Initial import

1 files changed, 448 insertions, 0 deletions

diff --git a/filter/faxe.c b/filter/faxe.c
new file mode 100644
index 00000000..20e776dd
--- /dev/null
+++ b/filter/faxe.c
@@ -0,0 +1,448 @@
+#include <fitz.h>
+
+#include "faxe.h"
+#include "faxc.h"
+
+/* TODO: honor Rows param */
+
+#define noDEBUGBITS 1
+#define noDEBUG 1
+
+#ifdef DEBUG
+#define DPRINT(...) fprintf(stderr, __VA_ARGS__)
+#else
+#define DPRINT(...)
+#endif
+
+typedef struct fz_faxe_s fz_faxe;
+
+struct fz_faxe_s
+{
+	fz_filter super;
+
+	int k;
+	int endofline;
+	int encodedbytealign;
+	int columns;
+	int endofblock;
+	int blackis1;
+
+	int stride;
+	int ridx;		/* how many rows in total */
+	int bidx;		/* how many bits are already used in out->wp */
+	unsigned char bsave;	/* partial byte saved between process() calls */
+
+	int stage;
+	int a0, c;		/* mid-line coding state */
+
+	unsigned char *ref;
+	unsigned char *src;
+};
+
+fz_error *
+fz_newfaxe(fz_filter **fp, fz_obj *params)
+{
+	fz_obj *obj;
+
+	FZ_NEWFILTER(fz_faxe, fax, faxe);
+
+	fax->ref = nil;
+	fax->src = nil;
+
+	fax->k = 0;
+	fax->endofline = 0;
+	fax->encodedbytealign = 0;
+	fax->columns = 1728;
+	fax->endofblock = 1;
+	fax->blackis1 = 0;
+
+	obj = fz_dictgets(params, "K");
+	if (obj) fax->k = fz_toint(obj);
+
+	obj = fz_dictgets(params, "EndOfLine");
+	if (obj) fax->endofline = fz_tobool(obj);
+
+	obj = fz_dictgets(params, "EncodedByteAlign");
+	if (obj) fax->encodedbytealign = fz_tobool(obj);
+
+	obj = fz_dictgets(params, "Columns");
+	if (obj) fax->columns = fz_toint(obj);
+
+	obj = fz_dictgets(params, "EndOfBlock");
+	if (obj) fax->endofblock = fz_tobool(obj);
+
+	obj = fz_dictgets(params, "BlackIs1");
+	if (obj) fax->blackis1 = fz_tobool(obj);
+
+	fax->stride = ((fax->columns - 1) >> 3) + 1;
+	fax->bidx = 0;
+	fax->ridx = 0;
+
+	fax->stage = 0;
+	fax->a0 = -1;
+	fax->c = 0;
+
+	fax->ref = fz_malloc(fax->stride);
+	if (!fax->ref) { fz_free(fax); return fz_outofmem; }
+
+	fax->src = fz_malloc(fax->stride);
+	if (!fax->src) { fz_free(fax); fz_free(fax->ref); return fz_outofmem; }
+
+	memset(fax->ref, 0, fax->stride);
+	memset(fax->src, 0, fax->stride);
+
+	return nil;
+}
+
+void
+fz_freefaxe(fz_filter *p)
+{
+	fz_faxe *fax = (fz_faxe*) p;
+	fz_free(fax->src);
+	fz_free(fax->ref);
+	fz_free(fax);
+}
+
+enum { codebytes = 2 };
+
+static inline int
+runbytes(int run)
+{
+	int m = (run / 64) / 40 + 1;	/* number of makeup codes */
+	return codebytes * (m + 1); /* bytes for makeup + term codes */
+}
+
+static void
+putbits(fz_faxe *fax, fz_buffer *out, int code, int nbits)
+{
+#ifdef DEBUGBITS
+	fprintf(stderr, "BITS ");
+	printbits(stderr, code, nbits);
+	fprintf(stderr, "\n");
+#endif
+
+	while (nbits > 0)
+	{
+		if (fax->bidx == 0) {
+			*out->wp = 0;
+		}
+
+		/* code does not fit: shift right */
+		if (nbits > (8 - fax->bidx)) {
+			*out->wp |= code >> (nbits - (8 - fax->bidx));
+			nbits = nbits - (8 - fax->bidx);
