unzip.c

著名SFC模拟器Snes9x的源代码。

	                       unz_file_info_internal * pfile_info_internal,
					                   char *szFileName,
				                   uLong fileNameBufferSize,
					                   void *extraField,
				                 uLong extraFieldBufferSize,
					                    char *szComment,
				                    uLong commentBufferSize)
{
    unz_s          *s;
    unz_file_info   file_info;
    unz_file_info_internal file_info_internal;
    int             err = UNZ_OK;
    uLong           uMagic;
    long            lSeek = 0;

    if (file == NULL)
	return UNZ_PARAMERROR;
    s = (unz_s *) file;
    if (fseek (s->file, s->pos_in_central_dir + s->byte_before_the_zipfile, SEEK_SET) != 0)
	err = UNZ_ERRNO;


    /* we check the magic */
    if (err == UNZ_OK)
    {
	if (unzlocal_getLong (s->file, &uMagic) != UNZ_OK)
	    err = UNZ_ERRNO;
	else if (uMagic != 0x02014b50)
	    err = UNZ_BADZIPFILE;
    }
    if (unzlocal_getShort (s->file, &file_info.version) != UNZ_OK)
	err = UNZ_ERRNO;

    if (unzlocal_getShort (s->file, &file_info.version_needed) != UNZ_OK)
	err = UNZ_ERRNO;

    if (unzlocal_getShort (s->file, &file_info.flag) != UNZ_OK)
	err = UNZ_ERRNO;

    if (unzlocal_getShort (s->file, &file_info.compression_method) != UNZ_OK)
	err = UNZ_ERRNO;

    if (unzlocal_getLong (s->file, &file_info.dosDate) != UNZ_OK)
	err = UNZ_ERRNO;

    unzlocal_DosDateToTmuDate (file_info.dosDate, &file_info.tmu_date);

    if (unzlocal_getLong (s->file, &file_info.crc) != UNZ_OK)
	err = UNZ_ERRNO;

    if (unzlocal_getLong (s->file, &file_info.compressed_size) != UNZ_OK)
	err = UNZ_ERRNO;

    if (unzlocal_getLong (s->file, &file_info.uncompressed_size) != UNZ_OK)
	err = UNZ_ERRNO;

    if (unzlocal_getShort (s->file, &file_info.size_filename) != UNZ_OK)
	err = UNZ_ERRNO;

    if (unzlocal_getShort (s->file, &file_info.size_file_extra) != UNZ_OK)
	err = UNZ_ERRNO;

    if (unzlocal_getShort (s->file, &file_info.size_file_comment) != UNZ_OK)
	err = UNZ_ERRNO;

    if (unzlocal_getShort (s->file, &file_info.disk_num_start) != UNZ_OK)
	err = UNZ_ERRNO;

    if (unzlocal_getShort (s->file, &file_info.internal_fa) != UNZ_OK)
	err = UNZ_ERRNO;

    if (unzlocal_getLong (s->file, &file_info.external_fa) != UNZ_OK)
	err = UNZ_ERRNO;

    if (unzlocal_getLong (s->file, &file_info_internal.offset_curfile) != UNZ_OK)
	err = UNZ_ERRNO;

    lSeek += file_info.size_filename;
    if ((err == UNZ_OK) && (szFileName != NULL))
    {
	uLong           uSizeRead;
	if (file_info.size_filename < fileNameBufferSize)
	{
	    *(szFileName + file_info.size_filename) = '\0';
	    uSizeRead = file_info.size_filename;
	} else
	    uSizeRead = fileNameBufferSize;

	if ((file_info.size_filename > 0) && (fileNameBufferSize > 0))
	    if (fread (szFileName, (uInt) uSizeRead, 1, s->file) != 1)
		err = UNZ_ERRNO;
	lSeek -= uSizeRead;
    }
    if ((err == UNZ_OK) && (extraField != NULL))
    {
	uLong           uSizeRead;
	if (file_info.size_file_extra < extraFieldBufferSize)
	    uSizeRead = file_info.size_file_extra;
	else
	    uSizeRead = extraFieldBufferSize;

	if (lSeek != 0)
	{
	    if (fseek (s->file, lSeek, SEEK_CUR) == 0)
		lSeek = 0;
	    else
		err = UNZ_ERRNO;
	}
	if ((file_info.size_file_extra > 0) && (extraFieldBufferSize > 0))
	    if (fread (extraField, (uInt) uSizeRead, 1, s->file) != 1)
		err = UNZ_ERRNO;
	lSeek += file_info.size_file_extra - uSizeRead;
    } else
	lSeek += file_info.size_file_extra;


    if ((err == UNZ_OK) && (szComment != NULL))
    {
	uLong           uSizeRead;
	if (file_info.size_file_comment < commentBufferSize)
	{
	    *(szComment + file_info.size_file_comment) = '\0';
	    uSizeRead = file_info.size_file_comment;
	} else
	    uSizeRead = commentBufferSize;

