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using System.Text;
using System.Collections.Generic;
using System.IO;
using System.Diagnostics.Contracts;
namespace Microsoft.Boogie {
[Immutable]
public interface IToken {
int kind {
get;
set;
} // token kind
string filename {
get;
set;
} // token file
int pos {
get;
set;
} // token position in the source text (starting at 0)
int col {
get;
set;
} // token column (starting at 0)
int line {
get;
set;
} // token line (starting at 1)
string/*!*/ val {
get;
set;
} // token value
bool IsValid {
get;
}
}
[Immutable]
public class Token : IToken {
public int _kind; // token kind
string _filename; // token file
public int _pos; // token position in the source text (starting at 0)
public int _col; // token column (starting at 1)
public int _line; // token line (starting at 1)
public string/*!*/ _val; // token value
public Token next; // ML 2005-03-11 Tokens are kept in linked list
public static readonly IToken/*!*/ NoToken = new Token();
public Token() {
this._val = "anything so that it is nonnull";
}
public Token(int linenum, int colnum)
: base() {
this._line = linenum;
this._col = colnum;
this._val = "anything so that it is nonnull";
}
public int kind {
get {
return this._kind;
}
set {
this._kind = value;
}
}
public string filename {
get {
return this._filename;
}
set {
this._filename = value;
}
}
public int pos {
get {
return this._pos;
}
set {
this._pos = value;
}
}
public int col {
get {
return this._col;
}
set {
this._col = value;
}
}
public int line {
get {
return this._line;
}
set {
this._line = value;
}
}
public string/*!*/ val {
get {
return this._val;
}
set {
this._val = value;
}
}
public bool IsValid {
get {
return this._filename != null;
}
}
}
public static class ParserHelper {
struct ReadState {
public bool hasSeenElse;
public bool mayStillIncludeAnotherAlternative;
public ReadState(bool hasSeenElse, bool mayStillIncludeAnotherAlternative) {
this.hasSeenElse = hasSeenElse;
this.mayStillIncludeAnotherAlternative = mayStillIncludeAnotherAlternative;
}
}
// "arg" is assumed to be trimmed
private static bool IfdefConditionSaysToInclude(string arg, List<string/*!*/>/*!*/ defines) {
Contract.Requires(arg != null);
Contract.Requires(cce.NonNullElements(defines));
bool sense = true;
while (arg.StartsWith("!")) {
sense = !sense;
arg = arg.Substring(1).TrimStart();
}
return defines.Contains(arg) == sense;
}
public static string Fill(Stream stream, List<string/*!*/>/*!*/ defines) {
Contract.Requires(stream != null);
Contract.Requires(cce.NonNullElements(defines));
Contract.Ensures(Contract.Result<string>() != null);
StreamReader/*!*/ reader = new StreamReader(stream);
return Fill(reader, defines);
}
public static string Fill(TextReader reader, List<string/*!*/>/*!*/ defines) {
Contract.Requires(reader != null);
Contract.Requires(cce.NonNullElements(defines));
Contract.Ensures(Contract.Result<string>() != null);
StringBuilder sb = new StringBuilder();
List<ReadState>/*!*/ readState = new List<ReadState>(); // readState.Count is the current nesting level of #if's
int ignoreCutoff = -1; // -1 means we're not ignoring; for 0<=n, n means we're ignoring because of something at nesting level n
while (true)
//invariant -1 <= ignoreCutoff && ignoreCutoff < readState.Count;
{
string s = reader.ReadLine();
if (s == null) {
if (readState.Count != 0) {
sb.AppendLine("#MalformedInput: missing #endif");
}
break;
}
string t = s.Trim();
if (t.StartsWith("#if")) {
ReadState rs = new ReadState(false, false);
if (ignoreCutoff != -1) {
// we're already in a state of ignoring, so continue to ignore
} else if (IfdefConditionSaysToInclude(t.Substring(3).TrimStart(), defines)) {
// include this branch
} else {
ignoreCutoff = readState.Count; // start ignoring
rs.mayStillIncludeAnotherAlternative = true; // allow some later "elsif" or "else" branch to be included
}
readState.Add(rs);
sb.AppendLine(); // ignore the #if line
} else if (t.StartsWith("#elsif")) {
ReadState rs;
if (readState.Count == 0 || (rs = readState[readState.Count - 1]).hasSeenElse) {
sb.AppendLine("#MalformedInput: misplaced #elsif"); // malformed input
break;
}
if (ignoreCutoff == -1) {
// we had included the previous branch
//Contract.Assert(!rs.mayStillIncludeAnotherAlternative);
ignoreCutoff = readState.Count - 1; // start ignoring
} else if (rs.mayStillIncludeAnotherAlternative && IfdefConditionSaysToInclude(t.Substring(6).TrimStart(), defines)) {
// include this branch, but no subsequent branch at this level
ignoreCutoff = -1;
rs.mayStillIncludeAnotherAlternative = false;
readState[readState.Count - 1] = rs;
}
sb.AppendLine(); // ignore the #elsif line
} else if (t == "#else") {
ReadState rs;
if (readState.Count == 0 || (rs = readState[readState.Count - 1]).hasSeenElse) {
sb.AppendLine("#MalformedInput: misplaced #else"); // malformed input
break;
}
rs.hasSeenElse = true;
if (ignoreCutoff == -1) {
// we had included the previous branch
//Contract.Assert(!rs.mayStillIncludeAnotherAlternative);
ignoreCutoff = readState.Count - 1; // start ignoring
} else if (rs.mayStillIncludeAnotherAlternative) {
// include this branch
ignoreCutoff = -1;
rs.mayStillIncludeAnotherAlternative = false;
}
readState[readState.Count - 1] = rs;
sb.AppendLine(); // ignore the #else line
} else if (t == "#endif") {
if (readState.Count == 0) {
sb.AppendLine("#MalformedInput: misplaced #endif"); // malformed input
break;
}
readState.RemoveAt(readState.Count - 1); // pop
if (ignoreCutoff == readState.Count) {
// we had ignored the branch that ends here; so, now we start including again
ignoreCutoff = -1;
}
sb.AppendLine(); // ignore the #endif line
} else if (ignoreCutoff == -1) {
sb.AppendLine(s); // included line
} else {
sb.AppendLine(); // ignore the line
}
}
return sb.ToString();
}
}
}
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