jpc_dec.c

用C语言实现的JPEG编码

		break;
	case JPC_TPH:
		if (!(tile = dec->curtile)) {
			return -1;
		}
		if (tile->partno > 0) {
			return -1;
		}
		jpc_dec_cp_setfromqcc(tile->cp, qcc);
		break;
	}
	return 0;
}

static int jpc_dec_process_poc(jpc_dec_t *dec, jpc_ms_t *ms)
{
	jpc_poc_t *poc = &ms->parms.poc;
	jpc_dec_tile_t *tile;
	switch (dec->state) {
	case JPC_MH:
		if (jpc_dec_cp_setfrompoc(dec->cp, poc, 1)) {
			return -1;
		}
		break;
	case JPC_TPH:
		if (!(tile = dec->curtile)) {
			return -1;
		}
		if (!tile->partno) {
			if (jpc_dec_cp_setfrompoc(tile->cp, poc, (!tile->partno))) {
				return -1;
			}
		} else {
			jpc_pi_addpchgfrompoc(tile->pi, poc);
		}
		break;
	}
	return 0;
}

static int jpc_dec_process_ppm(jpc_dec_t *dec, jpc_ms_t *ms)
{
	jpc_ppm_t *ppm = &ms->parms.ppm;
	jpc_ppxstabent_t *ppmstabent;

	if (!dec->ppmstab) {
		if (!(dec->ppmstab = jpc_ppxstab_create())) {
			return -1;
		}
	}

	if (!(ppmstabent = jpc_ppxstabent_create())) {
		return -1;
	}
	ppmstabent->ind = ppm->ind;
	ppmstabent->data = ppm->data;
	ppm->data = 0;
	ppmstabent->len = ppm->len;
	if (jpc_ppxstab_insert(dec->ppmstab, ppmstabent)) {
		return -1;
	}
	return 0;
}

static int jpc_dec_process_ppt(jpc_dec_t *dec, jpc_ms_t *ms)
{
	jpc_ppt_t *ppt = &ms->parms.ppt;
	jpc_dec_tile_t *tile;
	jpc_ppxstabent_t *pptstabent;

	tile = dec->curtile;
	if (!tile->pptstab) {
		if (!(tile->pptstab = jpc_ppxstab_create())) {
			return -1;
		}
	}
	if (!(pptstabent = jpc_ppxstabent_create())) {
		return -1;
	}
	pptstabent->ind = ppt->ind;
	pptstabent->data = ppt->data;
	ppt->data = 0;
	pptstabent->len = ppt->len;
	if (jpc_ppxstab_insert(tile->pptstab, pptstabent)) {
		return -1;
	}
	return 0;
}

static int jpc_dec_process_com(jpc_dec_t *dec, jpc_ms_t *ms)
{
	/* Eliminate compiler warnings about unused variables. */
	dec = 0;
	ms = 0;

	return 0;
}

static int jpc_dec_process_unk(jpc_dec_t *dec, jpc_ms_t *ms)
{
	/* Eliminate compiler warnings about unused variables. */
	dec = 0;

	fprintf(stderr, "warning: ignoring unknown marker segment\n");
	jpc_ms_dump(ms, stderr);
	return 0;
}

/******************************************************************************\
*
\******************************************************************************/

static jpc_dec_cp_t *jpc_dec_cp_create(uint_fast16_t numcomps)
{
	jpc_dec_cp_t *cp;
	jpc_dec_ccp_t *ccp;
	int compno;

	if (!(cp = jas_malloc(sizeof(jpc_dec_cp_t)))) {
		return 0;
	}
	cp->flags = 0;
	cp->numcomps = numcomps;
	cp->prgord = 0;
	cp->numlyrs = 0;
	cp->mctid = 0;
	cp->csty = 0;
	if (!(cp->ccps = jas_malloc(cp->numcomps * sizeof(jpc_dec_ccp_t)))) {
		return 0;
	}
	if (!(cp->pchglist = jpc_pchglist_create())) {
		jas_free(cp->ccps);
		return 0;
	}
	for (compno = 0, ccp = cp->ccps; compno < cp->numcomps;
	  ++compno, ++ccp) {
		ccp->flags = 0;
		ccp->numrlvls = 0;
		ccp->cblkwidthexpn = 0;
		ccp->cblkheightexpn = 0;
		ccp->qmfbid = 0;
		ccp->numstepsizes = 0;
		ccp->numguardbits = 0;
		ccp->roishift = 0;
		ccp->cblkctx = 0;
	}
	return cp;
}

