ustring.h File Reference

C API: Unicode string handling functions. More...

#include "unicode/utypes.h"
#include "unicode/putil.h"
#include "unicode/uiter.h"

Go to the source code of this file.

Defines

#define U_COMPARE_CODE_POINT_ORDER   0x8000
 Option bit for u_strCaseCompare, u_strcasecmp, unorm_compare, etc: Compare strings in code point order instead of code unit order.
#define U_STRING_DECL(var, cs, length)   static const wchar_t var[(length)+1]={ L ## cs }
 Unicode String literals in C.
#define U_STRING_INIT(var, cs, length)

Typedefs

typedef void UBreakIterator
 Simple declaration for u_strToTitle() to avoid including unicode/ubrk.h.

Functions

U_STABLE int32_t U_EXPORT2 u_strlen (const UChar *s)
 Determine the length of an array of UChar.
U_STABLE int32_t U_EXPORT2 u_countChar32 (const UChar *s, int32_t length)
 Count Unicode code points in the length UChar code units of the string.
U_STABLE UBool U_EXPORT2 u_strHasMoreChar32Than (const UChar *s, int32_t length, int32_t number)
 Check if the string contains more Unicode code points than a certain number.
U_STABLE UChar *U_EXPORT2 u_strcat (UChar *dst, const UChar *src)
 Concatenate two ustrings.
U_STABLE UChar *U_EXPORT2 u_strncat (UChar *dst, const UChar *src, int32_t n)
 Concatenate two ustrings.
U_STABLE UChar *U_EXPORT2 u_strstr (const UChar *s, const UChar *substring)
 Find the first occurrence of a substring in a string.
U_STABLE UChar *U_EXPORT2 u_strFindFirst (const UChar *s, int32_t length, const UChar *substring, int32_t subLength)
 Find the first occurrence of a substring in a string.
U_STABLE UChar *U_EXPORT2 u_strchr (const UChar *s, UChar c)
 Find the first occurrence of a BMP code point in a string.
U_STABLE UChar *U_EXPORT2 u_strchr32 (const UChar *s, UChar32 c)
 Find the first occurrence of a code point in a string.
U_STABLE UChar *U_EXPORT2 u_strrstr (const UChar *s, const UChar *substring)
 Find the last occurrence of a substring in a string.
U_STABLE UChar *U_EXPORT2 u_strFindLast (const UChar *s, int32_t length, const UChar *substring, int32_t subLength)
 Find the last occurrence of a substring in a string.
U_STABLE UChar *U_EXPORT2 u_strrchr (const UChar *s, UChar c)
 Find the last occurrence of a BMP code point in a string.
U_STABLE UChar *U_EXPORT2 u_strrchr32 (const UChar *s, UChar32 c)
 Find the last occurrence of a code point in a string.
U_STABLE UChar *U_EXPORT2 u_strpbrk (const UChar *string, const UChar *matchSet)
 Locates the first occurrence in the string string of any of the characters in the string matchSet.
U_STABLE int32_t U_EXPORT2 u_strcspn (const UChar *string, const UChar *matchSet)
 Returns the number of consecutive characters in string, beginning with the first, that do not occur somewhere in matchSet.
U_STABLE int32_t U_EXPORT2 u_strspn (const UChar *string, const UChar *matchSet)
 Returns the number of consecutive characters in string, beginning with the first, that occur somewhere in matchSet.
U_STABLE UChar *U_EXPORT2 u_strtok_r (UChar *src, const UChar *delim, UChar **saveState)
 The string tokenizer API allows an application to break a string into tokens.
U_STABLE int32_t U_EXPORT2 u_strcmp (const UChar *s1, const UChar *s2)
 Compare two Unicode strings for bitwise equality (code unit order).
U_STABLE int32_t U_EXPORT2 u_strcmpCodePointOrder (const UChar *s1, const UChar *s2)
 Compare two Unicode strings in code point order.
U_STABLE int32_t U_EXPORT2 u_strCompare (const UChar *s1, int32_t length1, const UChar *s2, int32_t length2, UBool codePointOrder)
 Compare two Unicode strings (binary order).
U_STABLE int32_t U_EXPORT2 u_strCompareIter (UCharIterator *iter1, UCharIterator *iter2, UBool codePointOrder)
 Compare two Unicode strings (binary order) as presented by UCharIterator objects.
U_STABLE int32_t U_EXPORT2 u_strCaseCompare (const UChar *s1, int32_t length1, const UChar *s2, int32_t length2, uint32_t options, UErrorCode *pErrorCode)
 Compare two strings case-insensitively using full case folding.
U_STABLE int32_t U_EXPORT2 u_strncmp (const UChar *ucs1, const UChar *ucs2, int32_t n)
 Compare two ustrings for bitwise equality.
U_STABLE int32_t U_EXPORT2 u_strncmpCodePointOrder (const UChar *s1, const UChar *s2, int32_t n)
 Compare two Unicode strings in code point order.
U_STABLE int32_t U_EXPORT2 u_strcasecmp (const UChar *s1, const UChar *s2, uint32_t options)
 Compare two strings case-insensitively using full case folding.
U_STABLE int32_t U_EXPORT2 u_strncasecmp (const UChar *s1, const UChar *s2, int32_t n, uint32_t options)
 Compare two strings case-insensitively using full case folding.
U_STABLE int32_t U_EXPORT2 u_memcasecmp (const UChar *s1, const UChar *s2, int32_t length, uint32_t options)
 Compare two strings case-insensitively using full case folding.
U_STABLE UChar *U_EXPORT2 u_strcpy (UChar *dst, const UChar *src)
 Copy a ustring.
U_STABLE UChar *U_EXPORT2 u_strncpy (UChar *dst, const UChar *src, int32_t n)
 Copy a ustring.
U_STABLE UChar *U_EXPORT2 u_uastrcpy (UChar *dst, const char *src)
 Copy a byte string encoded in the default codepage to a ustring.
U_STABLE UChar *U_EXPORT2 u_uastrncpy (UChar *dst, const char *src, int32_t n)
 Copy a byte string encoded in the default codepage to a ustring.
U_STABLE char *U_EXPORT2 u_austrcpy (char *dst, const UChar *src)
 Copy ustring to a byte string encoded in the default codepage.
U_STABLE char *U_EXPORT2 u_austrncpy (char *dst, const UChar *src, int32_t n)
 Copy ustring to a byte string encoded in the default codepage.
U_STABLE UChar *U_EXPORT2 u_memcpy (UChar *dest, const UChar *src, int32_t count)
 Synonym for memcpy(), but with UChars only.
U_STABLE UChar *U_EXPORT2 u_memmove (UChar *dest, const UChar *src, int32_t count)
 Synonym for memmove(), but with UChars only.
U_STABLE UChar *U_EXPORT2 u_memset (UChar *dest, UChar c, int32_t count)
 Initialize count characters of dest to c.
U_STABLE int32_t U_EXPORT2 u_memcmp (const UChar *buf1, const UChar *buf2, int32_t count)
 Compare the first count UChars of each buffer.
U_STABLE int32_t U_EXPORT2 u_memcmpCodePointOrder (const UChar *s1, const UChar *s2, int32_t count)
 Compare two Unicode strings in code point order.
U_STABLE UChar *U_EXPORT2 u_memchr (const UChar *s, UChar c, int32_t count)
 Find the first occurrence of a BMP code point in a string.
U_STABLE UChar *U_EXPORT2 u_memchr32 (const UChar *s, UChar32 c, int32_t count)
 Find the first occurrence of a code point in a string.
U_STABLE UChar *U_EXPORT2 u_memrchr (const UChar *s, UChar c, int32_t count)
 Find the last occurrence of a BMP code point in a string.
U_STABLE UChar *U_EXPORT2 u_memrchr32 (const UChar *s, UChar32 c, int32_t count)
 Find the last occurrence of a code point in a string.
U_STABLE int32_t U_EXPORT2 u_unescape (const char *src, UChar *dest, int32_t destCapacity)
 Unescape a string of characters and write the resulting Unicode characters to the destination buffer.
U_CDECL_BEGIN typedef UChar (U_CALLCONV *UNESCAPE_CHAR_AT)(int32_t offset
 Callback function for u_unescapeAt() that returns a character of the source text given an offset and a context pointer.
U_CDECL_END U_STABLE UChar32
U_EXPORT2 
u_unescapeAt (UNESCAPE_CHAR_AT charAt, int32_t *offset, int32_t length, void *context)
 Unescape a single sequence.
U_STABLE int32_t U_EXPORT2 u_strToUpper (UChar *dest, int32_t destCapacity, const UChar *src, int32_t srcLength, const char *locale, UErrorCode *pErrorCode)
 Uppercase the characters in a string.
U_STABLE int32_t U_EXPORT2 u_strToLower (UChar *dest, int32_t destCapacity, const UChar *src, int32_t srcLength, const char *locale, UErrorCode *pErrorCode)
 Lowercase the characters in a string.
U_STABLE int32_t U_EXPORT2 u_strToTitle (UChar *dest, int32_t destCapacity, const UChar *src, int32_t srcLength, UBreakIterator *titleIter, const char *locale, UErrorCode *pErrorCode)
 Titlecase a string.
U_STABLE int32_t U_EXPORT2 u_strFoldCase (UChar *dest, int32_t destCapacity, const UChar *src, int32_t srcLength, uint32_t options, UErrorCode *pErrorCode)
 Case-fold the characters in a string.
U_STABLE wchar_t *U_EXPORT2 u_strToWCS (wchar_t *dest, int32_t destCapacity, int32_t *pDestLength, const UChar *src, int32_t srcLength, UErrorCode *pErrorCode)
 Converts a sequence of UChars to wchar_t units.
U_STABLE UChar *U_EXPORT2 u_strFromWCS (UChar *dest, int32_t destCapacity, int32_t *pDestLength, const wchar_t *src, int32_t srcLength, UErrorCode *pErrorCode)
 Converts a sequence of wchar_t units to UChars.
U_STABLE char *U_EXPORT2 u_strToUTF8 (char *dest, int32_t destCapacity, int32_t *pDestLength, const UChar *src, int32_t srcLength, UErrorCode *pErrorCode)
 Converts a sequence of UChars (UTF-16) to UTF-8 bytes.
U_STABLE UChar *U_EXPORT2 u_strFromUTF8 (UChar *dest, int32_t destCapacity, int32_t *pDestLength, const char *src, int32_t srcLength, UErrorCode *pErrorCode)
 Converts a sequence of UTF-8 bytes to UChars (UTF-16).
U_STABLE UChar32 *U_EXPORT2 u_strToUTF32 (UChar32 *dest, int32_t destCapacity, int32_t *pDestLength, const UChar *src, int32_t srcLength, UErrorCode *pErrorCode)
 Converts a sequence of UChars (UTF-16) to UTF32 units.
U_STABLE UChar *U_EXPORT2 u_strFromUTF32 (UChar *dest, int32_t destCapacity, int32_t *pDestLength, const UChar32 *src, int32_t srcLength, UErrorCode *pErrorCode)
 Converts a sequence of UTF32 units to UChars (UTF-16).

