[1] | 1 | /* ANTLR Translator Generator |
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| 2 | * Project led by Terence Parr at http://www.jGuru.com |
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| 3 | * Software rights: http://www.antlr.org/license.html |
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| 4 | * |
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| 5 | * $Id: //depot/code/org.antlr/release/antlr-2.7.7/lib/cpp/src/InputBuffer.cpp#2 $ |
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| 6 | */ |
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| 7 | |
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| 8 | #include "antlr/config.hpp" |
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| 9 | #include "antlr/InputBuffer.hpp" |
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| 10 | |
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| 11 | #ifdef ANTLR_CXX_SUPPORTS_NAMESPACE |
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| 12 | namespace antlr { |
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| 13 | #endif |
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| 14 | |
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| 15 | /** Ensure that the character buffer is sufficiently full */ |
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| 16 | void InputBuffer::fill(unsigned int amount) |
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| 17 | { |
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| 18 | syncConsume(); |
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| 19 | // Fill the buffer sufficiently to hold needed characters |
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| 20 | while (queue.entries() < amount + markerOffset) |
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| 21 | { |
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| 22 | // Append the next character |
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| 23 | queue.append(getChar()); |
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| 24 | } |
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| 25 | } |
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| 26 | |
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| 27 | /** get the current lookahead characters as a string |
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| 28 | * @warning it may treat 0 and EOF values wrong |
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| 29 | */ |
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| 30 | ANTLR_USE_NAMESPACE(std)string InputBuffer::getLAChars( void ) const |
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| 31 | { |
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| 32 | ANTLR_USE_NAMESPACE(std)string ret; |
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| 33 | |
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| 34 | for(unsigned int i = markerOffset; i < queue.entries(); i++) |
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| 35 | ret += queue.elementAt(i); |
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| 36 | |
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| 37 | return ret; |
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| 38 | } |
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| 39 | |
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| 40 | /** get the current marked characters as a string |
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| 41 | * @warning it may treat 0 and EOF values wrong |
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| 42 | */ |
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| 43 | ANTLR_USE_NAMESPACE(std)string InputBuffer::getMarkedChars( void ) const |
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| 44 | { |
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| 45 | ANTLR_USE_NAMESPACE(std)string ret; |
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| 46 | |
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| 47 | for(unsigned int i = 0; i < markerOffset; i++) |
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| 48 | ret += queue.elementAt(i); |
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| 49 | |
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| 50 | return ret; |
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| 51 | } |
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| 52 | |
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| 53 | /** Return an integer marker that can be used to rewind the buffer to |
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| 54 | * its current state. |
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| 55 | */ |
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| 56 | unsigned int InputBuffer::mark() |
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| 57 | { |
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| 58 | syncConsume(); |
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| 59 | nMarkers++; |
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| 60 | return markerOffset; |
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| 61 | } |
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| 62 | |
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| 63 | /** Rewind the character buffer to a marker. |
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| 64 | * @param mark Marker returned previously from mark() |
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| 65 | */ |
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| 66 | void InputBuffer::rewind(unsigned int mark) |
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| 67 | { |
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| 68 | syncConsume(); |
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| 69 | markerOffset = mark; |
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| 70 | nMarkers--; |
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| 71 | } |
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| 72 | |
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| 73 | unsigned int InputBuffer::entries() const |
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| 74 | { |
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| 75 | //assert(queue.entries() >= markerOffset); |
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| 76 | return queue.entries() - markerOffset; |
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| 77 | } |
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| 78 | |
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| 79 | #ifdef ANTLR_CXX_SUPPORTS_NAMESPACE |
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| 80 | } |
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| 81 | #endif |
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