1/*
2 **********************************************************************
3 *   Copyright (C) 2005-2012, 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
37    if (input[0] == 0xFE && input[1] == 0xFF) {
38        confidence = 100;
39    }
40
41    // TODO: Do some statastics to check for unsigned UTF-16BE
42    results->set(textIn, this, confidence);
43    return (confidence > 0);
44}
45
46CharsetRecog_UTF_16_LE::~CharsetRecog_UTF_16_LE()
47{
48    // nothing to do
49}
50
51const char *CharsetRecog_UTF_16_LE::getName() const
52{
53    return "UTF-16LE";
54}
55
56UBool CharsetRecog_UTF_16_LE::match(InputText* textIn, CharsetMatch *results) const
57{
58    const uint8_t *input = textIn->fRawInput;
59    int32_t confidence = 0;
60
61    if (input[0] == 0xFF && input[1] == 0xFE && (input[2] != 0x00 || input[3] != 0x00)) {
62        confidence = 100;
63    }
64
65    // TODO: Do some statastics to check for unsigned UTF-16LE
66    results->set(textIn, this, confidence);
67    return (confidence > 0);
68}
69
70CharsetRecog_UTF_32::~CharsetRecog_UTF_32()
71{
72    // nothing to do
73}
74
75UBool CharsetRecog_UTF_32::match(InputText* textIn, CharsetMatch *results) const
76{
77    const uint8_t *input = textIn->fRawInput;
78    int32_t limit = (textIn->fRawLength / 4) * 4;
79    int32_t numValid = 0;
80    int32_t numInvalid = 0;
81    bool hasBOM = FALSE;
82    int32_t confidence = 0;
83
84    if (getChar(input, 0) == 0x0000FEFFUL) {
85        hasBOM = TRUE;
86    }
87
88    for(int32_t i = 0; i < limit; i += 4) {
89        int32_t ch = getChar(input, i);
90
91        if (ch < 0 || ch >= 0x10FFFF || (ch >= 0xD800 && ch <= 0xDFFF)) {
92            numInvalid += 1;
93        } else {
94            numValid += 1;
95        }
96    }
97
98
99    // Cook up some sort of confidence score, based on presense of a BOM
100    //    and the existence of valid and/or invalid multi-byte sequences.
101    if (hasBOM && numInvalid==0) {
102        confidence = 100;
103    } else if (hasBOM && numValid > numInvalid*10) {
104        confidence = 80;
105    } else if (numValid > 3 && numInvalid == 0) {
106        confidence = 100;
107    } else if (numValid > 0 && numInvalid == 0) {
108        confidence = 80;
109    } else if (numValid > numInvalid*10) {
110        // Probably corruput UTF-32BE data.  Valid sequences aren't likely by chance.
111        confidence = 25;
112    }
113
114    results->set(textIn, this, confidence);
115    return (confidence > 0);
116}
117
118CharsetRecog_UTF_32_BE::~CharsetRecog_UTF_32_BE()
119{
120    // nothing to do
121}
122
123const char *CharsetRecog_UTF_32_BE::getName() const
124{
125    return "UTF-32BE";
126}
127
128int32_t CharsetRecog_UTF_32_BE::getChar(const uint8_t *input, int32_t index) const
129{
130    return input[index + 0] << 24 | input[index + 1] << 16 |
131           input[index + 2] <<  8 | input[index + 3];
132}
133
134CharsetRecog_UTF_32_LE::~CharsetRecog_UTF_32_LE()
135{
136    // nothing to do
137}
138
139const char *CharsetRecog_UTF_32_LE::getName() const
140{
141    return "UTF-32LE";
142}
143
144int32_t CharsetRecog_UTF_32_LE::getChar(const uint8_t *input, int32_t index) const
145{
146    return input[index + 3] << 24 | input[index + 2] << 16 |
147           input[index + 1] <<  8 | input[index + 0];
148}
149
150U_NAMESPACE_END
151#endif
152
153