xref: /aosp_15_r20/external/antlr/runtime/ObjC/Framework/IntStream.h (revision 16467b971bd3e2009fad32dd79016f2c7e421deb)
1*16467b97STreehugger Robot // [The "BSD licence"]
2*16467b97STreehugger Robot // Copyright (c) 2006-2007 Kay Roepke 2010 Alan Condit
3*16467b97STreehugger Robot // All rights reserved.
4*16467b97STreehugger Robot //
5*16467b97STreehugger Robot // Redistribution and use in source and binary forms, with or without
6*16467b97STreehugger Robot // modification, are permitted provided that the following conditions
7*16467b97STreehugger Robot // are met:
8*16467b97STreehugger Robot // 1. Redistributions of source code must retain the above copyright
9*16467b97STreehugger Robot //    notice, this list of conditions and the following disclaimer.
10*16467b97STreehugger Robot // 2. Redistributions in binary form must reproduce the above copyright
11*16467b97STreehugger Robot //    notice, this list of conditions and the following disclaimer in the
12*16467b97STreehugger Robot //    documentation and/or other materials provided with the distribution.
13*16467b97STreehugger Robot // 3. The name of the author may not be used to endorse or promote products
14*16467b97STreehugger Robot //    derived from this software without specific prior written permission.
15*16467b97STreehugger Robot //
16*16467b97STreehugger Robot // THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17*16467b97STreehugger Robot // IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18*16467b97STreehugger Robot // OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19*16467b97STreehugger Robot // IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20*16467b97STreehugger Robot // INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21*16467b97STreehugger Robot // NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22*16467b97STreehugger Robot // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23*16467b97STreehugger Robot // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24*16467b97STreehugger Robot // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25*16467b97STreehugger Robot // THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26*16467b97STreehugger Robot 
27*16467b97STreehugger Robot #ifndef DEBUG_DEALLOC
28*16467b97STreehugger Robot #define DEBUG_DEALLOC
29*16467b97STreehugger Robot #endif
30*16467b97STreehugger Robot 
31*16467b97STreehugger Robot @protocol IntStream < NSObject, NSCopying >
32*16467b97STreehugger Robot 
33*16467b97STreehugger Robot - (void) consume;
34*16467b97STreehugger Robot 
35*16467b97STreehugger Robot // Get unichar at current input pointer + i ahead where i=1 is next character as int for including CharStreamEOF (-1) in the data range
36*16467b97STreehugger Robot - (NSInteger) LA:(NSInteger) i;
37*16467b97STreehugger Robot 
38*16467b97STreehugger Robot // Tell the stream to start buffering if it hasn't already.  Return
39*16467b97STreehugger Robot // current input position, index(), or some other marker so that
40*16467b97STreehugger Robot // when passed to rewind() you get back to the same spot.
41*16467b97STreehugger Robot // rewind(mark()) should not affect the input cursor.
42*16467b97STreehugger Robot // TODO: problem in that lexer stream returns not index but some marker
43*16467b97STreehugger Robot 
44*16467b97STreehugger Robot - (NSInteger) mark;
45*16467b97STreehugger Robot 
46*16467b97STreehugger Robot // Return the current input symbol index 0..n where n indicates the
47*16467b97STreehugger Robot // last symbol has been read.
48*16467b97STreehugger Robot 
49*16467b97STreehugger Robot - (NSInteger) index;
50*16467b97STreehugger Robot 
51*16467b97STreehugger Robot // Reset the stream so that next call to index would return marker.
52*16467b97STreehugger Robot // The marker will usually be -index but it doesn't have to be.  It's
53*16467b97STreehugger Robot // just a marker to indicate what state the stream was in.  This is
54*16467b97STreehugger Robot // essentially calling -release: and -seek:.  If there are markers
55*16467b97STreehugger Robot // created after this marker argument, this routine must unroll them
56*16467b97STreehugger Robot // like a stack.  Assume the state the stream was in when this marker
57*16467b97STreehugger Robot // was created.
58*16467b97STreehugger Robot 
59*16467b97STreehugger Robot - (void) rewind;
60*16467b97STreehugger Robot - (void) rewind:(NSInteger) marker;
61*16467b97STreehugger Robot 
62*16467b97STreehugger Robot // You may want to commit to a backtrack but don't want to force the
63*16467b97STreehugger Robot // stream to keep bookkeeping objects around for a marker that is
64*16467b97STreehugger Robot // no longer necessary.  This will have the same behavior as
65*16467b97STreehugger Robot // rewind() except it releases resources without the backward seek.
66*16467b97STreehugger Robot 
67*16467b97STreehugger Robot - (void) release:(NSInteger) marker;
68*16467b97STreehugger Robot 
69*16467b97STreehugger Robot // Set the input cursor to the position indicated by index.  This is
70*16467b97STreehugger Robot // normally used to seek ahead in the input stream.  No buffering is
71*16467b97STreehugger Robot // required to do this unless you know your stream will use seek to
72*16467b97STreehugger Robot // move backwards such as when backtracking.
73*16467b97STreehugger Robot // This is different from rewind in its multi-directional
74*16467b97STreehugger Robot // requirement and in that its argument is strictly an input cursor (index).
75*16467b97STreehugger Robot //
76*16467b97STreehugger Robot // For char streams, seeking forward must update the stream state such
77*16467b97STreehugger Robot // as line number.  For seeking backwards, you will be presumably
78*16467b97STreehugger Robot // backtracking using the mark/rewind mechanism that restores state and
79*16467b97STreehugger Robot // so this method does not need to update state when seeking backwards.
80*16467b97STreehugger Robot //
81*16467b97STreehugger Robot // Currently, this method is only used for efficient backtracking, but
82*16467b97STreehugger Robot // in the future it may be used for incremental parsing.
83*16467b97STreehugger Robot 
84*16467b97STreehugger Robot - (void) seek:(NSInteger) anIndex;
85*16467b97STreehugger Robot 
86*16467b97STreehugger Robot /** Only makes sense for streams that buffer everything up probably, but
87*16467b97STreehugger Robot  *  might be useful to display the entire stream or for testing.  This
88*16467b97STreehugger Robot  *  value includes a single EOF.
89*16467b97STreehugger Robot  */
90*16467b97STreehugger Robot - (NSUInteger) size;
91*16467b97STreehugger Robot /** Where are you getting symbols from?  Normally, implementations will
92*16467b97STreehugger Robot  *  pass the buck all the way to the lexer who can ask its input stream
93*16467b97STreehugger Robot  *  for the file name or whatever.
94*16467b97STreehugger Robot  */
95*16467b97STreehugger Robot - (NSString *)getSourceName;
96*16467b97STreehugger Robot 
97*16467b97STreehugger Robot //@property (assign) NSInteger index;
98*16467b97STreehugger Robot //@property (assign) NSUInteger line;
99*16467b97STreehugger Robot //@property (assign) NSUInteger charPositionInLine;
100*16467b97STreehugger Robot 
101*16467b97STreehugger Robot 
102*16467b97STreehugger Robot @end
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