail(const std::string &msg)
+    {
+      std::string err = "ESM Error: " + msg;
+      err += "\n  File: " + filename;
+      err += "\n  Record: " + string(recName.name,4);
+      err += "\n  Subrecord: " + string(subName.name,4);
+      throw str_exception(err);
+    }
+};
+
+int main(int argc, char**argv)
+{
+  if(argc != 2)
+    return 1;
+
+  ESMReader esm;
+  esm.open(argv[1]);
+
+  return 0;
+}