/**************************** omf.cpp *********************************
* Author: Agner Fog
* Date created: 2007-01-29
* Last modified: 2007-01-29
* Project: objconv
* Module: omf.cpp
* Description:
* Module for reading OMF files
*
* Class COMF is used for reading, interpreting and dumping OMF files.
*
* Copyright 2007-2008 GNU General Public License http://www.gnu.org/licenses
*****************************************************************************/
#include "stdafx.h"
// OMF Record type names
SIntTxt OMFRecordTypeNames[] = {
{OMF_THEADR, "Translator Header"},
{OMF_LHEADR, "Library Module Header"},
{OMF_COMENT, "Comment"},
{OMF_MODEND, "Module End"},
{OMF_EXTDEF, "External Names Definition"},
{OMF_PUBDEF, "Public Names Definition"},
{OMF_LINNUM, "Line Numbers"},
{OMF_LNAMES, "List of Names"},
{OMF_SEGDEF, "Segment Definition"},
{OMF_GRPDEF, "Group Definition"},
{OMF_FIXUPP, "Fixup"},
{OMF_LEDATA, "Enumerated Data"},
{OMF_LIDATA, "Iterated Data"},
{OMF_COMDEF, "Communal Names Definition"},
{OMF_BAKPAT, "Backpatch"},
{OMF_LEXTDEF, "Local External Names"},
{OMF_LPUBDEF, "Local Public Names"},
{OMF_LCOMDEF, "Local Communal Names"},
{OMF_CEXTDEF, "COMDAT External Names"},
{OMF_COMDAT, "Initialized Communal Data"},
{OMF_LINSYM, "Symbol Line Numbers"},
{OMF_ALIAS, "Alias Definition"},
{OMF_NBKPAT, "Named Backpatch"},
{OMF_LLNAMES, "Local Logical Names"},
{OMF_VERNUM, "OMF Version Number"},
{OMF_VENDEXT, "Vendor-specific OMF Extension"},
{OMF_LIBHEAD, "Library Header"},
{OMF_LIBEND, "Library End"}
};
// Segment combination names
SIntTxt OMFSegmentCombinationNames[] = {
{0, "Private"},
{1, "Invalid"},
{2, "Public"},
{3, "Invalid"},
{4, "Public 4"},
{5, "Stack"},
{6, "Common"},
{7, "Public 7"}
};
// Relocation mode names
static SIntTxt OMFRelocationModeNames[] = {
{0, "Relatv"},
{1, "Direct"}
};
// Fixup location names
static SIntTxt OMFFixupLocationNames[] = {
{OMF_Fixup_8bit, "8 bit"}, // 0
{OMF_Fixup_16bit, "16 bit"}, // 1
{OMF_Fixup_Segment, "segment selector, 16 bit"}, // 2
{OMF_Fixup_Far, "far pointer 16+16 bit"}, // 3
{OMF_Fixup_Hi8bit, "high 8 bit of 16 bits"}, // 4
{OMF_Fixup_16bitLoader, "16 bit loader resolved"}, // 5
{OMF_Fixup_Pharlab48, "farword 48 bit, Pharlab only"},// 6
{OMF_Fixup_32bit, "32 bit"}, // 9
{OMF_Fixup_Farword, "farword 32+16 bit"}, // 11
{OMF_Fixup_32bitLoader, "32 bit loader resolved"} // 13
};
// Alignment value translation table
static const uint32 OMFAlignTranslate[8] = {0,1,2,16,256,4,0,0};
// Class COMF members:
// Constructor
COMF::COMF() {
// Default constructor
memset(this, 0, sizeof(*this)); // reset everything
}
void COMF::ParseFile() {
// Parse file buffer
uint8 RecordType; // Type of current record
uint32 Checksum; // Record checksum
uint32 ChecksumZero = 0; // Count number of records with zero checksum
SOMFRecordPointer rec; // Current record pointer
// Make first entry zero in name lists
LocalNameOffset.PushZero();
SegmentNameOffset.PushZero();
GroupNameOffset.PushZero();
SymbolNameOffset.PushZero();
// Initialize record pointer
rec.Start(Buf(), 0, GetDataSize());
// Loop through records to set record pointers and store names
do {
// Read record
RecordType = rec.Type2; // First byte of record = type
// Compute checksum
Checksum = 0; rec.Index = 0;
while (rec.Index < rec.End) Checksum += rec.GetByte();
uint32 CheckByte = rec.GetByte();
if ((Checksum + CheckByte) & 0xFF) {
// Checksum failed
if (CheckByte == 0) {
ChecksumZero++;
}
else err.submit(1202); // Checksum error
}
