/// <summary>
/// Decodes the toptext multi page.
/// </summary>
/// <param name="cache">The cache.</param>
private void DecodeMultiPage(TeletextPageCache cache)
{
// multi page contains the number of subpages transmitted for each page (100-899);
if (!cache.PageExists(TOP_MULTI_PAGE))
{
return;
}
byte[] multiPage = cache.GetPage(TOP_MULTI_PAGE, 0);
for (int pageNr = 100; pageNr <= 899; pageNr++)
{
int row = ((pageNr - 100) / 40) + 1;
int col = ((pageNr - 100) % 40) + 2;
byte data = Hamming.Decode[multiPage[row * 42 + col]];
if (data == NotPresent)
{
//page is offair
_pageSubCount[pageNr] = 0;
}
else if (data == 0x0a)
{
//page has > 10 subpages
_pageSubCount[pageNr] = 10; //( or more)
}
else
{
int numberOfSubPages = data - 1;
_pageSubCount[pageNr] = numberOfSubPages;
}
}
}
/// <summary>
/// Initializes a new instance of the <see cref="TeletextDecoder"/> class.
/// </summary>
/// <param name="cache">The cache.</param>
public TeletextDecoder(TeletextPageCache cache)
{
_prevMagazine = 0;
_pageCache = cache;
for (int i = 0; i < MAX_MAGAZINE + 2; ++i)
{
_vbiLine[i] = "";
byte[] page = new byte[2100];
_workingPage.Add(page);
}
Clear();
}
/// <summary>
/// Decodes the additional toptext pages.
/// </summary>
/// <param name="cache">The cache.</param>
private void DecodeAdditionalPages(TeletextPageCache cache)
{
//addditional pages carry information to display on line 24
//
for (int pageNr = TOP_ADDITIONAL_PAGE; pageNr < 0x1fd; ++pageNr)
{
if (!cache.PageExists(pageNr))
{
continue;
}
byte[] additionalPage = cache.GetPage(pageNr, 0);
int lineCounter = 0;
while (true)
{
int row = 1 + (lineCounter / 2);
int col = (20 * (lineCounter % 2));
byte magazine = Hamming.Decode[additionalPage[row * 42 + 2 + col]];
byte pageTens = Hamming.Decode[additionalPage[row * 42 + 3 + col]];
byte pageUnits = Hamming.Decode[additionalPage[row * 42 + 4 + col]];
if (magazine >= 0 && magazine <= 7)
{
if (pageTens >= 0x0 && pageTens <= 9)
{
if (pageUnits >= 0x0 && pageUnits <= 9)
{
string description = String.Empty;
for (int i = 1; i < 12; ++i)
{
row = 1 + (lineCounter / 2);
col = 9 + i + (20 * (lineCounter % 2));
description += (char)(additionalPage[row * 42 + col] & 0x7f);
}
if (magazine == 0)
{
magazine = 8;
}
int pageNo = magazine * 100 + pageTens * 10 + pageUnits;
if (pageNo >= 100 && pageNo <= 899)
{
_pageDescription[pageNo] = description;
}
}
}
}
lineCounter++;
if (lineCounter >= 43)
{
break;
}
}
}
}
/// <summary>
/// Initializes a new instance of the <see cref="TeletextDecoder"/> class.
/// </summary>
/// <param name="cache">The cache.</param>
public TeletextDecoder(TeletextPageCache cache)
{
_prevMagazine = 0;
_pageCache = cache;
for (int i = 0; i < MAX_MAGAZINE + 2; ++i)
{
_vbiLine[i] = "";
byte[] page = new byte[2100];
_workingPage.Add(page);
}
Clear();
}
/// <summary>
/// Decodes the toptext for a specific page.
/// </summary>
/// <param name="cache">The cache.</param>
/// <param name="pageNumber">The page number.</param>
/// <returns>true when decoding succeeded</returns>
public bool Decode(TeletextPageCache cache, int pageNumber)
{
int red, green, yellow, blue;
string nextGroup, nextBlock;
if (!GetPageLinks(cache, pageNumber, out red, out green, out yellow, out blue, out nextGroup, out nextBlock))
{
return(false);
}
_pageRed = ConvertToHex(red);
_pageGreen = ConvertToHex(green);
_pageYellow = ConvertToHex(yellow);
_pageBlue = ConvertToHex(blue);
if (nextGroup == String.Empty)
{
nextGroup = green.ToString();
}
if (nextBlock == String.Empty)
{
nextBlock = yellow.ToString();
}
Hamming.SetPacketNumber(0, ref _row24, pageNumber, 24);
int spaces = 40 - (nextGroup.Length + nextBlock.Length + 3 + 3 + 4);
spaces /= 3;
string line = ((char)TeletextPageRenderer.Attributes.AlphaRed) + red.ToString();
for (int x = 0; x < spaces; x++)
{
line += " ";
}
line += ((char)TeletextPageRenderer.Attributes.AlphaGreen) + nextGroup;
for (int x = 0; x < spaces; x++)
{
line += " ";
}
line += ((char)TeletextPageRenderer.Attributes.AlphaYellow) + nextBlock;
for (int x = 0; x < spaces; x++)
{
line += " ";
}
line += ((char)TeletextPageRenderer.Attributes.AlphaCyan) + blue.ToString();
for (int i = 0; i < line.Length && i <= 40; ++i)
{
_row24[2 + i] = (byte)line[i];
}
return(true);
}
/// <summary>
/// Decodes the basic toptext page.
