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fold_string_w

Section: C Library Functions (3)
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NAME

fold_string_w - Maps one wide-character string to another, performing the specified Unicode character transformation  

LIBRARY

UCS4 Library (libucs4.a, libucs4.so)  

SYNOPSIS

#include <ucs4.h>

int fold_string_w(
        unsigned long map_flags,
        const wchar_t *src_wcs,
        int src_cnt,
        wchar_t *dest_wcs,
        int dest_cnt );  

PARAMETERS

Specifies one or more of the following flags: Folds compatibility zone characters into standard Unicode equivalents. For information on compatibility zone characters, see the DESCRIPTION section. Maps all digits to Unicode ASCII 0 to 9. Maps accented characters to precomposed characters. In this transformation, the multiple accent and base character values are combined into a single character value. The MAP_PRECOMPOSED flag cannot be combined with the MAP_COMPOSITE flag.
Maps accented characters to composite characters. In this transformation, the single value for an accented character is decomposed into multiple values for the base and accented characters. The MAP_COMPOSITE flag cannot be combined with the MAP_PRECOMPOSED flag. Points to a source buffer containing the wide-character string whose characters are to be transformed. Specifies the size (in number of wide characters) of the source buffer. If the wide-character string in the source buffer is null-terminated, applications can specify -1 as the src_cnt value and the function calculates the length of the string automatically. Points to a destination buffer to store the transformed wide-character string. Specifies the size (in number of wide characters) of the destination buffer.  

DESCRIPTION

The fold_string_w() function maps one wide-character string to another and performs the specified Unicode character transformation. The function then stores the transformed wide-character string in the destination buffer and returns the number of wide characters stored. The supported operations include the following: Transform separate values for accent and base characters into a single value for an accented character Transform a single value for an accented character into separate values for accent and base characters Transform all digit values to Unicode ASCII 0 to 9. for digits Transform all compatibility zone characters into standard Unicode equivalents

The compatibility zone in Unicode consists of characters that are in the range 0xF900 to 0xFFEF (values assigned to characters from other encoding standards) but are variants of characters that already exist in Unicode. The compatibility zone is used to support round-trip mapping of characters to and from these standards. Applications use the MAP_FOLDZONE flag to avoid supporting compatibility zone characters that are duplicates of those in Unicode.

The src_cnt value determines when the function stops processing characters. If src_cnt is -1, then character processing stops when a null is encountered. In this case, the null terminator is included in the destination string and also included in the return count. Otherwise, nulls are treated as other characters and may be embedded in the source string. In this case, the return count and destination string may or may not include a null.

The fold_string_w() function fails if dest_wcs is too small to contain the transformed string. The application can avoid this failure in one of the following ways: Allocate a buffer size large enough to store transformed strings resulting from any call to fold_string_w() Call fold_string_w() twice for each string transformation, once to calculate the length of the destination string and again to store the transformed string

If an application calls fold_string_w() with dest_cnt set to 0 (zero), the function calculates and returns the number of characters required for dest_wcs but does not store the transformation results in dest_wcs. The application can then specify the return value from the first call as the value for dest_wcs on a second call, on which the transformation results are stored.

The src_wcs and dest_wcs parameters cannot point to the same location. If they do, the function fails and sets errno to EINVAL.  

RETURN VALUES

On success, the fold_string_w() function returns the number of characters written to the destination wide-character string. On failure, the function returns 0 (zero) and sets errno to indicate the reason for failure.  

ERRORS

The fold_string_w() function sets errno to the following values for the specified conditions: Insufficient memory is available for the specified operations. A possible cause of this condition is a src_cnt value of -1 when the source string is not null terminated. A parameter value is invalid; for example, the source and destination strings point to the same location. This error can also occur if both the MAP_PRECOMPOSED and MAP_COMPOSITE flags are specified on the same call. The destination buffer is not large enough to store the transformed wide-character string. delim off


 

Index

NAME
LIBRARY
SYNOPSIS
PARAMETERS
DESCRIPTION
RETURN VALUES
ERRORS

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Time: 02:42:16 GMT, October 02, 2010