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fits_hdecompress.c
2614 lines (2434 loc) · 61.8 KB
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fits_hdecompress.c
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/* #########################################################################
These routines to apply the H-compress decompression algorithm to a 2-D Fits
image were written by R. White at the STScI and were obtained from the STScI at
http://www.stsci.edu/software/hcompress.html
This source file is a concatination of the following sources files in the
original distribution
hinv.c
hsmooth.c
undigitize.c
decode.c
dodecode.c
qtree_decode.c
qread.c
bit_input.c
The following modifications have been made to the original code:
- commented out redundant "include" statements
- added the nextchar global variable
- changed all the 'extern' declarations to 'static', since all the routines are in
the same source file
- changed the first parameter in decode (and in lower level routines from a file stream
to a char array
- modified the myread routine, and lower level byte reading routines, to copy
the input bytes to a char array, instead of reading them from a file stream
- changed the function declarations to the more modern ANSI C style
- changed calls to printf and perror to call the CFITSIO ffpmsg routine
- replace "exit" statements with "return" statements
############################################################################ */
#include <stdio.h>
#include <math.h>
#include <stdlib.h>
#include <string.h>
#include "fitsio2.h"
/* WDP added test to see if min and max are already defined */
#ifndef min
#define min(a,b) (((a)<(b))?(a):(b))
#endif
#ifndef max
#define max(a,b) (((a)>(b))?(a):(b))
#endif
static long nextchar;
static int decode(unsigned char *infile, int *a, int *nx, int *ny, int *scale);
static int decode64(unsigned char *infile, LONGLONG *a, int *nx, int *ny, int *scale);
static int hinv(int a[], int nx, int ny, int smooth ,int scale);
static int hinv64(LONGLONG a[], int nx, int ny, int smooth ,int scale);
static void undigitize(int a[], int nx, int ny, int scale);
static void undigitize64(LONGLONG a[], int nx, int ny, int scale);
static void unshuffle(int a[], int n, int n2, int tmp[]);
static void unshuffle64(LONGLONG a[], int n, int n2, LONGLONG tmp[]);
static void hsmooth(int a[], int nxtop, int nytop, int ny, int scale);
static void hsmooth64(LONGLONG a[], int nxtop, int nytop, int ny, int scale);
static void qread(unsigned char *infile,char *a, int n);
static int readint(unsigned char *infile);
static LONGLONG readlonglong(unsigned char *infile);
static int dodecode(unsigned char *infile, int a[], int nx, int ny, unsigned char nbitplanes[3]);
static int dodecode64(unsigned char *infile, LONGLONG a[], int nx, int ny, unsigned char nbitplanes[3]);
static int qtree_decode(unsigned char *infile, int a[], int n, int nqx, int nqy, int nbitplanes);
static int qtree_decode64(unsigned char *infile, LONGLONG a[], int n, int nqx, int nqy, int nbitplanes);
static void start_inputing_bits(void);
static int input_bit(unsigned char *infile);
static int input_nbits(unsigned char *infile, int n);
/* make input_nybble a separate routine, for added effiency */
/* #define input_nybble(infile) input_nbits(infile,4) */
static int input_nybble(unsigned char *infile);
static int input_nnybble(unsigned char *infile, int n, unsigned char *array);
static void qtree_expand(unsigned char *infile, unsigned char a[], int nx, int ny, unsigned char b[]);
static void qtree_bitins(unsigned char a[], int nx, int ny, int b[], int n, int bit);
static void qtree_bitins64(unsigned char a[], int nx, int ny, LONGLONG b[], int n, int bit);
static void qtree_copy(unsigned char a[], int nx, int ny, unsigned char b[], int n);
static void read_bdirect(unsigned char *infile, int a[], int n, int nqx, int nqy, unsigned char scratch[], int bit);
static void read_bdirect64(unsigned char *infile, LONGLONG a[], int n, int nqx, int nqy, unsigned char scratch[], int bit);
