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6502bench/SourceGen/DataAnalysis.cs
Andy McFadden 8c87ce3004 Check formatted string structure at load time 
If we have a bug, or somebody edits the project file manually, we
can end up with a very wrong string, such as a null-terminated
string that isn't, or a DCI string that has a mix of high and low
ASCII from start to finish.  We now check all incoming strings for
validity, and discard any that fail the test.  The verification
code is shared with the extension script inline data formatter.

Also, added a comment to an F8-ROM symbol I stumbled over.
2019-10-06 17:07:07 -07:00

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/*
* Copyright 2019 faddenSoft
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
using System;
using System.Diagnostics;
using Asm65;
using CommonUtil;
using TextScanMode = SourceGen.ProjectProperties.AnalysisParameters.TextScanMode;
namespace SourceGen {
/// <summary>
/// Auto-detection of structured data.
///
/// This class doesn't really hold any state. It's just a convenient place to collect
/// the items needed by the analyzer methods.
/// </summary>
public class DataAnalysis {
// Minimum number of consecutive identical bytes for something to be called a "run".
private const int MIN_RUN_LENGTH = 5;
// Minimum length for treating data as a run if the byte is a printable character.
// (Alternatively, the maximum length of a character string composed of a single value.)
// Anything shorter than this is handled with a string directive, anything this long or
// longer becomes FILL. This should be larger than the MinCharsForString parameter.
private const int MAX_STRING_RUN_LENGTH = 62;
// Absolute minimum string length for auto-detection. This is used when generating the
// data tables.
public const int MIN_STRING_LENGTH = 3;
// Minimum length for an ASCII string. Anything shorter is just output as bytes.
// This is the default value; the actual value is configured as a project preference.
public const int DEFAULT_MIN_STRING_LENGTH = 4;
// Set min chars to this to disable string detection.
public const int MIN_CHARS_FOR_STRING_DISABLED = int.MaxValue;
/// <summary>
/// Project with which we are associated.
/// </summary>
private DisasmProject mProject;
/// <summary>
/// Reference to 65xx data.
/// </summary>
private byte[] mFileData;
/// <summary>
/// Attributes, one per byte in input file.
/// </summary>
private Anattrib[] mAnattribs;
/// <summary>
/// Configurable parameters.
/// </summary>
private ProjectProperties.AnalysisParameters mAnalysisParams;
/// <summary>
/// Debug trace log.
/// </summary>
private DebugLog mDebugLog = new DebugLog(DebugLog.Priority.Silent);
public DebugLog DebugLog {
set {
mDebugLog = value;
}
}
public DataAnalysis(DisasmProject proj, Anattrib[] anattribs) {
mProject = proj;
mAnattribs = anattribs;
mFileData = proj.FileData;
mAnalysisParams = proj.ProjectProps.AnalysisParams;
}
// Internal log functions. If we're concerned about performance overhead due to
// call-site string concatenation, we can #ifdef these to nothing in release builds,
// which should allow the compiler to elide the concat.
#if false
private void LogV(int offset, string msg) {
if (mDebugLog.IsLoggable(DebugLog.Priority.Verbose)) {
mDebugLog.LogV("+" + offset.ToString("x6") + " " + msg);
}
}
#else
private void LogV(int offset, string msg) { }
#endif
private void LogD(int offset, string msg) {
if (mDebugLog.IsLoggable(DebugLog.Priority.Debug)) {
mDebugLog.LogD("+" + offset.ToString("x6") + " " + msg);
}
}
private void LogI(int offset, string msg) {
if (mDebugLog.IsLoggable(DebugLog.Priority.Info)) {
mDebugLog.LogI("+" + offset.ToString("x6") + " " + msg);
}
}
private void LogW(int offset, string msg) {
if (mDebugLog.IsLoggable(DebugLog.Priority.Warning)) {
mDebugLog.LogW("+" + offset.ToString("x6") + " " + msg);
}
}
private void LogE(int offset, string msg) {
if (mDebugLog.IsLoggable(DebugLog.Priority.Error)) {
mDebugLog.LogE("+" + offset.ToString("x6") + " " + msg);
}
}
/// <summary>
/// Analyzes instruction operands and Address data descriptors to identify references
/// to offsets within the file.
///
/// Instructions with format descriptors are left alone. Instructions with
/// operand offsets but no descriptor will have a descriptor generated
/// using the label at the target offset; if the target offset is unlabeled,
/// a unique label will be generated. Data descriptors with type=Address are
/// handled the same way.
///
/// In some cases, such as a reference to the middle of an instruction, we will
/// label a nearby location instead.
///
/// This should be called after code analysis has run, user labels and format
/// descriptors have been applied, and platform/project symbols have been merged
/// into the symbol table.
/// </summary>
/// <returns>True on success.</returns>
public void AnalyzeDataTargets() {
mDebugLog.LogI("Analyzing data targets...");
for (int offset = 0; offset < mAnattribs.Length; offset++) {
Anattrib attr = mAnattribs[offset];
if (attr.IsInstructionStart) {
if (attr.DataDescriptor != null) {
// It's being shown as numeric, or as a reference to some other symbol.
// Either way there's nothing further for us to do. (Technically we
// would want to treat it like the no-descriptor case if the type was
// numeric/Address, but we don't allow that for instructions.)
//
// Project and platform symbols are applied later.
Debug.Assert(attr.DataDescriptor.FormatSubType !=
FormatDescriptor.SubType.Address);
continue;
}
int operandOffset = attr.OperandOffset;
if (operandOffset >= 0) {
// This is an offset reference: a branch or data access instruction whose
// target is inside the file. Create a FormatDescriptor for it, and
// generate a label at the target if one is not already present.