// Store record pointer
rec.Index = 3; // Offset to current byte while parsing
Records.Push(rec); // Store record pointer in list
if (rec.Type2 == OMF_LNAMES) {
// LNAMES record. Store local names by name index
// Loop through strings in record
while (rec.Index < rec.End) {
char * LocalName = rec.GetString();
uint32 LocalNameIndex = NameBuffer.PushString(LocalName); // Store local name
LocalNameOffset.Push(LocalNameIndex);// Store local name index
}
if (rec.Index != rec.End) err.submit(1203); // Check for consistency
}
if (rec.Type2 == OMF_SEGDEF) {
// SEGDEF record. Store segment names by segment index
OMF_SAttrib Attributes;
if (rec.Type2 == OMF_SEGDEF) {
Attributes.b = rec.GetByte(); // Read attributes
if (Attributes.u.A == 0) {
// Frame and Offset only included if A = 0
rec.GetWord(); rec.GetByte();
}
rec.GetNumeric(); // Length
}
uint32 NameIndex = rec.GetIndex();
if (NameIndex < LocalNameOffset.GetNumEntries()) {
SegmentNameOffset.Push(LocalNameOffset[NameIndex]); // List by segment index
}
}
if (rec.Type2 == OMF_GRPDEF) {
// GRPDEF record. Store group name
uint32 NameIndex = rec.GetIndex();
if (NameIndex < LocalNameOffset.GetNumEntries()) {
GroupNameOffset.Push(LocalNameOffset[NameIndex]); // List by group index
}
}
if (rec.Type2 == OMF_EXTDEF) {
// EXTDEF record. Store external symbol names
// Loop through strings in record
while (rec.Index < rec.End) {
char * symbolname = rec.GetString();
rec.GetIndex();
uint32 SymbolNameIndex = NameBuffer.PushString(symbolname); // Store external name
SymbolNameOffset.Push(SymbolNameIndex); // Save in name index table
}
if (rec.Index != rec.End) err.submit(1203); // Check for consistency
}
if (rec.Type2 == OMF_CEXTDEF) {
// CEXTDEF record. Store communal symbol names
// Loop through entries in record
uint32 SymbolNameIndex; // Index into NameBuffer
while (rec.Index < rec.End) {
uint32 LIndex = rec.GetIndex(); // Index into preceding LNAMES
rec.GetIndex(); // Type index. Ignore
// Get name from LocalNameOffset and put into SymbolNameOffset.
if (LIndex < LocalNameOffset.GetNumEntries()) {
SymbolNameIndex = LocalNameOffset[LIndex];
}
else SymbolNameIndex = 0;
SymbolNameOffset.Push(SymbolNameIndex); // Save in name index table
}
if (rec.Index != rec.End) err.submit(1203); // Check for consistency
}
} // Point to next record
while (rec.GetNext()); // End of loop through records
NumRecords = Records.GetNumEntries(); // Number of records
if (ChecksumZero) printf("\nChecksums are zero"); // This is taken out of the loop to report it only once
}
void COMF::Dump(int options) {
// Dump file
if (options & DUMP_FILEHDR) DumpRecordTypes(); // Dump summary of record types
if (options & DUMP_STRINGTB) DumpNames(); // Dump names records
if (options & DUMP_SYMTAB) DumpSymbols(); // Dump public/external name records
if (options & DUMP_SECTHDR) DumpSegments(); // Dump segment records
if (options & DUMP_RELTAB) DumpRelocations(); // Dump fixup records
}
void COMF::DumpRecordTypes() {
// Dump summary of records
printf("\nSummary of records:");
for (uint32 i = 0; i < NumRecords; i++) {
// Print record type
printf("\n Record %02X, %s%s, total length %i", Records[i].Type,
Lookup(OMFRecordTypeNames, Records[i].Type2),
(Records[i].Type & 1) ? ".32" : "",
Records[i].End+1);
}
}
void COMF::DumpNames() {
// Dump local names records
uint32 i; // Record index
uint32 ln = 0; // Local name index
printf("\n\nLocal names:");
for (i = 0; i < NumRecords; i++) {
if (Records[i].Type2 == OMF_LNAMES) {