static int input_huffman(unsigned char *infile);
/* ---------------------------------------------------------------------- */
int fits_hdecompress(unsigned char *input, int smooth, int *a, int *ny, int *nx,
int *scale, int *status)
{
/*
decompress the input byte stream using the H-compress algorithm
input - input array of compressed bytes
a - pre-allocated array to hold the output uncompressed image
nx - returned X axis size
ny - returned Y axis size
NOTE: the nx and ny dimensions as defined within this code are reversed from
the usual FITS notation. ny is the fastest varying dimension, which is
usually considered the X axis in the FITS image display
*/
int stat;
if (*status > 0) return(*status);
/* decode the input array */
FFLOCK; /* decode uses the nextchar global variable */
stat = decode(input, a, nx, ny, scale);
FFUNLOCK;
*status = stat;
if (stat) return(*status);
/*
* Un-Digitize
*/
undigitize(a, *nx, *ny, *scale);
/*
* Inverse H-transform
*/
stat = hinv(a, *nx, *ny, smooth, *scale);
*status = stat;
return(*status);
}
/* ---------------------------------------------------------------------- */
int fits_hdecompress64(unsigned char *input, int smooth, LONGLONG *a, int *ny, int *nx,
int *scale, int *status)
{
/*
decompress the input byte stream using the H-compress algorithm
input - input array of compressed bytes
a - pre-allocated array to hold the output uncompressed image
nx - returned X axis size
ny - returned Y axis size
NOTE: the nx and ny dimensions as defined within this code are reversed from
the usual FITS notation. ny is the fastest varying dimension, which is
usually considered the X axis in the FITS image display
*/
int stat, *iarray, ii, nval;
if (*status > 0) return(*status);
/* decode the input array */
FFLOCK; /* decode uses the nextchar global variable */
stat = decode64(input, a, nx, ny, scale);
FFUNLOCK;
*status = stat;
if (stat) return(*status);
/*
* Un-Digitize
*/
undigitize64(a, *nx, *ny, *scale);
/*
* Inverse H-transform
*/
stat = hinv64(a, *nx, *ny, smooth, *scale);
*status = stat;
/* pack the I*8 values back into an I*4 array */
iarray = (int *) a;
nval = (*nx) * (*ny);
for (ii = 0; ii < nval; ii++)
iarray[ii] = (int) a[ii];
return(*status);
}
/* ############################################################################ */
/* ############################################################################ */
/* Copyright (c) 1993 Association of Universities for Research
* in Astronomy. All rights reserved. Produced under National
* Aeronautics and Space Administration Contract No. NAS5-26555.
*/
/* hinv.c Inverse H-transform of NX x NY integer image
*
* Programmer: R. White Date: 23 July 1993
*/
/* ############################################################################ */
static int
hinv(int a[], int nx, int ny, int smooth ,int scale)
/*
int smooth; 0 for no smoothing, else smooth during inversion
int scale; used if smoothing is specified
*/
{
int nmax, log2n, i, j, k;
int nxtop,nytop,nxf,nyf,c;
int oddx,oddy;
int shift, bit0, bit1, bit2, mask0, mask1, mask2,
prnd0, prnd1, prnd2, nrnd0, nrnd1, nrnd2, lowbit0, lowbit1;
int h0, hx, hy, hc;
int s10, s00;
int *tmp;
/*
* log2n is log2 of max(nx,ny) rounded up to next power of 2
*/
nmax = (nx>ny) ? nx : ny;
log2n = (int) (log((float) nmax)/log(2.0)+0.5);
if ( nmax > (1<<log2n) ) {
log2n += 1;
}
/*
* get temporary storage for shuffling elements
*/
tmp = (int *) malloc(((nmax+1)/2)*sizeof(int));
if (tmp == (int *) NULL) {
ffpmsg("hinv: insufficient memory");
return(DATA_DECOMPRESSION_ERR);
}
/*
* set up masks, rounding parameters
*/
shift = 1;
bit0 = 1 << (log2n - 1);
bit1 = bit0 << 1;
bit2 = bit0 << 2;
mask0 = -bit0;
mask1 = mask0 << 1;
mask2 = mask0 << 2;
prnd0 = bit0 >> 1;
prnd1 = bit1 >> 1;
prnd2 = bit2 >> 1;
nrnd0 = prnd0 - 1;
nrnd1 = prnd1 - 1;
nrnd2 = prnd2 - 1;
/*
* round h0 to multiple of bit2
*/
a[0] = (a[0] + ((a[0] >= 0) ? prnd2 : nrnd2)) & mask2;
/*
* do log2n expansions
*
* We're indexing a as a 2-D array with dimensions (nx,ny).