Variables

U_CDECL_BEGIN typedef void * context


Detailed Description

C API: Unicode string handling functions.

These C API functions provide general Unicode string handling.

Some functions are equivalent in name, signature, and behavior to the ANSI C <string.h> functions. (For example, they do not check for bad arguments like NULL string pointers.) In some cases, only the thread-safe variant of such a function is implemented here (see u_strtok_r()).

Other functions provide more Unicode-specific functionality like locale-specific upper/lower-casing and string comparison in code point order.

ICU uses 16-bit Unicode (UTF-16) in the form of arrays of UChar code units. UTF-16 encodes each Unicode code point with either one or two UChar code units. (This is the default form of Unicode, and a forward-compatible extension of the original, fixed-width form that was known as UCS-2. UTF-16 superseded UCS-2 with Unicode 2.0 in 1996.)

Some APIs accept a 32-bit UChar32 value for a single code point.

ICU also handles 16-bit Unicode text with unpaired surrogates. Such text is not well-formed UTF-16. Code-point-related functions treat unpaired surrogates as surrogate code points, i.e., as separate units.

Although UTF-16 is a variable-width encoding form (like some legacy multi-byte encodings), it is much more efficient even for random access because the code unit values for single-unit characters vs. lead units vs. trail units are completely disjoint. This means that it is easy to determine character (code point) boundaries from random offsets in the string.

Unicode (UTF-16) string processing is optimized for the single-unit case. Although it is important to support supplementary characters (which use pairs of lead/trail code units called "surrogates"), their occurrence is rare. Almost all characters in modern use require only a single UChar code unit (i.e., their code point values are <=0xffff).

For more details see the User Guide Strings chapter (http://oss.software.ibm.com/icu/userguide/strings.html). For a discussion of the handling of unpaired surrogates see also Jitterbug 2145 and its icu mailing list proposal on 2002-sep-18.

Definition in file ustring.h.


Define Documentation

#define U_COMPARE_CODE_POINT_ORDER   0x8000
 

Option bit for u_strCaseCompare, u_strcasecmp, unorm_compare, etc: Compare strings in code point order instead of code unit order.

ICU_Stable:
ICU 2.2

Definition at line 517 of file ustring.h.

#define U_STRING_DECL var,
cs,
length   )     static const wchar_t var[(length)+1]={ L ## cs }
 

Unicode String literals in C.

We need one macro to declare a variable for the string and to statically preinitialize it if possible, and a second macro to dynamically intialize such a string variable if necessary.