// LNAMES record. There should be only one
// Loop through strings in record
while (Records[i].Index < Records[i].End) {
printf("\n %2i %s", ++ln, Records[i].GetString());
}
if (Records[i].Index != Records[i].End) err.submit(1203); // Check for consistency
}
if (Records[i].Type2 == OMF_THEADR || Records[i].Type2 == OMF_LHEADR) {
// Module header record
// Loop through strings in record
while (Records[i].Index < Records[i].End) {
printf("\n Module: %s\n", Records[i].GetString());
}
if (Records[i].Index != Records[i].End) err.submit(1203); // Check for consistency
}
}
}
void COMF::DumpSymbols() {
// Dump public, external and communal names records
uint32 i; // Record index
uint32 xn = 0; // External name index
char * string;
uint32 TypeIndex;
uint32 Group;
uint32 Segment;
uint32 BaseFrame;
uint32 Offset;
for (i = 0; i < NumRecords; i++) {
if (Records[i].Type2 == OMF_EXTDEF) {
// EXTDEF record.
Records[i].Index = 3;
printf("\n\nExternal names:");
// Loop through strings in record
while (Records[i].Index < Records[i].End) {
string = Records[i].GetString();
TypeIndex = Records[i].GetIndex();
printf("\n %2i %s, Type %i", ++xn, string, TypeIndex);
}
if (Records[i].Index != Records[i].End) err.submit(1203); // Check for consistency
}
if (Records[i].Type2 == OMF_PUBDEF) {
// PUBDEF record.
printf("\n\nPublic names:");
Records[i].Index = 3;
Group = Records[i].GetIndex();
Segment = Records[i].GetIndex();
BaseFrame = 0;
if (Segment == 0) BaseFrame = Records[i].GetWord();
// Loop through strings in record
while (Records[i].Index < Records[i].End) {
string = Records[i].GetString();
Offset = Records[i].GetNumeric();
TypeIndex = Records[i].GetIndex();
printf("\n %s, Segment %s, Group %s, Offset 0x%X, Type %i",
string, GetSegmentName(Segment), GetGroupName(Group), Offset, TypeIndex);
if (BaseFrame) printf(", Frame %i", BaseFrame);
}
if (Records[i].Index != Records[i].End) err.submit(1203); // Check for consistency
}
if (Records[i].Type2 == OMF_CEXTDEF) {
// CEXTDEF record.
printf("\n\nCommunal names:");
Records[i].Index = 3;
while (Records[i].Index < Records[i].End) {
uint32 LIndex = Records[i].GetIndex(); // Index into preceding LNAMES
uint32 Type = Records[i].GetIndex(); // Type index. Ignored
printf("\n %2i %s, Type %i", ++xn, GetLocalName(LIndex), Type);
}
if (Records[i].Index != Records[i].End) err.submit(1203); // Check for consistency
}
}
}
void COMF::DumpSegments() {
// Dump all segment records
// Define structure of attributes
OMF_SAttrib Attributes;
// Record values
uint32 Frame, Offset, SegLength, NameIndex, ClassIndex, OverlayIndex;
uint32 i; // Record number
uint32 SegNum = 0; // Segment number
printf("\n\nSegment records:");
for (i = 0; i < NumRecords; i++) {
if (Records[i].Type2 == OMF_SEGDEF) {
// SEGDEF record
Records[i].Index = 3;
// Loop through entries in record. There should be only 1
while (Records[i].Index < Records[i].End) {
Attributes.b = Records[i].GetByte(); // Read attributes
if (Attributes.u.A == 0) {
// Frame and Offset only included if A = 0
Frame = Records[i].GetWord(); Offset = Records[i].GetByte();
}
else Frame = Offset = 0;
SegLength = Records[i].GetNumeric();
NameIndex = Records[i].GetIndex();
ClassIndex = Records[i].GetIndex();
OverlayIndex = Records[i].GetIndex();
printf("\n Segment %2i, Name %s, Class %s, Align %i, %s, %i bit",
++SegNum, GetLocalName(NameIndex), GetLocalName(ClassIndex),
OMFAlignTranslate[Attributes.u.A],
Lookup(OMFSegmentCombinationNames, Attributes.u.C),
Attributes.u.P ? 32 : 16);