SetDataTarget(offset, attr.Length, operandOffset);
}
// We advance by a single byte, rather than .Length, in case there's
// an instruction embedded inside another one.
} else if (attr.DataDescriptor != null) {
// We can't check IsDataStart / IsInlineDataStart because the bytes might
// still be uncategorized. If there's a user-specified format, check it
// to see if it's an address.
FormatDescriptor dfd = attr.DataDescriptor;
// Is this numeric/Address?
if ((dfd.FormatType == FormatDescriptor.Type.NumericLE ||
dfd.FormatType == FormatDescriptor.Type.NumericBE) &&
dfd.FormatSubType == FormatDescriptor.SubType.Address) {
// Treat like an absolute address. Convert the operand
// to an address, then resolve the file offset.
int address = RawData.GetWord(mFileData, offset, dfd.Length,
(dfd.FormatType == FormatDescriptor.Type.NumericBE));
if (dfd.Length < 3) {
// Bank not specified by data, add current program bank. Not always
// correct, but should be often enough. In most cases we'd just
// assume a correct data bank register, but here we need to find
// a file offset, so we have to assume data bank == program bank
// (unless we find a good way to track the data bank register).
address |= attr.Address & 0x7fff0000;
}
int operandOffset = mProject.AddrMap.AddressToOffset(offset, address);
if (operandOffset >= 0) {
SetDataTarget(offset, dfd.Length, operandOffset);
}
}
// For other formats, we don't need to do anything. Numeric/Address is
// the only one that represents an offset reference. Numeric/Symbol
// is a name reference. The others are just data.
// There shouldn't be any data items inside other data items, so we
// can just skip forward.
offset += mAnattribs[offset].DataDescriptor.Length - 1;
}
}
}
/// <summary>
/// Extracts the operand offset from a data item. Only useful for numeric/Address
/// and numeric/Symbol.
/// </summary>
/// <param name="proj">Project reference.</param>
/// <param name="offset">Offset of data item.</param>
/// <returns>Operand offset, or -1 if not applicable.</returns>
public static int GetDataOperandOffset(DisasmProject proj, int offset) {
Anattrib attr = proj.GetAnattrib(offset);
if (!attr.IsDataStart && !attr.IsInlineDataStart) {
return -1;
}
FormatDescriptor dfd = attr.DataDescriptor;
// Is this numeric/Address or numeric/Symbol?
if ((dfd.FormatType != FormatDescriptor.Type.NumericLE &&
dfd.FormatType != FormatDescriptor.Type.NumericBE) ||
(dfd.FormatSubType != FormatDescriptor.SubType.Address &&
dfd.FormatSubType != FormatDescriptor.SubType.Symbol)) {
return -1;
}
// Treat like an absolute address. Convert the operand
// to an address, then resolve the file offset.
int address = RawData.GetWord(proj.FileData, offset, dfd.Length,
(dfd.FormatType == FormatDescriptor.Type.NumericBE));
if (dfd.Length < 3) {
// Add the program bank where the data bank should go. Not perfect but
// we don't have anything better at the moment.
address |= attr.Address & 0x7fff0000;
}
int operandOffset = proj.AddrMap.AddressToOffset(offset, address);
return operandOffset;
}
/// <summary>
/// Returns the "base" operand offset. If the byte at the specified offset is not the
/// start of a code/data/inline-data item, walk backward until the start is found.
/// </summary>
/// <param name="proj">Project reference.</param>
/// <param name="offset">Start offset.</param>
/// <returns>Base offset.</returns>
public static int GetBaseOperandOffset(DisasmProject proj, int offset) {
Debug.Assert(offset >= 0 && offset < proj.FileDataLength);
while (!proj.GetAnattrib(offset).IsStart) {
offset--;
// Should not be possible to walk off the top of the list, since we're in
// the middle of something.
Debug.Assert(offset >= 0);
}
return offset;
}
/// <summary>
/// Creates a FormatDescriptor in the Anattrib array at srcOffset that links to
/// targetOffset, or a nearby label. If targetOffset doesn't have a useful label,
/// one will be generated.
///
/// This is used for both instruction and data operands.
/// </summary>
/// <param name="srcOffset">Offset of instruction or address data.</param>
/// <param name="srcLen">Length of instruction or data item.</param>
/// <param name="targetOffset">Offset of target.</param>
private void SetDataTarget(int srcOffset, int srcLen, int targetOffset) {
// NOTE: don't try to cache mAnattribs[targetOffset] -- we may be changing
// targetOffset and/or altering the Anattrib entry, so grabbing a copy of the
// struct may lead to problems.
// If the target offset has a symbol assigned, use it. Otherwise, try to
// find something nearby that might be more appropriate.
int origTargetOffset = targetOffset;
if (mAnattribs[targetOffset].Symbol == null) {
if (mAnalysisParams.SeekNearbyTargets) {
targetOffset = FindAlternateTarget(srcOffset, targetOffset);
}
// If we're not interested in seeking nearby targets, or we are but we failed
// to find something useful, we need to make sure that we're not pointing
// into the middle of the instruction. The assembler will only see labels on
// the opcode bytes, so if we're pointing at the middle we need to back up.
if (mAnattribs[targetOffset].IsInstruction &&
!mAnattribs[targetOffset].IsInstructionStart) {
while (!mAnattribs[--targetOffset].IsInstructionStart) {
// Should not be possible to move past the start of the file,
// since we know we're in the middle of an instruction.
Debug.Assert(targetOffset > 0);
}
} else if (!mAnattribs[targetOffset].IsInstruction &&
!mAnattribs[targetOffset].IsStart) {
// This is not part of an instruction, and is not the start of a formatted
// data area. However, it might be part of a formatted data area, in which
// case we need to avoid creating an auto label in the middle. So we seek
// backward, looking for the first offset with a descriptor. If that
// descriptor includes this offset, we set the target offset to that.