static jpc_dec_cp_t *jpc_dec_cp_copy(jpc_dec_cp_t *cp)
{
	jpc_dec_cp_t *newcp;
	jpc_dec_ccp_t *newccp;
	jpc_dec_ccp_t *ccp;
	int compno;

	if (!(newcp = jpc_dec_cp_create(cp->numcomps))) {
		return 0;
	}
	newcp->flags = cp->flags;
	newcp->prgord = cp->prgord;
	newcp->numlyrs = cp->numlyrs;
	newcp->mctid = cp->mctid;
	newcp->csty = cp->csty;
	jpc_pchglist_destroy(newcp->pchglist);
	newcp->pchglist = 0;
	if (!(newcp->pchglist = jpc_pchglist_copy(cp->pchglist))) {
		jas_free(newcp);
		return 0;
	}
	for (compno = 0, newccp = newcp->ccps, ccp = cp->ccps;
	  compno < cp->numcomps;
	  ++compno, ++newccp, ++ccp) {
		*newccp = *ccp;
	}
	return newcp;
}

static void jpc_dec_cp_resetflags(jpc_dec_cp_t *cp)
{
	int compno;
	jpc_dec_ccp_t *ccp;
	cp->flags &= (JPC_CSET | JPC_QSET);
	for (compno = 0, ccp = cp->ccps; compno < cp->numcomps;
	  ++compno, ++ccp) {
		ccp->flags = 0;
	}
}

static void jpc_dec_cp_destroy(jpc_dec_cp_t *cp)
{
	if (cp->ccps) {
		jas_free(cp->ccps);
	}
	if (cp->pchglist) {
		jpc_pchglist_destroy(cp->pchglist);
	}
	jas_free(cp);
}

static int jpc_dec_cp_isvalid(jpc_dec_cp_t *cp)
{
	uint_fast16_t compcnt;
	jpc_dec_ccp_t *ccp;

	if (!(cp->flags & JPC_CSET) || !(cp->flags & JPC_QSET)) {
		return 0;
	}
	for (compcnt = cp->numcomps, ccp = cp->ccps; compcnt > 0; --compcnt,
	  ++ccp) {
		/* Is there enough step sizes for the number of bands? */
		if ((ccp->qsty != JPC_QCX_SIQNT && JAS_CAST(int, ccp->numstepsizes) < 3 *
		  ccp->numrlvls - 2) || (ccp->qsty == JPC_QCX_SIQNT &&
		  ccp->numstepsizes != 1)) {
			return 0;
		}
	}
	return 1;
}

static void calcstepsizes(uint_fast16_t refstepsize, int numrlvls,
  uint_fast16_t *stepsizes)
{
	int bandno;
	int numbands;
	uint_fast16_t expn;
	uint_fast16_t mant;
	expn = JPC_QCX_GETEXPN(refstepsize);
	mant = JPC_QCX_GETMANT(refstepsize);
	numbands = 3 * numrlvls - 2;
	for (bandno = 0; bandno < numbands; ++bandno) {
		stepsizes[bandno] = JPC_QCX_MANT(mant) | JPC_QCX_EXPN(expn +
		  (numrlvls - 1) - (numrlvls - 1 - ((bandno > 0) ? ((bandno + 2) / 3) : (0))));
	}
}

static int jpc_dec_cp_prepare(jpc_dec_cp_t *cp)
{
	jpc_dec_ccp_t *ccp;
	int compno;
	int i;
	for (compno = 0, ccp = cp->ccps; compno < cp->numcomps;
	  ++compno, ++ccp) {
		if (!(ccp->csty & JPC_COX_PRT)) {
			for (i = 0; i < JPC_MAXRLVLS; ++i) {
				ccp->prcwidthexpns[i] = 15;
				ccp->prcheightexpns[i] = 15;
			}
		}
		if (ccp->qsty == JPC_QCX_SIQNT) {
			calcstepsizes(ccp->stepsizes[0], ccp->numrlvls, ccp->stepsizes);
		}
	}
	return 0;
}