if (Attributes.u.B) printf(", big");
if (Attributes.u.A == 0) printf(", Frame %i, Offset 0x%X", Frame, Offset);
printf(", Length %i", SegLength);
if (OverlayIndex) printf("\n Overlay %i", OverlayIndex);
}
if (Records[i].Index != Records[i].End) err.submit(1203); // Check for consistency
}
}
printf("\n\nGroup records:");
for (i = 0; i < NumRecords; i++) {
if (Records[i].Type2 == OMF_GRPDEF) {
// GRPDEF record
Records[i].Index = 3;
ClassIndex = Records[i].GetIndex();
printf("\n Group: %s\n Segments:", GetLocalName(ClassIndex));
// Loop through remaining entries in record
while (Records[i].Index < Records[i].End) {
uint8 Type = Records[i].GetByte();
if (Type != 0xFF) printf(" Type=%X:", Type);
NameIndex = Records[i].GetIndex();
printf(" %s", GetSegmentName(NameIndex));
}
if (Records[i].Index != Records[i].End) err.submit(1203); // Check for consistency
}
}
}
void COMF::DumpRelocations() {
// Dump all LEDATA, LIDATA, COMDAT and FIXUPP records
uint32 LastDataRecord = 0; // Index to the data record that relocations refer to
uint32 LastDataRecordSize = 0; // Size of the data record that relocations refer to
int8 * LastDataRecordPointer = 0; // Pointer to data in the data record that relocations refer to
uint32 i; // Loop counter
uint32 Segment, Offset, Size; // Contents of LEDATA or LIDATA record
uint32 LastOffset = 0; // Offset of last LEDATA or LIDATA record
uint32 Frame, Target, TargetDisplacement; // Contents of FIXUPP record
uint8 byte1, byte2; // First two bytes of subrecord
// Bitfields in subrecords
OMF_SLocat Locat; // Structure of first two bytes of FIXUP subrecord swapped = Locat field
OMF_SFixData FixData; // Structure of FixData field in FIXUP subrecord of FIXUPP record
OMF_STrdDat TrdDat; // Structure of Thread Data field in THREAD subrecord of FIXUPP record
printf("\n\nLEDATA, LIDATA, COMDAT and FIXUPP records:");
for (i = 0; i < NumRecords; i++) {
if (Records[i].Type2 == OMF_LEDATA) {
// LEDATA record
Segment = Records[i].GetIndex(); // Read segment and offset
Offset = Records[i].GetNumeric();
Size = Records[i].End - Records[i].Index; // Calculate size of data
LastDataRecord = i; // Save for later FIXUPP that refers to this record
LastDataRecordSize = Size;
LastDataRecordPointer = Records[i].buffer + Records[i].FileOffset + Records[i].Index;
printf("\n LEDATA: segment %s, Offset 0x%X, Size 0x%X", // Dump segment, offset, size
GetSegmentName(Segment), Offset, Size);
LastOffset = Offset;
}
if (Records[i].Type2 == OMF_LIDATA) {
// LIDATA record
Segment = Records[i].GetIndex();
Offset = Records[i].GetNumeric();
LastDataRecord = i;
LastDataRecordSize = Records[i].End - Records[i].Index; // Size before expansion of repeat blocks
LastDataRecordPointer = Records[i].buffer + Records[i].FileOffset + Records[i].Index;
printf("\n LIDATA: segment %s, Offset 0x%X, Size ",
GetSegmentName(Segment), Offset);
// Call recursive function to interpret repeat data block
Size = Records[i].InterpretLIDATABlock();
printf(" = 0x%X", Size);
LastOffset = Offset;
}
if (Records[i].Type2 == OMF_COMDAT) {
// COMDAT record
uint32 Flags = Records[i].GetByte(); // 1 = continuation, 2 = iterated, 4 = local, 8 = data in code segment
uint32 Attributes = Records[i].GetByte();
uint32 Base = 0;
// 0 = explicit, 1 = far code, 2 = far data, 3 = code32, 4 = data32
// 0x00 = no match, 0x10 = pick any, 0x20 = same size, 0x30 = exact match
uint32 Align = Records[i].GetByte(); // Alignment
Offset = Records[i].GetNumeric(); // Offset
uint32 TypeIndex = Records[i].GetIndex(); // Type index
