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1 /* | |
2 ********************************************************************** | |
3 * Copyright (C) 2000-2004, International Business Machines | |
4 * Corporation and others. All Rights Reserved. | |
5 ********************************************************************** | |
6 * ucnv_cb.h: | |
7 * External APIs for the ICU's codeset conversion library | |
8 * Helena Shih | |
9 * | |
10 * Modification History: | |
11 * | |
12 * Date Name Description | |
13 */ | |
14 | |
15 /** | |
16 * \file | |
17 * \brief C UConverter functions to aid the writers of callbacks | |
18 * | |
19 * <h2> Callback API for UConverter </h2> | |
20 * | |
21 * These functions are provided here for the convenience of the callback | |
22 * writer. If you are just looking for callback functions to use, please | |
23 * see ucnv_err.h. DO NOT call these functions directly when you are | |
24 * working with converters, unless your code has been called as a callback | |
25 * via ucnv_setFromUCallback or ucnv_setToUCallback !! | |
26 * | |
27 * A note about error codes and overflow. Unlike other ICU functions, | |
28 * these functions do not expect the error status to be U_ZERO_ERROR. | |
29 * Callbacks must be much more careful about their error codes. | |
30 * The error codes used here are in/out parameters, which should be passed | |
31 * back in the callback's error parameter. | |
32 * | |
33 * For example, if you call ucnv_cbfromUWriteBytes to write data out | |
34 * to the output codepage, it may return U_BUFFER_OVERFLOW_ERROR if | |
35 * the data did not fit in the target. But this isn't a failing error, | |
36 * in fact, ucnv_cbfromUWriteBytes may be called AGAIN with the error | |
37 * status still U_BUFFER_OVERFLOW_ERROR to attempt to write further bytes, | |
38 * which will also go into the internal overflow buffers. | |
39 * | |
40 * Concerning offsets, the 'offset' parameters here are relative to the start | |
41 * of SOURCE. For example, Suppose the string "ABCD" was being converted | |
42 * from Unicode into a codepage which doesn't have a mapping for 'B'. | |
43 * 'A' will be written out correctly, but | |
44 * The FromU Callback will be called on an unassigned character for 'B'. | |
45 * At this point, this is the state of the world: | |
46 * Target: A [..] [points after A] | |
47 * Source: A B [C] D [points to C - B has been consumed] | |
48 * 0 1 2 3 | |
49 * codePoint = "B" [the unassigned codepoint] | |
50 * | |
51 * Now, suppose a callback wants to write the substitution character '?' to | |
52 * the target. It calls ucnv_cbFromUWriteBytes() to write the ?. | |
53 * It should pass ZERO as the offset, because the offset as far as the | |
54 * callback is concerned is relative to the SOURCE pointer [which points | |
55 * before 'C'.] If the callback goes into the args and consumes 'C' also, | |
56 * it would call FromUWriteBytes with an offset of 1 (and advance the source | |
57 * pointer). | |
58 * | |
59 */ | |
60 | |
61 #ifndef UCNV_CB_H | |
62 #define UCNV_CB_H | |
63 | |
64 #include "unicode/utypes.h" | |
65 | |
66 #if !UCONFIG_NO_CONVERSION | |
67 | |
68 #include "unicode/ucnv.h" | |
69 #include "unicode/ucnv_err.h" | |
70 | |
71 /** | |
72 * ONLY used by FromU callback functions. | |
73 * Writes out the specified byte output bytes to the target byte buffer or to co
nverter internal buffers. | |
74 * | |
75 * @param args callback fromUnicode arguments | |
76 * @param source source bytes to write | |
77 * @param length length of bytes to write | |
78 * @param offsetIndex the relative offset index from callback. | |