// (Note the uncategorized data pass hasn't run yet, so only instructions
// and offsets identified by users or scripts have been categorized.)
//
// ?? Can we use GetBaseOperandOffset(), which searches for IsStart?
int scanOffset = targetOffset;
while (--scanOffset >= 0) {
FormatDescriptor dfd = mAnattribs[scanOffset].DataDescriptor;
if (dfd != null) {
if (scanOffset + dfd.Length > targetOffset) {
// Found a descriptor that encompasses target offset. Adjust
// target to point at the start of the region.
targetOffset = scanOffset;
}
// Descriptors aren't allowed to overlap, so either way we're done.
break;
}
}
}
}
if (mAnattribs[targetOffset].Symbol == null) {
// No label at target offset, generate one.
//
// Generally speaking, the label we generate will be unique, because it
// incorporates the address. It's possible through various means to end
// up with a user or platform label that matches an auto label, so we
// need to do some renaming in that case. Shouldn't happen often.
Symbol sym = AutoLabel.GenerateUniqueForAddress(mAnattribs[targetOffset].Address,
mProject.SymbolTable, "L");
mAnattribs[targetOffset].Symbol = sym;
// This will throw if the symbol already exists. That is the desired
// behavior, as that would be a bug.
mProject.SymbolTable.Add(sym);
}
// Create a Numeric/Symbol descriptor that references the target label. If the
// source offset already had a descriptor (e.g. Numeric/Address data item),
// this will replace it in the Anattrib array. (The user-specified format
// is unaffected.)
//
// Doing this by target symbol, rather than offset in a Numeric/Address item,
// allows us to avoid carrying the adjustment stuff everywhere. OTOH we have
// to manually refactor label renames in the display list if we don't want to
// redo the data analysis.
bool isBigEndian = false;
if (mAnattribs[srcOffset].DataDescriptor != null) {
LogD(srcOffset, "Replacing " + mAnattribs[srcOffset].DataDescriptor +
" with reference to " + mAnattribs[targetOffset].Symbol.Label +
", adj=" + (origTargetOffset - targetOffset));
if (mAnattribs[srcOffset].DataDescriptor.FormatType ==
FormatDescriptor.Type.NumericBE) {
isBigEndian = true;
}
} else {
LogV(srcOffset, "Creating weak reference to label " +
mAnattribs[targetOffset].Symbol.Label +
", adj=" + (origTargetOffset - targetOffset));
}
mAnattribs[srcOffset].DataDescriptor = FormatDescriptor.Create(srcLen,
new WeakSymbolRef(mAnattribs[targetOffset].Symbol.Label, WeakSymbolRef.Part.Low),
isBigEndian);
}
/// <summary>
/// Given a reference from srcOffset to targetOffset, check to see if there's a
/// nearby location that we'd prefer to refer to. For example, if targetOffset points
/// into the middle of an instruction, we'd rather have it refer to the first byte.
/// </summary>
/// <param name="srcOffset">Reference source.</param>
/// <param name="targetOffset">Reference target.</param>
/// <returns>New value for targetOffset, or original value if nothing better was
/// found.</returns>
private int FindAlternateTarget(int srcOffset, int targetOffset) {
int origTargetOffset = targetOffset;
// Is the target outside the instruction stream? If it's just referencing data,
// do a simple check and move on.
if (!mAnattribs[targetOffset].IsInstruction) {
// We want to use user-defined labels whenever possible. If they're accessing
// memory within a few bytes, use that. We don't want to do this for
// code references, though, or our branches will get all weird.
// TODO(someday): make MAX user-configurable? Seek forward as well as backward?
const int MAX = 4;
for (int probeOffset = targetOffset - 1;
probeOffset >= 0 && probeOffset != targetOffset - MAX; probeOffset--) {
Symbol sym = mAnattribs[probeOffset].Symbol;
if (sym != null && sym.SymbolSource == Symbol.Source.User) {
// Found a nearby user label. Make sure it's actually nearby.
int addrDiff = mAnattribs[targetOffset].Address -
mAnattribs[probeOffset].Address;
if (addrDiff == targetOffset - probeOffset) {
targetOffset = probeOffset;
} else {
Debug.WriteLine("NOT probing past address boundary change (src=+" +
srcOffset.ToString("x6") +
" targ=+" + targetOffset.ToString("x6") +
" probe=+" + probeOffset.ToString("x6") + ")");
}
break;
}
}
return targetOffset;
}
// Target is an instruction. Is the source an instruction or data element
// (e.g. ".dd2 <addr>").
if (!mAnattribs[srcOffset].IsInstructionStart) {
// Might be address-1 to set up an RTS. If the target address isn't
// an instruction start, check to see if the following byte is.
if (!mAnattribs[targetOffset].IsInstructionStart &&
targetOffset + 1 < mAnattribs.Length &&
mAnattribs[targetOffset + 1].IsInstructionStart) {
LogD(srcOffset, "Offsetting address reference");
targetOffset++;
}
return targetOffset;
}
// Source is an instruction, so we have an instruction referencing an instruction.
// Could be a branch, an address push, or self-modifying code.
OpDef op = mProject.CpuDef.GetOpDef(mProject.FileData[srcOffset]);
if (op.IsBranchOrSubCall) {
// Don't mess with jumps and branches -- always go directly to the
// target address.