The macros are defined for maximum performance. They work only for strings that contain "invariant characters", i.e., only latin letters, digits, and some punctuation. See utypes.h for details.

A pair of macros for a single string must be used with the same parameters. The string parameter must be a C string literal. The length of the string, not including the terminating NUL, must be specified as a constant. The U_STRING_DECL macro should be invoked exactly once for one such string variable before it is used.

Usage:

 &#32;   U_STRING_DECL(ustringVar1, "Quick-Fox 2", 11);
 &#32;   U_STRING_DECL(ustringVar2, "jumps 5%", 8);
 &#32;   static UBool didInit=FALSE;
 &#32;
 &#32;   int32_t function() {
 &#32;       if(!didInit) {
 &#32;           U_STRING_INIT(ustringVar1, "Quick-Fox 2", 11);
 &#32;           U_STRING_INIT(ustringVar2, "jumps 5%", 8);
 &#32;           didInit=TRUE;
 &#32;       }
 &#32;       return u_strcmp(ustringVar1, ustringVar2);
 &#32;   }
 
ICU_Stable:
ICU 2.0

Definition at line 962 of file ustring.h.

#define U_STRING_INIT var,
cs,
length   ) 
 

ICU_Stable:
ICU 2.0

Definition at line 965 of file ustring.h.


Typedef Documentation

typedef void UBreakIterator
 

Simple declaration for u_strToTitle() to avoid including unicode/ubrk.h.

ICU_Stable:
ICU 2.1

Definition at line 27 of file ustring.h.


Function Documentation

U_STABLE char* U_EXPORT2 u_austrcpy char *  dst,
const UChar *  src
 

Copy ustring to a byte string encoded in the default codepage.

Adds a null terminator. Performs a UChar to host byte conversion

Parameters:
dst The destination string.
src The source string.
Returns:
A pointer to dst.
ICU_Stable:
ICU 2.0

U_STABLE char* U_EXPORT2 u_austrncpy char *  dst,
const UChar *  src,
int32_t  n
 

Copy ustring to a byte string encoded in the default codepage.

Copies at most n characters. The result will be null terminated if the length of src is less than n. Performs a UChar to host byte conversion

Parameters:
dst The destination string.
src The source string.
n The maximum number of characters to copy.
Returns:
A pointer to dst.
ICU_Stable:
ICU 2.0

U_STABLE int32_t U_EXPORT2 u_countChar32 const UChar *  s,
int32_t  length
 

Count Unicode code points in the length UChar code units of the string.

A code point may occupy either one or two UChar code units. Counting code points involves reading all code units.

This functions is basically the inverse of the U16_FWD_N() macro (see utf.h).

Parameters:
s The input string.
length The number of UChar code units to be checked, or -1 to count all code points before the first NUL (U+0000).
Returns:
The number of code points in the specified code units.
ICU_Stable:
ICU 2.0

U_STABLE int32_t U_EXPORT2 u_memcasecmp const UChar *  s1,
const UChar *  s2,
int32_t  length,
uint32_t  options
 

Compare two strings case-insensitively using full case folding.

This is equivalent to u_strcmp(u_strFoldCase(s1, n, options), u_strFoldCase(s2, n, options)).

Parameters:
s1 A string to compare.
s2 A string to compare.
length The number of characters in each string to case-fold and then compare.
options A bit set of options:
  • U_FOLD_CASE_DEFAULT or 0 is used for default options: Comparison in code unit order with default case folding.
  • U_COMPARE_CODE_POINT_ORDER Set to choose code point order instead of code unit order (see u_strCompare for details).

  • U_FOLD_CASE_EXCLUDE_SPECIAL_I

Returns:
A negative, zero, or positive integer indicating the comparison result.
ICU_Stable:
ICU 2.0

U_STABLE UChar* U_EXPORT2 u_memchr const UChar *  s,
UChar  c,
int32_t  count
 

Find the first occurrence of a BMP code point in a string.

A surrogate code point is found only if its match in the text is not part of a surrogate pair. A NUL character is found at the string terminator.

Parameters:
s The string to search (contains count UChars).
c The BMP code point to find.
count The length of the string.
Returns:
A pointer to the first occurrence of c in s or NULL if c is not in s.
ICU_Stable:
ICU 2.0
See also:
u_strchr

u_memchr32

u_strFindFirst

U_STABLE UChar* U_EXPORT2 u_memchr32 const UChar *  s,
UChar32  c,
int32_t  count
 

Find the first occurrence of a code point in a string.

A surrogate code point is found only if its match in the text is not part of a surrogate pair. A NUL character is found at the string terminator.

Parameters:
s The string to search (contains count UChars).
c The code point to find.
count The length of the string.
Returns:
A pointer to the first occurrence of c in s or NULL if c is not in s.
ICU_Stable:
ICU 2.0
See also:
u_strchr32

u_memchr

u_strFindFirst

U_STABLE int32_t U_EXPORT2 u_memcmp const UChar *  buf1,
const UChar *  buf2,
int32_t  count
 

Compare the first count UChars of each buffer.

Parameters:
buf1 The first string to compare.
buf2 The second string to compare.
count The maximum number of UChars to compare.
Returns:
When buf1 < buf2, a negative number is returned. When buf1 == buf2, 0 is returned. When buf1 > buf2, a positive number is returned.
ICU_Stable:
ICU 2.0

U_STABLE int32_t U_EXPORT2 u_memcmpCodePointOrder const UChar *  s1,
const UChar *  s2,
int32_t  count
 

Compare two Unicode strings in code point order.

This is different in UTF-16 from u_memcmp() if supplementary characters are present. For details, see u_strCompare().

Parameters:
s1 A string to compare.
s2 A string to compare.
count The maximum number of characters to compare.
Returns:
a negative/zero/positive integer corresponding to whether the first string is less than/equal to/greater than the second one in code point order
ICU_Stable:
ICU 2.0

U_STABLE UChar* U_EXPORT2 u_memcpy UChar *  dest,
const UChar *  src,
int32_t  count
 

Synonym for memcpy(), but with UChars only.

Parameters:
dest The destination string
src The source string
count The number of characters to copy
Returns:
A pointer to dest
ICU_Stable:
ICU 2.0

U_STABLE UChar* U_EXPORT2 u_memmove UChar *  dest,
const UChar *  src,
int32_t  count
 

Synonym for memmove(), but with UChars only.

Parameters:
dest The destination string
src The source string
count The number of characters to move
Returns:
A pointer to dest
ICU_Stable:
ICU 2.0

U_STABLE UChar* U_EXPORT2 u_memrchr const UChar *  s,
UChar  c,
int32_t  count
 

Find the last occurrence of a BMP code point in a string.

A surrogate code point is found only if its match in the text is not part of a surrogate pair. A NUL character is found at the string terminator.

