1/*
2 **********************************************************************
3 *   Copyright (C) 2005-2013, 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#include "csmatch.h"
14
15U_NAMESPACE_BEGIN
16
17CharsetRecog_Unicode::~CharsetRecog_Unicode()
18{
19    // nothing to do
20}
21
22CharsetRecog_UTF_16_BE::~CharsetRecog_UTF_16_BE()
23{
24    // nothing to do
25}
26
27const char *CharsetRecog_UTF_16_BE::getName() const
28{
29    return "UTF-16BE";
30}
31
32UBool CharsetRecog_UTF_16_BE::match(InputText* textIn, CharsetMatch *results) const
33{
34    const uint8_t *input = textIn->fRawInput;
35    int32_t confidence = 0;
36    int32_t length = textIn->fRawLength;
37
38    if (length >=2 && input[0] == 0xFE && input[1] == 0xFF) {
39        confidence = 100;
40    }
41
42    // TODO: Do some statastics to check for unsigned UTF-16BE
43    results->set(textIn, this, confidence);
44    return (confidence > 0);
45}
46
47CharsetRecog_UTF_16_LE::~CharsetRecog_UTF_16_LE()
48{
49    // nothing to do
50}
51
52const char *CharsetRecog_UTF_16_LE::getName() const
53{
54    return "UTF-16LE";
55}
56
57UBool CharsetRecog_UTF_16_LE::match(InputText* textIn, CharsetMatch *results) const
58{
59    const uint8_t *input = textIn->fRawInput;
60    int32_t confidence = 0;
61    int32_t length = textIn->fRawLength;
62
63    if (length >= 4 && input[0] == 0xFF && input[1] == 0xFE && (input[2] != 0x00 || input[3] != 0x00)) {
64        confidence = 100;
65    }
66
67    // TODO: Do some statastics to check for unsigned UTF-16LE
68    results->set(textIn, this, confidence);
69    return (confidence > 0);
70}
71
72CharsetRecog_UTF_32::~CharsetRecog_UTF_32()
73{
74    // nothing to do
75}
76
77UBool CharsetRecog_UTF_32::match(InputText* textIn, CharsetMatch *results) const
78{
79    const uint8_t *input = textIn->fRawInput;
80    int32_t limit = (textIn->fRawLength / 4) * 4;
81    int32_t numValid = 0;
82    int32_t numInvalid = 0;
83    bool hasBOM = FALSE;
84    int32_t confidence = 0;
85
86    if (limit > 0 && getChar(input, 0) == 0x0000FEFFUL) {
87        hasBOM = TRUE;
88    }
89
90    for(int32_t i = 0; i < limit; i += 4) {
91        int32_t ch = getChar(input, i);
92
93        if (ch < 0 || ch >= 0x10FFFF || (ch >= 0xD800 && ch <= 0xDFFF)) {
94            numInvalid += 1;
95        } else {
96            numValid += 1;
97        }
98    }
99
100
101    // Cook up some sort of confidence score, based on presense of a BOM
102    //    and the existence of valid and/or invalid multi-byte sequences.
103    if (hasBOM && numInvalid==0) {
104        confidence = 100;
105    } else if (hasBOM && numValid > numInvalid*10) {
106        confidence = 80;
107    } else if (numValid > 3 && numInvalid == 0) {
108        confidence = 100;
109    } else if (numValid > 0 && numInvalid == 0) {
110        confidence = 80;
111    } else if (numValid > numInvalid*10) {
112        // Probably corruput UTF-32BE data.  Valid sequences aren't likely by chance.
113        confidence = 25;
114    }
115
116    results->set(textIn, this, confidence);
117    return (confidence > 0);
118}
119
120CharsetRecog_UTF_32_BE::~CharsetRecog_UTF_32_BE()
121{
122    // nothing to do
123}
124
125const char *CharsetRecog_UTF_32_BE::getName() const
126{
127    return "UTF-32BE";
128}
129
130int32_t CharsetRecog_UTF_32_BE::getChar(const uint8_t *input, int32_t index) const
131{
132    return input[index + 0] << 24 | input[index + 1] << 16 |
133           input[index + 2] <<  8 | input[index + 3];
134}
135
136CharsetRecog_UTF_32_LE::~CharsetRecog_UTF_32_LE()
137{
138    // nothing to do
139}
140
141const char *CharsetRecog_UTF_32_LE::getName() const
142{
143    return "UTF-32LE";
144}
145
146int32_t CharsetRecog_UTF_32_LE::getChar(const uint8_t *input, int32_t index) const
147{
148    return input[index + 3] << 24 | input[index + 2] << 16 |
149           input[index + 1] <<  8 | input[index + 0];
150}
151
152U_NAMESPACE_END
153#endif
154
155