1/*
2 * Copyright (C) 2012, 2013 Apple Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 *    notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 *    notice, this list of conditions and the following disclaimer in the
11 *    documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#ifndef ExpressionRangeInfo_h
27#define ExpressionRangeInfo_h
28
29#include <wtf/StdLibExtras.h>
30
31namespace JSC {
32
33struct ExpressionRangeInfo {
34    // Line and column values are encoded in 1 of 3 modes depending on the size
35    // of their values. These modes are:
36    //
37    //   1. FatLine: 22-bit line, 8-bit column.
38    //   2. FatColumn: 8-bit line, 22-bit column.
39    //   3. FatLineAndColumn: 32-bit line, 32-bit column.
40    //
41    // For the first 2 modes, the line and column will be encoded in the 30-bit
42    // position field in the ExpressionRangeInfo. For the FatLineAndColumn mode,
43    // the position field will hold an index into a FatPosition vector which
44    // holds the FatPosition records with the full 32-bit line and column values.
45
46    enum {
47        FatLineMode,
48        FatColumnMode,
49        FatLineAndColumnMode
50    };
51
52    struct FatPosition {
53        uint32_t line;
54        uint32_t column;
55    };
56
57    enum {
58        FatLineModeLineShift = 8,
59        FatLineModeLineMask = (1 << 22) - 1,
60        FatLineModeColumnMask = (1 << 8) - 1,
61        FatColumnModeLineShift = 22,
62        FatColumnModeLineMask = (1 << 8) - 1,
63        FatColumnModeColumnMask = (1 << 22) - 1
64    };
65
66    enum {
67        MaxOffset = (1 << 7) - 1,
68        MaxDivot = (1 << 25) - 1,
69        MaxFatLineModeLine = (1 << 22) - 1,
70        MaxFatLineModeColumn = (1 << 8) - 1,
71        MaxFatColumnModeLine = (1 << 8) - 1,
72        MaxFatColumnModeColumn = (1 << 22) - 1
73    };
74
75    void encodeFatLineMode(unsigned line, unsigned column)
76    {
77        ASSERT(line <= MaxFatLineModeLine);
78        ASSERT(column <= MaxFatLineModeColumn);
79        position = ((line & FatLineModeLineMask) << FatLineModeLineShift | (column & FatLineModeColumnMask));
80    }
81
82    void encodeFatColumnMode(unsigned line, unsigned column)
83    {
84        ASSERT(line <= MaxFatColumnModeLine);
85        ASSERT(column <= MaxFatColumnModeColumn);
86        position = ((line & FatColumnModeLineMask) << FatColumnModeLineShift | (column & FatColumnModeColumnMask));
87    }
88
89    void decodeFatLineMode(unsigned& line, unsigned& column)
90    {
91        line = (position >> FatLineModeLineShift) & FatLineModeLineMask;
92        column = position & FatLineModeColumnMask;
93    }
94
95    void decodeFatColumnMode(unsigned& line, unsigned& column)
96    {
97        line = (position >> FatColumnModeLineShift) & FatColumnModeLineMask;
98        column = position & FatColumnModeColumnMask;
99    }
100
101    uint32_t instructionOffset : 25;
102    uint32_t startOffset : 7;
103    uint32_t divotPoint : 25;
104    uint32_t endOffset : 7;
105    uint32_t mode : 2;
106    uint32_t position : 30;
107};
108
109} // namespace JSC
110
111#endif // ExpressionRangeInfo_h
112
113