PDFTemplate.bt

//---------------------------------------------------------------------------
/*
	010 Editor Template for PDF file format
	2010/08/06 v0.0.1

	As the PDF file format is not your usual binary file format for which it is easy to create
	010 templates, I had to resort to unusual template programming techniques.
	Some limitations of the 010 scripting language (like not being able to create local structures)
	also explain the unusual style.
	Summary of the algorithm used by this template:
		- search for keywords with FindAll (%PDF, %%EOF, obj, endobj): FindAllKeywords()
		- merge all found keywords into one array, and filter out found keywords that are not actual
		  PDF structures (like obj without preceding index and version): MergeAndFilterAllKeywords()
		- loop over all keywords and prepare data needed to create PDF structures: PrepareStructures()
		- create PDF structures: CreatePDFStructures()

	Source code put in public domain by Didier Stevens, no Copyright
	https://DidierStevens.com
	Use at your own risk

	History:
		2010/08/03: start development with 010 Editor v3.0.6
		2010/08/04: continue
		2010/08/05: continue
		2010/08/06: refactoring, cleanup
*/
//---------------------------------------------------------------------------

local int iCOLOR = 0x95E8FF; // Color used for highlighting PDF structures

enum int {TYPE_UNKNOWN, TYPE_HEADER, TYPE_TRAILER, TYPE_OBJ, TYPE_ENDOBJ};

// Global variables

local int iKeywordCount;
local int iStructureCount;
local TFindResults tfrHeaders;
local TFindResults tfrTrailers;
local TFindResults tfrObjs;
local TFindResults tfrEndobjs;

local int iPDFHeaderCount = 0;
local int iPDFTrailerCount = 0;
local int iPDFUnknownCount = 0;
local int iPDFCommentCount = 0;
local int iPDFWhitespaceCount = 0;
local int iPDFXrefCount = 0;
local int iPDFObjectCount = 0;

// Structures

local int iIndexLength;
local int iWhiteSpace1Length;
local int iVersionLength;
local int iWhiteSpace2Length;
local int iDataLength;
local int iFoundEndobj;
local int iWhiteSpace3Length;
typedef struct {
	BYTE Index[iIndexLength];
	BYTE WhiteSpace1[iWhiteSpace1Length];
	BYTE Version[iVersionLength];
	BYTE WhiteSpace2[iWhiteSpace2Length];
	BYTE Object[3];
	BYTE Data[iDataLength];
	if (iFoundEndobj)
		BYTE EndObject[6];
	BYTE WhiteSpace3[iWhiteSpace3Length];
} PDFObj <read=ReadPDFObj>;

string ReadPDFObj(PDFObj &sPDFObj)
{
	local string sResult;
	SPrintf(sResult, "%s %s obj %s", sPDFObj.Index, sPDFObj.Version, sPDFObj.Data);
	return sResult;
}

local int iHeaderSize;
typedef struct {
	BYTE Header[iHeaderSize];
} PDFHeader;

local int iTrailerSize;
typedef struct {
	BYTE Trailer[iTrailerSize];
} PDFTrailer;

local int iUnknownSize;
typedef struct {
	BYTE Data[iUnknownSize];
} PDFUnknown;

local int iCommentSize;
typedef struct {
	BYTE Comment[iCommentSize];
} PDFComment;

local int iWhitespaceSize;
typedef struct {
	BYTE Whitespace[iWhitespaceSize];
} PDFWhitespace;

local int iXrefSize;
typedef struct {
	BYTE Data[iXrefSize];
} PDFXref;

// Functions

int64 FindStartOfObj(int64 iStart, int &iIndexLength, int &iWhiteSpace1Length, int &iVersionLength, int &iWhiteSpace2Length)
{
	local int iIter;
	local BYTE bChar;
	local int64 iIndex;
	local int64 iStartIndex = -1;
	local int64 iEndIndex = -1;
	local int64 iStartVersion = -1;
	local int64 iEndVersion = -1;

	for(iIter = 1; iIter <= 20; iIter++)
	{
		iIndex = iStart - iIter;
		if (iIndex < 0)
			break;
		bChar = ReadByte(iIndex);
		if (iEndVersion == -1)
		{
			if (bChar == ' ')
				;
			else if (bChar >= '0' && bChar <= '9')
				iEndVersion = iIndex;
			else
				break;
		}
		else if (iStartVersion == -1)
		{
			if (bChar >= '0' && bChar <= '9')
				;
			else if (bChar == ' ')
				iStartVersion = iIndex + 1;
			else
				break;
		}
		else if (iEndIndex == -1)
		{
			if (bChar == ' ')
				;
			else if (bChar >= '0' && bChar <= '9')
				iEndIndex = iIndex;
			else
				break;
		}
		else if (iStartIndex == -1)
		{
			if (bChar < '0' || bChar > '9')
			{
				iStartIndex = iIndex + 1;
				break;
			}
		}
	}