} else if (op == OpDef.OpPEA_StackAbs || op == OpDef.OpPER_StackPCRelLong) {
// They might be pushing address-1 to set up an RTS. If the target address isn't
// an instruction start, check to see if the following byte is.
if (!mAnattribs[targetOffset].IsInstructionStart &&
targetOffset + 1 < mAnattribs.Length &&
mAnattribs[targetOffset + 1].IsInstructionStart) {
LogD(srcOffset, "Offsetting PEA/PER");
targetOffset++;
}
} else {
// Data operation (LDA, STA, etc). This could be self-modifying code, or
// an indexed access with an offset base address (LDA addr-1,Y) to an
// adjacent data area. Check to see if there's data right after this.
bool nearbyData = false;
for (int i = targetOffset + 1; i <= targetOffset + 2; i++) {
if (i < mAnattribs.Length && !mAnattribs[i].IsInstruction) {
targetOffset = i;
nearbyData = true;
break;
}
}
if (!nearbyData && !mAnattribs[targetOffset].IsInstructionStart) {
// There's no data nearby, and the target is not the start of the
// instruction, so this is probably self-modifying code. We want
// the label to be on the opcode, so back up to the instruction start.
while (!mAnattribs[--targetOffset].IsInstructionStart) {
// Should not be possible to move past the start of the file,
// since we know we're in the middle of an instruction.
Debug.Assert(targetOffset > 0);
}
}
}
if (targetOffset != origTargetOffset) {
LogV(srcOffset, "Creating instruction ref adj=" +
(origTargetOffset - targetOffset));
}
return targetOffset;
}
/// <summary>
/// Analyzes uncategorized regions of the file to see if they fit common patterns.
///
/// This is re-run after most changes to the project, so we don't want to do anything
/// crazily expensive.
/// </summary>
/// <returns>True on success.</returns>
public void AnalyzeUncategorized() {
FormatDescriptor oneByteDefault = FormatDescriptor.Create(1,
FormatDescriptor.Type.Default, FormatDescriptor.SubType.None);
FormatDescriptor.DebugPrefabBump(-1);
// If it hasn't been identified as code or data, set the "data" flag to
// give it a positive identification as data. (This should be the only
// place outside of CodeAnalysis that sets this flag.) This isn't strictly
// necessary, but it helps us assert things when pieces start moving around.
for (int offset = 0; offset < mAnattribs.Length; offset++) {
Anattrib attr = mAnattribs[offset];
if (attr.IsInlineData) {
// While we're here, add a default format descriptor for inline data
// that doesn't have one. We don't try to analyze it otherwise.
if (attr.DataDescriptor == null) {
mAnattribs[offset].DataDescriptor = oneByteDefault;
FormatDescriptor.DebugPrefabBump();
}
} else if (!attr.IsInstruction) {
mAnattribs[offset].IsData = true;
}
}
mDebugLog.LogI("Analyzing uncategorized data...");
int startOffset = -1;
for (int offset = 0; offset < mAnattribs.Length; ) {
// We want to find a contiguous series of offsets which are not known
// to hold code or data. We stop if we encounter a user-defined label
// or format descriptor.
Anattrib attr = mAnattribs[offset];
if (attr.IsInstruction || attr.IsInlineData || attr.IsDataStart) {
// Instruction, inline data, or formatted data known to be here. Analyze
// previous chunk, then advance past this.
if (startOffset >= 0) {
AnalyzeRange(startOffset, offset - 1);
startOffset = -1;
}
if (attr.IsInstruction) {
// Because of embedded instructions, we can't simply leap forward.
// [or can we?]
offset++;
} else {
Debug.Assert(attr.Length > 0);
offset += attr.Length;
}
} else if (attr.Symbol != null || mProject.HasCommentOrNote(offset)) {
// In an uncategorized area, but we want to break at this byte
// so the user or auto label doesn't get buried in the middle of
// a large chunk.
//
// This is similar to, but independent of, GroupedOffsetSetFromSelected()
// in ProjectView. This is for auto-detection, the other is for user
// selection. It's best if the two behave similarly though.
if (startOffset >= 0) {
AnalyzeRange(startOffset, offset - 1);
}
startOffset = offset;
offset++;
} else {
// This offset is uncategorized, keep gathering.
if (startOffset < 0) {
startOffset = offset;
}
offset++;
// Check to see if the address has changed from the previous entry.
if (offset < mAnattribs.Length &&
mAnattribs[offset-1].Address + 1 != mAnattribs[offset].Address) {
// Must be an ORG here. Scan previous region.
AnalyzeRange(startOffset, offset - 1);
startOffset = -1;
}
}
}
if (startOffset >= 0) {
AnalyzeRange(startOffset, mAnattribs.Length - 1);
}
}
/// <summary>
/// Analyzes a range of bytes, looking for opportunities to promote uncategorized
/// data to a more structured form.
/// </summary>
/// <param name="start">Offset of first byte in range.</param>
/// <param name="end">Offset of last byte in range.</param>
private void AnalyzeRange(int start, int end) {
// We want to identify runs of identical bytes, and runs of more than N human-
// readable characters (ASCII, high ASCII, PETSCII, whatever). There are a few
// ways to do this.
//
// The simple approach is to walk through the data from start to end, checking at
// each offset for runs of bytes matching the criteria. Because the data doesn't
// change, we can pre-analyze the data at project load time to speed things up.
//
// One approach is to put runs into TypedRangeSet (setting the type to the byte
// value so a run of 0x00 doesn't merge into an adjacent run of 0x01), and the
// various character encodings into individual RangeSets. Then, for any given
// byte address, you can query the length of a potential run directly. This could
// be made faster with a mergesort-like algorithm that walked through the various
// range sets, rather than iterating over every byte in the range. However, the
// ranges passed into this method tend to be small, so the initial setup time for
// each region can dominate the performance. (The optimized implementation of this
// approach is also fairly complicated.)