if ((Attributes & 0x0F) == 0) {
Base = Records[i].GetIndex(); // Public base
}
uint32 NameIndex = Records[i].GetIndex(); // LNAMES index
Size = Records[i].End - Records[i].Index; // Calculate size of data
printf("\n COMDAT: name %s, Offset 0x%X, Size 0x%X, Attrib 0x%02X, Align %i, Type %i, Base %i",
GetLocalName(NameIndex), Offset, Size, Attributes, Align, TypeIndex, Base);
LastOffset = Offset;
}
if (Records[i].Type2 == OMF_FIXUPP) {
// FIXUPP record
printf("\n FIXUPP:");
Records[i].Index = 3;
// Loop through entries in record
while (Records[i].Index < Records[i].End) {
// Read first byte
byte1 = Records[i].GetByte();
if (byte1 & 0x80) {
// This is a FIXUP subrecord
Frame = 0; Target = 0; TargetDisplacement = 0;
// read second byte
byte2 = Records[i].GetByte();
// swap bytes and put into byte12 bitfield
Locat.bytes[1] = byte1;
Locat.bytes[0] = byte2;
// Read FixData
FixData.b = Records[i].GetByte();
// print mode and location
printf("\n %s %s, Offset 0x%X",
Lookup(OMFRelocationModeNames, Locat.s.M),
Lookup(OMFFixupLocationNames, Locat.s.Location),
Locat.s.Offset + LastOffset);
// Read conditional fields
if (FixData.s.F == 0) {
if (FixData.s.Frame < 4) {
Frame = Records[i].GetIndex();
}
else Frame = 0;
switch (FixData.s.Frame) { // Frame method
case 0: // F0: segment
printf(", segment %s", GetSegmentName(Frame)); break;
case 1: // F1: group
printf(", group %s", GetGroupName(Frame)); break;
case 2: // F2: external symbol
printf(", external frame %s", GetSymbolName(Frame)); break;
case 4: // F4: frame = source,
// or Borland floating point emulation record (undocumented?)
printf(", frame = source; or Borland f.p. emulation record");
break;
case 5: // F5: frame = target
printf(", frame = target"); break;
default:
printf(", target frame %i method F%i", Frame, FixData.s.Frame);
}
}
else {
printf(", frame uses thread %i", FixData.s.Frame);
}
if (FixData.s.T == 0) {
// Target specified
Target = Records[i].GetIndex();
uint32 TargetMethod = FixData.s.Target + FixData.s.P * 4;
switch (FixData.s.Target) { // = Target method modulo 4
case 0: // T0 and T4: Target = segment
case 1: // T1 and T5: Target = segment group
printf(". Segment %s (T%i)",
GetSegmentName(Target), TargetMethod);
break;
case 2: // T2 and T6: Target = external symbol
printf(". Symbol %s (T%i)",
GetSymbolName(Target), TargetMethod);
break;
default: // Unknown method
printf(", target %i unknown method T%i", Target, TargetMethod);
}
}
else {
// Target specified in previous thread
printf(", target uses thread %i", FixData.s.Target);
}
if (FixData.s.P == 0) {
TargetDisplacement = Records[i].GetNumeric();
printf("\n target displacement %i", TargetDisplacement);
}
// Get inline addend
if (LastDataRecordPointer && Locat.s.Offset < LastDataRecordSize) {
int8 * inlinep = LastDataRecordPointer + Locat.s.Offset;
switch (Locat.s.Location) {
case 0: case 4: // 8 bit
printf(", inline 0x%X", *inlinep); break;
case 1: case 2: case 5: // 16 bit
printf(", inline 0x%X", *(int16*)inlinep); break;
case 3: // 16+16 bit
printf(", inline 0x%X:0x%X", *(int16*)(inlinep+2), *(int16*)inlinep); break;
case 9: case 13: // 32 bit
printf(", inline 0x%X", *(int32*)inlinep); break;
case 6: case 11: // 16+32 bit
printf(", inline 0x%X:0x%X", *(int16*)(inlinep+4), *(int32*)inlinep); break;
}
}
}
else {
// This is a THREAD subrecord
TrdDat.b = byte1; // Put byte into bitfield
uint32 Index = 0;
if (TrdDat.s.Method < 4) {
Index = Records[i].GetIndex(); // has index field if method < 4 ?