static int jpc_dec_cp_setfromcod(jpc_dec_cp_t *cp, jpc_cod_t *cod)
{
	jpc_dec_ccp_t *ccp;
	int compno;
	cp->flags |= JPC_CSET;
	cp->prgord = cod->prg;
	if (cod->mctrans) {
		cp->mctid = (cod->compparms.qmfbid == JPC_COX_INS) ? (JPC_MCT_ICT) : (JPC_MCT_RCT);
	} else {
		cp->mctid = JPC_MCT_NONE;
	}
	cp->numlyrs = cod->numlyrs;
	cp->csty = cod->csty & (JPC_COD_SOP | JPC_COD_EPH);
	for (compno = 0, ccp = cp->ccps; compno < cp->numcomps;
	  ++compno, ++ccp) {
		jpc_dec_cp_setfromcox(cp, ccp, &cod->compparms, 0);
	}
	cp->flags |= JPC_CSET;
	return 0;
}

static int jpc_dec_cp_setfromcoc(jpc_dec_cp_t *cp, jpc_coc_t *coc)
{
	jpc_dec_cp_setfromcox(cp, &cp->ccps[coc->compno], &coc->compparms, JPC_COC);
	return 0;
}

static int jpc_dec_cp_setfromcox(jpc_dec_cp_t *cp, jpc_dec_ccp_t *ccp,
  jpc_coxcp_t *compparms, int flags)
{
	int rlvlno;

	/* Eliminate compiler warnings about unused variables. */
	cp = 0;

	if ((flags & JPC_COC) || !(ccp->flags & JPC_COC)) {
		ccp->numrlvls = compparms->numdlvls + 1;
		ccp->cblkwidthexpn = JPC_COX_GETCBLKSIZEEXPN(
		  compparms->cblkwidthval);
		ccp->cblkheightexpn = JPC_COX_GETCBLKSIZEEXPN(
		  compparms->cblkheightval);
		ccp->qmfbid = compparms->qmfbid;
		ccp->cblkctx = compparms->cblksty;
		ccp->csty = compparms->csty & JPC_COX_PRT;
		for (rlvlno = 0; rlvlno < compparms->numrlvls; ++rlvlno) {
			ccp->prcwidthexpns[rlvlno] =
			  compparms->rlvls[rlvlno].parwidthval;
			ccp->prcheightexpns[rlvlno] =
			  compparms->rlvls[rlvlno].parheightval;
		}
		ccp->flags |= flags | JPC_CSET;
	}
	return 0;
}

static int jpc_dec_cp_setfromqcd(jpc_dec_cp_t *cp, jpc_qcd_t *qcd)
{
	int compno;
	jpc_dec_ccp_t *ccp;
	for (compno = 0, ccp = cp->ccps; compno < cp->numcomps;
	  ++compno, ++ccp) {
		jpc_dec_cp_setfromqcx(cp, ccp, &qcd->compparms, 0);
	}
	cp->flags |= JPC_QSET;
	return 0;
}

static int jpc_dec_cp_setfromqcc(jpc_dec_cp_t *cp, jpc_qcc_t *qcc)
{
	return jpc_dec_cp_setfromqcx(cp, &cp->ccps[qcc->compno], &qcc->compparms, JPC_QCC);
}

static int jpc_dec_cp_setfromqcx(jpc_dec_cp_t *cp, jpc_dec_ccp_t *ccp,
  jpc_qcxcp_t *compparms, int flags)
{
	int bandno;

