/** Finds the next nonblank line, skips past an expected preamble, and reads in a string if there is one, and returns it.
* Generates an error otherwise. */
public static string ReadStringWithPreamble(string preamble, IEvolutionState state, StreamReader reader)
{
DecodeReturn d = CheckPreamble(preamble, state, reader);
Decode(d);
if (d.Type != DecodeReturn.T_STRING)
{
state.Output.Fatal("Line " + d.LineNumber +
" has no string after preamble '" + preamble + "'\n-->" + d.Data);
}
return(d.S);
}
/// <summary>
/// Finds the next nonblank line, then trims the line and checks the preamble.
/// Returns a DecodeReturn on the line if successful, else posts a fatal error.
/// Sets the DecodeReturn's line number. The DecodeReturn has not yet been decoded.
/// You'll need to do that with Code.Decode(...)
/// If the "multiline" argument is true, this will append additional lines
/// up to the first one that is null or empty (blank).
/// Note that this multiline capability provides the means to reconstitute large blocks of data if needed.
/// The user must ensure that a blank line (or EOF) marks the end of such blocks.
/// </summary>
public static DecodeReturn CheckPreamble(string preamble, IEvolutionState state, StreamReader reader, bool multiline)
{
// BRS : TODO : Added Offset because the reader does not provide "linenumber". Check the actual behavior.
var offset = reader.BaseStream.Position;
var linenumber = 0; // throw it away later
try
{
// get non-blank line
var s = "";
while (s != null && s.Trim().Equals(""))
{
//linenumber = reader.GetLineNumber();
s = reader.ReadLine();
linenumber++;
}
// check the preamble
if (s == null || !(s = s.Trim()).StartsWith(preamble))
{
// uh oh
state.Output.Fatal("Stream Offset: " + offset + " Line: " + linenumber + " has bad preamble. Expected '" + preamble + "'. -->" + s);
}
// At this point we are exactly the same as the single line version
if (!multiline)
{
var d = new DecodeReturn(s, preamble.Length)
{
LineNumber = linenumber
};
return(d);
}
// multiline has been requested...
var sb = new StringBuilder(s); // Aggregate lines up to the first blank line following the preamble
while (!String.IsNullOrEmpty(s = reader.ReadLine()))
{
sb = sb.AppendLine(s);
}
return(new DecodeReturn(sb.ToString(), preamble.Length)
{
LineNumber = linenumber
});
}
catch (IOException e)
{
state.Output.Fatal("On line " + linenumber + "an IO error occurred:\n\n" + e);
return(null); // never happens
}
}
/// <summary>
/// Decodes the next item out of a DecodeReturn and modifies the DecodeReturn to hold the results.
/// See DecodeReturn for more explanations about how to interpret the results.
/// </summary>
public static void Decode(DecodeReturn d)
{
var dat = d.Data;
var x = d.Pos;
var len = d.Data.Length;
// look for whitespace or ( or )
for (; x < len; x++)
{
if (!Char.IsWhiteSpace(dat[x]) && dat[x] != '(' && dat[x] != ')')
{
break;
}
}
// am I at the end of my rope?
if (x == len)
{
d.Type = DecodeReturn.T_ERROR; d.S = "Out of tokens";
return;
}
// what type am I?
switch (dat[x])
{
case 't': // boolean (true)
if (x + 3 < len && dat[x + 1] == 'r' && dat[x + 2] == 'u' && dat[x + 3] == 'e')
{
d.Type = DecodeReturn.T_BOOLEAN;
d.B = true;
d.Pos = x + 4;
return;
}
else
{
d.Type = DecodeReturn.T_ERROR;
d.S = "Expected a (true) boolean";
return;
}
case 'T': // boolean (true)
{
d.Type = DecodeReturn.T_BOOLEAN;
d.B = true;
d.Pos = x + 1;
return;
}
case 'F': // boolean (false)
{
d.Type = DecodeReturn.T_BOOLEAN;
d.B = false;
d.Pos = x + 1;
return;
}
case 'f': // float or boolean
if (len == 1 || Char.IsWhiteSpace(dat[x + 1]) || dat[x + 1] == ')') // Then we must have a lowercase boolean ("false")?