*/
nxtop = 1;
nytop = 1;
nxf = nx;
nyf = ny;
c = 1<<log2n;
for (k = log2n-1; k>=0; k--) {
/*
* this somewhat cryptic code generates the sequence
* ntop[k-1] = (ntop[k]+1)/2, where ntop[log2n] = n
*/
c = c>>1;
nxtop = nxtop<<1;
nytop = nytop<<1;
if (nxf <= c) { nxtop -= 1; } else { nxf -= c; }
if (nyf <= c) { nytop -= 1; } else { nyf -= c; }
/*
* double shift and fix nrnd0 (because prnd0=0) on last pass
*/
if (k == 0) {
nrnd0 = 0;
shift = 2;
}
/*
* unshuffle in each dimension to interleave coefficients
*/
for (i = 0; i<nxtop; i++) {
unshuffle(&a[ny*i],nytop,1,tmp);
}
for (j = 0; j<nytop; j++) {
unshuffle(&a[j],nxtop,ny,tmp);
}
/*
* smooth by interpolating coefficients if SMOOTH != 0
*/
if (smooth) hsmooth(a,nxtop,nytop,ny,scale);
oddx = nxtop % 2;
oddy = nytop % 2;
for (i = 0; i<nxtop-oddx; i += 2) {
s00 = ny*i; /* s00 is index of a[i,j] */
s10 = s00+ny; /* s10 is index of a[i+1,j] */
for (j = 0; j<nytop-oddy; j += 2) {
h0 = a[s00 ];
hx = a[s10 ];
hy = a[s00+1];
hc = a[s10+1];
/*
* round hx and hy to multiple of bit1, hc to multiple of bit0
* h0 is already a multiple of bit2
*/
hx = (hx + ((hx >= 0) ? prnd1 : nrnd1)) & mask1;
hy = (hy + ((hy >= 0) ? prnd1 : nrnd1)) & mask1;
hc = (hc + ((hc >= 0) ? prnd0 : nrnd0)) & mask0;
/*
* propagate bit0 of hc to hx,hy
*/
lowbit0 = hc & bit0;
hx = (hx >= 0) ? (hx - lowbit0) : (hx + lowbit0);
hy = (hy >= 0) ? (hy - lowbit0) : (hy + lowbit0);
/*
* Propagate bits 0 and 1 of hc,hx,hy to h0.
* This could be simplified if we assume h0>0, but then
* the inversion would not be lossless for images with
* negative pixels.
*/
lowbit1 = (hc ^ hx ^ hy) & bit1;
h0 = (h0 >= 0)
? (h0 + lowbit0 - lowbit1)
: (h0 + ((lowbit0 == 0) ? lowbit1 : (lowbit0-lowbit1)));
/*
* Divide sums by 2 (4 last time)
*/
a[s10+1] = (h0 + hx + hy + hc) >> shift;
a[s10 ] = (h0 + hx - hy - hc) >> shift;
a[s00+1] = (h0 - hx + hy - hc) >> shift;
a[s00 ] = (h0 - hx - hy + hc) >> shift;
s00 += 2;
s10 += 2;
}
if (oddy) {
/*
* do last element in row if row length is odd
* s00+1, s10+1 are off edge
*/
h0 = a[s00 ];
hx = a[s10 ];
hx = ((hx >= 0) ? (hx+prnd1) : (hx+nrnd1)) & mask1;
lowbit1 = hx & bit1;
h0 = (h0 >= 0) ? (h0 - lowbit1) : (h0 + lowbit1);
a[s10 ] = (h0 + hx) >> shift;
a[s00 ] = (h0 - hx) >> shift;
}
}
if (oddx) {
/*
* do last row if column length is odd
* s10, s10+1 are off edge
*/
s00 = ny*i;
for (j = 0; j<nytop-oddy; j += 2) {
h0 = a[s00 ];
hy = a[s00+1];
hy = ((hy >= 0) ? (hy+prnd1) : (hy+nrnd1)) & mask1;
lowbit1 = hy & bit1;
h0 = (h0 >= 0) ? (h0 - lowbit1) : (h0 + lowbit1);
a[s00+1] = (h0 + hy) >> shift;
a[s00 ] = (h0 - hy) >> shift;
s00 += 2;
}
if (oddy) {
/*
* do corner element if both row and column lengths are odd
* s00+1, s10, s10+1 are off edge
*/
h0 = a[s00 ];
a[s00 ] = h0 >> shift;
}
}
/*
* divide all the masks and rounding values by 2
*/
bit2 = bit1;
bit1 = bit0;
bit0 = bit0 >> 1;
mask1 = mask0;
mask0 = mask0 >> 1;
prnd1 = prnd0;
prnd0 = prnd0 >> 1;
