ccfile.cpp File Reference

(r1785/r1607)

#include "camtypes.h"
#include "zstream.h"
#include <errno.h>

Go to the source code of this file.

Defines
#define	new   CAM_DEBUG_NEW
#define	CHAR_EOF   ((char)EOF)
Functions
	DECLARE_SOURCE ("$Revision: 1607 $")
	CC_IMPLEMENT_DYNAMIC (CCFile, CCObject)
	CC_IMPLEMENT_DYNAMIC (CCLexFile, CCFile)
	CC_IMPLEMENT_DYNAMIC (CCStreamFile, CCLexFile)
	CC_IMPLEMENT_DYNAMIC (CCDiskFile, CCStreamFile)
	CC_IMPLEMENT_DYNAMIC (CCMemFile, CCLexFile)
	CC_IMPLEMENT_DYNAMIC (CCMemTextFile, CCMemFile)
UINT_PTR	fake_filedesc (iostream &io)
	Creates a fake 'file-descriptor' that can be passed to C libraries, such as the Accusoft filter library, that allow the caller to redirect I/O.
iostream *	unfake_filedesc (UINT_PTR nFileDesc)
	Complementary function to fake_filedesc.
INT32 ACCUAPI_IO	stream_read (INT32 nFileDesc, char *pchBuffer, unsigned nBufSize)
	Adapts functions that call C-style I/O routines so that they can use C++ streams instead. This function substitutes for the standard C read() function. Instead of nFileDesc being a file-descriptor, it is expected to be an INT32 returned by fake_filedesc. Using this function we can persuade old code, such as the Accusoft library, to read and write from structured storage.
INT32 ACCUAPI_IO	stream_write (INT32 nFileDesc, char *pchBuffer, unsigned nBufSize)
	Adapts functions that call C-style I/O routines so that they can use C++ streams instead. This function substitutes for the standard C write() function. Instead of nFileDesc being a file-descriptor, it is expected to be an INT32 returned by fake_filedesc. Using this function we can persuade old code, such as the Accusoft library, to read and write from structured storage.
INT32 ACCUAPI_IO	stream_seek (INT32 nFileDesc, INT32 nOffset, unsigned fSeekType)
	Adapts functions that call C-style I/O routines so that they can use C++ streams instead. This function substitutes for the standard C seek() function. Instead of nFileDesc being a file-descriptor, it is expected to be an INT32 returned by fake_filedesc. Using this function we can persuade old code, such as the Accusoft library, to read and write from structured storage. Note that the function assumes that the stream has only one combined seek pointer, just like fstream and costream. If moving the input seek pointer doesn't also move the output seek pointer, as may be the case for some exotic iostream derivatives, then the function won't work properly.
Variables
const INT32	TokenBufSize = 256

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Define Documentation

#define CHAR_EOF   ((char)EOF)

Definition at line 137 of file ccfile.cpp.

#define new   CAM_DEBUG_NEW

Definition at line 135 of file ccfile.cpp.

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Function Documentation

CC_IMPLEMENT_DYNAMIC (  CCMemTextFile  , CCMemFile  )

CC_IMPLEMENT_DYNAMIC (  CCMemFile  , CCLexFile  )

CC_IMPLEMENT_DYNAMIC (  CCDiskFile  , CCStreamFile  )

CC_IMPLEMENT_DYNAMIC (  CCStreamFile  , CCLexFile  )

CC_IMPLEMENT_DYNAMIC (  CCLexFile  , CCFile  )

CC_IMPLEMENT_DYNAMIC (  CCFile  , CCObject  )

DECLARE_SOURCE (  "$Revision: 1607 $"   )

CCFile.cpp - Contains the function declarations of the Kernel CCFile derived classes. These include: CCDiskFile, CCMemFile and CCMemTextFile.