+			fax->bidx = 0;
+			out->wp ++;
+		}
+
+		/* shift left */
+		else {
+			*out->wp |= code << ((8 - fax->bidx) - nbits);
+			fax->bidx += nbits;
+			if (fax->bidx == 8) {
+				fax->bidx = 0;
+				out->wp ++;
+			}
+			nbits = 0;
+		}
+	}
+}
+
+static inline void
+putcode(fz_faxe *fax, fz_buffer *out, const cfe_code *run)
+{
+	putbits(fax, out, run->code, run->nbits);
+}
+
+static void
+putrun(fz_faxe *fax, fz_buffer *out, int run, int c)
+{
+	int m;
+
+	const cf_runs *codetable = c ? &cf_black_runs : &cf_white_runs;
+
+	if (run > 63) {
+		m = run / 64;
+		while (m > 40) {
+			DPRINT("%c %d\n", c?'b':'w', 40 * 64);
+			putcode(fax, out, &codetable->makeup[40]);
+			m -= 40;
+		}
+		if (m > 0) {
+			DPRINT("%c %d\n", c?'b':'w', m * 64);
+			putcode(fax, out, &codetable->makeup[m]);
+		}
+		DPRINT("%c %d\n", c?'b':'w', run % 64);
+		putcode(fax, out, &codetable->termination[run % 64]);
+	}
+	else {
+		DPRINT("%c %d\n", c?'b':'w', run);
+		putcode(fax, out, &codetable->termination[run]);
+	}
+}
+
+static fz_error *
+enc1d(fz_faxe *fax, unsigned char *line, fz_buffer *out)
+{
+	int run;
+
+#ifdef DEBUG
+if (fax->a0 < 0) {
+	DPRINT("1d scanline %d\n", fax->ridx + 1);
+	DPRINT("color = %d\n", fax->c);
+}
+#endif
+
+	if (fax->a0 < 0)
+		fax->a0 = 0;
+
+	while (fax->a0 < fax->columns)
+	{
+		run = getrun(line, fax->a0, fax->columns, fax->c);
+
+		if (out->wp + 1 + runbytes(run) > out->ep)
+			return fz_ioneedout;
+
+		putrun(fax, out, run, fax->c);
+
+		fax->a0 += run;
+		fax->c = !fax->c;
+	}
+
+	return 0;
+}
+
+static fz_error *
+enc2d(fz_faxe *fax, unsigned char *ref, unsigned char *src, fz_buffer *out)
+{
+	int a1, a2, b1, b2;
+	int run1, run2, n;
+
+
+#ifdef DEBUG
+if (fax->a0 < 0)
+{
+	DPRINT("2d scanline %d\n", fax->ridx + 1);
+}
+#endif
+
+	DPRINT("color = %d\n", fax->c);
+
+	while (fax->a0 < fax->columns)
+	{
+		a1 = findchanging(src, fax->a0, fax->columns);
+		b1 = findchangingcolor(ref, fax->a0, fax->columns, !fax->c);
+		b2 = findchanging(ref, b1, fax->columns);
+
+#ifdef DEBUGBITS
+		DPRINT("twod a0=%d a1=%d b1=%d b2=%d\n", fax->a0, a1, b1, b2);
+#endif
+
+		/* pass */
+		if (b2 < a1)
+		{
+			if (out->wp + 1 + codebytes > out->ep)
+				return fz_ioneedout;
+
+			DPRINT("P\n");
+
+			putcode(fax, out, &cf2_run_pass);
+
+			fax->a0 = b2;
+		}
+
+		/* vertical */
+		else if (ABS(b1 - a1) <= 3)
+		{
+			if (out->wp + 1 + codebytes > out->ep)
+				return fz_ioneedout;
+
+#ifdef DEBUG
+			if (b1 - a1 == 0)
+				DPRINT("V0\n");
+			else if (b1 - a1 < 0)
+				DPRINT("VR%d\n", a1 - b1);
+			else
+				DPRINT("VL%d\n", b1 - a1);
+#endif
+
+			putcode(fax, out, &cf2_run_vertical[b1 - a1 + 3]);
+
+			fax->a0 = a1;
+			fax->c = !fax->c;
+		}
+
+		/* horizontal */
+		else
+		{
+			a2 = findchanging(src, a1, fax->columns);
+			run1 = a1 - fax->a0;
+			run2 = a2 - a1;
+			n = codebytes + runbytes(run1) + runbytes(run2);
+
+			if (out->wp + 1 + n > out->ep)
+				return fz_ioneedout;