{
d.Type = DecodeReturn.T_BOOLEAN;
d.B = false;
d.Pos = x + 1;
return;
}
if (x + 4 < len && dat[x + 1] == 'a' && dat[x + 2] == 'l' && dat[x + 3] == 's' && dat[x + 4] == 'e')
{
d.Type = DecodeReturn.T_BOOLEAN; d.B = false; d.Pos = x + 5;
return;
}
else
{
var readHuman = false;
string sf = null;
var initial = x + 1;
// look for next '|'
for (; x < len; x++)
{
if (dat[x] == '|')
{
break;
}
}
if (x == initial)
{
readHuman = true;
}
if (x >= len)
{
d.Type = DecodeReturn.T_ERROR; d.S = "Expected a float";
return;
}
if (!readHuman)
{
sf = dat.Substring(initial, (x) - (initial));
}
x++;
// look for next '|'
var initial2 = x; // x is now just past first |
for (; x < len; x++)
{
if (dat[x] == '|')
{
break;
}
}
if (x >= len)
{
d.Type = DecodeReturn.T_ERROR; d.S = "Expected a float";
return;
}
if (readHuman)
{
sf = dat.Substring(initial2, (x) - (initial2));
}
float f;
try
{
if (readHuman)
{
f = Single.Parse(sf);
}
else
{
f = (float)BitConverter.Int64BitsToDouble(Int64.Parse(sf));
}
}
catch (FormatException)
{
d.Type = DecodeReturn.T_ERROR; d.S = "Expected a float";
return;
}
d.Type = DecodeReturn.T_FLOAT;
d.D = f;
d.Pos = x + 1;
return;
}
case 'd': // double
{
var readHuman = false;
string sf = null;
var initial = x + 1;
// look for next '|'
for (; x < len; x++)
{
if (dat[x] == '|')
{
break;
}
}
if (x == initial)
{
readHuman = true;
}
if (x >= len)
{
d.Type = DecodeReturn.T_ERROR; d.S = "Expected a double";
return;
}
if (!readHuman)
{
sf = dat.Substring(initial, (x) - (initial));
}
x++;
// look for next '|'
var initial2 = x; // x is now just past first |
for (; x < len; x++)
{
if (dat[x] == '|')
{
break;
}
}
if (x >= len)
{
d.Type = DecodeReturn.T_ERROR; d.S = "Expected a double";
return;
}
if (readHuman)
{
sf = dat.Substring(initial2, (x) - (initial2));
}
double f;
try
{
if (readHuman)
{
f = Double.Parse(sf);
}
else
{
f = BitConverter.Int64BitsToDouble(Int64.Parse(sf));
}
}
catch (FormatException)
{
d.Type = DecodeReturn.T_ERROR; d.S = "Expected a double";
return;
}
d.Type = DecodeReturn.T_DOUBLE;
d.D = f;
d.Pos = x + 1;
return;
}
case 'b': // byte
{
var initial = x + 1;
// look for next '|'
for (; x < len; x++)
{
if (dat[x] == '|')
{
break;
}
}
if (x >= len)
{
d.Type = DecodeReturn.T_ERROR; d.S = "Expected a byte";
return;
}
var sf = dat.Substring(initial, (x) - (initial));
sbyte f;
try
{
f = SByte.Parse(sf);
}
catch (FormatException)
{
d.Type = DecodeReturn.T_ERROR; d.S = "Expected a byte";
return;
}
d.Type = DecodeReturn.T_BYTE;
d.L = f;
d.Pos = x + 1;
return;
}
case 's': // short
{
var initial = x + 1;
// look for next '|'
for (; x < len; x++)
{
if (dat[x] == '|')
{
break;
}
}
if (x >= len)
{
d.Type = DecodeReturn.T_ERROR; d.S = "Expected a short";
return;
}
var sf = dat.Substring(initial, (x) - (initial));
short f;
try
{
f = Int16.Parse(sf);
}
catch (FormatException)
{
d.Type = DecodeReturn.T_ERROR; d.S = "Expected a short";
return;
}
d.Type = DecodeReturn.T_SHORT;
d.L = f;
d.Pos = x + 1;
return;
}
case 'i': // int
{
var initial = x + 1;
// look for next '|'
for (; x < len; x++)
{
if (dat[x] == '|')
{
break;
}
}
if (x >= len)
{
d.Type = DecodeReturn.T_ERROR; d.S = "Expected an int";
return;
}
var sf = dat.Substring(initial, (x) - (initial));
int f;
try
{
f = int.Parse(sf);
}
catch (FormatException)
{
d.Type = DecodeReturn.T_ERROR; d.S = "Expected an int";