	if (iEndIndex != -1 && iStartVersion != -1 && iEndVersion != -1)
	{
		if (iStartIndex == -1)
		{
			if (iIndex == -1)
				iStartIndex = 0;
			else
				return -1;
		}
		iIndexLength = iEndIndex - iStartIndex + 1;
		iWhiteSpace1Length = iStartVersion - iEndIndex - 1;
		iVersionLength = iEndVersion - iStartVersion + 1;
		iWhiteSpace2Length = iStart - iEndVersion;
		return iStartIndex;
	}
	else
		return -1;
}

int64 FindEOL(int64 iStart)
{
	local int64 iIter;
	for(iIter = iStart; iIter < FileSize(); iIter++)
		if (ReadByte(iIter) == 0x0D && iIter + 1 < FileSize() && ReadByte(iIter + 1) == 0x0A)
			return iIter + 1;
		else if (ReadByte(iIter) == 0x0D || ReadByte(iIter) == 0x0A)
			return iIter;
	return -1;
}

void FindAllKeywords(void)
{
	tfrHeaders = FindAll("%PDF");
	tfrTrailers = FindAll("%%EOF");
	tfrObjs = FindAll(" obj");
	tfrEndobjs = FindAll("endobj");
	iKeywordCount = tfrHeaders.count + tfrTrailers.count + tfrObjs.count + tfrEndobjs.count;
}

int MergeKeywords(int iMerge1Size, int iMerge2Size)
{
	local int64 iIndex1 = 0;
	local int64 iIndex2 = 0;
	local int64 iIndex3 = 0;

	while (true)
	{
		if (iIndex1 == iMerge1Size)
		{
			while (iIndex2 < iMerge2Size)
			{
				aiMerge3KeywordType[iIndex3] = aiMerge2KeywordType[iIndex2];
				aiMerge3KeywordStart[iIndex3] = aiMerge2KeywordStart[iIndex2];
				aiMerge3KeywordSize[iIndex3] = aiMerge2KeywordSize[iIndex2];
				iIndex2++;
				iIndex3++;
			}
			break;
		}
		if (iIndex2 == iMerge2Size)
		{
			while (iIndex1 < iMerge1Size)
			{
				aiMerge3KeywordType[iIndex3] = aiMerge1KeywordType[iIndex1];
				aiMerge3KeywordStart[iIndex3] = aiMerge1KeywordStart[iIndex1];
				aiMerge3KeywordSize[iIndex3] = aiMerge1KeywordSize[iIndex1];
				iIndex1++;
				iIndex3++;
			}
			break;
		}
		if (aiMerge1KeywordStart[iIndex1] < aiMerge2KeywordStart[iIndex2])
		{
			aiMerge3KeywordType[iIndex3] = aiMerge1KeywordType[iIndex1];
			aiMerge3KeywordStart[iIndex3] = aiMerge1KeywordStart[iIndex1];
			aiMerge3KeywordSize[iIndex3] = aiMerge1KeywordSize[iIndex1];
			iIndex1++;
			iIndex3++;
		}
		else
		{
			aiMerge3KeywordType[iIndex3] = aiMerge2KeywordType[iIndex2];
			aiMerge3KeywordStart[iIndex3] = aiMerge2KeywordStart[iIndex2];
			aiMerge3KeywordSize[iIndex3] = aiMerge2KeywordSize[iIndex2];
			iIndex2++;
			iIndex3++;
		}
	}
	for(iIndex1 = 0; iIndex1 < iMerge1Size + iMerge2Size; iIndex1++)
	{
		aiMerge1KeywordType[iIndex1] = aiMerge3KeywordType[iIndex1];
		aiMerge1KeywordStart[iIndex1] = aiMerge3KeywordStart[iIndex1];
		aiMerge1KeywordSize[iIndex1] = aiMerge3KeywordSize[iIndex1];
	}
	return iMerge1Size + iMerge2Size;
}

void MergeAndFilterAllKeywords(void)
{
	local int iIter;
	local int iIter2;
	local int iTempCount;