}
printf("\n %s Thread %i. Method %s%i, index %i",
(TrdDat.s.D ? "Frame" : "Target"), TrdDat.s.Thread,
(TrdDat.s.D ? "F" : "T"), TrdDat.s.Method, Index);
}
} // Finished loop through subrecords
if (Records[i].Index != Records[i].End) err.submit(1203); // Check for consistency
}
} // Finished loop through records
}
void COMF::PublicNames(CMemoryBuffer * Strings, CSList<SStringEntry> * Index, int m) {
// Make list of public names
// Strings will receive ASCIIZ strings
// Index will receive records of type SStringEntry with Member = m
SOMFRecordPointer rec; // Current OMF record
char * string; // Symbol name
SStringEntry se; // String entry record to save
// Initialize record pointer
rec.Start(Buf(), 0, GetDataSize());
// Loop through records and search for PUBDEF records
do {
// Read record
if (rec.Type2 == OMF_PUBDEF) {
// Public symbols definition found
rec.GetIndex(); // Read group
uint32 Segment = rec.GetIndex(); // Read segment
if (Segment == 0) rec.GetWord(); // Read base frame
// Loop through strings in record
while (rec.Index < rec.End) {
string = rec.GetString(); // Read name
rec.GetNumeric(); // Read offset
rec.GetIndex(); // Read type
// Make SStringEntry record
se.Member = m;
// Store name
se.String = Strings->PushString(string);
// Store name index
Index->Push(se);
}
if (rec.Index != rec.End) err.submit(1203); // Check for consistency
}
if (rec.Type2 == OMF_CEXTDEF) {
// CEXTDEF record. Store communal symbol names
// Loop through entries in record
while (rec.Index < rec.End) {
uint32 LIndex = rec.GetIndex() - 1; // Index into preceding LNAMES
rec.GetIndex(); // Type index. Ignore
// Check if index valid
if (LIndex < LocalNameOffset.GetNumEntries()) {
// Make SStringEntry record
se.Member = m;
// Get name
char * name = GetLocalName(LIndex);
if (strlen(name) > 0) {
// Store name
se.String = Strings->PushString(name);
// Store name index
Index->Push(se);
}
}
}
if (rec.Index != rec.End) err.submit(1203); // Check for consistency
}
if (rec.Type2 == OMF_LNAMES) {
// LNAMES record. Check if file has been parsed
if (Records.GetNumEntries() == 0) {
// ParseFile has not been called. We need to store LNAMES table because
// these names may be needed by subsequent EXTDEF records.