UINT_PTR fake_filedesc (  iostream &  io  )

Creates a fake 'file-descriptor' that can be passed to C libraries, such as the Accusoft filter library, that allow the caller to redirect I/O. Author: Justin_Flude (Xara Group Ltd) <camelotdev@xara.com> Date: 11/8/96 Parameters: io  - a reference to an iostream object (not constant). [INPUTS] Returns: An integer 'file-descriptor'. This can be passed to the stream_* functions to identify the stream they should work on. See also: unfake_filedesc; stream_read; stream_write; stream_seek; _read; _write; _lseek; fstream::fd Definition at line 6063 of file ccfile.cpp. { // Make sure this dirty trick is possible. ERROR3IF(sizeof(INT32) < sizeof(void*), "type 'INT32' too small for type 'istream*' in fake_filedesc"); // Return a "magic number" file-descriptor which is really a pointer to an iostream. return ~UINT32( (UINT_PTR)(&io) ); }

INT32 ACCUAPI_IO stream_read (  INT32  nFileDesc, char *  pchBuffer, unsigned  nBufSize )

Adapts functions that call C-style I/O routines so that they can use C++ streams instead. This function substitutes for the standard C read() function. Instead of nFileDesc being a file-descriptor, it is expected to be an INT32 returned by fake_filedesc. Using this function we can persuade old code, such as the Accusoft library, to read and write from structured storage. Author: Justin_Flude (Xara Group Ltd) <camelotdev@xara.com> Date: 5/8/96 Parameters: nFileDesc  - the "file-descriptor" of the "file" to read from. This [INPUTS] is really an iostream* cast to an INT32. pchBuffer - where to put the data that is read. nBufSize - the size of the input buffer pointed to by pchBuffer Returns: The number of bytes read by the call, or zero if at the end of the file, or -1 if there is an error. Errors: ERROR3 if the given buffer is larger than that allowed by istream. See also: stream_write; stream_seek; fake_filedesc; unfake_filedesc; iostream; istream::read; ios::eof; ios::bad; costream; fstream; _read Definition at line 6124 of file ccfile.cpp. { // Extract the input stream object associated with this request. iostream* ps = unfake_filedesc(nFileDesc); if (ps == 0 || ps->bad()) return -1; // Make sure the buffer isn't too big for a signed integer. if (nBufSize > INT_MAX) { ERROR3("Buffer too large for type 'signed INT32' in stream_read"); nBufSize = INT_MAX; } // If we're already at the end of the file then indicate this. if (ps->eof()) return 0; // Try to read the data into the given buffer. if (!ps->read(pchBuffer, (INT32) nBufSize) && !ps->eof()) return -1; // Return the number of bytes actually read. return ps->gcount(); }

INT32 ACCUAPI_IO stream_seek (  INT32  nFileDesc, INT32  nOffset, unsigned  fSeekType )