	/* Eliminate compiler warnings about unused variables. */
	cp = 0;

	if ((flags & JPC_QCC) || !(ccp->flags & JPC_QCC)) {
		ccp->flags |= flags | JPC_QSET;
		for (bandno = 0; bandno < compparms->numstepsizes; ++bandno) {
			ccp->stepsizes[bandno] = compparms->stepsizes[bandno];
		}
		ccp->numstepsizes = compparms->numstepsizes;
		ccp->numguardbits = compparms->numguard;
		ccp->qsty = compparms->qntsty;
	}
	return 0;
}

static int jpc_dec_cp_setfromrgn(jpc_dec_cp_t *cp, jpc_rgn_t *rgn)
{
	jpc_dec_ccp_t *ccp;
	ccp = &cp->ccps[rgn->compno];
	ccp->roishift = rgn->roishift;
	return 0;
}

static int jpc_pi_addpchgfrompoc(jpc_pi_t *pi, jpc_poc_t *poc)
{
	int pchgno;
	jpc_pchg_t *pchg;
	for (pchgno = 0; pchgno < poc->numpchgs; ++pchgno) {
		if (!(pchg = jpc_pchg_copy(&poc->pchgs[pchgno]))) {
			return -1;
		}
		if (jpc_pchglist_insert(pi->pchglist, -1, pchg)) {
			return -1;
		}
	}
	return 0;
}

static int jpc_dec_cp_setfrompoc(jpc_dec_cp_t *cp, jpc_poc_t *poc, int reset)
{
	int pchgno;
	jpc_pchg_t *pchg;
	if (reset) {
		while (jpc_pchglist_numpchgs(cp->pchglist) > 0) {
			pchg = jpc_pchglist_remove(cp->pchglist, 0);
			jpc_pchg_destroy(pchg);
		}
	}
	for (pchgno = 0; pchgno < poc->numpchgs; ++pchgno) {
		if (!(pchg = jpc_pchg_copy(&poc->pchgs[pchgno]))) {
			return -1;
		}
		if (jpc_pchglist_insert(cp->pchglist, -1, pchg)) {
			return -1;
		}
	}
	return 0;
}

static jpc_fix_t jpc_calcabsstepsize(int stepsize, int numbits)
{
	jpc_fix_t absstepsize;
	int n;

	absstepsize = jpc_inttofix(1);
	n = JPC_FIX_FRACBITS - 11;
	absstepsize |= (n >= 0) ? (JPC_QCX_GETMANT(stepsize) << n) :
	  (JPC_QCX_GETMANT(stepsize) >> (-n));
	n = numbits - JPC_QCX_GETEXPN(stepsize);
	absstepsize = (n >= 0) ? (absstepsize << n) : (absstepsize >> (-n));
	return absstepsize;
}

static void jpc_dequantize(jas_matrix_t *x, jpc_fix_t absstepsize)
{
	int i;
	int j;
	int t;

	assert(absstepsize >= 0);
	if (absstepsize == jpc_inttofix(1)) {
		return;
	}

	for (i = 0; i < jas_matrix_numrows(x); ++i) {
		for (j = 0; j < jas_matrix_numcols(x); ++j) {
			t = jas_matrix_get(x, i, j);
			if (t) {
				t = jpc_fix_mul(t, absstepsize);
			} else {
				t = 0;
			}
			jas_matrix_set(x, i, j, t);
		}
	}

}

static void jpc_undo_roi(jas_matrix_t *x, int roishift, int bgshift, int numbps)
{
	int i;
	int j;
	int thresh;
	jpc_fix_t val;
	jpc_fix_t mag;
	bool warn;
	uint_fast32_t mask;

	if (roishift == 0 && bgshift == 0) {
		return;
	}
	thresh = 1 << roishift;

	warn = false;
	for (i = 0; i < jas_matrix_numrows(x); ++i) {
		for (j = 0; j < jas_matrix_numcols(x); ++j) {
			val = jas_matrix_get(x, i, j);
			mag = JAS_ABS(val);
			if (mag >= thresh) {
				/* We are dealing with ROI data. */
				mag >>= roishift;
				val = (val < 0) ? (-mag) : mag;
				jas_matrix_set(x, i, j, val);
			} else {
				/* We are dealing with non-ROI (i.e., background) data. */
				mag <<= bgshift;
				mask = (1 << numbps) - 1;
				/* Perform a basic sanity check on the sample value. */
				/* Some implementations write garbage in the unused
				  most-significant bit planes introduced by ROI shifting.
				  Here we ensure that any such bits are masked off. */
				if (mag & (~mask)) {
					if (!warn) {
						fprintf(stderr,
						  "warning: possibly corrupt code stream\n");
						warn = true;
					}
					mag &= mask;
				}
				val = (val < 0) ? (-mag) : mag;