//
// A memory-hungry alternative is to create arrays of integers, one entry per byte
// in the file, and set each entry to the number of bytes in the run that would
// follow at that point. So if a run of 20 zeroes began at off set 5, you would
// set run[5]=20, run[6]=19, and so on. That avoids searching in the sets, at the
// cost of potentially several megabytes for a large 65816 file.
//
// It's even possible that Regex would handle this faster and more easily. This
// can be done fairly quickly with "unsafe" code, e.g.:
// https://stackoverflow.com/questions/3028768/net-regular-expressions-on-bytes-instead-of-chars
// https://stackoverflow.com/questions/1660694/regular-expression-to-match-any-character-being-repeated-more-than-10-times
//
// Ultimately we're just not spending that much time here. Setting
// AnalyzeUncategorizedData=false reveals that most of the time is spent in
// the caller, identifying the regions, so a significant improvement here won't
// have much impact on the user experience.
//
// Vague idea: figure out how to re-use the results from the previous analysis
// pass. At a superficial level we can cache the result of calling here with a
// particular (start, end) pair. At a higher level we may be able to avoid
// the search for uncategorized data, certainly at the bank level, possibly within
// a bank.
mDebugLog.LogI("Analyzing [+" + start.ToString("x6") + ",+" + end.ToString("x6") +"]");
FormatDescriptor oneByteDefault = FormatDescriptor.Create(1,
FormatDescriptor.Type.Default, FormatDescriptor.SubType.None);
FormatDescriptor.DebugPrefabBump(-1);
if (!mAnalysisParams.AnalyzeUncategorizedData) {
// Analysis is disabled, so just mark everything as single-byte data.
while (start <= end) {
mAnattribs[start].DataDescriptor = oneByteDefault;
FormatDescriptor.DebugPrefabBump();
start++;
}
return;
}
int minStringChars = mAnalysisParams.MinCharsForString;
#if DATA_PRESCAN // this is actually slower (and uses more memory)
while (start <= end) {
// This is used to let us skip forward. It starts past the end of the block,
// and moves backward as we identify potential points of interest.
int minNextStart = end + 1;
bool found = mProject.RepeatedBytes.GetContainingOrSubsequentRange(start,
out TypedRangeSet.TypedRange tyRange);
if (found) {
if (tyRange.Low <= start) {
// found a matching range
Debug.Assert(tyRange.Low <= start && tyRange.High >= start);
int clampEnd = Math.Min(tyRange.High, end);
int repLen = clampEnd - start + 1;
if (repLen >= MIN_RUN_LENGTH) {
bool isAscii =
TextUtil.IsPrintableAscii((char)(mFileData[start] & 0x7f));
// IF the run isn't ASCII, OR it's so long that we don't want to
// encode it as a string, OR it's so short that we don't want to
// treat it as a string, THEN output it as a run. Otherwise, just
// let the ASCII-catcher handle it later.
if (!isAscii ||
repLen > MIN_RUN_LENGTH_ASCII || repLen < minStringChars) {
LogV(start, "Run of 0x" + mFileData[start].ToString("x2") + ": " +
repLen + " bytes");
mAnattribs[start].DataDescriptor = FormatDescriptor.Create(
repLen, FormatDescriptor.Type.Fill,
FormatDescriptor.SubType.None);
start += repLen;
continue;
}
}
// We didn't like this range. We probably won't like it for any other
// point within the range, so start again past it. Ideally we'd use
// Range.Low of the range that followed the one that was returned, but
// we don't have that handy.
minNextStart = Math.Min(minNextStart, tyRange.High + 1);
} else {
// no match; try to advance to the start of the next range.
Debug.Assert(tyRange.Low > start);
minNextStart = Math.Min(minNextStart, tyRange.Low);
}
}
found = mProject.StdAsciiBytes.GetContainingOrSubsequentRange(start,
out RangeSet.Range range);
if (found) {
if (range.Low <= start) {
// found a matching range
Debug.Assert(range.Low <= start && range.High >= start);
int clampEnd = Math.Min(range.High, end);
int repLen = clampEnd - start + 1;
if (repLen >= minStringChars) {
LogV(start, "Std ASCII string, len=" + repLen + " bytes");
mAnattribs[start].DataDescriptor = FormatDescriptor.Create(repLen,
FormatDescriptor.Type.String, FormatDescriptor.SubType.None);
start += repLen;
continue;
}
minNextStart = Math.Min(minNextStart, range.High + 1);
} else {
Debug.Assert(range.Low > start);
minNextStart = Math.Min(minNextStart, range.Low);
}
}
found = mProject.HighAsciiBytes.GetContainingOrSubsequentRange(start,
out range);
if (found) {
if (range.Low <= start) {
// found a matching range
Debug.Assert(range.Low <= start && range.High >= start);
int clampEnd = Math.Min(range.High, end);
int repLen = clampEnd - start + 1;
if (repLen >= minStringChars) {
LogV(start, "High ASCII string, len=" + repLen + " bytes");
mAnattribs[start].DataDescriptor = FormatDescriptor.Create(repLen,
FormatDescriptor.Type.String, FormatDescriptor.SubType.None);
start += repLen;
continue;
}
minNextStart = Math.Min(minNextStart, range.High + 1);
} else {
Debug.Assert(range.Low > start);
minNextStart = Math.Min(minNextStart, range.Low);
}
}
// Advance to the next possible run location.
int nextStart = minNextStart > 0 ? minNextStart : start + 1;
Debug.Assert(nextStart > start);
// No runs found, output as single bytes. This is the easiest form for users
// to edit.
while (start < nextStart) {
mAnattribs[start].DataDescriptor = oneByteDefault;
FormatDescriptor.DebugPrefabBump();
start++;
}
}
#else
// Select "is printable" test. We use the extended version to include some
// control characters.
