From c93cb8feaecb274aab9a4e176aa108f20bc8b1a5 Mon Sep 17 00:00:00 2001
From: Wolfgang Thaller <wolfgang.thaller@gmx.net>
Date: Tue, 14 Oct 2014 00:11:21 +0200
Subject: [PATCH] implement $$byte, $$word, $$long, $$bitfield

---
 Rez/Expression.cc          | 23 +++++++++++++++++++++++
 Rez/Expression.h           | 10 ++++++++++
 Rez/ResourceCompiler.cc    | 36 +++++++++++++++++++++++++++++++++++-
 Rez/ResourceCompiler.h     |  8 +++++++-
 Rez/ResourceDefinitions.cc |  7 ++-----
 Rez/RezParser.yy           |  8 ++++----
 6 files changed, 81 insertions(+), 11 deletions(-)

diff --git a/Rez/Expression.cc b/Rez/Expression.cc
index 02aa7a4f21..6994541c39 100644
--- a/Rez/Expression.cc
+++ b/Rez/Expression.cc
@@ -136,6 +136,8 @@ ExprPtr IdentifierExpr::lookup(ResourceCompiler *ctx)
 
 int IdentifierExpr::evaluateInt(ResourceCompiler *ctx)
 {
+	if(ctx->isPrePass())
+		return 0;
 	return lookup(ctx)->evaluateInt(ctx);
 }
 
@@ -186,3 +188,24 @@ std::string UnimplementedExpr::evaluateString(ResourceCompiler *ctx)
 	std::cerr << msg << std::endl;
 	return "";
 }
+
+
+PeekExpr::PeekExpr(ExprPtr addr, ExprPtr offset, ExprPtr size)
+	: addr(addr), offset(offset), size(size)
+{
+}
+
+PeekExpr::PeekExpr(ExprPtr addr, int size)
+	: addr(addr),
+	  offset(std::make_shared<IntExpr>(0)),
+	  size(std::make_shared<IntExpr>(size))
+{
+}
+
+int PeekExpr::evaluateInt(ResourceCompiler *ctx)
+{
+	int p = addr->evaluateInt(ctx) + offset->evaluateInt(ctx);
+	int s = size->evaluateInt(ctx);
+
+	return ctx->peek(p, s);
+}
diff --git a/Rez/Expression.h b/Rez/Expression.h
index 2e950c26b9..0300ec6aec 100644
--- a/Rez/Expression.h
+++ b/Rez/Expression.h
@@ -148,5 +148,15 @@ public:
 	virtual std::string evaluateString(ResourceCompiler *ctx);
 };
 
+class PeekExpr : public Expression
+{
+	ExprPtr addr;
+	ExprPtr offset;
+	ExprPtr size;
+public:
+	PeekExpr(ExprPtr addr, ExprPtr offset, ExprPtr size);
+	PeekExpr(ExprPtr addr, int size);
+	virtual int evaluateInt(ResourceCompiler *ctx);
+};
 
 #endif // EXPRESSION_H
diff --git a/Rez/ResourceCompiler.cc b/Rez/ResourceCompiler.cc
index b22419b727..ebc86a8e92 100644
--- a/Rez/ResourceCompiler.cc
+++ b/Rez/ResourceCompiler.cc
@@ -41,6 +41,37 @@ void ResourceCompiler::write(int nBits, int value)
 	//currentOffset += nBits;
 }
 
+int ResourceCompiler::peek(int bitPos, int size)
+{
+	int bytePos = bitPos / 8;
+	int endBytePos = (bitPos + size - 1) / 8 + 1;
+
+	unsigned bitPosInByte = bitPos % 8;
+	unsigned outPos = 32 - size;
+
+	unsigned val = 0;
+
+	for(int i = bytePos; i != endBytePos; ++i)
+	{
+		unsigned byte;
+		if(i < data.size())
+			byte = data[i];
+		else if(i < prePassData.size())
+			byte = prePassData[i];
+		else
+			byte = 0;
+
+		unsigned read = byte << (bitPosInByte + 24);
+		val |= (read >> outPos);
+
+		outPos += 8 - bitPosInByte;
+
+		bitPosInByte = 0;
+	}
+
+	return val;
+}
+
 ExprPtr ResourceCompiler::lookupIdentifier(std::string name, const Subscripts &sub)
 {
 	if(currentField)
@@ -70,10 +101,13 @@ void ResourceCompiler::compile()
 	if(verboseFlag) std::cout << "(first pass)\n";
 	currentOffset = 0;
 	data.clear();
+	prePass = true;
 	typeDefinition->compile(body, this, true);
 	if(verboseFlag) std::cout << "(second pass)\n";
 	currentOffset = 0;
-	data.clear();
+	prePassData = std::move(data);
+	data.clear();	// ###
+	prePass = false;
 	typeDefinition->compile(body, this, false);
 	if(verboseFlag) std::cout << "(done)\n";
 