Parameters:
s The string to search (contains count UChars).
c The BMP code point to find.
count The length of the string.
Returns:
A pointer to the last occurrence of c in s or NULL if c is not in s.
ICU_Stable:
ICU 2.4
See also:
u_strrchr

u_memrchr32

u_strFindLast

U_STABLE UChar* U_EXPORT2 u_memrchr32 const UChar *  s,
UChar32  c,
int32_t  count
 

Find the last occurrence of a code point in a string.

A surrogate code point is found only if its match in the text is not part of a surrogate pair. A NUL character is found at the string terminator.

Parameters:
s The string to search (contains count UChars).
c The code point to find.
count The length of the string.
Returns:
A pointer to the last occurrence of c in s or NULL if c is not in s.
ICU_Stable:
ICU 2.4
See also:
u_strrchr32

u_memrchr

u_strFindLast

U_STABLE UChar* U_EXPORT2 u_memset UChar *  dest,
UChar  c,
int32_t  count
 

Initialize count characters of dest to c.

Parameters:
dest The destination string.
c The character to initialize the string.
count The maximum number of characters to set.
Returns:
A pointer to dest.
ICU_Stable:
ICU 2.0

U_STABLE int32_t U_EXPORT2 u_strcasecmp const UChar *  s1,
const UChar *  s2,
uint32_t  options
 

Compare two strings case-insensitively using full case folding.

This is equivalent to u_strcmp(u_strFoldCase(s1, options), u_strFoldCase(s2, options)).

Parameters:
s1 A string to compare.
s2 A string to compare.
options A bit set of options:
  • U_FOLD_CASE_DEFAULT or 0 is used for default options: Comparison in code unit order with default case folding.
  • U_COMPARE_CODE_POINT_ORDER Set to choose code point order instead of code unit order (see u_strCompare for details).

  • U_FOLD_CASE_EXCLUDE_SPECIAL_I

Returns:
A negative, zero, or positive integer indicating the comparison result.
ICU_Stable:
ICU 2.0

U_STABLE int32_t U_EXPORT2 u_strCaseCompare const UChar *  s1,
int32_t  length1,
const UChar *  s2,
int32_t  length2,
uint32_t  options,
UErrorCode pErrorCode
 

Compare two strings case-insensitively using full case folding.

This is equivalent to u_strCompare(u_strFoldCase(s1, options), u_strFoldCase(s2, options), (options&U_COMPARE_CODE_POINT_ORDER)!=0).

The comparison can be done in UTF-16 code unit order or in code point order. They differ only when comparing supplementary code points (U+10000..U+10ffff) to BMP code points near the end of the BMP (i.e., U+e000..U+ffff). In code unit order, high BMP code points sort after supplementary code points because they are stored as pairs of surrogates which are at U+d800..U+dfff.

This functions works with strings of different explicitly specified lengths unlike the ANSI C-like u_strcmp() and u_memcmp() etc. NUL-terminated strings are possible with length arguments of -1.

Parameters:
s1 First source string.
length1 Length of first source string, or -1 if NUL-terminated.
s2 Second source string.
length2 Length of second source string, or -1 if NUL-terminated.
options A bit set of options:
  • U_FOLD_CASE_DEFAULT or 0 is used for default options: Comparison in code unit order with default case folding.
  • U_COMPARE_CODE_POINT_ORDER Set to choose code point order instead of code unit order (see u_strCompare for details).

  • U_FOLD_CASE_EXCLUDE_SPECIAL_I

Parameters:
pErrorCode Must be a valid pointer to an error code value, which must not indicate a failure before the function call.
Returns:
<0 or 0 or >0 as usual for string comparisons
ICU_Stable:
ICU 2.2

U_STABLE UChar* U_EXPORT2 u_strcat UChar *  dst,
const UChar *  src
 

Concatenate two ustrings.

Appends a copy of src, including the null terminator, to dst. The initial copied character from src overwrites the null terminator in dst.

Parameters:
dst The destination string.
src The source string.
Returns:
A pointer to dst.
ICU_Stable:
ICU 2.0

U_STABLE UChar* U_EXPORT2 u_strchr const UChar *  s,
UChar  c
 

Find the first occurrence of a BMP code point in a string.

A surrogate code point is found only if its match in the text is not part of a surrogate pair. A NUL character is found at the string terminator.

Parameters:
s The string to search (NUL-terminated).
c The BMP code point to find.
Returns:
A pointer to the first occurrence of c in s or NULL if c is not in s.
ICU_Stable:
ICU 2.0
See also:
u_strchr32

u_memchr

u_strstr

u_strFindFirst

U_STABLE UChar* U_EXPORT2 u_strchr32 const UChar *  s,
UChar32  c
 

Find the first occurrence of a code point in a string.

A surrogate code point is found only if its match in the text is not part of a surrogate pair. A NUL character is found at the string terminator.

Parameters:
s The string to search (NUL-terminated).
c The code point to find.
Returns:
A pointer to the first occurrence of c in s or NULL if c is not in s.
ICU_Stable:
ICU 2.0
See also:
u_strchr

u_memchr32

u_strstr

u_strFindFirst

U_STABLE int32_t U_EXPORT2 u_strcmp const UChar *  s1,
const UChar *  s2
 

Compare two Unicode strings for bitwise equality (code unit order).

Parameters:
s1 A string to compare.
s2 A string to compare.
Returns:
0 if s1 and s2 are bitwise equal; a negative value if s1 is bitwise less than s2,; a positive value if s1 is bitwise greater than s2.
ICU_Stable:
ICU 2.0

U_STABLE int32_t U_EXPORT2 u_strcmpCodePointOrder const UChar *  s1,
const UChar *  s2
 

Compare two Unicode strings in code point order.

See u_strCompare for details.

Parameters:
s1 A string to compare.
s2 A string to compare.
Returns:
a negative/zero/positive integer corresponding to whether the first string is less than/equal to/greater than the second one in code point order
ICU_Stable:
ICU 2.0

U_STABLE int32_t U_EXPORT2 u_strCompare const UChar *  s1,
int32_t  length1,
const UChar *  s2,
int32_t  length2,
UBool  codePointOrder
 

Compare two Unicode strings (binary order).

The comparison can be done in code unit order or in code point order. They differ only in UTF-16 when comparing supplementary code points (U+10000..U+10ffff) to BMP code points near the end of the BMP (i.e., U+e000..U+ffff). In code unit order, high BMP code points sort after supplementary code points because they are stored as pairs of surrogates which are at U+d800..U+dfff.

This functions works with strings of different explicitly specified lengths unlike the ANSI C-like u_strcmp() and u_memcmp() etc. NUL-terminated strings are possible with length arguments of -1.