	if (lSeek != 0)
	{
	    if (fseek (s->file, lSeek, SEEK_CUR) == 0)
		lSeek = 0;
	    else
		err = UNZ_ERRNO;
	}
	if ((file_info.size_file_comment > 0) && (commentBufferSize > 0))
	    if (fread (szComment, (uInt) uSizeRead, 1, s->file) != 1)
		err = UNZ_ERRNO;
	lSeek += file_info.size_file_comment - uSizeRead;
    } else
	lSeek += file_info.size_file_comment;

    if ((err == UNZ_OK) && (pfile_info != NULL))
	*pfile_info = file_info;

    if ((err == UNZ_OK) && (pfile_info_internal != NULL))
	*pfile_info_internal = file_info_internal;

    return err;
}



/*
 * Write info about the ZipFile in the *pglobal_info structure. No
 * preparation of the structure is needed return UNZ_OK if there is no
 * problem.
 */
extern int ZEXPORT 
unzGetCurrentFileInfo (
		       unzFile file,
		       unz_file_info * pfile_info,
		       char *szFileName,
		       uLong fileNameBufferSize,
		       void *extraField,
		       uLong extraFieldBufferSize,
		       char *szComment,
		       uLong commentBufferSize)
{
    return unzlocal_GetCurrentFileInfoInternal (file, pfile_info, NULL,
					     szFileName, fileNameBufferSize,
					   extraField, extraFieldBufferSize,
					      szComment, commentBufferSize);
}

/*
 * Set the current file of the zipfile to the first file. return UNZ_OK if
 * there is no problem
 */
extern int ZEXPORT 
unzGoToFirstFile (unzFile file)
{
    int             err = UNZ_OK;
    unz_s          *s;
    if (file == NULL)
	return UNZ_PARAMERROR;
    s = (unz_s *) file;
    s->pos_in_central_dir = s->offset_central_dir;
    s->num_file = 0;
    err = unzlocal_GetCurrentFileInfoInternal (file, &s->cur_file_info,
					       &s->cur_file_info_internal,
					       NULL, 0, NULL, 0, NULL, 0);
    s->current_file_ok = (err == UNZ_OK);
    return err;
}


/*
 * Set the current file of the zipfile to the next file. return UNZ_OK if
 * there is no problem return UNZ_END_OF_LIST_OF_FILE if the actual file was
 * the latest.
 */
extern int ZEXPORT 
unzGoToNextFile (unzFile file)
{
    unz_s          *s;
    int             err;

    if (file == NULL)
	return UNZ_PARAMERROR;
    s = (unz_s *) file;
    if (!s->current_file_ok)
	return UNZ_END_OF_LIST_OF_FILE;
    if (s->num_file + 1 == s->gi.number_entry)
	return UNZ_END_OF_LIST_OF_FILE;

    s->pos_in_central_dir += SIZECENTRALDIRITEM + s->cur_file_info.size_filename +
	s->cur_file_info.size_file_extra + s->cur_file_info.size_file_comment;
    s->num_file++;
    err = unzlocal_GetCurrentFileInfoInternal (file, &s->cur_file_info,
					       &s->cur_file_info_internal,
					       NULL, 0, NULL, 0, NULL, 0);
    s->current_file_ok = (err == UNZ_OK);
    return err;
}


/*
 * Try locate the file szFileName in the zipfile. For the iCaseSensitivity
 * signification, see unzipStringFileNameCompare
 * 
 * return value : UNZ_OK if the file is found. It becomes the current file.
 * UNZ_END_OF_LIST_OF_FILE if the file is not found
 */
extern int ZEXPORT 
unzLocateFile (
	       unzFile file,
	       const char *szFileName,
	       int iCaseSensitivity)
{
    unz_s          *s;
    int             err;


    uLong           num_fileSaved;
    uLong           pos_in_central_dirSaved;


    if (file == NULL)
	return UNZ_PARAMERROR;

    if (strlen (szFileName) >= UNZ_MAXFILENAMEINZIP)
	return UNZ_PARAMERROR;

    s = (unz_s *) file;
    if (!s->current_file_ok)
	return UNZ_END_OF_LIST_OF_FILE;

    num_fileSaved = s->num_file;
    pos_in_central_dirSaved = s->pos_in_central_dir;

    err = unzGoToFirstFile (file);

    while (err == UNZ_OK)
    {
	char            szCurrentFileName[UNZ_MAXFILENAMEINZIP + 1];
	unzGetCurrentFileInfo (file, NULL,
			  szCurrentFileName, sizeof (szCurrentFileName) - 1,
			       NULL, 0, NULL, 0);
	if (unzStringFileNameCompare (szCurrentFileName,
				      szFileName, iCaseSensitivity) == 0)
	    return UNZ_OK;
	err = unzGoToNextFile (file);
    }

    s->num_file = num_fileSaved;
    s->pos_in_central_dir = pos_in_central_dirSaved;
    return err;
}