nrnd1 = nrnd0;
nrnd0 = prnd0 - 1;
}
free(tmp);
return(0);
}
/* ############################################################################ */
static int
hinv64(LONGLONG a[], int nx, int ny, int smooth ,int scale)
/*
int smooth; 0 for no smoothing, else smooth during inversion
int scale; used if smoothing is specified
*/
{
int nmax, log2n, i, j, k;
int nxtop,nytop,nxf,nyf,c;
int oddx,oddy;
int shift;
LONGLONG mask0, mask1, mask2, prnd0, prnd1, prnd2, bit0, bit1, bit2;
LONGLONG nrnd0, nrnd1, nrnd2, lowbit0, lowbit1;
LONGLONG h0, hx, hy, hc;
int s10, s00;
LONGLONG *tmp;
/*
* log2n is log2 of max(nx,ny) rounded up to next power of 2
*/
nmax = (nx>ny) ? nx : ny;
log2n = (int) (log((float) nmax)/log(2.0)+0.5);
if ( nmax > (1<<log2n) ) {
log2n += 1;
}
/*
* get temporary storage for shuffling elements
*/
tmp = (LONGLONG *) malloc(((nmax+1)/2)*sizeof(LONGLONG));
if (tmp == (LONGLONG *) NULL) {
ffpmsg("hinv64: insufficient memory");
return(DATA_DECOMPRESSION_ERR);
}
/*
* set up masks, rounding parameters
*/
shift = 1;
bit0 = ((LONGLONG) 1) << (log2n - 1);
bit1 = bit0 << 1;
bit2 = bit0 << 2;
mask0 = -bit0;
mask1 = mask0 << 1;
mask2 = mask0 << 2;
prnd0 = bit0 >> 1;
prnd1 = bit1 >> 1;
prnd2 = bit2 >> 1;
nrnd0 = prnd0 - 1;
nrnd1 = prnd1 - 1;
nrnd2 = prnd2 - 1;
/*
* round h0 to multiple of bit2
*/
a[0] = (a[0] + ((a[0] >= 0) ? prnd2 : nrnd2)) & mask2;
/*
* do log2n expansions
*
* We're indexing a as a 2-D array with dimensions (nx,ny).
*/
nxtop = 1;
nytop = 1;
nxf = nx;
nyf = ny;
c = 1<<log2n;
for (k = log2n-1; k>=0; k--) {
/*
* this somewhat cryptic code generates the sequence
* ntop[k-1] = (ntop[k]+1)/2, where ntop[log2n] = n
*/
c = c>>1;
nxtop = nxtop<<1;
nytop = nytop<<1;
if (nxf <= c) { nxtop -= 1; } else { nxf -= c; }
if (nyf <= c) { nytop -= 1; } else { nyf -= c; }
/*
* double shift and fix nrnd0 (because prnd0=0) on last pass
*/
if (k == 0) {
nrnd0 = 0;
shift = 2;
}
/*
* unshuffle in each dimension to interleave coefficients
*/
for (i = 0; i<nxtop; i++) {
unshuffle64(&a[ny*i],nytop,1,tmp);
}
for (j = 0; j<nytop; j++) {
unshuffle64(&a[j],nxtop,ny,tmp);
}
/*
* smooth by interpolating coefficients if SMOOTH != 0
*/
if (smooth) hsmooth64(a,nxtop,nytop,ny,scale);
oddx = nxtop % 2;
oddy = nytop % 2;
for (i = 0; i<nxtop-oddx; i += 2) {
s00 = ny*i; /* s00 is index of a[i,j] */
s10 = s00+ny; /* s10 is index of a[i+1,j] */
for (j = 0; j<nytop-oddy; j += 2) {
h0 = a[s00 ];
hx = a[s10 ];
hy = a[s00+1];
hc = a[s10+1];
/*
* round hx and hy to multiple of bit1, hc to multiple of bit0
* h0 is already a multiple of bit2
*/
hx = (hx + ((hx >= 0) ? prnd1 : nrnd1)) & mask1;
hy = (hy + ((hy >= 0) ? prnd1 : nrnd1)) & mask1;
hc = (hc + ((hc >= 0) ? prnd0 : nrnd0)) & mask0;
/*
* propagate bit0 of hc to hx,hy
*/
lowbit0 = hc & bit0;
hx = (hx >= 0) ? (hx - lowbit0) : (hx + lowbit0);
hy = (hy >= 0) ? (hy - lowbit0) : (hy + lowbit0);
/*
* Propagate bits 0 and 1 of hc,hx,hy to h0.