/// </summary>
/// <param name="cache">The cache.</param>
/// <returns></returns>
private bool DecodeBasicPage(TeletextPageCache cache)
{
//basic toppage contains information which teletext pages are onair
//and if onair if it has subpages or not
//also contains the type for each page
if (!cache.PageExists(TOP_BASIC_PAGE))
{
return(false);
}
byte[] basicPage = cache.GetPage(TOP_BASIC_PAGE, 0);
for (int pageNr = 100; pageNr <= 899; pageNr++)
{
int row = ((pageNr - 100) / 40) + 1;
int col = ((pageNr - 100) % 40) + 2;
byte data = Hamming.Decode[basicPage[row * 42 + col]];
if (data == ProgramInfoBlockPageMulti ||
data == BlockPageMulti ||
data == GroupPageMulti ||
data == NormalPageMulti ||
data == NormalPageMultiInfo
)
{
//page is onair and has subpages
_pageType[pageNr] = data;
}
if (data == ProgramInfoBlockPageSingle ||
data == BlockPageSingle ||
data == GroupPageSingle ||
data == NormalPage ||
data == NormalPageInfo)
{
//page is onair and has subpages
_pageType[pageNr] = data;
}
if (data == NotPresent)
{
//page is not onair
_pageType[pageNr] = data;
_pageSubCount[pageNr] = 0;
}
}
return(true);
}
/// <summary>
/// Gets the page links for a page.
/// </summary>
/// <param name="cache">The cache.</param>
/// <param name="pageNumber">The page number.</param>
/// <param name="redPage">The red page.</param>
/// <param name="greenPage">The green page.</param>
/// <param name="yellowPage">The yellow page.</param>
/// <param name="bluePage">The blue page.</param>
/// <param name="nextGroup">The next group.</param>
/// <param name="nextBlock">The next block.</param>
/// <returns></returns>
public bool GetPageLinks(TeletextPageCache cache, int pageNumber, out int redPage, out int greenPage,
out int yellowPage, out int bluePage, out string nextGroup, out string nextBlock)
{
//red = previous page in current
//green = first page of next group
//yellow= first page of next block
//blue = next page
int mag = pageNumber / 0x100;
int tens = (pageNumber - mag * 0x100) / 0x10;
int units = (pageNumber - mag * 0x100) - tens * 0x10;
int decimalPage = mag * 100 + tens * 10 + units;
Clear();
nextGroup = "";
nextBlock = "";
redPage = greenPage = yellowPage = bluePage = -1;
if (!DecodeBasicPage(cache))
{
return(false);
}
DecodeMultiPage(cache);
DecodeAdditionalPages(cache);
//red: prev page
for (int page = decimalPage - 1; page > 100; page--)
{
if (_pageType[page] != NotPresent)
{
redPage = page;
break;
}
}
if (redPage == -1)
{
for (int page = 899; page > 100; page--)
{
if (_pageType[page] != NotPresent)
{
redPage = page;
break;
}
}
}
for (int page = decimalPage + 1; page <= 899; page++)
{
if (greenPage == -1)
{
if (_pageType[page] == GroupPageSingle || _pageType[page] == GroupPageMulti)
{
greenPage = page;
nextGroup = _pageDescription[greenPage] ?? greenPage.ToString();
}
}
if (yellowPage == -1)
{
if (_pageType[page] == BlockPageSingle || _pageType[page] == BlockPageMulti)
{
yellowPage = page;
nextBlock = _pageDescription[yellowPage] ?? yellowPage.ToString();
}
}
}
for (int page = 100; page <= decimalPage; page++)
{
if (greenPage == -1)
{
if (_pageType[page] == GroupPageSingle || _pageType[page] == GroupPageMulti)
{
greenPage = page;
nextGroup = _pageDescription[greenPage] ?? greenPage.ToString();
}
}
if (yellowPage == -1)
{
if (_pageType[page] == BlockPageSingle || _pageType[page] == BlockPageMulti)
{
yellowPage = page;
nextBlock = _pageDescription[yellowPage] ?? yellowPage.ToString();
}
}
}
//blue : next page
for (int page = decimalPage + 1; page <= 899; page++)
{
if (_pageType[page] != NotPresent)
{
bluePage = page;
break;
}
}
if (bluePage == -1)
{
for (int page = 100; page <= 899; page++)
{
if (_pageType[page] != NotPresent)
{
bluePage = page;
break;
}
}
}
nextGroup = nextGroup.Trim();
nextBlock = nextBlock.Trim();
return(true);
}
/// <summary>
/// Decodes the additional toptext pages.