/*
 * Read the local header of the current zipfile Check the coherency of the
 * local header and info in the end of central directory about this file
 * store in *piSizeVar the size of extra info in local header (filename and
 * size of extra field data)
 */
local int 
unzlocal_CheckCurrentFileCoherencyHeader (
					  unz_s * s,
					  uInt * piSizeVar,
					  uLong * poffset_local_extrafield,
					  uInt * psize_local_extrafield)
{
    uLong           uMagic, uData, uFlags;
    uLong           size_filename;
    uLong           size_extra_field;
    int             err = UNZ_OK;

    *piSizeVar = 0;
    *poffset_local_extrafield = 0;
    *psize_local_extrafield = 0;

    if (fseek (s->file, s->cur_file_info_internal.offset_curfile +
	       s->byte_before_the_zipfile, SEEK_SET) != 0)
	return UNZ_ERRNO;


    if (err == UNZ_OK)
    {
	if (unzlocal_getLong (s->file, &uMagic) != UNZ_OK)
	    err = UNZ_ERRNO;
	else if (uMagic != 0x04034b50)
	    err = UNZ_BADZIPFILE;
    }

    if (unzlocal_getShort (s->file, &uData) != UNZ_OK)
	err = UNZ_ERRNO;
    /*
     * else if ((err==UNZ_OK) && (uData!=s->cur_file_info.wVersion))
     * err=UNZ_BADZIPFILE;
     */
    if (unzlocal_getShort (s->file, &uFlags) != UNZ_OK)
	err = UNZ_ERRNO;

    if (unzlocal_getShort (s->file, &uData) != UNZ_OK)
	err = UNZ_ERRNO;
    else if ((err == UNZ_OK) && (uData != s->cur_file_info.compression_method))
	err = UNZ_BADZIPFILE;

    if ((err == UNZ_OK) &&
	s->cur_file_info.compression_method > Z_DEFLATED)
	err = UNZ_BADZIPFILE;

    if (unzlocal_getLong (s->file, &uData) != UNZ_OK)	/* date/time */
	err = UNZ_ERRNO;

    if (unzlocal_getLong (s->file, &uData) != UNZ_OK)	/* crc */
	err = UNZ_ERRNO;
    else if ((err == UNZ_OK) && (uData != s->cur_file_info.crc) &&
	     ((uFlags & 8) == 0))
	err = UNZ_BADZIPFILE;

    if (unzlocal_getLong (s->file, &uData) != UNZ_OK)	/* size compr */
	err = UNZ_ERRNO;
    else if ((err == UNZ_OK) && (uData != s->cur_file_info.compressed_size) &&
	     ((uFlags & 8) == 0))
	err = UNZ_BADZIPFILE;

    if (unzlocal_getLong (s->file, &uData) != UNZ_OK)	/* size uncompr */
	err = UNZ_ERRNO;
    else if ((err == UNZ_OK) && (uData != s->cur_file_info.uncompressed_size) &&
	     ((uFlags & 8) == 0))
	err = UNZ_BADZIPFILE;


    if (unzlocal_getShort (s->file, &size_filename) != UNZ_OK)
	err = UNZ_ERRNO;
    else if ((err == UNZ_OK) && (size_filename != s->cur_file_info.size_filename))
	err = UNZ_BADZIPFILE;

    *piSizeVar += (uInt) size_filename;

    if (unzlocal_getShort (s->file, &size_extra_field) != UNZ_OK)
	err = UNZ_ERRNO;
    *poffset_local_extrafield = s->cur_file_info_internal.offset_curfile +
	SIZEZIPLOCALHEADER + size_filename;
    *psize_local_extrafield = (uInt) size_extra_field;

    *piSizeVar += (uInt) size_extra_field;

    return err;
}

/*
 * Open for reading data the current file in the zipfile. If there is no
 * error and the file is opened, the return value is UNZ_OK.
 */
extern int ZEXPORT 
unzOpenCurrentFile (unzFile file)
{
    int             err = UNZ_OK;
    uInt            iSizeVar;
    unz_s          *s;
    file_in_zip_read_info_s *pfile_in_zip_read_info;
    uLong           offset_local_extrafield;	/* offset of the local extra
						 * field */
    uInt            size_local_extrafield;	/* size of the local extra
						 * field */

    if (file == NULL)
	return UNZ_PARAMERROR;
    s = (unz_s *) file;
    if (!s->current_file_ok)
	return UNZ_PARAMERROR;

    if (s->pfile_in_zip_read != NULL)
	unzCloseCurrentFile (file);

    if (unzlocal_CheckCurrentFileCoherencyHeader (s, &iSizeVar,
		&offset_local_extrafield, &size_local_extrafield) != UNZ_OK)
	return UNZ_BADZIPFILE;

    pfile_in_zip_read_info = (file_in_zip_read_info_s *)
	ALLOC (sizeof (file_in_zip_read_info_s));
    if (pfile_in_zip_read_info == NULL)
	return UNZ_INTERNALERROR;

    pfile_in_zip_read_info->read_buffer = (char *) ALLOC (UNZ_BUFSIZE);
    pfile_in_zip_read_info->offset_local_extrafield = offset_local_extrafield;