* This could be simplified if we assume h0>0, but then
* the inversion would not be lossless for images with
* negative pixels.
*/
lowbit1 = (hc ^ hx ^ hy) & bit1;
h0 = (h0 >= 0)
? (h0 + lowbit0 - lowbit1)
: (h0 + ((lowbit0 == 0) ? lowbit1 : (lowbit0-lowbit1)));
/*
* Divide sums by 2 (4 last time)
*/
a[s10+1] = (h0 + hx + hy + hc) >> shift;
a[s10 ] = (h0 + hx - hy - hc) >> shift;
a[s00+1] = (h0 - hx + hy - hc) >> shift;
a[s00 ] = (h0 - hx - hy + hc) >> shift;
s00 += 2;
s10 += 2;
}
if (oddy) {
/*
* do last element in row if row length is odd
* s00+1, s10+1 are off edge
*/
h0 = a[s00 ];
hx = a[s10 ];
hx = ((hx >= 0) ? (hx+prnd1) : (hx+nrnd1)) & mask1;
lowbit1 = hx & bit1;
h0 = (h0 >= 0) ? (h0 - lowbit1) : (h0 + lowbit1);
a[s10 ] = (h0 + hx) >> shift;
a[s00 ] = (h0 - hx) >> shift;
}
}
if (oddx) {
/*
* do last row if column length is odd
* s10, s10+1 are off edge
*/
s00 = ny*i;
for (j = 0; j<nytop-oddy; j += 2) {
h0 = a[s00 ];
hy = a[s00+1];
hy = ((hy >= 0) ? (hy+prnd1) : (hy+nrnd1)) & mask1;
lowbit1 = hy & bit1;
h0 = (h0 >= 0) ? (h0 - lowbit1) : (h0 + lowbit1);
a[s00+1] = (h0 + hy) >> shift;
a[s00 ] = (h0 - hy) >> shift;
s00 += 2;
}
if (oddy) {
/*
* do corner element if both row and column lengths are odd
* s00+1, s10, s10+1 are off edge
*/
h0 = a[s00 ];
a[s00 ] = h0 >> shift;
}
}
/*
* divide all the masks and rounding values by 2
*/
bit2 = bit1;
bit1 = bit0;
bit0 = bit0 >> 1;
mask1 = mask0;
mask0 = mask0 >> 1;
prnd1 = prnd0;
prnd0 = prnd0 >> 1;
nrnd1 = nrnd0;
nrnd0 = prnd0 - 1;
}
free(tmp);
return(0);
}
/* ############################################################################ */
static void
unshuffle(int a[], int n, int n2, int tmp[])
/*
int a[]; array to shuffle
int n; number of elements to shuffle
int n2; second dimension
int tmp[]; scratch storage
*/
{
int i;
int nhalf;
int *p1, *p2, *pt;
/*
* copy 2nd half of array to tmp
*/
nhalf = (n+1)>>1;
pt = tmp;
p1 = &a[n2*nhalf]; /* pointer to a[i] */
for (i=nhalf; i<n; i++) {
*pt = *p1;
p1 += n2;
pt += 1;
}
/*
* distribute 1st half of array to even elements
*/
p2 = &a[ n2*(nhalf-1) ]; /* pointer to a[i] */
p1 = &a[(n2*(nhalf-1))<<1]; /* pointer to a[2*i] */
for (i=nhalf-1; i >= 0; i--) {
*p1 = *p2;
p2 -= n2;
p1 -= (n2+n2);
}
/*
* now distribute 2nd half of array (in tmp) to odd elements
*/
pt = tmp;
p1 = &a[n2]; /* pointer to a[i] */
for (i=1; i<n; i += 2) {
*p1 = *pt;
p1 += (n2+n2);
pt += 1;
}
}
/* ############################################################################ */
static void
unshuffle64(LONGLONG a[], int n, int n2, LONGLONG tmp[])
/*
LONGLONG a[]; array to shuffle
int n; number of elements to shuffle
int n2; second dimension
LONGLONG tmp[]; scratch storage
*/
{
int i;
int nhalf;
LONGLONG *p1, *p2, *pt;
/*
* copy 2nd half of array to tmp
*/
