<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"><head><meta http-equiv=Content-Type content="text/html; charset=us-ascii"><meta name=Generator content="Microsoft Word 15 (filtered medium)"><style><!--
/* Font Definitions */
@font-face
{font-family:"Cambria Math";
panose-1:2 4 5 3 5 4 6 3 2 4;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0cm;
margin-bottom:.0001pt;
font-size:11.0pt;
font-family:"Calibri",sans-serif;
mso-fareast-language:EN-US;}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:#0563C1;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:#954F72;
text-decoration:underline;}
span.EmailStyle17
{mso-style-type:personal-compose;
font-family:"Calibri",sans-serif;
color:windowtext;}
.MsoChpDefault
{mso-style-type:export-only;
font-family:"Calibri",sans-serif;
mso-fareast-language:EN-US;}
@page WordSection1
{size:612.0pt 792.0pt;
margin:72.0pt 72.0pt 72.0pt 72.0pt;}
div.WordSection1
{page:WordSection1;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]--></head><body lang=EN-AU link="#0563C1" vlink="#954F72"><div class=WordSection1><p class=MsoNormal><span lang=EN-US>I’ve been looking at how much work it might take to implement a new NITF compression value (IC=CC and IC=MC) which is basically just ZLIB DEFLATE encoded blocks.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US>I’m mostly following the pattern used for JPEG, and its down to the part where I just need to do the compression:<o:p></o:p></span></p><p class=MsoNormal style='line-height:14.25pt;background:#1E1E1E'><span style='font-size:10.5pt;font-family:"Courier New";color:#569CD6;mso-fareast-language:EN-AU'>int</span><span style='font-size:10.5pt;font-family:"Courier New";color:#D4D4D4;mso-fareast-language:EN-AU'><o:p></o:p></span></p><p class=MsoNormal style='line-height:14.25pt;background:#1E1E1E'><span style='font-size:10.5pt;font-family:"Courier New";color:#DCDCAA;mso-fareast-language:EN-AU'>NITFWriteZLIBBlock</span><span style='font-size:10.5pt;font-family:"Courier New";color:#D4D4D4;mso-fareast-language:EN-AU'>( GDALDataset *poSrcDS, VSILFILE *fp,<o:p></o:p></span></p><p class=MsoNormal style='line-height:14.25pt;background:#1E1E1E'><span style='font-size:10.5pt;font-family:"Courier New";color:#D4D4D4;mso-fareast-language:EN-AU'> </span><span style='font-size:10.5pt;font-family:"Courier New";color:#569CD6;mso-fareast-language:EN-AU'>int</span><span style='font-size:10.5pt;font-family:"Courier New";color:#D4D4D4;mso-fareast-language:EN-AU'> nBlockXOff, </span><span style='font-size:10.5pt;font-family:"Courier New";color:#569CD6;mso-fareast-language:EN-AU'>int</span><span style='font-size:10.5pt;font-family:"Courier New";color:#D4D4D4;mso-fareast-language:EN-AU'> nBlockYOff,<o:p></o:p></span></p><p class=MsoNormal style='line-height:14.25pt;background:#1E1E1E'><span style='font-size:10.5pt;font-family:"Courier New";color:#D4D4D4;mso-fareast-language:EN-AU'> </span><span style='font-size:10.5pt;font-family:"Courier New";color:#569CD6;mso-fareast-language:EN-AU'>int</span><span style='font-size:10.5pt;font-family:"Courier New";color:#D4D4D4;mso-fareast-language:EN-AU'> nBlockXSize, </span><span style='font-size:10.5pt;font-family:"Courier New";color:#569CD6;mso-fareast-language:EN-AU'>int</span><span style='font-size:10.5pt;font-family:"Courier New";color:#D4D4D4;mso-fareast-language:EN-AU'> nBlockYSize,<o:p></o:p></span></p><p class=MsoNormal style='line-height:14.25pt;background:#1E1E1E'><span style='font-size:10.5pt;font-family:"Courier New";color:#D4D4D4;mso-fareast-language:EN-AU'> GDALProgressFunc pfnProgress, </span><span style='font-size:10.5pt;font-family:"Courier New";color:#569CD6;mso-fareast-language:EN-AU'>void</span><span style='font-size:10.5pt;font-family:"Courier New";color:#D4D4D4;mso-fareast-language:EN-AU'> * pProgressData )<o:p></o:p></span></p><p class=MsoNormal style='line-height:14.25pt;background:#1E1E1E'><span style='font-size:10.5pt;font-family:"Courier New";color:#D4D4D4;mso-fareast-language:EN-AU'>{<o:p></o:p></span></p><p class=MsoNormal style='line-height:14.25pt;background:#1E1E1E'><span style='font-size:10.5pt;font-family:"Courier New";color:#D4D4D4;mso-fareast-language:EN-AU'> </span><span style='font-size:10.5pt;font-family:"Courier New";color:#DCDCAA;mso-fareast-language:EN-AU'>CPLDebug</span><span style='font-size:10.5pt;font-family:"Courier New";color:#D4D4D4;mso-fareast-language:EN-AU'>(</span><span style='font-size:10.5pt;font-family:"Courier New";color:#CE9178;mso-fareast-language:EN-AU'>"NITF"</span><span style='font-size:10.5pt;font-family:"Courier New";color:#D4D4D4;mso-fareast-language:EN-AU'>, </span><span style='font-size:10.5pt;font-family:"Courier New";color:#CE9178;mso-fareast-language:EN-AU'>"nBlockXOff=%d/%d, nBlockYOff=%d/%d"</span><span style='font-size:10.5pt;font-family:"Courier New";color:#D4D4D4;mso-fareast-language:EN-AU'>,<o:p></o:p></span></p><p class=MsoNormal style='line-height:14.25pt;background:#1E1E1E'><span style='font-size:10.5pt;font-family:"Courier New";color:#D4D4D4;mso-fareast-language:EN-AU'> nBlockXOff, nBlockXSize, nBlockYOff, nBlockYSize);<o:p></o:p></span></p><p class=MsoNormal style='line-height:14.25pt;background:#1E1E1E'><span style='font-size:10.5pt;font-family:"Courier New";color:#D4D4D4;mso-fareast-language:EN-AU'> </span><span style='font-size:10.5pt;font-family:"Courier New";color:#C586C0;mso-fareast-language:EN-AU'>return</span><span style='font-size:10.5pt;font-family:"Courier New";color:#D4D4D4;mso-fareast-language:EN-AU'> </span><span style='font-size:10.5pt;font-family:"Courier New";color:#569CD6;mso-fareast-language:EN-AU'>true</span><span style='font-size:10.5pt;font-family:"Courier New";color:#D4D4D4;mso-fareast-language:EN-AU'>;<o:p></o:p></span></p><p class=MsoNormal style='line-height:14.25pt;background:#1E1E1E'><span style='font-size:10.5pt;font-family:"Courier New";color:#D4D4D4;mso-fareast-language:EN-AU'>}<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US>Before I start to dig around in zlib, is there any support in the RasterIO level to do this? Anything else I could copy before reimplementing it poorly?<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US>Brad<o:p></o:p></span></p></div></body></html>