diff --git a/Rez/ResourceCompiler.h b/Rez/ResourceCompiler.h
index 2ae56d4c58..056f55da91 100644
--- a/Rez/ResourceCompiler.h
+++ b/Rez/ResourceCompiler.h
@@ -31,10 +31,12 @@ class ResourceCompiler
 	Field* currentField;
 	Subscripts currentSubscripts;
 
-	std::vector<unsigned char>	data;
+	std::vector<unsigned char>	data, prePassData;
 	bool verboseFlag;
 
 	void beginArrayScope(std::string& arrayName, int index);
+
+	bool prePass;
 public:
 	ResourceCompiler(TypeDefinitionPtr type, CompoundExprPtr body, bool verboseFlag);
 
@@ -44,6 +46,8 @@ public:
 	void write(int nBits, int value);
 	int tell() { return currentOffset; }
 
+	int peek(int bitPos, int size);
+
 	ExprPtr lookupIdentifier(std::string name, const Subscripts& sub = Subscripts());
 
 	void defineLabel(const std::string& name);
@@ -52,6 +56,8 @@ public:
 	int getArrayCount(const std::string& arrayName);
 	int getArrayIndex(const std::string& arrayName);
 
+	bool isPrePass() { return prePass; }
+
 	class FieldScope
 	{
 		ResourceCompiler *compiler;
diff --git a/Rez/ResourceDefinitions.cc b/Rez/ResourceDefinitions.cc
index 08c8ce44d8..6d55f9ad0b 100644
--- a/Rez/ResourceDefinitions.cc
+++ b/Rez/ResourceDefinitions.cc
@@ -169,11 +169,8 @@ void SimpleField::compileInt(ExprPtr expr, ResourceCompiler *compiler, bool preP
 	}
 
 	int actualValue = 0;
-	if(!prePass)
-	{
-		ResourceCompiler::FieldScope scope(compiler, this);
-		actualValue = (value ? value : expr)->evaluateInt(compiler);
-	}
+	ResourceCompiler::FieldScope scope(compiler, this);
+	actualValue = (value ? value : expr)->evaluateInt(compiler);
 
 	compiler->write(bitSize, actualValue);
 }
diff --git a/Rez/RezParser.yy b/Rez/RezParser.yy
index 2384fa6ef6..ff4d421476 100644
--- a/Rez/RezParser.yy
+++ b/Rez/RezParser.yy
@@ -371,13 +371,13 @@ expression8	: INTLIT	{ $$ = std::make_shared<IntExpr>($1); }
 			| "$$arrayindex" "(" identifier_expression ")"
 				{ $$ = std::make_shared<ArrayIndexExpr>($identifier_expression); }
 			| "$$bitfield" "(" expression "," expression "," expression ")"
-				{ $$ = std::make_shared<UnimplementedExpr>("$$bitfield"); }
+				{ $$ = std::make_shared<PeekExpr>($3, $5, $7); }
 			| "$$word" "(" expression ")"
-				{ $$ = std::make_shared<UnimplementedExpr>("$$word"); }
+				{ $$ = std::make_shared<PeekExpr>($3, 16); }
 			| "$$byte" "(" expression ")"
-				{ $$ = std::make_shared<UnimplementedExpr>("$$byte"); }
+				{ $$ = std::make_shared<PeekExpr>($3, 8); }
 			| "$$long" "(" expression ")"
-				{ $$ = std::make_shared<UnimplementedExpr>("$$long"); }
+				{ $$ = std::make_shared<PeekExpr>($3, 32); }
 			;
 
 %type <IdentifierExprPtr> identifier_expression;