openoffice osl模块学习1

由“ can i get a char* ,
please?"看起：

Just barely. OO.o has at least six string wrappers, although the C
implementations are of little interest:

• rtl_String — sal/inc/rtl/string.h
  "Normal" string plus
  reference
  counting. rtlstring->buffer is useful,
  as is rtlstring->length. This object
  encapsulates an generic 8bit string - of unknown encoding. Feel free to
  treat rtlstring->buffer as your
  beloved char *. If you really want to look at the
  implementation of some rtl_String function and lxr nor
  grep can help you, have a look at sal/rtl/source/strtmpl.c.



• OString — sal/inc/rtl/string.hxx
  Simply a rtl_String
  wrapped inside a class; you can
  use ostring.pData to get at the rtl_String (it‘s
  public). OString has reasonably useful methods for if
  you need them.


• rtl_uString — sal/inc/rtl/ustring.h
  "Normal" Unicode
  string, similar to rtl_String, and refcounted as well. However, this one
  always comes in UCS-2 encoding, presumably to be compatible with Java‘s
  questionable choices. See rtl_String above to find
  where the implementation of some rtl_uStringfunctions is
  hidden.


• OUString — sal/inc/rtl/ustring.hxx
  An rtl_uString
  wrapped inside a class. This is what most of the OO.o code
  uses to pass strings around. To convert an OString to
  an OUString it is necessary to specify the character
  set of
  the OString see; sal/inc/rtl/textenc.h —
  the only interesting case is RTL_TEXTENCODING_UTF8


• String — tools/inc/string.hxx
  This is an obsolete
  string class, aliased to ‘UniString‘. It has a number of limitations such as a
  64k length limit. You can have the buffer with GetBuffer(),
  but it‘s Utf-16 encoded.

A couple of conversion functions are really useful here,
particularly:
rtl::OString aOString = ::rtl::OUStringToOString
(aOUString, RTL_TEXTENCODING_UTF8); 
And the
reverse:
rtl::OUString aOUString = ::rtl::OStringToOUString
(aOString, RTL_TEXTENCODING_UTF8);

If you just want to programattically print out a string for debugging
purposes you probably want define a macro like :
#define
CHAR_POINTER(THE_OUSTRING) ::rtl::OUStringToOString (THE_OUSTRING,
RTL_TEXTENCODING_UTF8).pData->buffer 
and use it
like :
printf ( "SvXMLNamespaceMap::AddIfKnown : %s
/ %s\n", CHAR_POINTER(rPrefix), CHAR_POINTER(rName) );. 
For
the obsolete String class, aliased UniString, it‘s like :
printf (
"rGrfName : %s\n", ByteString( rGrfName,
RTL_TEXTENCODING_UTF8).GetBuffer() );

To print the value of rtl::OUString directly in the debugger, you can
use dbg_dump(). It is intended to be called interactively from
the debugger, in both debug and non-debug builds of OOo. You can see the
definition in sal/rtl/source/debugprint.cxx.

Some code snippets about manipulating those objects can be found on the
codesnippets service page : [1]

原文链接：https://wiki.openoffice.org/wiki/Hacking#Can_I_get_a_char_.2A.2C_please.3F

继续看sal模块源码，摘录：

/********************************************************************************/
/*
Data types
*/

/* Boolean */
typedef unsigned char sal_Bool;
#
define sal_False ((sal_Bool)0)
# define sal_True
((sal_Bool)1)

/* char is assumed to
always be 1 byte long */
typedef signed char
sal_Int8;
typedef unsigned char sal_uInt8;

#if
SAL_TYPES_SIZEOFSHORT == 2
typedef signed short sal_Int16;
typedef
unsigned shortsal_uInt16;//2字节
#else
#error "Could
not find 16-bit type, add support for your
architecture"
#endif

typedef charsal_Char;//1字节

#if ( defined(SAL_W32) &&
!defined(__MINGW32__) )
typedef wchar_tsal_Unicode;
#else
#define
SAL_UNICODE_NOTEQUAL_WCHAR_T
typedef sal_uInt16
sal_Unicode;//2字节
#endif

“Normal”string,
8-bit string, unknown encoding 字符串操作c函数

/** The implementation of a byte
string.

@internal
*/
typedef struct _rtl_String
{

oslInterlockedCount refCount; /* opaque */
sal_Int32
length;
sal_Char
buffer[1];
} rtl_String;//1字节，8bit
string

rtlstring
wrapped inside a class openoffice的字符串类OString

class OString
{
public:

/** @internal */
rtl_String * pData;

usc-2
encoding 一组对unicode字符串操作的c函数

/** The implementation of a
Unicode string.

@internal
*/
typedef struct
_rtl_uString
{
oslInterlockedCount refCount; /* opaque */

sal_Int32 length;
sal_Unicode buffer[1];
} rtl_uString;

void SAL_CALL rtl_string2UString(
rtl_uString ** newStr, const sal_Char * str, sal_Int32 len, rtl_TextEncoding
encoding, sal_uInt32 convertFlags ) SAL_THROW_EXTERN_C();

rtl_ustring
wrapped in a class openoffice的OUString类，封装rtl_ustring的c++类

#include
<rtl/ustring.h> //rtl_uString

#include
<rtl/string.hxx>// OString

class
OUString
{
public:
/** @internal */
rtl_uString *
pData;

OUString(
const sal_Char * value, sal_Int32 length,

rtl_TextEncoding encoding,

sal_uInt32
convertFlags = OSTRING_TO_OUSTRING_CVTFLAGS )

{

pData =
0;

rtl_string2UString( &pData, value,
length, encoding, convertFlags );

#if defined
EXCEPTIONS_OFF

OSL_ASSERT(pData != NULL);

#else

if (pData
== 0) {

throw
std::bad_alloc();

}

#endif

}

inline
OUString OStringToOUString( const OString & rStr,

rtl_TextEncoding encoding,

sal_uInt32
convertFlags = OSTRING_TO_OUSTRING_CVTFLAGS )

{

return
OUString( rStr.getStr(), rStr.getLength(), encoding, convertFlags );

}

inline
OString OUStringToOString( const OUString & rUnicode,

rtl_TextEncoding encoding,

sal_uInt32 convertFlags = OUSTRING_TO_OSTRING_CVTFLAGS
)

{

return
OString( rUnicode.getStr(), rUnicode.getLength(), encoding, convertFlags
);

}

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