+
+			DPRINT("H\n");
+
+			putcode(fax, out, &cf2_run_horizontal);
+			putrun(fax, out, run1, fax->c);
+			putrun(fax, out, run2, !fax->c);
+
+			fax->a0 = a2;
+		}
+	}
+
+	return 0;
+}
+
+static fz_error *
+process(fz_faxe *fax, fz_buffer *in, fz_buffer *out)
+{
+	fz_error *err;
+	int i, n;
+
+	while (1)
+	{
+		if (in->rp == in->wp && in->eof)
+			goto rtc;
+
+		switch (fax->stage)
+		{
+		case 0:
+			if (fax->encodedbytealign)
+			{
+				if (fax->endofline) {
+					if (out->wp + 1 + 1 > out->ep)
+						return fz_ioneedout;
+
+					/* make sure that EOL ends on a byte border */
+					putbits(fax, out, 0, (12 - fax->bidx) & 7);
+				}
+				else {
+					if (fax->bidx) {
+						if (out->wp + 1 > out->ep)
+							return fz_ioneedout;
+						fax->bidx = 0;
+						out->wp ++;
+					}
+				}
+			}
+
+			fax->stage ++;
+
+		case 1:
+			if (fax->endofline)
+			{
+				if (out->wp + 1 + codebytes + 1 > out->ep)
+					return fz_ioneedout;
+
+				DPRINT("EOL\n");
+				if (fax->k > 0) {
+					if (fax->ridx % fax->k == 0)
+						putcode(fax, out, &cf2_run_eol_1d);
+					else
+						putcode(fax, out, &cf2_run_eol_2d);
+				}
+				else {
+					putcode(fax, out, &cf_run_eol);
+				}
+			}
+
+			fax->stage ++;
+
+		case 2:
+			if (in->rp + fax->stride > in->wp) {
+				if (in->eof) /* XXX barf here? */
+					goto rtc;
+				return fz_ioneedin;
+			}
+
+			memcpy(fax->ref, fax->src, fax->stride);
+			memcpy(fax->src, in->rp, fax->stride);
+
+			if (!fax->blackis1)
+			{
+				for (i = 0; i < fax->stride; i++)
+					fax->src[i] = ~fax->src[i];
+			}
+
+			in->rp += fax->stride;
+
+			fax->c = 0;
+			fax->a0 = -1;
+
+#ifdef DEBUGBITS
+			DPRINT("LINE %d\n", fax->ridx);
+			printline(stderr, fax->ref, fax->columns);
+			printline(stderr, fax->src, fax->columns);
+#endif
+
+			fax->stage ++;
+			
+		case 3:
+			err = 0; /* to silence compiler */
+
+			if (fax->k < 0) {
+				err = enc2d(fax, fax->ref, fax->src, out);
+			}
+			else if (fax->k == 0) {
+				err = enc1d(fax, fax->src, out);
+			}
+			else if (fax->k > 0) {
+				if (fax->ridx % fax->k == 0) {
+					err = enc1d(fax, fax->src, out);
+				}
+				else {
+					err = enc2d(fax, fax->ref, fax->src, out);
+				}
+			}
+
+			if (err) return err;
+
+			fax->ridx ++;
+
+			fax->stage = 0;
+		}
+	}
+
+rtc:
+	if (fax->endofblock)
+	{
+		n = fax->k < 0 ? 2 : 6;
+
+		if (out->wp + 1 + codebytes * n > out->ep)
+			return fz_ioneedout;
+
+		for (i = 0; i < n; i++) {
+			putcode(fax, out, &cf_run_eol);
+			if (fax->k > 0)
+				putbits(fax, out, 1, 1);
+		}
+		DPRINT("RTC\n");
+	}
+
+	if (fax->bidx)
+		out->wp ++;
+	out->eof = 1;
+
+	return fz_iodone;
+}
+
+fz_error *
+fz_processfaxe(fz_filter *p, fz_buffer *in, fz_buffer *out)
+{
+	fz_faxe *fax = (fz_faxe*) p;
+	fz_error *err;
+
+	/* restore partial bits */
+	*out->wp = fax->bsave;
+
+	err = process(fax, in, out);
+
+	/* save partial bits */
+	fax->bsave = *out->wp;
+
+	return err;
+}
+