nhalf = (n+1)>>1;
pt = tmp;
p1 = &a[n2*nhalf]; /* pointer to a[i] */
for (i=nhalf; i<n; i++) {
*pt = *p1;
p1 += n2;
pt += 1;
}
/*
* distribute 1st half of array to even elements
*/
p2 = &a[ n2*(nhalf-1) ]; /* pointer to a[i] */
p1 = &a[(n2*(nhalf-1))<<1]; /* pointer to a[2*i] */
for (i=nhalf-1; i >= 0; i--) {
*p1 = *p2;
p2 -= n2;
p1 -= (n2+n2);
}
/*
* now distribute 2nd half of array (in tmp) to odd elements
*/
pt = tmp;
p1 = &a[n2]; /* pointer to a[i] */
for (i=1; i<n; i += 2) {
*p1 = *pt;
p1 += (n2+n2);
pt += 1;
}
}
/* ############################################################################ */
/* ############################################################################ */
/* Copyright (c) 1993 Association of Universities for Research
* in Astronomy. All rights reserved. Produced under National
* Aeronautics and Space Administration Contract No. NAS5-26555.
*/
/* hsmooth.c Smooth H-transform image by adjusting coefficients toward
* interpolated values
*
* Programmer: R. White Date: 13 April 1992
*/
/* ############################################################################ */
static void
hsmooth(int a[], int nxtop, int nytop, int ny, int scale)
/*
int a[]; array of H-transform coefficients
int nxtop,nytop; size of coefficient block to use
int ny; actual 1st dimension of array
int scale; truncation scale factor that was used
*/
{
int i, j;
int ny2, s10, s00, diff, dmax, dmin, s, smax;
int hm, h0, hp, hmm, hpm, hmp, hpp, hx2, hy2;
int m1,m2;
/*
* Maximum change in coefficients is determined by scale factor.
* Since we rounded during division (see digitize.c), the biggest
* permitted change is scale/2.
*/
smax = (scale >> 1);
if (smax <= 0) return;
ny2 = ny << 1;
/*
* We're indexing a as a 2-D array with dimensions (nxtop,ny) of which
* only (nxtop,nytop) are used. The coefficients on the edge of the
* array are not adjusted (which is why the loops below start at 2
* instead of 0 and end at nxtop-2 instead of nxtop.)
*/
/*
* Adjust x difference hx
*/
for (i = 2; i<nxtop-2; i += 2) {
s00 = ny*i; /* s00 is index of a[i,j] */
s10 = s00+ny; /* s10 is index of a[i+1,j] */
for (j = 0; j<nytop; j += 2) {
/*
* hp is h0 (mean value) in next x zone, hm is h0 in previous x zone
*/
hm = a[s00-ny2];
h0 = a[s00];
hp = a[s00+ny2];
/*
* diff = 8 * hx slope that would match h0 in neighboring zones
*/
diff = hp-hm;
/*
* monotonicity constraints on diff
*/
dmax = max( min( (hp-h0), (h0-hm) ), 0 ) << 2;
dmin = min( max( (hp-h0), (h0-hm) ), 0 ) << 2;
/*
* if monotonicity would set slope = 0 then don't change hx.
* note dmax>=0, dmin<=0.
*/
if (dmin < dmax) {
diff = max( min(diff, dmax), dmin);
/*
* Compute change in slope limited to range +/- smax.
* Careful with rounding negative numbers when using
* shift for divide by 8.