79 * @param err error status. If <TT>U_BUFFER_OVERFLOW</TT> is returned, then U_BU
FFER_OVERFLOW <STRONG>must</STRONG> | |
80 * be returned to the user, because it means that not all data could be written
into the target buffer, and some is | |
81 * in the converter error buffer. | |
82 * @see ucnv_cbFromUWriteSub | |
83 * @stable ICU 2.0 | |
84 */ | |
85 U_STABLE void U_EXPORT2 | |
86 ucnv_cbFromUWriteBytes (UConverterFromUnicodeArgs *args, | |
87 const char* source, | |
88 int32_t length, | |
89 int32_t offsetIndex, | |
90 UErrorCode * err); | |
91 | |
92 /** | |
93 * ONLY used by FromU callback functions. | |
94 * This function will write out the correct substitution character sequence | |
95 * to the target. | |
96 * | |
97 * @param args callback fromUnicode arguments | |
98 * @param offsetIndex the relative offset index from the current source pointer
to be used | |
99 * @param err error status. If <TT>U_BUFFER_OVERFLOW</TT> is returned, then U_BU
FFER_OVERFLOW <STRONG>must</STRONG> | |
100 * be returned to the user, because it means that not all data could be written
into the target buffer, and some is | |
101 * in the converter error buffer. | |
102 * @see ucnv_cbFromUWriteBytes | |
103 * @stable ICU 2.0 | |
104 */ | |
105 U_STABLE void U_EXPORT2 | |
106 ucnv_cbFromUWriteSub (UConverterFromUnicodeArgs *args, | |
107 int32_t offsetIndex, | |
108 UErrorCode * err); | |
109 | |
110 /** | |
111 * ONLY used by fromU callback functions. | |
112 * This function will write out the error character(s) to the target UChar buffe
r. | |
113 * | |
114 * @param args callback fromUnicode arguments | |
115 * @param source pointer to pointer to first UChar to write [on exit: 1 after la
st UChar processed] | |
116 * @param sourceLimit pointer after last UChar to write | |
117 * @param offsetIndex the relative offset index from callback which will be set | |
118 * @param err error status <TT>U_BUFFER_OVERFLOW</TT> | |
119 * @see ucnv_cbToUWriteSub | |
120 * @stable ICU 2.0 | |
121 */ | |
122 U_STABLE void U_EXPORT2 ucnv_cbFromUWriteUChars(UConverterFromUnicodeArgs *args, | |
123 const UChar** source, | |
124 const UChar* sourceLimit, | |
125 int32_t offsetIndex, | |
126 UErrorCode * err); | |
127 | |
128 /** | |
129 * ONLY used by ToU callback functions. | |
130 * This function will write out the specified characters to the target | |
131 * UChar buffer. | |
132 * | |
133 * @param args callback toUnicode arguments | |
134 * @param source source string to write | |
135 * @param length the length of source string | |
136 * @param offsetIndex the relative offset index which will be written. | |
137 * @param err error status <TT>U_BUFFER_OVERFLOW</TT> | |
138 * @see ucnv_cbToUWriteSub | |
139 * @stable ICU 2.0 | |
140 */ | |
141 U_STABLE void U_EXPORT2 ucnv_cbToUWriteUChars (UConverterToUnicodeArgs *args, | |
142 const UChar* source, | |
143 int32_t length, | |
144 int32_t offsetIndex, | |
145 UErrorCode * err); | |
146 | |
147 /** | |
148 * ONLY used by ToU callback functions. | |
149 * This function will write out the Unicode substitution character (U+FFFD). | |
150 * | |
151 * @param args callback fromUnicode arguments | |
152 * @param offsetIndex the relative offset index from callback. | |
153 * @param err error status <TT>U_BUFFER_OVERFLOW</TT> | |
154 * @see ucnv_cbToUWriteUChars | |
155 * @stable ICU 2.0 | |
156 */ | |
157 U_STABLE void U_EXPORT2 ucnv_cbToUWriteSub (UConverterToUnicodeArgs *args, | |
158 int32_t offsetIndex, | |
159 UErrorCode * err); | |
160 #endif | |
161 | |
162 #endif | |
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