/// </summary>
/// <param name="cache">The cache.</param>
private void DecodeAdditionalPages(TeletextPageCache cache)
{
//addditional pages carry information to display on line 24
//
for (int pageNr = TOP_ADDITIONAL_PAGE; pageNr < 0x1fd; ++pageNr)
{
if (!cache.PageExists(pageNr))
continue;
byte[] additionalPage = cache.GetPage(pageNr, 0);
int lineCounter = 0;
while (true)
{
int row = 1 + (lineCounter / 2);
int col = (20 * (lineCounter % 2));
byte magazine = Hamming.Decode[additionalPage[row * 42 + 2 + col]];
byte pageTens = Hamming.Decode[additionalPage[row * 42 + 3 + col]];
byte pageUnits = Hamming.Decode[additionalPage[row * 42 + 4 + col]];
if (magazine >= 0 && magazine <= 7)
{
if (pageTens >= 0x0 && pageTens <= 9)
{
if (pageUnits >= 0x0 && pageUnits <= 9)
{
string description = String.Empty;
for (int i = 1; i < 12; ++i)
{
row = 1 + (lineCounter / 2);
col = 9 + i + (20 * (lineCounter % 2));
description += (char)(additionalPage[row * 42 + col] & 0x7f);
}
if (magazine == 0)
magazine = 8;
int pageNo = magazine * 100 + pageTens * 10 + pageUnits;
if (pageNo >= 100 && pageNo <= 899)
{
_pageDescription[pageNo] = description;
}
}
}
}
lineCounter++;
if (lineCounter >= 43)
break;
}
}
}
/// <summary>
/// Decodes the toptext multi page.
/// </summary>
/// <param name="cache">The cache.</param>
private void DecodeMultiPage(TeletextPageCache cache)
{
// multi page contains the number of subpages transmitted for each page (100-899);
if (!cache.PageExists(TOP_MULTI_PAGE))
return;
byte[] multiPage = cache.GetPage(TOP_MULTI_PAGE, 0);
for (int pageNr = 100; pageNr <= 899; pageNr++)
{
int row = ((pageNr - 100) / 40) + 1;
int col = ((pageNr - 100) % 40) + 2;
byte data = Hamming.Decode[multiPage[row * 42 + col]];
if (data == NotPresent)
{
//page is offair
_pageSubCount[pageNr] = 0;
}
else if (data == 0x0a)
{
//page has > 10 subpages
_pageSubCount[pageNr] = 10; //( or more)
}
else
{
int numberOfSubPages = data - 1;
_pageSubCount[pageNr] = numberOfSubPages;
}
}
}
/// <summary>
/// Decodes the basic toptext page.
/// </summary>
/// <param name="cache">The cache.</param>
/// <returns></returns>
private bool DecodeBasicPage(TeletextPageCache cache)
{
//basic toppage contains information which teletext pages are onair
//and if onair if it has subpages or not
//also contains the type for each page
if (!cache.PageExists(TOP_BASIC_PAGE))
return false;
byte[] basicPage = cache.GetPage(TOP_BASIC_PAGE, 0);
for (int pageNr = 100; pageNr <= 899; pageNr++)
{
int row = ((pageNr - 100) / 40) + 1;
int col = ((pageNr - 100) % 40) + 2;
byte data = Hamming.Decode[basicPage[row * 42 + col]];
if (data == ProgramInfoBlockPageMulti ||
data == BlockPageMulti ||
data == GroupPageMulti ||
data == NormalPageMulti ||
data == NormalPageMultiInfo
)
{
//page is onair and has subpages
_pageType[pageNr] = data;
}
if (data == ProgramInfoBlockPageSingle ||
data == BlockPageSingle ||
data == GroupPageSingle ||
data == NormalPage ||
data == NormalPageInfo)
{
//page is onair and has subpages
_pageType[pageNr] = data;
}
if (data == NotPresent)
{
//page is not onair
_pageType[pageNr] = data;
_pageSubCount[pageNr] = 0;
}
}
return true;
}
/// <summary>
/// Gets the page links for a page.