*/
s = diff-(a[s10]<<3);
s = (s>=0) ? (s>>3) : ((s+7)>>3) ;
s = max( min(s, smax), -smax);
a[s10] = a[s10]+s;
}
s00 += 2;
s10 += 2;
}
}
/*
* Adjust y difference hy
*/
for (i = 0; i<nxtop; i += 2) {
s00 = ny*i+2;
s10 = s00+ny;
for (j = 2; j<nytop-2; j += 2) {
hm = a[s00-2];
h0 = a[s00];
hp = a[s00+2];
diff = hp-hm;
dmax = max( min( (hp-h0), (h0-hm) ), 0 ) << 2;
dmin = min( max( (hp-h0), (h0-hm) ), 0 ) << 2;
if (dmin < dmax) {
diff = max( min(diff, dmax), dmin);
s = diff-(a[s00+1]<<3);
s = (s>=0) ? (s>>3) : ((s+7)>>3) ;
s = max( min(s, smax), -smax);
a[s00+1] = a[s00+1]+s;
}
s00 += 2;
s10 += 2;
}
}
/*
* Adjust curvature difference hc
*/
for (i = 2; i<nxtop-2; i += 2) {
s00 = ny*i+2;
s10 = s00+ny;
for (j = 2; j<nytop-2; j += 2) {
/*
* ------------------ y
* | hmp | | hpp | |
* ------------------ |
* | | h0 | | |
* ------------------ -------x
* | hmm | | hpm |
* ------------------
*/
hmm = a[s00-ny2-2];
hpm = a[s00+ny2-2];
hmp = a[s00-ny2+2];
hpp = a[s00+ny2+2];
h0 = a[s00];
/*
* diff = 64 * hc value that would match h0 in neighboring zones
*/
diff = hpp + hmm - hmp - hpm;
/*
* 2 times x,y slopes in this zone
*/
hx2 = a[s10 ]<<1;
hy2 = a[s00+1]<<1;
/*
* monotonicity constraints on diff
*/
m1 = min(max(hpp-h0,0)-hx2-hy2, max(h0-hpm,0)+hx2-hy2);
m2 = min(max(h0-hmp,0)-hx2+hy2, max(hmm-h0,0)+hx2+hy2);
dmax = min(m1,m2) << 4;
m1 = max(min(hpp-h0,0)-hx2-hy2, min(h0-hpm,0)+hx2-hy2);
m2 = max(min(h0-hmp,0)-hx2+hy2, min(hmm-h0,0)+hx2+hy2);
dmin = max(m1,m2) << 4;
/*
* if monotonicity would set slope = 0 then don't change hc.
* note dmax>=0, dmin<=0.
*/
if (dmin < dmax) {
diff = max( min(diff, dmax), dmin);
/*
* Compute change in slope limited to range +/- smax.
* Careful with rounding negative numbers when using
* shift for divide by 64.
*/
s = diff-(a[s10+1]<<6);
s = (s>=0) ? (s>>6) : ((s+63)>>6) ;
s = max( min(s, smax), -smax);
a[s10+1] = a[s10+1]+s;
}
s00 += 2;
s10 += 2;
}
}
}
/* ############################################################################ */
static void
hsmooth64(LONGLONG a[], int nxtop, int nytop, int ny, int scale)
/*
LONGLONG a[]; array of H-transform coefficients
int nxtop,nytop; size of coefficient block to use
int ny; actual 1st dimension of array
int scale; truncation scale factor that was used
*/
{
int i, j;
int ny2, s10, s00;
LONGLONG hm, h0, hp, hmm, hpm, hmp, hpp, hx2, hy2, diff, dmax, dmin, s, smax, m1, m2;
/*
* Maximum change in coefficients is determined by scale factor.
* Since we rounded during division (see digitize.c), the biggest
* permitted change is scale/2.
*/
smax = (scale >> 1);
if (smax <= 0) return;
ny2 = ny << 1;
/*
* We're indexing a as a 2-D array with dimensions (nxtop,ny) of which
* only (nxtop,nytop) are used. The coefficients on the edge of the
* array are not adjusted (which is why the loops below start at 2
* instead of 0 and end at nxtop-2 instead of nxtop.)
