#pragma hdrstop
#endif
-#if wxUSE_WCHAR_T
-
-#ifndef WX_PRECOMP
-#endif //WX_PRECOMP
-
#include "wx/convauto.h"
// we use latin1 by default as it seems the least bad choice: the files we need
/* static */
wxConvAuto::BOMType wxConvAuto::DetectBOM(const char *src, size_t srcLen)
{
- if ( srcLen < 2 )
- {
- // minimal BOM is 2 bytes so bail out immediately and simplify the code
- // below which wouldn't need to check for length for UTF-16 cases
- return BOM_None;
- }
-
// examine the buffer for BOM presence
//
- // see http://www.unicode.org/faq/utf_bom.html#BOM
- switch ( *src++ )
+ // quoting from http://www.unicode.org/faq/utf_bom.html#BOM:
+ //
+ // Bytes Encoding Form
+ //
+ // 00 00 FE FF UTF-32, big-endian
+ // FF FE 00 00 UTF-32, little-endian
+ // FE FF UTF-16, big-endian
+ // FF FE UTF-16, little-endian
+ // EF BB BF UTF-8
+ //
+ // as some BOMs are prefixes of other ones we may need to read more bytes
+ // to disambiguate them
+
+ switch ( srcLen )
{
- case '\0':
- // could only be big endian UTF-32 (00 00 FE FF)
- if ( srcLen >= 4 &&
- src[0] == '\0' &&
- src[1] == '\xfe' &&
- src[2] == '\xff' )
+ case 0:
+ return BOM_Unknown;
+
+ case 1:
+ if ( src[0] == '\x00' || src[0] == '\xFF' ||
+ src[0] == '\xFE' || src[0] == '\xEF')
{
- return BOM_UTF32BE;
+ // this could be a BOM but we don't know yet
+ return BOM_Unknown;
}
break;
- case '\xfe':
- // could only be big endian UTF-16 (FE FF)
- if ( *src++ == '\xff' )
+ case 2:
+ case 3:
+ if ( src[0] == '\xEF' && src[1] == '\xBB' )
{
- return BOM_UTF16BE;
+ if ( srcLen == 3 )
+ return src[2] == '\xBF' ? BOM_UTF8 : BOM_None;
+
+ return BOM_Unknown;
}
- break;
- case '\xff':
- // could be either little endian UTF-16 or UTF-32, both start
- // with FF FE
- if ( *src++ == '\xfe' )
+ if ( src[0] == '\xFE' && src[1] == '\xFF' )
+ return BOM_UTF16BE;
+
+ if ( src[0] == '\xFF' && src[1] == '\xFE' )
{
- return srcLen >= 4 && src[0] == '\0' && src[1] == '\0'
- ? BOM_UTF32LE
- : BOM_UTF16LE;
+ // if the next byte is 0, it could be an UTF-32LE BOM but if it
+ // isn't we can be sure it's UTF-16LE
+ if ( srcLen == 3 && src[2] != '\x00' )
+ return BOM_UTF16LE;
+
+ return BOM_Unknown;
}
- break;
- case '\xef':
- // is this UTF-8 BOM (EF BB BF)?