Adapts functions that call C-style I/O routines so that they can use C++ streams instead. This function substitutes for the standard C seek() function. Instead of nFileDesc being a file-descriptor, it is expected to be an INT32 returned by fake_filedesc. Using this function we can persuade old code, such as the Accusoft library, to read and write from structured storage. Note that the function assumes that the stream has only one combined seek pointer, just like fstream and costream. If moving the input seek pointer doesn't also move the output seek pointer, as may be the case for some exotic iostream derivatives, then the function won't work properly. Author: Justin_Flude (Xara Group Ltd) <camelotdev@xara.com> Date: 5/8/96 Parameters: nFileDesc  - the "file-descriptor" of the "file" to write to. This [INPUTS] is really an iostream* cast to an INT32. nOffset - the amount to seek by or the position to seek to. fSeekType - the direction of the seek (see the run-time docs for the _lseek function to get these flags). Returns: The new seek position, or -1 if there was an error. Errors: ERROR3 if the seek type is invalid or if the put and get seek positions aren't tied, as the semantics of the stream require. See also: stream_read; stream_write; fake_filedesc; iostream; iostream::seekg; fstream; costream; _lseek Definition at line 6219 of file ccfile.cpp. { // Extract the stream object associated with this request. Note that in disk-based // streams (including the costream), the get and put seek positions are tied, so // moving one moves the other. Hence we can use a plain istream here. iostream* ps = unfake_filedesc(nFileDesc); if (ps == 0 || ps->bad()) return -1; // Convert the standard C flags for fSeekType into the iostream equivalents. // NB. make sure the flags as passed by Accusoft are the same as those used by // the Microsoft run-time library! ios::seekdir dir; switch (fSeekType) { case SEEK_SET: dir = ios::beg; break; case SEEK_CUR: dir = ios::cur; break; case SEEK_END: dir = ios::end; break; default: ERROR3("Bad seek direction in stream_seek"); return -1; } // Try to seek to the new position. if( !ps->seekg( (streampos)nOffset, ios_base::seekdir(dir) ) ) return -1; // Check if the iostream has similar semantics to fstream. ERROR3IF(ps->tellp() != ps->tellg(), "Put and get seek pointers aren't tied in stream_seek"); // Return the new seek position. return (INT32) ps->tellg(); }

INT32 ACCUAPI_IO stream_write (  INT32  nFileDesc, char *  pchBuffer, unsigned  nBufSize )

Adapts functions that call C-style I/O routines so that they can use C++ streams instead. This function substitutes for the standard C write() function. Instead of nFileDesc being a file-descriptor, it is expected to be an INT32 returned by fake_filedesc. Using this function we can persuade old code, such as the Accusoft library, to read and write from structured storage. Author: Justin_Flude (Xara Group Ltd) <camelotdev@xara.com> Date: 5/8/96 Parameters: nFileDesc  - the "file-descriptor" of the "file" to write to. This [INPUTS] is really an iostream* cast to an INT32. pchBuffer - where to get the data that is to be written. nBufSize - the size of the output buffer pointed to by pchBuffer Returns: The number of bytes written by the call, or -1 if there is an error. Errors: ERROR3 if the given buffer is larger than that allowed by ostream. See also: stream_read; stream_seek; fake_filedesc; iostream; ostream::write; costream; fstream; _write Definition at line 6170 of file ccfile.cpp. { // Extract the output stream object associated with this request. iostream* ps = unfake_filedesc(nFileDesc); if (ps == 0 || ps->bad()) return -1; // Make sure the buffer isn't too big for a signed integer. if (nBufSize > INT_MAX) { ERROR3("Buffer too large for type 'signed INT32' in stream_write"); nBufSize = INT_MAX; } // Try to write the data from the given buffer. if (!ps->write(pchBuffer, (INT32) nBufSize)) return -1; // Return the number of bytes actually written, which is always all or none. return (INT32) nBufSize; }

iostream* unfake_filedesc (  UINT_PTR  nFileDesc  )

Complementary function to fake_filedesc. Author: Justin_Flude (Xara Group Ltd) <camelotdev@xara.com> Date: 12/8/96 Parameters: nFileDesc  - the integer fake 'file-descriptor' previously obtained [INPUTS] by a call to fake_filedesc. Returns: A pointer to the iostream object the 'file-descriptor' refers to. See also: fake_filedesc; stream_read; stream_write; stream_seek; _read; _write; _lseek; fstream::fd Definition at line 6088 of file ccfile.cpp. { // Make sure this dirty trick is possible. ERROR3IF(sizeof(INT32) < sizeof(void*), "type 'INT32' too small for type 'istream*' in unfake_filedesc"); // Convert this magic number back into a pointer to an iostream. iostream* ps = (iostream*) (void*) ~nFileDesc; ERROR3IF(ps == 0, "Null 'file-descriptor' in unfake_filedesc"); return ps; }

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Variable Documentation

const INT32 TokenBufSize = 256

Definition at line 840 of file ccfile.cpp.

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