return;
}
d.Type = DecodeReturn.T_INT;
d.L = f;
d.Pos = x + 1;
return;
}
case 'l': // long
{
var initial = x + 1;
// look for next '|'
for (; x < len; x++)
{
if (dat[x] == '|')
{
break;
}
}
if (x >= len)
{
d.Type = DecodeReturn.T_ERROR; d.S = "Expected a long";
return;
}
var sf = dat.Substring(initial, (x) - (initial));
long f;
try
{
f = Int64.Parse(sf);
}
catch (FormatException)
{
d.Type = DecodeReturn.T_ERROR; d.S = "Expected a long";
return;
}
d.Type = DecodeReturn.T_LONG;
d.L = f;
d.Pos = x + 1;
return;
}
case '"': // string
{
var sb = new StringBuilder();
var inUnicode = false;
x++;
for (; x < len; x++)
{
var c = dat[x];
if (c == '"')
{
// done with the string
if (inUnicode)
// uh oh
{
d.Type = DecodeReturn.T_ERROR; d.S = "Forgot to terminate Unicode with a '\\u' in the string";
return;
}
d.Type = DecodeReturn.T_STRING;
d.S = sb.ToString();
d.Pos = x + 1;
return;
}
else if (c == '\\') // escape
{
x++;
if (x >= len)
{
d.Type = DecodeReturn.T_ERROR; d.S = "Unterminated String";
return;
}
if (dat[x] != 'u' && inUnicode)
{
d.Type = DecodeReturn.T_ERROR; d.S = "Escape character in Unicode sequence";
return;
}
switch (dat[x])
{
case 'u': inUnicode = !inUnicode; break;
case 'b': sb.Append('\b'); break;
case 'n': sb.Append('\n'); break;
case '"': sb.Append('"'); break;
case '\'': sb.Append('\''); break;
case 't': sb.Append('\t'); break;
case '\\': sb.Append('\\'); break;
case '0': sb.Append('\x0000'); break;
default:
{
d.Type = DecodeReturn.T_ERROR; d.S = "Bad escape char in String";
return;
}
}
}
else if (inUnicode)
{
if (x + 3 >= len)
{
d.Type = DecodeReturn.T_ERROR; d.S = "Unterminated String";
return;
}
try
{
sb.Append((char)(int.Parse("0x" + c + dat[x + 1] + dat[x + 2] + dat[x + 3])));
;
x += 3;
}
catch (System.FormatException)
{
d.Type = DecodeReturn.T_ERROR; d.S = "Bad Unicode in String";
return;
}
}
else
{
sb.Append(c);
}
}
d.Type = DecodeReturn.T_ERROR; d.S = "Unterminated String";
return;
}
case '\'': // char
{
x++;
if (x >= len)
{
d.Type = DecodeReturn.T_ERROR; d.S = "Unterminated char"; return;
}
var c = dat[x];
if (c == '\\')
{
x++;
if (x >= len)
{
d.Type = DecodeReturn.T_ERROR; d.S = "Unterminated char";
return;
}
switch (dat[x])
{
case 'u':
if (x + 4 >= len)
{
d.Type = DecodeReturn.T_ERROR; d.S = "Unterminated char";
return;
}
try
{
c = (char)(int.Parse("0x" + dat[x + 1] + dat[x + 2] + dat[x + 3] + dat[x + 4]));
}
catch (System.FormatException)
{
d.Type = DecodeReturn.T_ERROR; d.S = "Bad Unicode in char";
return;
}
x += 5;
break;
case 'b': c = '\b'; x++; break;
case 'n': c = '\n'; x++; break;
case '"': c = '"'; x++; break;
case '\'': c = '\''; x++; break;
case 't': c = '\t'; x++; break;
case '\\': c = '\\'; x++; break;
case '0': c = '\x0000'; x++; break;
default:
{
d.Type = DecodeReturn.T_ERROR; d.S = "Bad escape char in char";
return;
}
}
if (dat[x] != '\'')
{
d.Type = DecodeReturn.T_ERROR; d.S = "Bad char";
return;
}
d.Type = DecodeReturn.T_CHAR;
d.C = c;
d.Pos = x + 1;
return;
}
else
{
x++;
if (x >= len)
{
d.Type = DecodeReturn.T_ERROR; d.S = "Unterminated char";
return;
}
if (dat[x] != '\'')
{
d.Type = DecodeReturn.T_ERROR; d.S = "Bad char";
return;
}
d.Type = DecodeReturn.T_CHAR;
d.C = c;
d.Pos = x + 1;
return;
}
}
default:
d.Type = DecodeReturn.T_ERROR; d.S = "Unknown token";
return;
}
}