	for(iIter = 0; iIter < tfrHeaders.count; iIter++)
	{
		aiMerge1KeywordType[iIter] = TYPE_HEADER;
		aiMerge1KeywordStart[iIter] = tfrHeaders.start[iIter];
		aiMerge1KeywordSize[iIter] = tfrHeaders.size[iIter];
	}
	for(iIter = 0; iIter < tfrTrailers.count; iIter++)
	{
		aiMerge2KeywordType[iIter] = TYPE_TRAILER;
		aiMerge2KeywordStart[iIter] = tfrTrailers.start[iIter];
		aiMerge2KeywordSize[iIter] = tfrTrailers.size[iIter];
	}
	iTempCount = MergeKeywords(tfrHeaders.count, tfrTrailers.count);
	iIter2 = 0;
	for(iIter = 0; iIter < tfrObjs.count; iIter++)
	{
		if (-1 != FindStartOfObj(tfrObjs.start[iIter], iIndexLength, iWhiteSpace1Length, iVersionLength, iWhiteSpace2Length))
		{
			aiMerge2KeywordType[iIter2] = TYPE_OBJ;
			aiMerge2KeywordStart[iIter2] = tfrObjs.start[iIter];
			aiMerge2KeywordSize[iIter2] = tfrObjs.size[iIter];
			iIter2++;
		}
	}
	iTempCount = MergeKeywords(iTempCount, iIter2);
	for(iIter = 0; iIter < tfrEndobjs.count; iIter++)
	{
		aiMerge2KeywordType[iIter] = TYPE_ENDOBJ;
		aiMerge2KeywordStart[iIter] = tfrEndobjs.start[iIter];
		aiMerge2KeywordSize[iIter] = tfrEndobjs.size[iIter];
	}
	iKeywordCount = MergeKeywords(iTempCount, tfrEndobjs.count);
}

int CalculateSizeWithEOL(int64 iStart)
{
	local int64 iIndexEOL;

	iIndexEOL = FindEOL(iStart);
	if (iIndexEOL == -1)
		return -1;
	else
		return iIndexEOL - iStart + 1;
}

void PrepareStructures(void)
{
	local int iIter;
	local int64 iEndPreviousStructure = 0;
	local int iSize;
	local int64 iStartIndirectObject;
	local BYTE bRead;
	local int iWhitespaceCount;
	iStructureCount = 0;

	for(iIter = 0; iIter < iKeywordCount; iIter++)
	{
		if (aiMerge1KeywordType[iIter] == TYPE_OBJ)
			iStartIndirectObject = FindStartOfObj(aiMerge1KeywordStart[iIter], iIndexLength, iWhiteSpace1Length, iVersionLength, iWhiteSpace2Length);
		else
			iStartIndirectObject = aiMerge1KeywordStart[iIter];

		if (iStartIndirectObject != iEndPreviousStructure && aiMerge1KeywordType[iIter] != TYPE_ENDOBJ)
		{
			aiStructureType[iStructureCount] = TYPE_UNKNOWN;
			aiStructureStart[iStructureCount] = iEndPreviousStructure;
			aiStructureSize[iStructureCount] = iStartIndirectObject - iEndPreviousStructure;
			iStructureCount++;
		}

		if (aiMerge1KeywordType[iIter] == TYPE_HEADER)
		{
			iSize = CalculateSizeWithEOL(aiMerge1KeywordStart[iIter]);
			if (iSize == -1)
				iSize = aiMerge1KeywordSize[iIter];
			aiStructureType[iStructureCount] = TYPE_HEADER;
			aiStructureStart[iStructureCount] = aiMerge1KeywordStart[iIter];
			aiStructureSize[iStructureCount] = iSize;
			iEndPreviousStructure = aiStructureStart[iStructureCount] + aiStructureSize[iStructureCount];
			iStructureCount++;
		}
		else if (aiMerge1KeywordType[iIter] == TYPE_TRAILER)
		{
			iSize = CalculateSizeWithEOL(aiMerge1KeywordStart[iIter]);
			if (iSize == -1)
				iSize = aiMerge1KeywordSize[iIter];
			aiStructureType[iStructureCount] = TYPE_TRAILER;
			aiStructureStart[iStructureCount] = aiMerge1KeywordStart[iIter];
			aiStructureSize[iStructureCount] = iSize;
			iEndPreviousStructure = aiStructureStart[iStructureCount] + aiStructureSize[iStructureCount];
			iStructureCount++;
		}
		else if (aiMerge1KeywordType[iIter] == TYPE_OBJ)
		{
			iSize = aiMerge1KeywordStart[iIter + 1] - iStartIndirectObject;
			if (aiMerge1KeywordType[iIter + 1] == TYPE_ENDOBJ)
				iSize += 6;
			iWhitespaceCount = 0;
			bRead = ReadByte(iStartIndirectObject + iSize);
			while (bRead == 0x0D || bRead == 0x0A || bRead == 0x20)
			{
				iWhitespaceCount++;
				bRead = ReadByte(iStartIndirectObject + iSize + iWhitespaceCount);
			}
			iSize += iWhitespaceCount;
			aiStructureType[iStructureCount] = TYPE_OBJ;
			aiStructureStart[iStructureCount] = iStartIndirectObject;
			aiStructureSize[iStructureCount] = iSize;
			aiStructureExtraParameter1[iStructureCount] = iIndexLength;
			aiStructureExtraParameter2[iStructureCount] = iWhiteSpace1Length;
			aiStructureExtraParameter3[iStructureCount] = iVersionLength;
			aiStructureExtraParameter4[iStructureCount] = iWhiteSpace2Length;
			aiStructureExtraParameter5[iStructureCount] = aiMerge1KeywordType[iIter + 1] == TYPE_ENDOBJ;
			aiStructureExtraParameter6[iStructureCount] = iWhitespaceCount;
			iEndPreviousStructure = aiStructureStart[iStructureCount] + aiStructureSize[iStructureCount];
			iStructureCount++;
		}
	}