Parameters:
s1 First source string.
length1 Length of first source string, or -1 if NUL-terminated.
s2 Second source string.
length2 Length of second source string, or -1 if NUL-terminated.
codePointOrder Choose between code unit order (FALSE) and code point order (TRUE).
Returns:
<0 or 0 or >0 as usual for string comparisons
ICU_Stable:
ICU 2.2

U_STABLE int32_t U_EXPORT2 u_strCompareIter UCharIterator iter1,
UCharIterator iter2,
UBool  codePointOrder
 

Compare two Unicode strings (binary order) as presented by UCharIterator objects.

Works otherwise just like u_strCompare().

Both iterators are reset to their start positions. When the function returns, it is undefined where the iterators have stopped.

Parameters:
iter1 First source string iterator.
iter2 Second source string iterator.
codePointOrder Choose between code unit order (FALSE) and code point order (TRUE).
Returns:
<0 or 0 or >0 as usual for string comparisons
See also:
u_strCompare
ICU_Stable:
ICU 2.6

U_STABLE UChar* U_EXPORT2 u_strcpy UChar *  dst,
const UChar *  src
 

Copy a ustring.

Adds a null terminator.

Parameters:
dst The destination string.
src The source string.
Returns:
A pointer to dst.
ICU_Stable:
ICU 2.0

U_STABLE int32_t U_EXPORT2 u_strcspn const UChar *  string,
const UChar *  matchSet
 

Returns the number of consecutive characters in string, beginning with the first, that do not occur somewhere in matchSet.

Works just like C's strcspn but with Unicode.

Parameters:
string The string in which to search, NUL-terminated.
matchSet A NUL-terminated string defining a set of code points for which to search in the text string.
Returns:
The number of initial characters in string that do not occur in matchSet.
See also:
u_strspn
ICU_Stable:
ICU 2.0

U_STABLE UChar* U_EXPORT2 u_strFindFirst const UChar *  s,
int32_t  length,
const UChar *  substring,
int32_t  subLength
 

Find the first occurrence of a substring in a string.

The substring is found at code point boundaries. That means that if the substring begins with a trail surrogate or ends with a lead surrogate, then it is found only if these surrogates stand alone in the text. Otherwise, the substring edge units would be matched against halves of surrogate pairs.

Parameters:
s The string to search.
length The length of s (number of UChars), or -1 if it is NUL-terminated.
substring The substring to find (NUL-terminated).
subLength The length of substring (number of UChars), or -1 if it is NUL-terminated.
Returns:
A pointer to the first occurrence of substring in s, or s itself if the substring is empty, or NULL if substring is not in s.
ICU_Stable:
ICU 2.4
See also:
u_strstr

u_strFindLast

U_STABLE UChar* U_EXPORT2 u_strFindLast const UChar *  s,
int32_t  length,
const UChar *  substring,
int32_t  subLength
 

Find the last occurrence of a substring in a string.

The substring is found at code point boundaries. That means that if the substring begins with a trail surrogate or ends with a lead surrogate, then it is found only if these surrogates stand alone in the text. Otherwise, the substring edge units would be matched against halves of surrogate pairs.

Parameters:
s The string to search.
length The length of s (number of UChars), or -1 if it is NUL-terminated.
substring The substring to find (NUL-terminated).
subLength The length of substring (number of UChars), or -1 if it is NUL-terminated.
Returns:
A pointer to the last occurrence of substring in s, or s itself if the substring is empty, or NULL if substring is not in s.
ICU_Stable:
ICU 2.4
See also:
u_strstr

u_strFindLast

U_STABLE int32_t U_EXPORT2 u_strFoldCase UChar *  dest,
int32_t  destCapacity,
const UChar *  src,
int32_t  srcLength,
uint32_t  options,
UErrorCode pErrorCode
 

Case-fold the characters in a string.

Case-folding is locale-independent and not context-sensitive, but there is an option for whether to include or exclude mappings for dotted I and dotless i that are marked with 'I' in CaseFolding.txt. The result may be longer or shorter than the original. The source string and the destination buffer are allowed to overlap.

Parameters:
dest A buffer for the result string. The result will be zero-terminated if the buffer is large enough.
destCapacity The size of the buffer (number of UChars). If it is 0, then dest may be NULL and the function will only return the length of the result without writing any of the result string.
src The original string
srcLength The length of the original string. If -1, then src must be zero-terminated.
options Either U_FOLD_CASE_DEFAULT or U_FOLD_CASE_EXCLUDE_SPECIAL_I
pErrorCode Must be a valid pointer to an error code value, which must not indicate a failure before the function call.
Returns:
The length of the result string. It may be greater than destCapacity. In that case, only some of the result was written to the destination buffer.
ICU_Stable:
ICU 2.0

U_STABLE UChar* U_EXPORT2 u_strFromUTF32 UChar *  dest,
int32_t  destCapacity,
int32_t *  pDestLength,
const UChar32 src,
int32_t  srcLength,
UErrorCode pErrorCode
 

Converts a sequence of UTF32 units to UChars (UTF-16).

Parameters:
dest A buffer for the result string. The result will be zero-terminated if the buffer is large enough.
destCapacity The size of the buffer (number of UChars). If it is 0, then dest may be NULL and the function will only return the length of the result without writing any of the result string (pre-flighting).
pDestLength A pointer to receive the number of units written to the destination. If pDestLength!=NULL then *pDestLength is always set to the number of output units corresponding to the transformation of all the input units, even in case of a buffer overflow.
src The original source string
srcLength The length of the original string. If -1, then src must be zero-terminated.
pErrorCode Must be a valid pointer to an error code value, which must not indicate a failure before the function call.
Returns:
The pointer to destination buffer.
ICU_Stable:
ICU 2.0

U_STABLE UChar* U_EXPORT2 u_strFromUTF8 UChar *  dest,
int32_t  destCapacity,
int32_t *  pDestLength,
const char *  src,
int32_t  srcLength,
UErrorCode pErrorCode
 

Converts a sequence of UTF-8 bytes to UChars (UTF-16).

Parameters:
dest A buffer for the result string. The result will be zero-terminated if the buffer is large enough.
destCapacity The size of the buffer (number of UChars). If it is 0, then dest may be NULL and the function will only return the length of the result without writing any of the result string (pre-flighting).
pDestLength A pointer to receive the number of units written to the destination. If pDestLength!=NULL then *pDestLength is always set to the number of output units corresponding to the transformation of all the input units, even in case of a buffer overflow.
src The original source string
srcLength The length of the original string. If -1, then src must be zero-terminated.
pErrorCode Must be a valid pointer to an error code value, which must not indicate a failure before the function call.
Returns:
The pointer to destination buffer.
ICU_Stable:
ICU 2.0

U_STABLE UChar* U_EXPORT2 u_strFromWCS UChar *  dest,
int32_t  destCapacity,
int32_t *  pDestLength,
const wchar_t *  src,
int32_t  srcLength,
UErrorCode pErrorCode
 

Converts a sequence of wchar_t units to UChars.

