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comparison: src/DataBuffer.h

src/DataBuffer.h

changeset 119
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parent 118
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child 120
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118:e3361cf7cbf4 119:bdf8d46c145f
1 /*
2 Copyright 2012-2014 Santeri Piippo
3 All rights reserved.
4
5 Redistribution and use in source and binary forms, with or without
6 modification, are permitted provided that the following conditions
7 are met:
8
9 1. Redistributions of source code must retain the above copyright
10 notice, this list of conditions and the following disclaimer.
11 2. Redistributions in binary form must reproduce the above copyright
12 notice, this list of conditions and the following disclaimer in the
13 documentation and/or other materials provided with the distribution.
14 3. The name of the author may not be used to endorse or promote products
15 derived from this software without specific prior written permission.
16
17 THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29 #ifndef BOTC_DATABUFFER_H
30 #define BOTC_DATABUFFER_H
31
32 #include <stdio.h>
33 #include <string.h>
34 #include "Main.h"
35 #include "StringTable.h"
36
37 /**
38 * @class DataBuffer
39 * @brief Stores a buffer of bytecode
40 *
41 * The DataBuffer class stores a section of bytecode. Buffers are allocated on
42 * the heap and written to using the @c write* functions. Buffers can be cut and
43 * pasted together with @c mergeAndDestroy, note that this function destroys the
44 * parameter buffer in the process
45 *
46 * A mark is a "pointer" to a particular position in the bytecode. The actual
47 * permanent position cannot be predicted in any way or form, thus these things
48 * are used to "bookmark" a position like that for future use.
49 *
50 * A reference acts as a pointer to a mark. The reference is four bytes in the
51 * bytecode which will be replaced with its mark's position when the bytecode
52 * is written to the output file.
53 *
54 * This mark/reference system is used to know bytecode offset values when
55 * compiling, even though actual final positions cannot be known.
56 */
57 class DataBuffer
58 {
59 //! @
60 PROPERTY (private, char*, buffer, setBuffer, STOCK_WRITE)
61 PROPERTY (private, int, allocatedSize, setAllocatedSize, STOCK_WRITE)
62 PROPERTY (private, char*, position, setPosition, STOCK_WRITE)
63 PROPERTY (private, List<ByteMark*>, marks, setMarks, STOCK_WRITE)
64 PROPERTY (private, List<MarkReference*>, references, setReferences, STOCK_WRITE)
65
66 public:
67 //! Constructs a new databuffer with @c size bytes.
68 DataBuffer (int size = 128);
69
70 //! Destructs the databuffer.
71 ~DataBuffer();
72
73 //! Adds a new mark to the current position with the name @c name.
74 //! @param name the name of the new mark
75 //! @return a pointer to the new mark
76 ByteMark* addMark (const String& name);
77
78 //! Adds a new reference to @c mark at the current position. This
79 //! function will write 4 bytes to the buffer whose value will
80 //! be determined at final output writing.
81 //! @param mark the mark which the new reference will attach to
82 //! @return a pointer to the new reference
83 MarkReference* addReference (ByteMark* mark);
84
85 //! Moves @c mark to the current bytecode position.
86 //! @param mark the mark to adjust
87 void adjustMark (ByteMark* mark);
88
89 //! Ensures there's at least @c bytes left in the buffer. Will resize
90 //! if necessary, no-op if not. On resize, 512 extra bytes are allocated
91 //! to reduce the amount of resizes.
92 //! @param bytes the amount of space in bytes to ensure allocated
93 void checkSpace (int bytes);
94
95 //! Creates a clone of this data buffer.
96 //! @note All marks will be moved into the new databuffer as marks are
97 //! @note never duplicated.
98 //! @return The newly cloned databuffer.
99 DataBuffer* clone();
100
101 //! Prints the buffer to stdout. Useful for debugging.
102 void dump();
103
104 //! Finds the given mark by name.
105 //! @param name the name of the mark to find
106 ByteMark* findMarkByName (const String& name);
107
108 //! Merge another data buffer into this one.
109 //! Note: @c other is destroyed in the process.
110 //! @param other the buffer to merge in
111 void mergeAndDestroy (DataBuffer* other);
112
113 //! Moves @c mark to the given bytecode position.
114 //! @param mark the mark to adjust
115 //! @param position where to adjust the mark
116 void offsetMark (ByteMark* mark, int position);
117
118 //! Transfers all marks of this buffer to @c other.
119 //! @param other the data buffer to transfer marks to
120 void transferMarksTo (DataBuffer* other);
121
122 //! Writes the index of the given string to the databuffer.
123 //! 4 bytes will be written to the bytecode.
124 //! @param a the string whose index to write
125 void writeStringIndex (const String& a);
126
127 //! Writes the given string as-is into the databuffer.
128 //! @c a.length + 4 bytes will be written to the buffer.
129 //! @param a the string to write
130 void writeString (const String& a);
131
132 //! Writes the given byte to the buffer. 1 byte will be written.
133 //! @c data the byte to write
134 void writeByte (int8_t data);
135
136 //! Writes the given word to the buffer. 2 byte will be written.
137 //! @c data the word to write
138 void writeWord (int16_t data);
139
140 //! Writes the given double word to the buffer. 4 bytes will be written.
141 //! @c data the double word to write
142 void writeDWord (int32_t data);
143
144 //! @return the amount of bytes written to this buffer.
145 inline int writtenSize() const
146 {
147 return position() - buffer();
148 }
149
150 protected:
151 //! Writes the buffer's contents from @c buf.
152 //! @c buf.writtenSize() bytes will be written.
153 //! @param buf the buffer to copy
154 void copyBuffer (const DataBuffer* buf);
155 };
156
157 #endif // BOTC_DATABUFFER_H

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