	// code for unknown structure after last keyword
	if (FileSize() - aiStructureStart[iStructureCount - 1] - aiStructureSize[iStructureCount - 1] != 0)
	{
		aiStructureType[iStructureCount] = TYPE_UNKNOWN;
		aiStructureStart[iStructureCount] = aiStructureStart[iStructureCount - 1] + aiStructureSize[iStructureCount - 1];
		aiStructureSize[iStructureCount] = FileSize() - aiStructureStart[iStructureCount - 1] - aiStructureSize[iStructureCount - 1];
		iStructureCount++;
	}
}

void CreatePDFHeader(int64 iStart, int iSize)
{
	iPDFHeaderCount++;
	FSeek(iStart);
	iHeaderSize = iSize;
	PDFHeader sPDFHeader;
}

void CreatePDFTrailer(int64 iStart, int iSize)
{
	iPDFTrailerCount++;
	FSeek(iStart);
	iTrailerSize = iSize;
	PDFTrailer sPDFTrailer;
}

void CreatePDFUnknown(int64 iStart, int iSize)
{
	iPDFUnknownCount++;
	FSeek(iStart);
	iUnknownSize = iSize;
	PDFUnknown sPDFUnknown;
}

void CreatePDFComment(int64 iStart, int iSize)
{
	iPDFCommentCount++;
	FSeek(iStart);
	iCommentSize = iSize;
	PDFComment sPDFComment;
}

int IsWhitespace(int64 iStart, int iSize)
{
	local int64 iIter;
	local BYTE bRead;

	for(iIter = iStart; iIter < iStart + iSize; iIter++)
	{
		bRead = ReadByte(iIter);
		if (bRead != 0x09 && bRead != 0x0A && bRead != 0x0D && bRead != 0x20)
			return false;
	}
	return true;
}

void CreatePDFWhitespace(int64 iStart, int iSize)
{
	iPDFWhitespaceCount++;
	FSeek(iStart);
	iWhitespaceSize = iSize;
	PDFWhitespace sPDFWhitespace;
}

int StartsWith(int64 iStart, int iSize, string sData)
{
	local int64 iIter;

	if (Strlen(sData) > iSize)
		return false;

	for(iIter = 0; iIter < Strlen(sData); iIter++)
		if (ReadByte(iStart + iIter) != sData[iIter])
			return false;
	return true;
}

void CreatePDFXref(int64 iStart, int iSize)
{
	iPDFXrefCount++;
	FSeek(iStart);
	iXrefSize = iSize;
	PDFXref sPDFXref;
}

void CreatePDFObject(int64 iStart, int iSize, int iIndexLengthArg, int iWhiteSpace1LengthArg, int iVersionLengthArg, int iWhiteSpace2LengthArg, int iFoundEndobjArg, int iWhiteSpace3LengthArg)
{
	iPDFObjectCount++;
	iIndexLength = iIndexLengthArg;
	iWhiteSpace1Length = iWhiteSpace1LengthArg;
	iVersionLength = iVersionLengthArg;
	iWhiteSpace2Length = iWhiteSpace2LengthArg;
	iFoundEndobj = iFoundEndobjArg;
	iWhiteSpace3Length = iWhiteSpace3LengthArg;
	FSeek(iStart);
	iDataLength = iSize - iIndexLength - iWhiteSpace1Length - iVersionLength - iWhiteSpace2Length - 6 - 3 - iWhiteSpace3LengthArg;
	PDFObj sPDFObj;
}