Parameters:
dest A buffer for the result string. The result will be zero-terminated if the buffer is large enough.
destCapacity The size of the buffer (number of UChars). If it is 0, then dest may be NULL and the function will only return the length of the result without writing any of the result string (pre-flighting).
pDestLength A pointer to receive the number of units written to the destination. If pDestLength!=NULL then *pDestLength is always set to the number of output units corresponding to the transformation of all the input units, even in case of a buffer overflow.
src The original source string
srcLength The length of the original string. If -1, then src must be zero-terminated.
pErrorCode Must be a valid pointer to an error code value, which must not indicate a failure before the function call.
Returns:
The pointer to destination buffer.
ICU_Stable:
ICU 2.0

U_STABLE UBool U_EXPORT2 u_strHasMoreChar32Than const UChar *  s,
int32_t  length,
int32_t  number
 

Check if the string contains more Unicode code points than a certain number.

This is more efficient than counting all code points in the entire string and comparing that number with a threshold. This function may not need to scan the string at all if the length is known (not -1 for NUL-termination) and falls within a certain range, and never needs to count more than 'number+1' code points. Logically equivalent to (u_countChar32(s, length)>number). A Unicode code point may occupy either one or two UChar code units.

Parameters:
s The input string.
length The length of the string, or -1 if it is NUL-terminated.
number The number of code points in the string is compared against the 'number' parameter.
Returns:
Boolean value for whether the string contains more Unicode code points than 'number'. Same as (u_countChar32(s, length)>number).
ICU_Stable:
ICU 2.4

U_STABLE int32_t U_EXPORT2 u_strlen const UChar *  s  ) 
 

Determine the length of an array of UChar.

Parameters:
s The array of UChars, NULL (U+0000) terminated.
Returns:
The number of UChars in chars, minus the terminator.
ICU_Stable:
ICU 2.0

Referenced by UnicodeString::indexOf().

U_STABLE int32_t U_EXPORT2 u_strncasecmp const UChar *  s1,
const UChar *  s2,
int32_t  n,
uint32_t  options
 

Compare two strings case-insensitively using full case folding.

This is equivalent to u_strcmp(u_strFoldCase(s1, at most n, options), u_strFoldCase(s2, at most n, options)).

Parameters:
s1 A string to compare.
s2 A string to compare.
n The maximum number of characters each string to case-fold and then compare.
options A bit set of options:
  • U_FOLD_CASE_DEFAULT or 0 is used for default options: Comparison in code unit order with default case folding.
  • U_COMPARE_CODE_POINT_ORDER Set to choose code point order instead of code unit order (see u_strCompare for details).

  • U_FOLD_CASE_EXCLUDE_SPECIAL_I

Returns:
A negative, zero, or positive integer indicating the comparison result.
ICU_Stable:
ICU 2.0

U_STABLE UChar* U_EXPORT2 u_strncat UChar *  dst,
const UChar *  src,
int32_t  n
 

Concatenate two ustrings.

Appends at most n characters from src to dst. Adds a terminating NUL. If src is too long, then only n-1 characters will be copied before the terminating NUL. If n<=0 then dst is not modified.

Parameters:
dst The destination string.
src The source string.
n The maximum number of characters to compare.
Returns:
A pointer to dst.
ICU_Stable:
ICU 2.0

U_STABLE int32_t U_EXPORT2 u_strncmp const UChar *  ucs1,
const UChar *  ucs2,
int32_t  n
 

Compare two ustrings for bitwise equality.

Compares at most n characters.

Parameters:
ucs1 A string to compare.
ucs2 A string to compare.
n The maximum number of characters to compare.
Returns:
0 if s1 and s2 are bitwise equal; a negative value if s1 is bitwise less than s2; a positive value if s1 is bitwise greater than s2.
ICU_Stable:
ICU 2.0

U_STABLE int32_t U_EXPORT2 u_strncmpCodePointOrder const UChar *  s1,
const UChar *  s2,
int32_t  n
 

Compare two Unicode strings in code point order.

This is different in UTF-16 from u_strncmp() if supplementary characters are present. For details, see u_strCompare().

Parameters:
s1 A string to compare.
s2 A string to compare.
n The maximum number of characters to compare.
Returns:
a negative/zero/positive integer corresponding to whether the first string is less than/equal to/greater than the second one in code point order
ICU_Stable:
ICU 2.0

U_STABLE UChar* U_EXPORT2 u_strncpy UChar *  dst,
const UChar *  src,
int32_t  n
 

Copy a ustring.

Copies at most n characters. The result will be null terminated if the length of src is less than n.

Parameters:
dst The destination string.
src The source string.
n The maximum number of characters to copy.
Returns:
A pointer to dst.
ICU_Stable:
ICU 2.0

U_STABLE UChar* U_EXPORT2 u_strpbrk const UChar *  string,
const UChar *  matchSet
 

Locates the first occurrence in the string string of any of the characters in the string matchSet.

Works just like C's strpbrk but with Unicode.

Parameters:
string The string in which to search, NUL-terminated.
matchSet A NUL-terminated string defining a set of code points for which to search in the text string.
Returns:
A pointer to the character in string that matches one of the characters in matchSet, or NULL if no such character is found.
ICU_Stable:
ICU 2.0

U_STABLE UChar* U_EXPORT2 u_strrchr const UChar *  s,
UChar  c
 

Find the last occurrence of a BMP code point in a string.

A surrogate code point is found only if its match in the text is not part of a surrogate pair. A NUL character is found at the string terminator.

Parameters:
s The string to search (NUL-terminated).
c The BMP code point to find.
Returns:
A pointer to the last occurrence of c in s or NULL if c is not in s.
ICU_Stable:
ICU 2.4
See also:
u_strrchr32

u_memrchr

u_strrstr

u_strFindLast

U_STABLE UChar* U_EXPORT2 u_strrchr32 const UChar *  s,
UChar32  c
 

Find the last occurrence of a code point in a string.

A surrogate code point is found only if its match in the text is not part of a surrogate pair. A NUL character is found at the string terminator.

Parameters:
s The string to search (NUL-terminated).
c The code point to find.
Returns:
A pointer to the last occurrence of c in s or NULL if c is not in s.
ICU_Stable:
ICU 2.4
See also:
u_strrchr

u_memchr32

u_strrstr

u_strFindLast

U_STABLE UChar* U_EXPORT2 u_strrstr const UChar *  s,
const UChar *  substring
 

Find the last occurrence of a substring in a string.

The substring is found at code point boundaries. That means that if the substring begins with a trail surrogate or ends with a lead surrogate, then it is found only if these surrogates stand alone in the text. Otherwise, the substring edge units would be matched against halves of surrogate pairs.

