From d2077b8962a084651b0f40fde79c91e0bc9923a4 Mon Sep 17 00:00:00 2001
From: chriseth <c@ethdev.com>
Date: Thu, 19 Mar 2015 18:15:16 +0100
Subject: [PATCH] Byte size checked for zero; coding style.

---
 libsolidity/ArrayUtils.cpp         | 27 ++++++++++++++-------------
 libsolidity/ArrayUtils.h           |  2 +-
 libsolidity/ExpressionCompiler.cpp |  1 +
 3 files changed, 16 insertions(+), 14 deletions(-)

diff --git a/libsolidity/ArrayUtils.cpp b/libsolidity/ArrayUtils.cpp
index a46dea3c8..bbf7f985a 100644
--- a/libsolidity/ArrayUtils.cpp
+++ b/libsolidity/ArrayUtils.cpp
@@ -440,9 +440,10 @@ void ArrayUtils::retrieveLength(ArrayType const& _arrayType) const
 	}
 }
 
-void ArrayUtils::incrementByteOffset(unsigned byteSize, unsigned byteOffsetPosition, unsigned storageOffsetPosition) const
+void ArrayUtils::incrementByteOffset(unsigned _byteSize, unsigned _byteOffsetPosition, unsigned _storageOffsetPosition) const
 {
-	solAssert(byteSize < 32, "");
+	solAssert(_byteSize < 32, "");
+	solAssert(_byteSize != 0, "");
 	// We do the following, but avoiding jumps:
 	// byteOffset += byteSize
 	// if (byteOffset + byteSize > 32)
@@ -450,28 +451,28 @@ void ArrayUtils::incrementByteOffset(unsigned byteSize, unsigned byteOffsetPosit
 	//     storageOffset++;
 	//     byteOffset = 0;
 	// }
-	if (byteOffsetPosition > 1)
-		m_context << eth::swapInstruction(byteOffsetPosition - 1);
-	m_context << u256(byteSize) << eth::Instruction::ADD;
-	if (byteOffsetPosition > 1)
-		m_context << eth::swapInstruction(byteOffsetPosition - 1);
+	if (_byteOffsetPosition > 1)
+		m_context << eth::swapInstruction(_byteOffsetPosition - 1);
+	m_context << u256(_byteSize) << eth::Instruction::ADD;
+	if (_byteOffsetPosition > 1)
+		m_context << eth::swapInstruction(_byteOffsetPosition - 1);
 	// compute, X := (byteOffset + byteSize - 1) / 32, should be 1 iff byteOffset + bytesize > 32
 	m_context
-		<< u256(32) << eth::dupInstruction(1 + byteOffsetPosition) << u256(byteSize - 1)
+		<< u256(32) << eth::dupInstruction(1 + _byteOffsetPosition) << u256(_byteSize - 1)
 		<< eth::Instruction::ADD << eth::Instruction::DIV;
 	// increment storage offset if X == 1 (just add X to it)
 	// stack: X
 	m_context
-		<< eth::swapInstruction(storageOffsetPosition) << eth::dupInstruction(storageOffsetPosition + 1)
-		<< eth::Instruction::ADD << eth::swapInstruction(storageOffsetPosition);
+		<< eth::swapInstruction(_storageOffsetPosition) << eth::dupInstruction(_storageOffsetPosition + 1)
+		<< eth::Instruction::ADD << eth::swapInstruction(_storageOffsetPosition);
 	// stack: X
 	// set source_byte_offset to zero if X == 1 (using source_byte_offset *= 1 - X)
 	m_context << u256(1) << eth::Instruction::SUB;
 	// stack: 1 - X
-	if (byteOffsetPosition == 1)
+	if (_byteOffsetPosition == 1)
 		m_context << eth::Instruction::MUL;
 	else
 		m_context
-			<< eth::dupInstruction(byteOffsetPosition + 1) << eth::Instruction::MUL
-			<< eth::swapInstruction(byteOffsetPosition) << eth::Instruction::POP;
+			<< eth::dupInstruction(_byteOffsetPosition + 1) << eth::Instruction::MUL
+			<< eth::swapInstruction(_byteOffsetPosition) << eth::Instruction::POP;
 }
diff --git a/libsolidity/ArrayUtils.h b/libsolidity/ArrayUtils.h
index 6e4ceec1c..22c0646a5 100644
--- a/libsolidity/ArrayUtils.h
+++ b/libsolidity/ArrayUtils.h
@@ -76,7 +76,7 @@ private:
 	/// the storage offset if adding this number again would increase the counter over 32.
 	/// @param byteOffsetPosition the stack offset of the storage byte offset
 	/// @param storageOffsetPosition the stack offset of the storage slot offset
-	void incrementByteOffset(unsigned byteSize, unsigned byteOffsetPosition, unsigned storageOffsetPosition) const;
+	void incrementByteOffset(unsigned _byteSize, unsigned _byteOffsetPosition, unsigned _storageOffsetPosition) const;
 
 	CompilerContext& m_context;
 };
diff --git a/libsolidity/ExpressionCompiler.cpp b/libsolidity/ExpressionCompiler.cpp
index 144827d44..da762147a 100644
--- a/libsolidity/ExpressionCompiler.cpp
+++ b/libsolidity/ExpressionCompiler.cpp
@@ -839,6 +839,7 @@ bool ExpressionCompiler::visit(IndexAccess const& _indexAccess)
 					// goal:
 					// <ref> <byte_number> = <base_ref + index / itemsPerSlot> <(index % itemsPerSlot) * byteSize>
 					unsigned byteSize = arrayType.getBaseType()->getStorageBytes();
+					solAssert(byteSize != 0, "");
 					unsigned itemsPerSlot = 32 / byteSize;
 					m_context << u256(itemsPerSlot) << eth::Instruction::SWAP2;
 					// stack: itemsPerSlot index data_ref