jpc_qmfb.c

用C语言实现的JPEG编码

		ptr = &startptr[((llen - 1) << 1) * step];
		n = llen >> 1;
		tmpptr = buf;
		while (n-- > 0) {
			*tmpptr = *ptr;
			*ptr = *lptr;
			++tmpptr;
			ptr -= twostep;
			lptr -= step;
		}
		n = llen - (llen >> 1);
		while (n-- > 0) {
			*ptr = *lptr;
			ptr -= twostep;
			lptr -= step;
		}
		/* Copy the appropriate samples into the second phase of
		  the output signal (corresponding to odd indexed
		  samples). */
		ptr = &startptr[step];
		hptr = hstartptr;
		state = !(llen & 1);
		n = hlen;
		while (n-- > 0) {
			if (state) {
				--tmpptr;
				*ptr = *tmpptr;
			} else {
				*ptr = *hptr;
			}
			hptr += step;
			ptr += twostep;
			state ^= 1;
		}
	}

#if defined(WIN32)
	/* If the join buffer was allocated on the heap, free this memory. */
	if (buf != joinbuf) {
		jas_free(buf);
	}
#endif
}

/******************************************************************************\
* Code for 5/3 transform.
\******************************************************************************/

static int jpc_ft_getnumchans(jpc_qmfb1d_t *qmfb)
{
	/* Avoid compiler warnings about unused parameters. */
	qmfb = 0;

	return 2;
}

static int jpc_ft_getanalfilters(jpc_qmfb1d_t *qmfb, int len, jas_seq2d_t **filters)
{
	/* Avoid compiler warnings about unused parameters. */
	qmfb = 0;
	len = 0;
	filters = 0;
	abort();
	return -1;
}

static int jpc_ft_getsynfilters(jpc_qmfb1d_t *qmfb, int len, jas_seq2d_t **filters)
{
	jas_seq_t *lf;
	jas_seq_t *hf;

	/* Avoid compiler warnings about unused parameters. */
	qmfb = 0;

	lf = 0;
	hf = 0;

	if (len > 1 || (!len)) {
		if (!(lf = jas_seq_create(-1, 2))) {
			goto error;
		}
		jas_seq_set(lf, -1, jpc_dbltofix(0.5));
		jas_seq_set(lf, 0, jpc_dbltofix(1.0));
		jas_seq_set(lf, 1, jpc_dbltofix(0.5));
		if (!(hf = jas_seq_create(-1, 4))) {
			goto error;
		}
		jas_seq_set(hf, -1, jpc_dbltofix(-0.125));
		jas_seq_set(hf, 0, jpc_dbltofix(-0.25));
		jas_seq_set(hf, 1, jpc_dbltofix(0.75));
		jas_seq_set(hf, 2, jpc_dbltofix(-0.25));
		jas_seq_set(hf, 3, jpc_dbltofix(-0.125));
	} else if (len == 1) {
		if (!(lf = jas_seq_create(0, 1))) {
			goto error;
		}
		jas_seq_set(lf, 0, jpc_dbltofix(1.0));
		if (!(hf = jas_seq_create(0, 1))) {
			goto error;
		}
		jas_seq_set(hf, 0, jpc_dbltofix(2.0));
	} else {
		abort();
	}

	filters[0] = lf;
	filters[1] = hf;

	return 0;

error:
	if (lf) {
		jas_seq_destroy(lf);
	}
	if (hf) {
		jas_seq_destroy(hf);
	}
	return -1;
}

#define	NFT_LIFT0(lstartptr, lstartind, lendind, hstartptr, hstartind, hendind, step, pluseq) \
{ \
	register jpc_fix_t *lptr = (lstartptr); \
	register jpc_fix_t *hptr = (hstartptr); \
	register int n = (hendind) - (hstartind); \
	if ((hstartind) < (lstartind)) { \
		pluseq(*hptr, *lptr); \
		hptr += (step); \
		--n; \
	} \
	if ((hendind) >= (lendind)) { \
		--n; \
	} \
	while (n-- > 0) { \
		pluseq(*hptr, jpc_fix_asr(jpc_fix_add(*lptr, lptr[(step)]), 1)); \
		hptr += (step); \
		lptr += (step); \
	} \
	if ((hendind) >= (lendind)) { \
		pluseq(*hptr, *lptr); \
	} \
}