- if ( srcLen >= 3 && src[0] == '\xbb' && src[1] == '\xbf' )
+ if ( src[0] == '\x00' && src[1] == '\x00' )
{
- return BOM_UTF8;
+ // this could only be UTF-32BE, check that the data we have so
+ // far allows for it
+ if ( srcLen == 3 && src[2] != '\xFE' )
+ return BOM_None;
+
+ return BOM_Unknown;
}
break;
+
+ default:
+ // we have at least 4 characters so we may finally decide whether
+ // we have a BOM or not
+ if ( src[0] == '\xEF' && src[1] == '\xBB' && src[2] == '\xBF' )
+ return BOM_UTF8;
+
+ if ( src[0] == '\x00' && src[1] == '\x00' &&
+ src[2] == '\xFE' && src[3] == '\xFF' )
+ return BOM_UTF32BE;
+
+ if ( src[0] == '\xFF' && src[1] == '\xFE' &&
+ src[2] == '\x00' && src[3] == '\x00' )
+ return BOM_UTF32LE;
+
+ if ( src[0] == '\xFE' && src[1] == '\xFF' )
+ return BOM_UTF16BE;
+
+ if ( src[0] == '\xFF' && src[1] == '\xFE' )
+ return BOM_UTF16LE;
}
return BOM_None;
switch ( bomType )
{
+ case BOM_Unknown:
+ wxFAIL_MSG( "shouldn't be called for this BOM type" );
+ break;
+
+ case BOM_None:
+ // use the default
+ break;
+
case BOM_UTF32BE:
m_conv = new wxMBConvUTF32BE;
m_ownsConv = true;
break;
default:
- wxFAIL_MSG( wxT("unexpected BOM type") );
- // fall through: still need to create something
+ wxFAIL_MSG( "unknown BOM type" );
+ }
- case BOM_None:
- InitWithUTF8();
- m_consumedBOM = true; // as there is nothing to consume
+ if ( !m_conv )
+ {
+ // we end up here if there is no BOM or we didn't recognize it somehow
+ // (this shouldn't happen but still don't crash if it does), so use the
+ // default encoding
+ InitWithUTF8();
+ m_consumedBOM = true; // as there is nothing to consume
}
}
int ofs;
switch ( m_bomType )
{
+ case BOM_Unknown:
+ wxFAIL_MSG( "shouldn't be called for this BOM type" );
+ return;
+
+ case BOM_None:
+ ofs = 0;
+ break;
+
case BOM_UTF32BE:
case BOM_UTF32LE:
ofs = 4;
break;
default:
- wxFAIL_MSG( wxT("unexpected BOM type") );
- // fall through: still need to create something
-
- case BOM_None:
- ofs = 0;
+ wxFAIL_MSG( "unknown BOM type" );
+ return;
}
*src += ofs;
*len -= ofs;
}
-void wxConvAuto::InitFromInput(const char **src, size_t *len)
+bool wxConvAuto::InitFromInput(const char *src, size_t len)
{
- m_bomType = DetectBOM(*src, *len);
+ m_bomType = DetectBOM(src, len == wxNO_LEN ? strlen(src) : len);
+ if ( m_bomType == BOM_Unknown )
+ return false;
+
InitFromBOM(m_bomType);
- SkipBOM(src, len);
+
+ return true;
}
size_t
// dst as typically we're first called with NULL dst to calculate the
// needed buffer size
wxConvAuto *self = const_cast<wxConvAuto *>(this);
+
+
if ( !m_conv )
{
- self->InitFromInput(&src, &srcLen);
- if ( dst )
- self->m_consumedBOM = true;
+ if ( !self->InitFromInput(src, srcLen) )
+ {
+ // there is not enough data to determine whether we have a BOM or
+ // not, so fail for now -- the caller is supposed to call us again
+ // with more data
+ return wxCONV_FAILED;
+ }
}
- if ( !m_consumedBOM && dst )
+ if ( !m_consumedBOM )
{
- self->m_consumedBOM = true;
SkipBOM(&src, &srcLen);
+ if ( srcLen == 0 )
+ {
+ // there is nothing left except the BOM so we'd return 0 below but
+ // this is unexpected: decoding a non-empty string must either fail
+ // or return something non-empty, in particular this would break
+ // the code in wxTextInputStream::NextChar()
+ //
+ // so still return an error as we need some more data to be able to
+ // decode it
+ return wxCONV_FAILED;
+ }
}
// try to convert using the auto-detected encoding
}
}
+ // don't skip the BOM again the next time if we really consumed it
+ if ( rc != wxCONV_FAILED && dst && !m_consumedBOM )
+ self->m_consumedBOM = true;
+
return rc;
}
return m_conv->FromWChar(dst, dstLen, src, srcLen);
}
-
-#endif // wxUSE_WCHAR_T
-
projects / wxWidgets.git / blobdiff