NAME

_XConvertCTToMB − conversion from CT string to multibyte string

SYNOPSIS

int _XConvertCTToMB(xlocale, ct_str, ct_bytes, mb_str, mb_bytes,
scanned_bytes, state)
XLocale xlocale;
unsigned char *ct_str;
int ct_bytes;
unsigned char *mb_str;
int *mb_bytes;
int *scanned_bytes;
_State *state;

ARGUMENTS

xlocaleIn: specifies locale, the default NULL is the current locale. 

ct_strIn: multibyte string. 

mb_bytesIn: length of mb strings, counted in bytes. 

ct_strOut: conversion buffer of result CT string. 

ct_bytesIn/Out: as "In" it is length of buffer ct_str passed by caller; as "Out" it is the returned number of converted CT string, counted in bytes. 

scanned_bytes
Number of mb bytes converted when the function returns.

stateIn/Out: as "In" it is the state at the beginning of the CT string; as "Out" it is the current state stopped at last converted CT encoding.  The state is defined internally by Xlib.  If this pointer is null, the function will assume the state to be the default CT state. Of course, nothing will be put in the null pointer. Do not modify or free this data which is owned by the Xlib. 

DESCRIPTION

The _XConvertCTToMB converts the string encoded in CT to string encoded in the specified xlocale.  After a successful conversion, the null character ’\0’ will be appended to mb_str if there is more room for it in the buffer.  The null character of mb string is not counted in length of output buffer mb_bytes. 

The returned state will point to a state of the encoding in the internal table, so do not modify or free this pointer. 

When function returns at any time, scanned_bytes always remembers where stopped, and state always remembers the current CT state if it is not null pointer. 

The caller of this function has to provide the output buffer mb_str, and store the buffer length into mb_bytes as input.  By using scanned_bytes and state, the caller can break a large CT string into pieces, and convert one piece at a time. 

In other hand caller can pass any broken CT string to this function for doing conversion.  For example, caller can still be trying of conversion when the error BadBuffer is occurred(output buffer was exhausted).  Usually, the application passes the NULL to state for first conversion as following:

char *state = NULL;
_XConvertCTToMB(NULL, ct_str, ct_len, mb_str,
            &mb_len, &scanned, &state)

If the value of state is invalid or null-pointer, the function will suppose the default state of CT as initial.  The default state of CT is defined in 3 cases of encoding:

1. no control sequence, GL and GR of Latin-1 is supposed. 

2. control sequence of Latin-1 GL only, GR of Latin-1 is supposed too. 

3. control sequence of Latin-1 GR only, GL of Latin-1 is supposed too. 

The function returns the BadBuffer meaning that the output buffer mb_str was exhausted.  The function returns the BadTerminate meaning that the CT string ct_str is terminated uncompletely, e.g., uncompleted ESC sequence or uncompleted code point ended at tail of ct_str. 

Only in both the case of BadBuffer and BadTerminate the caller can move pointer ct_str to (ct_str + *scanned_bytes), then continue to do conversion.  And function ensure that the mb_str stores the already converted mb string; mb_bytes counts the number of them in bytes; the state stores the last state of encoding. 

The function returns a number greater than zero meaning a number of wrong codepoints recovered by the function.  The wrong codepoint will be recovered with the first codepoint of the charset at which the wrong codepoint occurs.  After replaced, the function will continue to do conversion untill one of the results Success, BadTerminate, BadBuffer or BadEncoding is met. 

The function returns BadEncoding meaning for unrecoverable wrong code which is wrong escape sequence, or not registered by system yet. 

Both the null character and ct_bytes will terminate the conversion. 

All error status are defined to be less than zero, i.e.:

#define Success          0

#define BadBuffer       -1

#define BadTerminate    -2

#define BadEncoding     -3

RETURNED VALUE

The _XConvertCTToMB will return the following values:

Success
successful conversion.

BadBuffer
output buffer(mb_str) was exhausted.

BadTerminate
CT string was terminated uncompletely.

BadEncoding
wrong codepoints can not be recovered.

> 0 number of wrong codepoints, but recovered. 

SEE ALSO

Refer to "CT and WC" for their definitions.