// TODO(maybe): require some *actually* printable characters in each string
CharEncoding.InclusionTest testPrintable;
FormatDescriptor.SubType baseSubType;
switch (mAnalysisParams.DefaultTextScanMode) {
case TextScanMode.LowAscii:
testPrintable = CharEncoding.IsExtendedAscii;
baseSubType = FormatDescriptor.SubType.Ascii;
break;
case TextScanMode.LowHighAscii:
testPrintable = CharEncoding.IsExtendedLowOrHighAscii;
baseSubType = FormatDescriptor.SubType.ASCII_GENERIC;
break;
case TextScanMode.C64Petscii:
testPrintable = CharEncoding.IsExtendedC64Petscii;
baseSubType = FormatDescriptor.SubType.C64Petscii;
break;
case TextScanMode.C64ScreenCode:
testPrintable = CharEncoding.IsExtendedC64ScreenCode;
baseSubType = FormatDescriptor.SubType.C64Screen;
break;
default:
Debug.Assert(false);
testPrintable = CharEncoding.IsExtendedLowOrHighAscii;
baseSubType = FormatDescriptor.SubType.ASCII_GENERIC;
break;
}
while (start <= end) {
// Check for block of repeated values.
int runLen = RecognizeRun(mFileData, start, end);
int printLen = 0;
FormatDescriptor.SubType subType = baseSubType;
if (testPrintable(mFileData[start])) {
// The run byte is printable, and the run is shorter than a line. It's
// possible the run is followed by additional printable characters, e.g.
// "*****hello". Text is easier for humans to understand, so we prefer
// that unless the run is longer than one line.
if (runLen <= MAX_STRING_RUN_LENGTH) {
// See if the run is followed by additional printable characters.
printLen = runLen;
// For LowHighAscii we allow a string to be either low or high, but it
// must be entirely one thing. Refine our test.
CharEncoding.InclusionTest refinedTest = testPrintable;
if (mAnalysisParams.DefaultTextScanMode == TextScanMode.LowHighAscii) {
if (CharEncoding.IsExtendedAscii(mFileData[start])) {
refinedTest = CharEncoding.IsExtendedAscii;
subType = FormatDescriptor.SubType.Ascii;
} else {
refinedTest = CharEncoding.IsExtendedHighAscii;
subType = FormatDescriptor.SubType.HighAscii;
}
}
for (int i = start + runLen; i <= end; i++) {
if (!refinedTest(mFileData[i])) {
break;
}
printLen++;
}
}
}
if (printLen >= minStringChars) {
// This either a short run followed by printable characters, or just a
// (possibly very large) bunch of printable characters.
Debug.Assert(subType != FormatDescriptor.SubType.ASCII_GENERIC);
LogD(start, "Character string (" + subType + "), len=" + printLen + " bytes");
mAnattribs[start].DataDescriptor = FormatDescriptor.Create(printLen,
FormatDescriptor.Type.StringGeneric, subType);
start += printLen;
} else if (runLen >= MIN_RUN_LENGTH) {
// Didn't qualify as a string, but it's long enough to be a run.
//
// TODO(someday): allow .fill pseudo-ops to have character encoding
// sub-types, so we can ".fill 64,'*'". Easy to do here, but
// proper treatment requires tweaking data operand editor to allow
// char encoding to be specified.
LogV(start, "Run of 0x" + mFileData[start].ToString("x2") + ": " +
runLen + " bytes");
mAnattribs[start].DataDescriptor = FormatDescriptor.Create(
runLen, FormatDescriptor.Type.Fill,
FormatDescriptor.SubType.None);
start += runLen;
} else {
// Nothing useful found, output 1+ values as single bytes. This is the
// easiest form for users to edit. If we found a run, but it was too short,
// we can go ahead and mark all bytes in the run because we know the later
// matches will also be too short.
Debug.Assert(runLen > 0);
while (runLen-- != 0) {
mAnattribs[start++].DataDescriptor = oneByteDefault;
FormatDescriptor.DebugPrefabBump();
}
}
}
#endif
}
#region Static analyzer methods
/// <summary>
/// Checks for a repeated run of the same byte.
/// </summary>
/// <param name="fileData">Raw data.</param>
/// <param name="start">Offset of first byte in range.</param>
/// <param name="end">Offset of last byte in range.</param>
/// <returns>Length of run.</returns>
public static int RecognizeRun(byte[] fileData, int start, int end) {
byte first = fileData[start];
int index = start;
while (++index <= end) {
if (fileData[index] != first) {
break;
}
}
return index - start;
}
/// <summary>
/// Counts the number of low-ASCII, high-ASCII, and non-ASCII values in the
/// specified region.
/// </summary>
/// <param name="fileData">Raw data.</param>
/// <param name="start">Offset of first byte in range.</param>
/// <param name="end">Offset of last byte in range</param>
/// <param name="charTest">Character test delegate. Must match on both high and
/// low characters.</param>
/// <param name="lowVal">Set to the number of low-range characters found.</param>
/// <param name="highVal">Set to the number of high-range characters found.</param>
/// <param name="nonChar">Set to the number of non-character bytes found.</param>
public static void CountHighLowBytes(byte[] fileData, int start, int end,
CharEncoding.InclusionTest charTest,
out int lowVal, out int highVal, out int nonChar) {
lowVal = highVal = nonChar = 0;
for (int i = start; i <= end; i++) {
byte val = fileData[i];
if (!charTest(val)) {
nonChar++;
} else if ((val & 0x80) == 0) {
lowVal++;
} else {
highVal++;
}
}
}
/// <summary>
/// Counts the number of bytes that match the character test.