#define	NFT_LIFT1(lstartptr, lstartind, lendind, hstartptr, hstartind, hendind, step, pluseq) \
{ \
	register jpc_fix_t *lptr = (lstartptr); \
	register jpc_fix_t *hptr = (hstartptr); \
	register int n = (lendind) - (lstartind); \
	if ((hstartind) >= (lstartind)) { \
		pluseq(*lptr, *hptr); \
		lptr += (step); \
		--n; \
	} \
	if ((lendind) > (hendind)) { \
		--n; \
	} \
	while (n-- > 0) { \
		pluseq(*lptr, jpc_fix_asr(jpc_fix_add(*hptr, hptr[(step)]), 2)); \
		lptr += (step); \
		hptr += (step); \
	} \
	if ((lendind) > (hendind)) { \
		pluseq(*lptr, *hptr); \
	} \
}

#define	RFT_LIFT0(lstartptr, lstartind, lendind, hstartptr, hstartind, hendind, step, pmeqop) \
{ \
	register jpc_fix_t *lptr = (lstartptr); \
	register jpc_fix_t *hptr = (hstartptr); \
	register int n = (hendind) - (hstartind); \
	if ((hstartind) < (lstartind)) { \
		*hptr pmeqop *lptr; \
		hptr += (step); \
		--n; \
	} \
	if ((hendind) >= (lendind)) { \
		--n; \
	} \
	while (n-- > 0) { \
		*hptr pmeqop (*lptr + lptr[(step)]) >> 1; \
		hptr += (step); \
		lptr += (step); \
	} \
	if ((hendind) >= (lendind)) { \
		*hptr pmeqop *lptr; \
	} \
}

#define	RFT_LIFT1(lstartptr, lstartind, lendind, hstartptr, hstartind, hendind, step, pmeqop) \
{ \
	register jpc_fix_t *lptr = (lstartptr); \
	register jpc_fix_t *hptr = (hstartptr); \
	register int n = (lendind) - (lstartind); \
	if ((hstartind) >= (lstartind)) { \
		*lptr pmeqop ((*hptr << 1) + 2) >> 2; \
		lptr += (step); \
		--n; \
	} \
	if ((lendind) > (hendind)) { \
		--n; \
	} \
	while (n-- > 0) { \
		*lptr pmeqop ((*hptr + hptr[(step)]) + 2) >> 2; \
		lptr += (step); \
		hptr += (step); \
	} \
	if ((lendind) > (hendind)) { \
		*lptr pmeqop ((*hptr << 1) + 2) >> 2; \
	} \
}

static void jpc_ft_analyze(jpc_qmfb1d_t *qmfb, int flags, jas_seq2d_t *x)
{
	jpc_fix_t *startptr;
	int startind;
	int endind;
	jpc_fix_t *  lstartptr;
	int   lstartind;
	int   lendind;
	jpc_fix_t *  hstartptr;
	int   hstartind;
	int   hendind;
	int interstep;
	int intrastep;
	int numseq;

	/* Avoid compiler warnings about unused parameters. */
	qmfb = 0;

	if (flags & JPC_QMFB1D_VERT) {
		interstep = 1;
		intrastep = jas_seq2d_rowstep(x);
		numseq = jas_seq2d_width(x);
		startind = jas_seq2d_ystart(x);
		endind = jas_seq2d_yend(x);
	} else {
		interstep = jas_seq2d_rowstep(x);
		intrastep = 1;
		numseq = jas_seq2d_height(x);
		startind = jas_seq2d_xstart(x);
		endind = jas_seq2d_xend(x);
	}

	assert(startind < endind);

	startptr = jas_seq2d_getref(x, jas_seq2d_xstart(x), jas_seq2d_ystart(x));
	if (flags & JPC_QMFB1D_RITIMODE) {
		while (numseq-- > 0) {
			jpc_qmfb1d_setup(startptr, startind, endind, intrastep,
			  &lstartptr, &lstartind, &lendind, &hstartptr,
			  &hstartind, &hendind);
			if (endind - startind > 1) {
				jpc_qmfb1d_split(startptr, startind, endind,
				  intrastep, lstartptr, lstartind, lendind,
				  hstartptr, hstartind, hendind);
				RFT_LIFT0(lstartptr, lstartind, lendind,
				  hstartptr, hstartind, hendind, intrastep, -=);
				RFT_LIFT1(lstartptr, lstartind, lendind,
				  hstartptr, hstartind, hendind, intrastep, +=);
			} else {
				if (lstartind == lendind) {
					*startptr <<= 1;
				}
			}
			startptr += interstep;
		}
	} else {
		while (numseq-- > 0) {
			jpc_qmfb1d_setup(startptr, startind, endind, intrastep,
			  &lstartptr, &lstartind, &lendind, &hstartptr,
			  &hstartind, &hendind);
			if (endind - startind > 1) {
				jpc_qmfb1d_split(startptr, startind, endind,
				  intrastep, lstartptr, lstartind, lendind,
				  hstartptr, hstartind, hendind);
				NFT_LIFT0(lstartptr, lstartind, lendind,
				  hstartptr, hstartind, hendind, intrastep,
				  jpc_fix_minuseq);
				NFT_LIFT1(lstartptr, lstartind, lendind,
				  hstartptr, hstartind, hendind, intrastep,
				  jpc_fix_pluseq);
			} else {
				if (lstartind == lendind) {
					*startptr = jpc_fix_asl(*startptr, 1);
				}
			}
			startptr += interstep;
		}
	}
}