/// </summary>
/// <param name="cache">The cache.</param>
/// <param name="pageNumber">The page number.</param>
/// <param name="redPage">The red page.</param>
/// <param name="greenPage">The green page.</param>
/// <param name="yellowPage">The yellow page.</param>
/// <param name="bluePage">The blue page.</param>
/// <param name="nextGroup">The next group.</param>
/// <param name="nextBlock">The next block.</param>
/// <returns></returns>
public bool GetPageLinks(TeletextPageCache cache, int pageNumber, out int redPage, out int greenPage,
out int yellowPage, out int bluePage, out string nextGroup, out string nextBlock)
{
//red = previous page in current
//green = first page of next group
//yellow= first page of next block
//blue = next page
int mag = pageNumber / 0x100;
int tens = (pageNumber - mag * 0x100) / 0x10;
int units = (pageNumber - mag * 0x100) - tens * 0x10;
int decimalPage = mag * 100 + tens * 10 + units;
Clear();
nextGroup = "";
nextBlock = "";
redPage = greenPage = yellowPage = bluePage = -1;
if (!DecodeBasicPage(cache))
return false;
DecodeMultiPage(cache);
DecodeAdditionalPages(cache);
//red: prev page
for (int page = decimalPage - 1; page > 100; page--)
{
if (_pageType[page] != NotPresent)
{
redPage = page;
break;
}
}
if (redPage == -1)
{
for (int page = 899; page > 100; page--)
{
if (_pageType[page] != NotPresent)
{
redPage = page;
break;
}
}
}
for (int page = decimalPage + 1; page <= 899; page++)
{
if (greenPage == -1)
{
if (_pageType[page] == GroupPageSingle || _pageType[page] == GroupPageMulti)
{
greenPage = page;
nextGroup = _pageDescription[greenPage] ?? greenPage.ToString();
}
}
if (yellowPage == -1)
{
if (_pageType[page] == BlockPageSingle || _pageType[page] == BlockPageMulti)
{
yellowPage = page;
nextBlock = _pageDescription[yellowPage] ?? yellowPage.ToString();
}
}
}
for (int page = 100; page <= decimalPage; page++)
{
if (greenPage == -1)
{
if (_pageType[page] == GroupPageSingle || _pageType[page] == GroupPageMulti)
{
greenPage = page;
nextGroup = _pageDescription[greenPage] ?? greenPage.ToString();
}
}
if (yellowPage == -1)
{
if (_pageType[page] == BlockPageSingle || _pageType[page] == BlockPageMulti)
{
yellowPage = page;
nextBlock = _pageDescription[yellowPage] ?? yellowPage.ToString();
}
}
}
//blue : next page
for (int page = decimalPage + 1; page <= 899; page++)
{
if (_pageType[page] != NotPresent)
{
bluePage = page;
break;
}
}
if (bluePage == -1)
{
for (int page = 100; page <= 899; page++)
{
if (_pageType[page] != NotPresent)
{
bluePage = page;
break;
}
}
}
nextGroup = nextGroup.Trim();
nextBlock = nextBlock.Trim();
return true;
}
/// <summary>
/// Decodes the toptext for a specific page.
/// </summary>
/// <param name="cache">The cache.</param>
/// <param name="pageNumber">The page number.</param>
/// <returns>true when decoding succeeded</returns>
public bool Decode(TeletextPageCache cache, int pageNumber)
{
int red, green, yellow, blue;
string nextGroup, nextBlock;
if (!GetPageLinks(cache, pageNumber, out red, out green, out yellow, out blue, out nextGroup, out nextBlock))
return false;
_pageRed = ConvertToHex(red);
_pageGreen = ConvertToHex(green);
_pageYellow = ConvertToHex(yellow);
_pageBlue = ConvertToHex(blue);
if (nextGroup == String.Empty)
nextGroup = green.ToString();
if (nextBlock == String.Empty)
nextBlock = yellow.ToString();
Hamming.SetPacketNumber(0, ref _row24, pageNumber, 24);
int spaces = 40 - (nextGroup.Length + nextBlock.Length + 3 + 3 + 4);
spaces /= 3;
string line = ((char)TeletextPageRenderer.Attributes.AlphaRed) + red.ToString();
for (int x = 0; x < spaces; x++)
line += " ";
line += ((char)TeletextPageRenderer.Attributes.AlphaGreen) + nextGroup;
for (int x = 0; x < spaces; x++)
line += " ";
line += ((char)TeletextPageRenderer.Attributes.AlphaYellow) + nextBlock;
for (int x = 0; x < spaces; x++)
line += " ";
line += ((char)TeletextPageRenderer.Attributes.AlphaCyan) + blue.ToString();
for (int i = 0; i < line.Length && i <= 40; ++i)
{
_row24[2 + i] = (byte)line[i];
}
return true;
}