// Loop through strings in record
while (rec.Index < rec.End) {
char * LocalName = rec.GetString();
uint32 LocalNameIndex = NameBuffer.PushString(LocalName); // Store local name
LocalNameOffset.Push(LocalNameIndex);// Store local name index
}
if (rec.Index != rec.End) err.submit(1203); // Check for consistency
}
}
} // Get next record
while (rec.GetNext()); // End of loop through records
}
char * COMF::GetLocalName(uint32 i) {
// Get section name or class name by name index
if (i == 0) return (char*)"null";
if (i < LocalNameOffset.GetNumEntries()) {
return NameBuffer.Buf() + LocalNameOffset[i];
}
return (char*)"?";
}
const char * COMF::GetSegmentName(uint32 i) {
// Get section name by segment index
if (i == 0) return "none";
if (i <= NumRecords) {
return NameBuffer.Buf() + SegmentNameOffset[i];
}
return "?";
}
const char * COMF::GetSymbolName(uint32 i) {
// Get external symbol name by index
if (i == 0) return "null";
if (i < SymbolNameOffset.GetNumEntries()) {
return NameBuffer.Buf() + SymbolNameOffset[i];
}
return "?";
}
const char * COMF::GetGroupName(uint32 i) {
// Get group name by index
if (i == 0) return "none";
if (i <= NumRecords) {
return NameBuffer.Buf() + GroupNameOffset[i];
}
return "?";
}
const char * COMF::GetRecordTypeName(uint32 i) {
// Get record type name
return Lookup(OMFRecordTypeNames, i);
}
// Member functions for parsing SOMFRecordPointer
uint8 SOMFRecordPointer::GetByte() {
// Read next byte from buffer
return *(buffer + FileOffset + Index++);
}
uint16 SOMFRecordPointer::GetWord() {
// Read next 16 bit word from buffer
uint16 x = *(uint16*)(buffer + FileOffset + Index);
Index += 2;
return x;
}
uint32 SOMFRecordPointer::GetDword() {
// Read next 32 bit dword from buffer
uint32 x = *(uint32*)(buffer + FileOffset + Index);
Index += 4;
return x;
}
uint32 SOMFRecordPointer::GetIndex() {
// Read byte or word, depending on sign of first byte
uint32 byte1, byte2;
byte1 = GetByte();
if (byte1 & 0x80) {
// Two byte index
byte2 = GetByte();
return ((byte1 & 0x7F) << 8) | byte2;
}
else {
// One byte index
return byte1;
}
}
uint32 SOMFRecordPointer::GetNumeric(){
// Read word or dword, depending on record type even or odd
if (Type & 1) {
// Odd record type. Number is 32 bits
return GetDword();
}
else {
// Even record type. Number is 16 bit s
return GetWord();
}
}
char * SOMFRecordPointer::GetString() {
// Read string and return as ASCIIZ string in static buffer
static char String[256];
uint8 Length = GetByte();
if (Length == 0) {
String[0] = 0;
}
else {
// Copy string
memcpy(String, buffer + FileOffset + Index, Length);
// Terminate by 0
String[Length] = 0;
}
// Point to next
Index += Length;
return String;
}
void SOMFRecordPointer::Start(int8 * Buffer, uint32 FileOffset, uint32 FileEnd) {
// Start scanning through records
this->buffer = Buffer;
this->FileOffset = FileOffset;
this->FileEnd = FileEnd;
Index = 0;
Type = GetByte();
Type2 = Type; if (Type2 < OMF_LIBHEAD) Type2 &= ~1; // Make even
uint16 RecordSize = GetWord();
End = Index + RecordSize - 1;
if (FileOffset + RecordSize + 3 > FileEnd) err.submit(2301); // Extends beyond end of file
}
uint8 SOMFRecordPointer::GetNext(uint32 align) {
// Get next record. Returns record type, made even. Returns 0 if finished
// align = alignment after MODEND records = page size. Applies to lib files only
FileOffset += End + 1;
// Check if alignment needed
if (align > 1 && Type2 == OMF_MODEND) {
// Align after MODEND record in library
FileOffset = (FileOffset + align - 1) & - (int32)align;
}
if (FileOffset >= FileEnd) return 0; // End of file
Index = 0; // Start reading record
Type = GetByte(); // Get record type
Type2 = Type; if (Type2 < OMF_LIBHEAD) Type2 &= ~1; // Make even
uint16 RecordSize = GetWord(); // Get record size
End = Index + RecordSize - 1; // Point to checksum byte
if (FileOffset + RecordSize + 3 > FileEnd) err.submit(2301); // Extends beyond end of file
return Type2;
}
uint32 SOMFRecordPointer::InterpretLIDATABlock() {
// Interpret Data block in LIDATA record recursively
// Prints repeat count and returns total size
uint32 RepeatCount = GetNumeric();