local int iToggleColor = iCOLOR;
void ToggleBackColor()
{
	if (iToggleColor == iCOLOR)
		iToggleColor = cNone;
	else
		iToggleColor = iCOLOR;
	SetBackColor(iToggleColor);
}

void CreatePDFStructures(void)
{
	local int iIter;
	for(iIter = 0; iIter < iStructureCount; iIter++)
	{
		ToggleBackColor();
		if (aiStructureType[iIter] == TYPE_UNKNOWN && StartsWith(aiStructureStart[iIter], aiStructureSize[iIter], "%"))
			CreatePDFComment(aiStructureStart[iIter], aiStructureSize[iIter]);
		else if (aiStructureType[iIter] == TYPE_UNKNOWN && StartsWith(aiStructureStart[iIter], aiStructureSize[iIter], "xref"))
			CreatePDFXref(aiStructureStart[iIter], aiStructureSize[iIter]);
		else if (aiStructureType[iIter] == TYPE_UNKNOWN && IsWhitespace(aiStructureStart[iIter], aiStructureSize[iIter]))
			CreatePDFWhitespace(aiStructureStart[iIter], aiStructureSize[iIter]);
		else if (aiStructureType[iIter] == TYPE_UNKNOWN)
			CreatePDFUnknown(aiStructureStart[iIter], aiStructureSize[iIter]);
		else if (aiStructureType[iIter] == TYPE_HEADER)
			CreatePDFHeader(aiStructureStart[iIter], aiStructureSize[iIter]);
		else if (aiStructureType[iIter] == TYPE_TRAILER)
			CreatePDFTrailer(aiStructureStart[iIter], aiStructureSize[iIter]);
		else if (aiStructureType[iIter] == TYPE_OBJ)
			CreatePDFObject(aiStructureStart[iIter], aiStructureSize[iIter], aiStructureExtraParameter1[iIter], aiStructureExtraParameter2[iIter], aiStructureExtraParameter3[iIter], aiStructureExtraParameter4[iIter], aiStructureExtraParameter5[iIter], aiStructureExtraParameter6[iIter]);
	}
	SetBackColor(cNone);
}

void PrintPDFCounters(void)
{
	Printf("Structure counts:\n");
	Printf("  PDFHeader     = %5d\n", iPDFHeaderCount);
	Printf("  PDFTrailer    = %5d\n", iPDFTrailerCount);
	Printf("  PDFObject     = %5d\n", iPDFObjectCount);
	Printf("  PDFComment    = %5d\n", iPDFCommentCount);
	Printf("  PDFXref       = %5d\n", iPDFXrefCount);
	Printf("  PDFWhitespace = %5d\n", iPDFWhitespaceCount);
	Printf("  PDFUnknown    = %5d\n", iPDFUnknownCount);
}

// Main

FindAllKeywords();
if (iKeywordCount == 0)
{
	Printf("Keywords not found, not a PDF file!\n");
	return;
}

local int aiMerge1KeywordType[iKeywordCount];
local int64 aiMerge1KeywordStart[iKeywordCount];
local int aiMerge1KeywordSize[iKeywordCount];
local int aiMerge2KeywordType[iKeywordCount];
local int64 aiMerge2KeywordStart[iKeywordCount];
local int aiMerge2KeywordSize[iKeywordCount];
local int aiMerge3KeywordType[iKeywordCount];
local int64 aiMerge3KeywordStart[iKeywordCount];
local int aiMerge3KeywordSize[iKeywordCount];

MergeAndFilterAllKeywords();

local int aiStructureType[iKeywordCount * 2 + 1];
local int64 aiStructureStart[iKeywordCount * 2 + 1];
local int aiStructureSize[iKeywordCount * 2 + 1];
local int aiStructureExtraParameter1[iKeywordCount * 2 + 1];
local int aiStructureExtraParameter2[iKeywordCount * 2 + 1];
local int aiStructureExtraParameter3[iKeywordCount * 2 + 1];
local int aiStructureExtraParameter4[iKeywordCount * 2 + 1];
local int aiStructureExtraParameter5[iKeywordCount * 2 + 1];
local int aiStructureExtraParameter6[iKeywordCount * 2 + 1];

PrepareStructures();

CreatePDFStructures();

PrintPDFCounters();