Parameters:
s The string to search (NUL-terminated).
substring The substring to find (NUL-terminated).
Returns:
A pointer to the last occurrence of substring in s, or s itself if the substring is empty, or NULL if substring is not in s.
ICU_Stable:
ICU 2.4
See also:
u_strstr

u_strFindFirst

u_strFindLast

U_STABLE int32_t U_EXPORT2 u_strspn const UChar *  string,
const UChar *  matchSet
 

Returns the number of consecutive characters in string, beginning with the first, that occur somewhere in matchSet.

Works just like C's strspn but with Unicode.

Parameters:
string The string in which to search, NUL-terminated.
matchSet A NUL-terminated string defining a set of code points for which to search in the text string.
Returns:
The number of initial characters in string that do occur in matchSet.
See also:
u_strcspn
ICU_Stable:
ICU 2.0

U_STABLE UChar* U_EXPORT2 u_strstr const UChar *  s,
const UChar *  substring
 

Find the first occurrence of a substring in a string.

The substring is found at code point boundaries. That means that if the substring begins with a trail surrogate or ends with a lead surrogate, then it is found only if these surrogates stand alone in the text. Otherwise, the substring edge units would be matched against halves of surrogate pairs.

Parameters:
s The string to search (NUL-terminated).
substring The substring to find (NUL-terminated).
Returns:
A pointer to the first occurrence of substring in s, or s itself if the substring is empty, or NULL if substring is not in s.
ICU_Stable:
ICU 2.0
See also:
u_strrstr

u_strFindFirst

u_strFindLast

U_STABLE UChar* U_EXPORT2 u_strtok_r UChar *  src,
const UChar *  delim,
UChar **  saveState
 

The string tokenizer API allows an application to break a string into tokens.

Unlike strtok(), the saveState (the current pointer within the original string) is maintained in saveState. In the first call, the argument src is a pointer to the string. In subsequent calls to return successive tokens of that string, src must be specified as NULL. The value saveState is set by this function to maintain the function's position within the string, and on each subsequent call you must give this argument the same variable. This function does handle surrogate pairs. This function is similar to the strtok_r() the POSIX Threads Extension (1003.1c-1995) version.

Parameters:
src String containing token(s). This string will be modified. After the first call to u_strtok_r(), this argument must be NULL to get to the next token.
delim Set of delimiter characters (Unicode code points).
saveState The current pointer within the original string, which is set by this function. The saveState parameter should the address of a local variable of type UChar *. (i.e. defined "Uhar *myLocalSaveState" and use &myLocalSaveState for this parameter).
Returns:
A pointer to the next token found in src, or NULL when there are no more tokens.
ICU_Stable:
ICU 2.0

U_STABLE int32_t U_EXPORT2 u_strToLower UChar *  dest,
int32_t  destCapacity,
const UChar *  src,
int32_t  srcLength,
const char *  locale,
UErrorCode pErrorCode
 

Lowercase the characters in a string.

Casing is locale-dependent and context-sensitive. The result may be longer or shorter than the original. The source string and the destination buffer are allowed to overlap.

Parameters:
dest A buffer for the result string. The result will be zero-terminated if the buffer is large enough.
destCapacity The size of the buffer (number of UChars). If it is 0, then dest may be NULL and the function will only return the length of the result without writing any of the result string.
src The original string
srcLength The length of the original string. If -1, then src must be zero-terminated.
locale The locale to consider, or "" for the root locale or NULL for the default locale.
pErrorCode Must be a valid pointer to an error code value, which must not indicate a failure before the function call.
Returns:
The length of the result string. It may be greater than destCapacity. In that case, only some of the result was written to the destination buffer.
ICU_Stable:
ICU 2.0

U_STABLE int32_t U_EXPORT2 u_strToTitle UChar *  dest,
int32_t  destCapacity,
const UChar *  src,
int32_t  srcLength,
UBreakIterator titleIter,
const char *  locale,
UErrorCode pErrorCode
 

Titlecase a string.

Casing is locale-dependent and context-sensitive. Titlecasing uses a break iterator to find the first characters of words that are to be titlecased. It titlecases those characters and lowercases all others.

The titlecase break iterator can be provided to customize for arbitrary styles, using rules and dictionaries beyond the standard iterators. It may be more efficient to always provide an iterator to avoid opening and closing one for each string. The standard titlecase iterator for the root locale implements the algorithm of Unicode TR 21.

This function uses only the first() and next() methods of the provided break iterator.

The result may be longer or shorter than the original. The source string and the destination buffer are allowed to overlap.

Parameters:
dest A buffer for the result string. The result will be zero-terminated if the buffer is large enough.
destCapacity The size of the buffer (number of UChars). If it is 0, then dest may be NULL and the function will only return the length of the result without writing any of the result string.
src The original string
srcLength The length of the original string. If -1, then src must be zero-terminated.
titleIter A break iterator to find the first characters of words that are to be titlecased. If none is provided (NULL), then a standard titlecase break iterator is opened.
locale The locale to consider, or "" for the root locale or NULL for the default locale.
pErrorCode Must be a valid pointer to an error code value, which must not indicate a failure before the function call.
Returns:
The length of the result string. It may be greater than destCapacity. In that case, only some of the result was written to the destination buffer.
ICU_Stable:
ICU 2.1

U_STABLE int32_t U_EXPORT2 u_strToUpper UChar *  dest,
int32_t  destCapacity,
const UChar *  src,
int32_t  srcLength,
const char *  locale,
UErrorCode pErrorCode
 

Uppercase the characters in a string.

Casing is locale-dependent and context-sensitive. The result may be longer or shorter than the original. The source string and the destination buffer are allowed to overlap.

Parameters:
dest A buffer for the result string. The result will be zero-terminated if the buffer is large enough.
destCapacity The size of the buffer (number of UChars). If it is 0, then dest may be NULL and the function will only return the length of the result without writing any of the result string.
src The original string
srcLength The length of the original string. If -1, then src must be zero-terminated.
locale The locale to consider, or "" for the root locale or NULL for the default locale.
pErrorCode Must be a valid pointer to an error code value, which must not indicate a failure before the function call.
Returns:
The length of the result string. It may be greater than destCapacity. In that case, only some of the result was written to the destination buffer.
ICU_Stable:
ICU 2.0

U_STABLE UChar32* U_EXPORT2 u_strToUTF32 UChar32 dest,
int32_t  destCapacity,
int32_t *  pDestLength,
const UChar *  src,
int32_t  srcLength,
UErrorCode pErrorCode
 

Converts a sequence of UChars (UTF-16) to UTF32 units.

