/**
* Decompress a character buffer.
*
* inbuf - the compressed buffer.
* inbufsz - size of the compressed buffer.
* outbufsz - suggested initial size for the output buffer,
* set to inbufsz if 0.
* outbuf - the decompressed buffer, use free_gzip to release it.
*/
void decode_gzip( const char *inbuf, size_t inbufsz, size_t &outbufsz,
char *&outbuf )
{
Compress compressor;
int insize = (int) inbufsz;
int outsize = (int) outbufsz;
/* Allocate the initial quantity of memory suggested. */
outbuf = (char *) malloc( outbufsz ? outbufsz : inbufsz );
compressor.decompress( inbuf, insize, outbuf, outsize,
Compress::GZIP_COMPRESS );
outbufsz = (size_t) outsize;
}
/*
* Given a URL pointing to preview data (FITS image or tab table data),
* request the data from the server and return 0 if all is OK. On
* return, if there were no errors, the "ctype" argument is set to the
* Content-type of the result to indicate the type of data. The data is
* automatically decompressed if needed (if the content-type is
* recognized). The "tmpfile()" method gives the name of the file
* containing the results on success.
*/
int AstroCatalog::getPreview(const char* url, char*& ctype)
{
// we need to use a new file, since the old one may be still in use
// (even after it was deleted, since it may still be open and/or mmapped)
newTempFile();
// open the tmp file
std::ofstream f(tmpfile_);
if (!f)
return sys_error("could not open file for writing: ", tmpfile_);
if (http_.get(url, f) != 0) {
unlink(tmpfile_);
return ERROR;
}
f.close();
// check the Content-type of the return data to determine whether it
// needs to be decompressed and if so, how...
ctype = http_.content_type();
if (!ctype)
ctype = (char *)"";
if (strcmp(ctype, "text/html") == 0) {
// most likely an HTML formatted server error message
std::ifstream is(tmpfile_);
unlink(tmpfile_);
return http_.html_error(is);
}
// for now, assume uncompressed table if the Content-type is not recognized
char* t = ctype;
int is_image = 0;
if (strncmp(ctype, "image/", 6) == 0) {
t = ctype+6;
is_image++;
}
else if (strncmp(ctype, "text/", 5) == 0) {
t = ctype+5;
}
else {
// unknown content type, check if it might be a FITS file
Mem m(tmpfile_);
if (m.status() == 0
&& m.size() >= 2880
&& strncmp((const char*)m.ptr(), "SIMPLE", 6) == 0) {
ctype = (char *)"image/x-fits"; // assume FITS file
is_image++;
} else {
ctype = (char *)"text/x-starbase"; // assume catalog data
}
return 0;
}
// In some cases the Content-type only gives the general type and
// we need to check the Content-Encoding also. For example "file.fits.gz"
// might have a Content-type of image/x-fits and Content-Encoding of
// x-gzip
char* ce = http_.content_encoding();
if (is_image && strcmp(t, "x-fits") == 0 && ce != NULL) {
if (strcmp(ce, "x-gzip") == 0) {
ctype = (char *)"image/x-gfits";
t = ctype+6;
}
else if (strcmp(ce, "x-compress") == 0) {
ctype = (char *)"image/x-cfits";
t = ctype+6;
}
}
// pure FITS or starbase table ?
if (strcmp(t, "x-fits") == 0
|| strcmp(t, "fits" ) == 0
|| strcmp(t, "fits") == 0
|| strcmp(t, "x-starbase") == 0
|| strcmp(t, "plain") == 0
|| strcmp(t, "tab-separated-values") == 0) {
return 0; // not compressed, just return filename
}
Compress::CompressType type = Compress::NO_COMPRESS;
if (strcmp(t, "x-hfits") == 0) {
type = Compress::H_COMPRESS; // Hcompressed FITS file
}
else if (strcmp(t, "x-gfits") == 0 || strcmp(t, "x-gstarbase") == 0) {
type = Compress::GZIP_COMPRESS; // GZIPed FITS or tab table
}
else if (strcmp(t, "x-cfits") == 0 || strcmp(t, "x-cstarbase") == 0) {
type = Compress::UNIX_COMPRESS; // UNIX Compressed FITS ir tab table
}
else if (strcmp(t, "x-sfits") == 0) { // Compressed FITS file (Stark)
// type = Compress::S_COMPRESS;
unlink(tmpfile_);
return error("x-sfits compression (Stark) not supported");
}
else {
unlink(tmpfile_);
return error("unknown preview data Content-type: ", ctype);
}
// do the decompression
FILE* feedback = http_.feedback();
if (feedback) {
fprintf(feedback, "decompressing data...\n");
fflush(feedback);
}
Compress c;
if (c.decompress(tmpfile_, type) != 0) {
unlink(tmpfile_);
return ERROR;
}
// correct Content-type after decompression
ctype = (char*)(is_image ? "image/x-fits" : "text/x-starbase");
// if we got here, then we have the FITS file, so return the file name
return 0;
}