/// </summary>
/// <param name="fileData">Raw data.</param>
/// <param name="start">Offset of first byte in range.</param>
/// <param name="end">Offset of last byte in range.</param>
/// <param name="charTest">Character test delegate.</param>
/// <returns>Number of matching characters.</returns>
public static int CountCharacterBytes(byte[] fileData, int start, int end,
CharEncoding.InclusionTest charTest) {
int count = 0;
for (int i = start; i <= end; i++) {
if (charTest(fileData[i])) {
count++;
}
}
return count;
}
/// <summary>
/// Counts the number of null-terminated strings in the buffer.
///
/// Zero-length strings are allowed but not included in the count.
///
/// If any bad data is found, the scan aborts and returns -1.
/// </summary>
/// <param name="fileData">Raw data.</param>
/// <param name="start">Offset of first byte in range.</param>
/// <param name="end">Offset of last byte in range.</param>
/// <param name="charTest">Character test delegate.</param>
/// <param name="limitHiBit">If set, the high bit in all character must be the
/// same. Used to enforce a single encoding when "low or high ASCII" is used.</param>
/// <returns>Number of strings found, or -1 if bad data identified.</returns>
public static int RecognizeNullTerminatedStrings(byte[] fileData, int start, int end,
CharEncoding.InclusionTest charTest, bool limitHiBit) {
// Quick test.
if (fileData[end] != 0x00) {
return -1;
}
int stringCount = 0;
int expectedHiBit = -1;
int stringLen = 0;
for (int i = start; i <= end; i++) {
byte val = fileData[i];
if (val == 0x00) {
// End of string. Only update count if string wasn't empty.
if (stringLen != 0) {
stringCount++;
}
stringLen = 0;
expectedHiBit = -1;
} else {
if (limitHiBit) {
if (expectedHiBit == -1) {
// First byte in string, set hi/lo expectation.
expectedHiBit = val & 0x80;
} else if ((val & 0x80) != expectedHiBit) {
// Mixed ASCII or non-ASCII, fail.
return -1;
}
}
if (!charTest(val)) {
// Not a matching character, fail.
return -1;
}
stringLen++;
}
}
return stringCount;
}
/// <summary>
/// Counts strings prefixed with an 8-bit length.
///
/// Zero-length strings are allowed but not counted.
/// </summary>
/// <param name="fileData">Raw data.</param>
/// <param name="start">Offset of first byte in range.</param>
/// <param name="end">Offset of last byte in range.</param>
/// <param name="charTest">Character test delegate.</param>
/// <param name="limitHiBit">If set, the high bit in all character must be the
/// same. Used to enforce a single encoding when "low or high ASCII" is used.</param>
/// <returns>Number of strings found, or -1 if bad data identified.</returns>
public static int RecognizeLen8Strings(byte[] fileData, int start, int end,
CharEncoding.InclusionTest charTest, bool limitHiBit) {
int posn = start;
int remaining = end - start + 1;
int stringCount = 0;
while (remaining > 0) {
int strLen = fileData[posn++];
if (strLen > --remaining) {
// Buffer doesn't hold entire string, fail.
return -1;
}
if (strLen == 0) {
continue;
}
stringCount++;
remaining -= strLen;
int expectedHiBit = fileData[posn] & 0x80;
while (strLen-- != 0) {
byte val = fileData[posn++];
if (limitHiBit && (val & 0x80) != expectedHiBit) {
// Mixed ASCII, fail.
return -1;
}
if (!charTest(val)) {
// Not a matching character, fail.
return -1;
}
}
}
return stringCount;
}
/// <summary>
/// Counts strings prefixed with a 16-bit length.
///
/// Zero-length strings are allowed but not counted.
/// </summary>
/// <param name="fileData">Raw data.</param>
/// <param name="start">Offset of first byte in range.</param>
/// <param name="end">Offset of last byte in range.</param>
/// <param name="charTest">Character test delegate.</param>
/// <param name="limitHiBit">If set, the high bit in all character must be the
/// same. Used to enforce a single encoding when "low or high ASCII" is used.</param>
/// <returns>Number of strings found, or -1 if bad data identified.</returns>
public static int RecognizeLen16Strings(byte[] fileData, int start, int end,
CharEncoding.InclusionTest charTest, bool limitHiBit) {
int posn = start;
int remaining = end - start + 1;
int stringCount = 0;
while (remaining > 0) {
if (remaining < 2) {
// Not enough bytes for length, fail.
return -1;
}
int strLen = fileData[posn++];
strLen |= fileData[posn++] << 8;
remaining -= 2;
if (strLen > remaining) {
// Buffer doesn't hold entire string, fail.
return -1;
}
if (strLen == 0) {
continue;
}
stringCount++;
remaining -= strLen;
int expectedHiBit = fileData[posn] & 0x80;
while (strLen-- != 0) {
byte val = fileData[posn++];
if (limitHiBit && (val & 0x80) != expectedHiBit) {
// Mixed ASCII, fail.
return -1;
}
if (!charTest(val)) {
// Not a matching character, fail.
return -1;
}
}
}
return stringCount;
}
/// <summary>
/// Counts strings in Dextral Character Inverted format, meaning the high bit on the
/// last byte is the opposite of the preceding.
///
/// Each string must be at least two bytes. To reduce false-positives, we require
/// that all strings have the same hi/lo pattern.
/// </summary>
/// <remarks>
/// For C64Petscii, this will identify strings that are entirely in lower case except
/// for the last letteR, or vice-versa.
