Fix HN conversion and add JBIG2 support.

Signed-off-by: yzrh <yzrh@noema.org>

17 files changed, 506 insertions, 187 deletions

diff --git a/src/Makefile b/src/Makefile
index 7016c6c..6943af3 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -4,19 +4,19 @@
 # SPDX-License-Identifier: Apache-2.0
 #
 
-src =	melon.c iconv.c zlib.c jbig.c jpeg.c \
+src =	melon.c iconv.c zlib.c jbig.c jbig2.c jpeg.c \
 	cnki_caj.c cnki_hn.c cnki_kdh.c cnki_outline_tree.c \
-	cnki_pdf.c cnki_xml.c cnki_zlib.c cnki_jbig.c cnki.c \
+	cnki_pdf.c cnki_zlib.c cnki_jbig.c cnki_jbig2.c cnki.c \
 	pdf_cnki.c pdf_get.c pdf_parser.c pdf_writer.c pdf.c
-inc =	extern.h version.h iconv.h zlib.h jbig.h jpeg.h \
+inc =	extern.h version.h iconv.h zlib.h jbig.h jbig2.h jpeg.h \
 	cnki.h pdf_cnki.h cnki_jbig.h pdf.h
 
 obj = ${src:.c=.o}
 
 PREFIX = /usr/local
 
-CFLAGS = -O2 -pipe -flto -Wall -Wextra -Wno-unused-parameter
-LDFLAGS = -Wl,-O2 -lcrypto -liconv -lz -ljbig -ljpeg -Wl,--as-needed
+CFLAGS = -O2 -pipe -flto -Wall -Wextra
+LDFLAGS = -Wl,-O2 -lcrypto -liconv -lz -ljbig2dec -ljpeg -Wl,--as-needed
 
 CFLAGS += -I/usr/local/include
 LDFLAGS += -L/usr/local/lib
diff --git a/src/cnki.h b/src/cnki.h
index 569cea7..237a2c1 100644
--- a/src/cnki.h
+++ b/src/cnki.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020-2021, yzrh <yzrh@noema.org>
+ * Copyright (c) 2020-2022, yzrh <yzrh@noema.org>
  *
  * SPDX-License-Identifier: Apache-2.0
  */
@@ -97,5 +97,7 @@ int cnki_jbig(char **bitmap, int *bitmap_size,
 	int *bitmap_width, int *bitmap_height,
 	const char * restrict jbig, int jbig_size);
 
-/* cnki_xml.c */
-int cnki_xml(char **xml, FILE **fp);
+/* cnki_jbig2.c */
+int cnki_jbig2(char **bitmap, int *bitmap_size,
+	int *bitmap_width, int *bitmap_height,
+	const char * restrict jbig, int jbig_size);
diff --git a/src/cnki_jbig.c b/src/cnki_jbig.c
index 02040be..f35d1d5 100644
--- a/src/cnki_jbig.c
+++ b/src/cnki_jbig.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020-2021, yzrh <yzrh@noema.org>
+ * Copyright (c) 2020-2022, yzrh <yzrh@noema.org>
  *
  * SPDX-License-Identifier: Apache-2.0
  */
@@ -22,68 +22,22 @@ cnki_jbig(char **bitmap, int *bitmap_size,
 
 	memcpy(dib, jbig, 40);
 
-	bih_t *bih = malloc(sizeof(bih_t));
+	int width_padded = (dib->width * dib->depth + 7) / 8;
 
-	if (bih == NULL) {
-		free(dib);
-		return 1;
-	}
-
-	memset(bih, 0, sizeof(bih_t));
-
-	bih->d_l = 0;
-	bih->d = 0;
-
-	bih->p = 1;
-
-	bih->fill = 0;
-
-	bih->x_d = dib->width;
-	bih->y_d = dib->height;
-	bih->l_0 = bih->y_d / 35;
-
-	while (bih->l_0 > 128)
-		bih->l_0--;
-	if (bih->l_0 < 2)
-		bih->l_0 = 2;
+	*bitmap_size = dib->height * width_padded;
+	*bitmap = malloc(*bitmap_size);
 
