1/*
2 **********************************************************************
3 *   Copyright (C) 2005-2006, International Business Machines
4 *   Corporation and others.  All Rights Reserved.
5 **********************************************************************
6 */
7
8#include "unicode/utypes.h"
9
10#if !UCONFIG_NO_CONVERSION
11
12#include "csrucode.h"
13
14U_NAMESPACE_BEGIN
15
16CharsetRecog_Unicode::~CharsetRecog_Unicode()
17{
18    // nothing to do
19}
20
21CharsetRecog_UTF_16_BE::~CharsetRecog_UTF_16_BE()
22{
23    // nothing to do
24}
25
26const char *CharsetRecog_UTF_16_BE::getName() const
27{
28    return "UTF-16BE";
29}
30
31int32_t CharsetRecog_UTF_16_BE::match(InputText* textIn)
32{
33    const uint8_t *input = textIn->fRawInput;
34
35    if (input[0] == 0xFE && input[1] == 0xFF) {
36        return 100;
37    }
38
39    // TODO: Do some statastics to check for unsigned UTF-16BE
40    return 0;
41}
42
43CharsetRecog_UTF_16_LE::~CharsetRecog_UTF_16_LE()
44{
45    // nothing to do
46}
47
48const char *CharsetRecog_UTF_16_LE::getName() const
49{
50    return "UTF-16LE";
51}
52
53int32_t CharsetRecog_UTF_16_LE::match(InputText* textIn)
54{
55    const uint8_t *input = textIn->fRawInput;
56
57    if (input[0] == 0xFF && input[1] == 0xFE && (input[2] != 0x00 || input[3] != 0x00)) {
58        return 100;
59    }
60
61    // TODO: Do some statastics to check for unsigned UTF-16LE
62    return 0;
63}
64
65CharsetRecog_UTF_32::~CharsetRecog_UTF_32()
66{
67    // nothing to do
68}
69
70int32_t CharsetRecog_UTF_32::match(InputText* textIn)
71{
72    const uint8_t *input = textIn->fRawInput;
73    int32_t limit = (textIn->fRawLength / 4) * 4;
74    int32_t numValid = 0;
75    int32_t numInvalid = 0;
76    bool hasBOM = FALSE;
77    int32_t confidence = 0;
78
79    if (getChar(input, 0) == 0x0000FEFFUL) {
80        hasBOM = TRUE;
81    }
82
83    for(int32_t i = 0; i < limit; i += 4) {
84        int32_t ch = getChar(input, i);
85
86        if (ch < 0 || ch >= 0x10FFFF || (ch >= 0xD800 && ch <= 0xDFFF)) {
87            numInvalid += 1;
88        } else {
89            numValid += 1;
90        }
91    }
92
93
94    // Cook up some sort of confidence score, based on presense of a BOM
95    //    and the existence of valid and/or invalid multi-byte sequences.
96    if (hasBOM && numInvalid==0) {
97        confidence = 100;
98    } else if (hasBOM && numValid > numInvalid*10) {
99        confidence = 80;
100    } else if (numValid > 3 && numInvalid == 0) {
101        confidence = 100;
102    } else if (numValid > 0 && numInvalid == 0) {
103        confidence = 80;
104    } else if (numValid > numInvalid*10) {
105        // Probably corruput UTF-32BE data.  Valid sequences aren't likely by chance.
106        confidence = 25;
107    }
108
109    return confidence;
110}
111
112CharsetRecog_UTF_32_BE::~CharsetRecog_UTF_32_BE()
113{
114    // nothing to do
115}
116
117const char *CharsetRecog_UTF_32_BE::getName() const
118{
119    return "UTF-32BE";
120}
121
122int32_t CharsetRecog_UTF_32_BE::getChar(const uint8_t *input, int32_t index) const
123{
124    return input[index + 0] << 24 | input[index + 1] << 16 |
125           input[index + 2] <<  8 | input[index + 3];
126}
127
128CharsetRecog_UTF_32_LE::~CharsetRecog_UTF_32_LE()
129{
130    // nothing to do
131}
132
133const char *CharsetRecog_UTF_32_LE::getName() const
134{
135    return "UTF-32LE";
136}
137
138int32_t CharsetRecog_UTF_32_LE::getChar(const uint8_t *input, int32_t index) const
139{
140    return input[index + 3] << 24 | input[index + 2] << 16 |
141           input[index + 1] <<  8 | input[index + 0];
142}
143
144U_NAMESPACE_END
145#endif
146
147