/// </remarks>
/// <param name="fileData">Raw data.</param>
/// <param name="start">Offset of first byte in range.</param>
/// <param name="end">Offset of last byte in range.</param>
/// <param name="charTest">Character test delegate.</param>
/// <returns>Number of strings found, or -1 if bad data identified.</returns>
public static int RecognizeDciStrings(byte[] fileData, int start, int end,
CharEncoding.InclusionTest charTest) {
int expectedHiBit = fileData[start] & 0x80;
int stringCount = 0;
int stringLen = 0;
// Quick test on last byte.
if ((fileData[end] & 0x80) == expectedHiBit) {
return -1;
}
for (int i = start; i <= end; i++) {
byte val = fileData[i];
if ((val & 0x80) != expectedHiBit) {
// end of string
if (stringLen == 0) {
// Got two consecutive bytes with end-marker polarity... fail.
return -1;
}
stringCount++;
stringLen = 0;
} else {
stringLen++;
}
if (!charTest((byte)(val & 0x7f))) {
// Not a matching character, fail.
return -1;
}
}
return stringCount;
}
/// <summary>
/// Counts strings in reverse Dextral Character Inverted format, meaning the string is
/// stored in reverse order in memory, and the high bit on the first (last) byte is
/// the opposite of the rest.
///
/// Each string must be at least two bytes. To reduce false-positives, we require
/// that all strings have the same hi/lo pattern.
/// </summary>
/// <param name="fileData">Raw data.</param>
/// <param name="start">Offset of first byte in range.</param>
/// <param name="end">Offset of last byte in range.</param>
/// <returns>Number of strings found, or -1 if bad data identified.</returns>
public static int RecognizeReverseDciStrings(byte[] fileData, int start, int end) {
int expectedHiBit = fileData[end] & 0x80;
int stringCount = 0;
int stringLen = 0;
// Quick test on last (first) byte.
if ((fileData[start] & 0x80) == expectedHiBit) {
return -1;
}
for (int i = end; i >= start; i--) {
byte val = fileData[i];
if ((val & 0x80) != expectedHiBit) {
// end of string
if (stringLen == 0) {
// Got two consecutive bytes with end-marker polarity... fail.
return -1;
}
stringCount++;
stringLen = 0;
} else {
stringLen++;
}
val &= 0x7f;
if (val < 0x20 || val == 0x7f) {
// Non-ASCII, fail.
return -1;
}
}
return stringCount;
}
/// <summary>
/// Verifies that the string data is what is expected. Does not attempt to check
/// the character encoding, just the structure.
/// </summary>
/// <param name="fileData">Raw data.</param>
/// <param name="offset">Start offset of string.</param>
/// <param name="length">Length of string, including leading length and terminating
/// null bytes.</param>
/// <param name="type">Expected string type.</param>
/// <param name="failMsg">Detailed failure message.</param>
/// <returns>True if all is well.</returns>
public static bool VerifyStringData(byte[] fileData, int offset, int length,
FormatDescriptor.Type type, out string failMsg) {
failMsg = string.Empty;
switch (type) {
case FormatDescriptor.Type.StringGeneric:
case FormatDescriptor.Type.StringReverse:
return true;
case FormatDescriptor.Type.StringNullTerm:
// must end in null byte, and have no null bytes before the end
int chk = offset;
while (length-- != 0) {
byte val = fileData[chk++];
if (val == 0x00) {
if (length != 0) {
failMsg = Res.Strings.STR_VFY_NULL_INSIDE_NULL_TERM;
return false;
} else {
return true;
}
}
}
failMsg = Res.Strings.STR_VFY_MISSING_NULL_TERM;
return false;
case FormatDescriptor.Type.StringL8:
if (fileData[offset] != length - 1) {
failMsg = Res.Strings.STR_VFY_L1_LENGTH_MISMATCH;
return false;
}
return true;
case FormatDescriptor.Type.StringL16:
int len = RawData.GetWord(fileData, offset, 2, false);
if (len != length - 2) {
failMsg = Res.Strings.STR_VFY_L2_LENGTH_MISMATCH;
return false;
}
return true;
case FormatDescriptor.Type.StringDci:
if (length < 2) {
failMsg = Res.Strings.STR_VFY_DCI_SHORT;
return false;
}
byte first = (byte)(fileData[offset] & 0x80);
for (int i = offset + 1; i < offset + length - 1; i++) {
if ((fileData[i] & 0x80) != first) {
failMsg = Res.Strings.STR_VFY_DCI_MIXED_DATA;
return false;
}
}
if ((fileData[offset + length - 1] & 0x80) == first) {
failMsg = Res.Strings.STR_VFY_DCI_NOT_TERMINATED;
return false;
}
return true;
default:
Debug.Assert(false);
return false;
}
}
#endregion // Static analyzers
}
}
#if DATA_PRESCAN
/// <summary>
/// Iterator that generates a list of offsets which are not known to hold code or data.
///
/// Generates a set of integers in ascending order.
/// </summary>
private class UndeterminedValueIterator : IEnumerator {
/// <summary>
/// Index of current item, or -1 if we're not started yet.
/// </summary>
private int mCurIndex;
/// <summary>
/// Reference to Anattrib array we're iterating over.
/// </summary>
private Anattrib[] mAnattribs;
/// <summary>
/// Constructor.
/// </summary>
public UndeterminedValueIterator(Anattrib[] anattribs) {
mAnattribs = anattribs;
Reset();
}
// IEnumerator: current element
public object Current {
get {
if (mCurIndex < 0) {
// not started
return null;
}
return mCurIndex;
}
}
// IEnumerator: move to the next element, returning false if there isn't one
public bool MoveNext() {
while (++mCurIndex < mAnattribs.Length) {
Anattrib attr = mAnattribs[mCurIndex];
if (attr.IsInstructionStart) {
// skip past instruction
mCurIndex += attr.Length - 1;
} else if (attr.IsUncategorized) {
// got one
return true;
}
}
return false;
}
// IEnumerator: reset state
public void Reset() {
mCurIndex = -1;
}
}
#endif
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