//----------------------------------------------------------------
// Private implementation
//----------------------------------------------------------------
/**
* Parse an ID into component pieces. Take IDs of the form T,
* T/V, S-T, S-T/V, or S/V-T. If the source is missing, return a
* source of ANY.
* @param id the id string, in any of several forms
* @param pos INPUT-OUTPUT parameter. On input, pos[0] is the
* offset of the first character to parse in id. On output,
* pos[0] is the offset after the last parsed character. If the
* parse failed, pos[0] will be unchanged.
* @param allowFilter if true, a UnicodeSet pattern is allowed
* at any location between specs or delimiters, and is returned
* as the fifth string in the array.
* @return a Specs object, or null if the parse failed. If
* neither source nor target was seen in the parsed id, then the
* parse fails. If allowFilter is true, then the parsed filter
* pattern is returned in the Specs object, otherwise the returned
* filter reference is null. If the parse fails for any reason
* null is returned.
*/
private static Specs ParseFilterID(string id, int[] pos,
bool allowFilter)
{
string first = null;
string source = null;
string target = null;
string variant = null;
string filter = null;
char delimiter = (char)0;
int specCount = 0;
int start = pos[0];
// This loop parses one of the following things with each
// pass: a filter, a delimiter character (either '-' or '/'),
// or a spec (source, target, or variant).
for (; ;)
{
pos[0] = PatternProps.SkipWhiteSpace(id, pos[0]);
if (pos[0] == id.Length)
{
break;
}
// Parse filters
if (allowFilter && filter == null &&
UnicodeSet.ResemblesPattern(id, pos[0]))
{
ParsePosition ppos = new ParsePosition(pos[0]);
// Parse the set to get the position.
new UnicodeSet(id, ppos, null);
filter = id.Substring(pos[0], ppos.Index - pos[0]); // ICU4N: Corrected 2nd parameter
pos[0] = ppos.Index;
continue;
}
if (delimiter == 0)
{
char c = id[pos[0]];
if ((c == TARGET_SEP && target == null) ||
(c == VARIANT_SEP && variant == null))
{
delimiter = c;
++pos[0];
continue;
}
}
// We are about to try to parse a spec with no delimiter
// when we can no longer do so (we can only do so at the
// start); break.
if (delimiter == 0 && specCount > 0)
{
break;
}
string spec = Utility.ParseUnicodeIdentifier(id, pos);
if (spec == null)
{
// Note that if there was a trailing delimiter, we
// consume it. So Foo-, Foo/, Foo-Bar/, and Foo/Bar-
// are legal.
break;
}
switch (delimiter)
{
case (char)0:
first = spec;
break;
case TARGET_SEP:
target = spec;
break;
case VARIANT_SEP:
variant = spec;
break;
}
++specCount;
delimiter = (char)0;
}
// A spec with no prior character is either source or target,
// depending on whether an explicit "-target" was seen.
if (first != null)
{
if (target == null)
{
target = first;
}
else
{
source = first;
}
}
// Must have either source or target
if (source == null && target == null)
{
pos[0] = start;
return(null);
}
// Empty source or target defaults to ANY
bool sawSource = true;
if (source == null)
{
source = ANY;
sawSource = false;
}
if (target == null)
{
target = ANY;
}
return(new Specs(source, target, variant, sawSource, filter));
}
/**
* Parse a global filter of the form "[f]" or "([f])", depending
* on 'withParens'.
* @param id the pattern the parse
* @param pos INPUT-OUTPUT parameter. On input, the position of
* the first character to parse. On output, the position after
* the last character parsed.
* @param dir the direction.
* @param withParens INPUT-OUTPUT parameter. On entry, if
* withParens[0] is 0, then parens are disallowed. If it is 1,
* then parens are requires. If it is -1, then parens are
* optional, and the return result will be set to 0 or 1.
* @param canonID OUTPUT parameter. The pattern for the filter
* added to the canonID, either at the end, if dir is FORWARD, or
* at the start, if dir is REVERSE. The pattern will be enclosed
* in parentheses if appropriate, and will be suffixed with an
* ID_DELIM character. May be null.
* @return a UnicodeSet object or null. A non-null results
* indicates a successful parse, regardless of whether the filter
* applies to the given direction. The caller should discard it
* if withParens != (dir == REVERSE).
*/
public static UnicodeSet ParseGlobalFilter(string id, int[] pos, TransliterationDirection dir,
int[] withParens,
StringBuffer canonID)
{
UnicodeSet filter = null;
int start = pos[0];
if (withParens[0] == -1)
{
withParens[0] = Utility.ParseChar(id, pos, OPEN_REV) ? 1 : 0;
}
else if (withParens[0] == 1)
{
if (!Utility.ParseChar(id, pos, OPEN_REV))
{
pos[0] = start;
return(null);
}
}
pos[0] = PatternProps.SkipWhiteSpace(id, pos[0]);
if (UnicodeSet.ResemblesPattern(id, pos[0]))
{
ParsePosition ppos = new ParsePosition(pos[0]);
try
{
filter = new UnicodeSet(id, ppos, null);
}
catch (ArgumentException)
{
pos[0] = start;
return(null);
}
string pattern = id.Substring(pos[0], ppos.Index - pos[0]); // ICU4N: Corrected 2nd parameter
pos[0] = ppos.Index;
if (withParens[0] == 1 && !Utility.ParseChar(id, pos, CLOSE_REV))
{
pos[0] = start;
return(null);
}
// In the forward direction, append the pattern to the
// canonID. In the reverse, insert it at zero, and invert
// the presence of parens ("A" <-> "(A)").
if (canonID != null)
{
if (dir == Forward)
{
if (withParens[0] == 1)
{
pattern = OPEN_REV + pattern + CLOSE_REV;
}
canonID.Append(pattern + ID_DELIM);
}
else
{
if (withParens[0] == 0)
{
pattern = OPEN_REV + pattern + CLOSE_REV;
}
canonID.Insert(0, pattern + ID_DELIM);
}
}
}
return(filter);
}