*/
/*
* Adjust x difference hx
*/
for (i = 2; i<nxtop-2; i += 2) {
s00 = ny*i; /* s00 is index of a[i,j] */
s10 = s00+ny; /* s10 is index of a[i+1,j] */
for (j = 0; j<nytop; j += 2) {
/*
* hp is h0 (mean value) in next x zone, hm is h0 in previous x zone
*/
hm = a[s00-ny2];
h0 = a[s00];
hp = a[s00+ny2];
/*
* diff = 8 * hx slope that would match h0 in neighboring zones
*/
diff = hp-hm;
/*
* monotonicity constraints on diff
*/
dmax = max( min( (hp-h0), (h0-hm) ), 0 ) << 2;
dmin = min( max( (hp-h0), (h0-hm) ), 0 ) << 2;
/*
* if monotonicity would set slope = 0 then don't change hx.
* note dmax>=0, dmin<=0.
*/
if (dmin < dmax) {
diff = max( min(diff, dmax), dmin);
/*
* Compute change in slope limited to range +/- smax.
* Careful with rounding negative numbers when using
* shift for divide by 8.
*/
s = diff-(a[s10]<<3);
s = (s>=0) ? (s>>3) : ((s+7)>>3) ;
s = max( min(s, smax), -smax);
a[s10] = a[s10]+s;
}
s00 += 2;
s10 += 2;
}
}
/*
* Adjust y difference hy
*/
for (i = 0; i<nxtop; i += 2) {
s00 = ny*i+2;
s10 = s00+ny;
for (j = 2; j<nytop-2; j += 2) {
hm = a[s00-2];
h0 = a[s00];
hp = a[s00+2];
diff = hp-hm;
dmax = max( min( (hp-h0), (h0-hm) ), 0 ) << 2;
dmin = min( max( (hp-h0), (h0-hm) ), 0 ) << 2;
if (dmin < dmax) {
diff = max( min(diff, dmax), dmin);
s = diff-(a[s00+1]<<3);
s = (s>=0) ? (s>>3) : ((s+7)>>3) ;
s = max( min(s, smax), -smax);
a[s00+1] = a[s00+1]+s;
}
s00 += 2;
s10 += 2;
}
}
/*
* Adjust curvature difference hc
*/
for (i = 2; i<nxtop-2; i += 2) {
s00 = ny*i+2;
s10 = s00+ny;
for (j = 2; j<nytop-2; j += 2) {
/*
* ------------------ y
* | hmp | | hpp | |
* ------------------ |
* | | h0 | | |
* ------------------ -------x
* | hmm | | hpm |
* ------------------
*/
hmm = a[s00-ny2-2];
hpm = a[s00+ny2-2];
hmp = a[s00-ny2+2];
hpp = a[s00+ny2+2];
h0 = a[s00];
/*
* diff = 64 * hc value that would match h0 in neighboring zones
*/
diff = hpp + hmm - hmp - hpm;
/*
* 2 times x,y slopes in this zone
*/
hx2 = a[s10 ]<<1;
hy2 = a[s00+1]<<1;
/*
* monotonicity constraints on diff
*/
m1 = min(max(hpp-h0,0)-hx2-hy2, max(h0-hpm,0)+hx2-hy2);
m2 = min(max(h0-hmp,0)-hx2+hy2, max(hmm-h0,0)+hx2+hy2);
dmax = min(m1,m2) << 4;
m1 = max(min(hpp-h0,0)-hx2-hy2, min(h0-hpm,0)+hx2-hy2);
m2 = max(min(h0-hmp,0)-hx2+hy2, min(hmm-h0,0)+hx2+hy2);
dmin = max(m1,m2) << 4;
/*
* if monotonicity would set slope = 0 then don't change hc.
* note dmax>=0, dmin<=0.
*/
if (dmin < dmax) {
diff = max( min(diff, dmax), dmin);
/*
* Compute change in slope limited to range +/- smax.
* Careful with rounding negative numbers when using
* shift for divide by 64.
*/
s = diff-(a[s10+1]<<6);
s = (s>=0) ? (s>>6) : ((s+63)>>6) ;
s = max( min(s, smax), -smax);
a[s10+1] = a[s10+1]+s;
}
s00 += 2;
s10 += 2;
}
}
}
/* ############################################################################ */
/* ############################################################################ */
/* Copyright (c) 1993 Association of Universities for Research
* in Astronomy. All rights reserved. Produced under National
* Aeronautics and Space Administration Contract No. NAS5-26555.
*/
/* undigitize.c undigitize H-transform
*
* Programmer: R. White Date: 9 May 1991
*/