Parameters:
dest A buffer for the result string. The result will be zero-terminated if the buffer is large enough.
destCapacity The size of the buffer (number of UChar32s). If it is 0, then dest may be NULL and the function will only return the length of the result without writing any of the result string (pre-flighting).
pDestLength A pointer to receive the number of units written to the destination. If pDestLength!=NULL then *pDestLength is always set to the number of output units corresponding to the transformation of all the input units, even in case of a buffer overflow.
src The original source string
srcLength The length of the original string. If -1, then src must be zero-terminated.
pErrorCode Must be a valid pointer to an error code value, which must not indicate a failure before the function call.
Returns:
The pointer to destination buffer.
ICU_Stable:
ICU 2.0

U_STABLE char* U_EXPORT2 u_strToUTF8 char *  dest,
int32_t  destCapacity,
int32_t *  pDestLength,
const UChar *  src,
int32_t  srcLength,
UErrorCode pErrorCode
 

Converts a sequence of UChars (UTF-16) to UTF-8 bytes.

Parameters:
dest A buffer for the result string. The result will be zero-terminated if the buffer is large enough.
destCapacity The size of the buffer (number of chars). If it is 0, then dest may be NULL and the function will only return the length of the result without writing any of the result string (pre-flighting).
pDestLength A pointer to receive the number of units written to the destination. If pDestLength!=NULL then *pDestLength is always set to the number of output units corresponding to the transformation of all the input units, even in case of a buffer overflow.
src The original source string
srcLength The length of the original string. If -1, then src must be zero-terminated.
pErrorCode Must be a valid pointer to an error code value, which must not indicate a failure before the function call.
Returns:
The pointer to destination buffer.
ICU_Stable:
ICU 2.0

U_STABLE wchar_t* U_EXPORT2 u_strToWCS wchar_t *  dest,
int32_t  destCapacity,
int32_t *  pDestLength,
const UChar *  src,
int32_t  srcLength,
UErrorCode pErrorCode
 

Converts a sequence of UChars to wchar_t units.

Parameters:
dest A buffer for the result string. The result will be zero-terminated if the buffer is large enough.
destCapacity The size of the buffer (number of wchar_t's). If it is 0, then dest may be NULL and the function will only return the length of the result without writing any of the result string (pre-flighting).
pDestLength A pointer to receive the number of units written to the destination. If pDestLength!=NULL then *pDestLength is always set to the number of output units corresponding to the transformation of all the input units, even in case of a buffer overflow.
src The original source string
srcLength The length of the original string. If -1, then src must be zero-terminated.
pErrorCode Must be a valid pointer to an error code value, which must not indicate a failure before the function call.
Returns:
The pointer to destination buffer.
ICU_Stable:
ICU 2.0

U_STABLE UChar* U_EXPORT2 u_uastrcpy UChar *  dst,
const char *  src
 

Copy a byte string encoded in the default codepage to a ustring.

Adds a null terminator. Performs a host byte to UChar conversion

Parameters:
dst The destination string.
src The source string.
Returns:
A pointer to dst.
ICU_Stable:
ICU 2.0

U_STABLE UChar* U_EXPORT2 u_uastrncpy UChar *  dst,
const char *  src,
int32_t  n
 

Copy a byte string encoded in the default codepage to a ustring.

Copies at most n characters. The result will be null terminated if the length of src is less than n. Performs a host byte to UChar conversion

Parameters:
dst The destination string.
src The source string.
n The maximum number of characters to copy.
Returns:
A pointer to dst.
ICU_Stable:
ICU 2.0

U_STABLE int32_t U_EXPORT2 u_unescape const char *  src,
UChar *  dest,
int32_t  destCapacity
 

Unescape a string of characters and write the resulting Unicode characters to the destination buffer.

The following escape sequences are recognized:

\uhhhh 4 hex digits; h in [0-9A-Fa-f] \Uhhhhhhhh 8 hex digits \xhh 1-2 hex digits \x{h...} 1-8 hex digits \ooo 1-3 octal digits; o in [0-7] \cX control-X; X is masked with 0x1F

as well as the standard ANSI C escapes:

\a => U+0007, \b => U+0008, \t => U+0009, \n => U+000A, \v => U+000B, \f => U+000C, \r => U+000D, \e => U+001B, \" => U+0022, \' => U+0027, \? => U+003F, \\ => U+005C

Anything else following a backslash is generically escaped. For example, "[a\\-z]" returns "[a-z]".

If an escape sequence is ill-formed, this method returns an empty string. An example of an ill-formed sequence is "\\u" followed by fewer than 4 hex digits.

The above characters are recognized in the compiler's codepage, that is, they are coded as 'u', '\', etc. Characters that are not parts of escape sequences are converted using u_charsToUChars().

This function is similar to UnicodeString::unescape() but not identical to it. The latter takes a source UnicodeString, so it does escape recognition but no conversion.

Parameters:
src a zero-terminated string of invariant characters
dest pointer to buffer to receive converted and unescaped text and, if there is room, a zero terminator. May be NULL for preflighting, in which case no UChars will be written, but the return value will still be valid. On error, an empty string is stored here (if possible).
destCapacity the number of UChars that may be written at dest. Ignored if dest == NULL.
Returns:
the length of unescaped string.
See also:
u_unescapeAt

UnicodeString::unescape()

UnicodeString::unescapeAt()

ICU_Stable:
ICU 2.0

U_CDECL_END U_STABLE UChar32 U_EXPORT2 u_unescapeAt UNESCAPE_CHAR_AT  charAt,
int32_t *  offset,
int32_t  length,
void *  context
 

Unescape a single sequence.

The character at offset-1 is assumed (without checking) to be a backslash. This method takes a callback pointer to a function that returns the UChar at a given offset. By varying this callback, ICU functions are able to unescape char* strings, UnicodeString objects, and UFILE pointers.

If offset is out of range, or if the escape sequence is ill-formed, (UChar32)0xFFFFFFFF is returned. See documentation of u_unescape() for a list of recognized sequences.

Parameters:
charAt callback function that returns a UChar of the source text given an offset and a context pointer.
offset pointer to the offset that will be passed to charAt. The offset value will be updated upon return to point after the last parsed character of the escape sequence. On error the offset is unchanged.
length the number of characters in the source text. The last character of the source text is considered to be at offset length-1.
context an opaque pointer passed directly into charAt.
Returns:
the character represented by the escape sequence at offset, or (UChar32)0xFFFFFFFF on error.
See also:
u_unescape()

UnicodeString::unescape()

UnicodeString::unescapeAt()

ICU_Stable:
ICU 2.0

U_CDECL_BEGIN typedef UChar U_CALLCONV *  UNESCAPE_CHAR_AT  ) 
 

Callback function for u_unescapeAt() that returns a character of the source text given an offset and a context pointer.

The context pointer will be whatever is passed into u_unescapeAt().

Parameters:
offset pointer to the offset that will be passed to u_unescapeAt().
context an opaque pointer passed directly into u_unescapeAt()
Returns:
the character represented by the escape sequence at offset
See also:
u_unescapeAt
ICU_Stable:
ICU 2.0


Generated on Tue Nov 16 10:03:13 2004 for ICU 3.2 by  doxygen 1.3.9.1