static void jpc_ft_synthesize(jpc_qmfb1d_t *qmfb, int flags, jas_seq2d_t *x)
{
	jpc_fix_t *startptr;
	int startind;
	int endind;
	jpc_fix_t *lstartptr;
	int lstartind;
	int lendind;
	jpc_fix_t *hstartptr;
	int hstartind;
	int hendind;
	int interstep;
	int intrastep;
	int numseq;

	/* Avoid compiler warnings about unused parameters. */
	qmfb = 0;

	if (flags & JPC_QMFB1D_VERT) {
		interstep = 1;
		intrastep = jas_seq2d_rowstep(x);
		numseq = jas_seq2d_width(x);
		startind = jas_seq2d_ystart(x);
		endind = jas_seq2d_yend(x);
	} else {
		interstep = jas_seq2d_rowstep(x);
		intrastep = 1;
		numseq = jas_seq2d_height(x);
		startind = jas_seq2d_xstart(x);
		endind = jas_seq2d_xend(x);
	}

	assert(startind < endind);

	startptr = jas_seq2d_getref(x, jas_seq2d_xstart(x), jas_seq2d_ystart(x));
	if (flags & JPC_QMFB1D_RITIMODE) {
		while (numseq-- > 0) {
			jpc_qmfb1d_setup(startptr, startind, endind, intrastep,
			  &lstartptr, &lstartind, &lendind, &hstartptr,
			  &hstartind, &hendind);
			if (endind - startind > 1) {
				RFT_LIFT1(lstartptr, lstartind, lendind,
				  hstartptr, hstartind, hendind, intrastep, -=);
				RFT_LIFT0(lstartptr, lstartind, lendind,
				  hstartptr, hstartind, hendind, intrastep, +=);
				jpc_qmfb1d_join(startptr, startind, endind,
				  intrastep, lstartptr, lstartind, lendind,
				  hstartptr, hstartind, hendind);
			} else {
				if (lstartind == lendind) {
					*startptr >>= 1;
				}
			}
			startptr += interstep;
		}
	} else {
		while (numseq-- > 0) {
			jpc_qmfb1d_setup(startptr, startind, endind, intrastep,
			  &lstartptr, &lstartind, &lendind, &hstartptr,
			  &hstartind, &hendind);
			if (endind - startind > 1) {
				NFT_LIFT1(lstartptr, lstartind, lendind,
				  hstartptr, hstartind, hendind, intrastep,
				  jpc_fix_minuseq);
				NFT_LIFT0(lstartptr, lstartind, lendind,
				  hstartptr, hstartind, hendind, intrastep,
				  jpc_fix_pluseq);
				jpc_qmfb1d_join(startptr, startind, endind,
				  intrastep, lstartptr, lstartind, lendind,
				  hstartptr, hstartind, hendind);
			} else {
				if (lstartind == lendind) {
					*startptr = jpc_fix_asr(*startptr, 1);
				}
			}
			startptr += interstep;
		}
	}
}

/******************************************************************************\
* Code for 9/7 transform.
\******************************************************************************/

static int jpc_ns_getnumchans(jpc_qmfb1d_t *qmfb)
{
	/* Avoid compiler warnings about unused parameters. */
	qmfb = 0;

	return 2;
}

static int jpc_ns_getanalfilters(jpc_qmfb1d_t *qmfb, int len, jas_seq2d_t **filters)
{
	/* Avoid compiler warnings about unused parameters. */
	qmfb = 0;
	len = 0;
	filters = 0;