uint32 BlockCount = GetWord();
uint32 Size = 0;
printf("%i * ", RepeatCount);
if (BlockCount == 0) {
Size = GetByte();
Index += Size;
printf("%i", Size);
return RepeatCount * Size;
}
// Nested repeat blocks
printf("(");
for (uint32 i = 0; i < BlockCount; i++) {
// Recursion
Size += InterpretLIDATABlock();
if (i+1 < BlockCount) printf(" + ");
}
printf(")");
return RepeatCount * Size;
}
uint32 SOMFRecordPointer::UnpackLIDATABlock(int8 * destination, uint32 MaxSize) {
// Unpack Data block in LIDATA record recursively and store data at destination
uint32 RepeatCount = GetNumeric(); // Outer repeat count
uint32 BlockCount = GetWord(); // Inner repeat count
uint32 Size = 0; // Size of data expanded so far
uint32 RSize; // Size of recursively expanded data
uint32 SaveIndex; // Save Index for repetition
uint32 i, j; // Loop counters
if (BlockCount == 0) {
// Contains one repeated block
Size = GetByte(); // Size of repeated block
if (RepeatCount * Size > MaxSize) {
// Data outside allowed area
err.submit(2310); // Error message
Index += Size; // Point to after block
return 0; // No data stored
}
// Loop RepeatCount times
for (i = 0; i < RepeatCount; i++) {
// copy data block into destination
memcpy(destination, buffer + FileOffset + Index, Size);
destination += Size;
}
Index += Size; // Point to after block
return RepeatCount * Size; // Size of expanded data
}
// Nested repeat blocks
SaveIndex = Index;
// Loop RepeatCount times
for (i = 0; i < RepeatCount; i++) {
// Go back and repeat unpacking
Index = SaveIndex;
// Loop BlockCount times
for (j = 0; j < BlockCount; j++) {
// Recursion
RSize = UnpackLIDATABlock(destination, MaxSize);
destination += RSize;
MaxSize -= RSize;
Size += RSize;
}
}
return Size;
}
// Members of COMFFileBuilder, class for building OMF files
COMFFileBuilder::COMFFileBuilder() {
// Constructor
Index = 0;
}
void COMFFileBuilder::StartRecord(uint8 type) {
// Start building new record
this->Type = type; // Save type
RecordStart = Index = GetDataSize(); // Remember start position
PutByte(Type); // Put type into record
PutWord(0); // Reserve space for size, put in later
}
void COMFFileBuilder::EndRecord() {
// Finish building current record
// Update length
Get<uint16>(RecordStart + 1) = GetSize() + 1;
// Make checksum
int8 checksum = 0;
for (uint32 i = RecordStart; i < Index; i++) checksum += Buf()[i];
PutByte(-checksum);
// Check size limit
if (GetSize() > 1030) err.submit(9005);
}
void COMFFileBuilder::PutByte(uint8 x) {
// Put byte into buffer
Push(&x, 1);
Index++;
}
void COMFFileBuilder::PutWord(uint16 x) {
// Put 16 bit word into buffer
Push(&x, 2);
Index += 2;
}
void COMFFileBuilder::PutDword(uint32 x) {
// Put 32 bit dword into buffer
Push(&x, 4);
Index += 4;
}
void COMFFileBuilder::PutIndex(uint32 x) {
// Put byte or word into buffer (word if > 0x7F)
if (x < 0x80) {
// One byte
PutByte(x);
}
else {
// Two bytes
if (x > 0x7fff) {
err.submit(2303); // Index out of range
}
PutByte((uint8)(x >> 8) | 0x80); // First byte = high byte | 0x80
PutByte(uint8(x)); // Second byte = low byte
}
}
void COMFFileBuilder::PutNumeric(uint32 x) {
// Put word or dword into buffer, depending on type being even or odd
if (Type & 1) {
PutDword(x); // Type is odd, put 32 bits
}
else {
if (x > 0xffff) err.submit(2304);// Index out of range
PutWord(uint16(x)); // Type is even, put 16 bits
}
}
void COMFFileBuilder::PutString(const char * s) {
// Put ASCII string into buffer, preceded by size
uint32 len = (uint32)strlen(s); // Check length
if (len > 255) {
// String too long
err.submit(1204, s); // Issue warning
len = 255; // Truncate string to 255 characters
}
PutByte(uint8(len)); // Store length
Push(s, len); // Store len bytes
Index += len; // Update index
}
void COMFFileBuilder::PutBinary(void * p, uint32 Size) {
// Put binary data of any length
if (Size > 1024) {err.submit(9000); Size = 1024;} // 1024 bytes size limit
Push(p, Size);
Index += Size;
}
uint32 COMFFileBuilder::GetSize() {
// Get size of data added so far
if (Index <= RecordStart + 3) return 0;
return Index - RecordStart - 3; // Type and size fields not included in size
}
