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author | toma <toma@283d02a7-25f6-0310-bc7c-ecb5cbfe19da> | 2009-11-25 17:56:58 +0000 |
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committer | toma <toma@283d02a7-25f6-0310-bc7c-ecb5cbfe19da> | 2009-11-25 17:56:58 +0000 |
commit | 114a878c64ce6f8223cfd22d76a20eb16d177e5e (patch) | |
tree | acaf47eb0fa12142d3896416a69e74cbf5a72242 /lib/antlr/src/TokenBuffer.cpp | |
download | tdevelop-114a878c64ce6f8223cfd22d76a20eb16d177e5e.tar.gz tdevelop-114a878c64ce6f8223cfd22d76a20eb16d177e5e.zip |
Copy the KDE 3.5 branch to branches/trinity for new KDE 3.5 features.
BUG:215923
git-svn-id: svn://anonsvn.kde.org/home/kde/branches/trinity/kdevelop@1054174 283d02a7-25f6-0310-bc7c-ecb5cbfe19da
Diffstat (limited to 'lib/antlr/src/TokenBuffer.cpp')
-rw-r--r-- | lib/antlr/src/TokenBuffer.cpp | 96 |
1 files changed, 96 insertions, 0 deletions
diff --git a/lib/antlr/src/TokenBuffer.cpp b/lib/antlr/src/TokenBuffer.cpp new file mode 100644 index 00000000..ed69d6e0 --- /dev/null +++ b/lib/antlr/src/TokenBuffer.cpp @@ -0,0 +1,96 @@ +/* ANTLR Translator Generator + * Project led by Terence Parr at http://www.jGuru.com + * Software rights: http://www.antlr.org/license.html + * + * $Id$ + */ + +#include "antlr/TokenBuffer.hpp" + +#ifdef ANTLR_CXX_SUPPORTS_NAMESPACE +namespace antlr { +#endif + +/**A Stream of Token objects fed to the parser from a TokenStream that can + * be rewound via mark()/rewind() methods. + * <p> + * A dynamic array is used to buffer up all the input tokens. Normally, + * "k" tokens are stored in the buffer. More tokens may be stored during + * guess mode (testing syntactic predicate), or when LT(i>k) is referenced. + * Consumption of tokens is deferred. In other words, reading the next + * token is not done by conume(), but deferred until needed by LA or LT. + * <p> + * + * @see antlr.Token + * @see antlr.TokenStream + * @see antlr.TokenQueue + */ + +/** Create a token buffer */ +TokenBuffer::TokenBuffer( TokenStream& inp ) +: input(inp) +, nMarkers(0) +, markerOffset(0) +, numToConsume(0) +{ +} + +TokenBuffer::~TokenBuffer( void ) +{ +} + +/** Ensure that the token buffer is sufficiently full */ +void TokenBuffer::fill(unsigned int amount) +{ + syncConsume(); + // Fill the buffer sufficiently to hold needed tokens + while (queue.entries() < (amount + markerOffset)) + { + // Append the next token + queue.append(input.nextToken()); + } +} + +/** Get a lookahead token value */ +int TokenBuffer::LA(unsigned int i) +{ + fill(i); + return queue.elementAt(markerOffset+i-1)->getType(); +} + +/** Get a lookahead token */ +RefToken TokenBuffer::LT(unsigned int i) +{ + fill(i); + return queue.elementAt(markerOffset+i-1); +} + +/** Return an integer marker that can be used to rewind the buffer to + * its current state. + */ +unsigned int TokenBuffer::mark() +{ + syncConsume(); + nMarkers++; + return markerOffset; +} + +/**Rewind the token buffer to a marker. + * @param mark Marker returned previously from mark() + */ +void TokenBuffer::rewind(unsigned int mark) +{ + syncConsume(); + markerOffset=mark; + nMarkers--; +} + +/// Get number of non-consumed tokens +unsigned int TokenBuffer::entries() const +{ + return queue.entries() - markerOffset; +} + +#ifdef ANTLR_CXX_SUPPORTS_NAMESPACE + } +#endif |