-	bih->m_x = 8;
-	bih->m_y = 0;
-
-	bih->order |= 1 << 1;
-	bih->order |= 1 << 0;
-
-	bih->options |= 1 << 4;
-	bih->options |= 1 << 3;
-	bih->options |= 1 << 2;
-
-	bih->dptable = NULL;
-
-	int bie_size = jbig_size - 28; /* - 40 - 8 + 20 */
-	char *bie = malloc(bie_size);
-
-	if (bie == NULL) {
+	if (*bitmap == NULL) {
 		free(dib);
-		free(bih);
 		return 1;
 	}
 
-	memcpy(bie, bih, 20);
-	memcpy(bie + 20, jbig + 48, jbig_size - 48);
+	strdec_jbig(bitmap, dib->width, dib->height, jbig + 48, jbig_size - 48);
 
-	int ret = strdec_jbig(bitmap, bitmap_size, bie, bie_size);
-
-	if (ret == 0) {
-		*bitmap_width = bih->x_d;
-		*bitmap_height = bih->y_d;
-	}
+	*bitmap_width = dib->width;
+	*bitmap_height = dib->height;
 
 	free(dib);
-	free(bih);
-	free(bie);
-
-	if (ret != 0)
-		return 1;
 
 	return 0;
 }
diff --git a/src/cnki_jbig.h b/src/cnki_jbig.h
index 96e4ea8..701b4df 100644
--- a/src/cnki_jbig.h
+++ b/src/cnki_jbig.h
@@ -1,48 +1,11 @@
 /*
- * Copyright (c) 2020-2021, yzrh <yzrh@noema.org>
+ * Copyright (c) 2020-2022, yzrh <yzrh@noema.org>
  *
  * SPDX-License-Identifier: Apache-2.0
  */
 
 #include <stdint.h>
 
-/*
- * order (MSB first):
- * 0
- * 0
- * 0
- * 0
- * HITOLO
- * SEQ
- * ILEAVE (default)
- * SMID (default)
- *
- * options (MSB first):
- * 0
- * LRLTWO
- * VLENGTH
- * TPDON (default)
- * TPBON (default)
- * DPON (default)
- * DPPRIV
- * DPLAST
- */
-typedef struct _bih_t {
-	char d_l; /* Initial resolution layer */
-	char d; /* Final resolution layer */
-	char p; /* Number of bit-planes, for bi-level image, always 1 */
-	char fill; /* Always 0 */
-	/* MSB first */
-	int32_t x_d; /* Horizontal dimension at highestresolution */
-	int32_t y_d; /* Vertical dimension at highest resolution */
-	int32_t l_0; /* Number of lines per stripe at lowest resolution */
-	char m_x; /* Maximum horizontal offsets (default: 8) */
-	char m_y; /* Maximum vertical offsets (default: 0) */
-	char order;
-	char options;
-	char *dptable; /* 0 or 1728 */
-} bih_t;
-
 typedef enum _dib_compression_code {
 	BI_RGB,
 	BI_RLE8,
diff --git a/src/cnki_jbig2.c b/src/cnki_jbig2.c
new file mode 100644
index 0000000..69f4a5b
--- /dev/null
+++ b/src/cnki_jbig2.c
@@ -0,0 +1,43 @@
+/*
+ * Copyright (c) 2022, yzrh <yzrh@noema.org>
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <stdlib.h>
+#include <string.h>
+
+#include "cnki_jbig.h"
+#include "jbig2.h"
+
+int
+cnki_jbig2(char **bitmap, int *bitmap_size,
+	int *bitmap_width, int *bitmap_height,
+	const char * restrict jbig, int jbig_size)
+{
+	dib_t *dib = malloc(sizeof(dib_t));
+
+	if (dib == NULL)
+		return 1;
+
+	memcpy(dib, jbig, 40);
+
+	int width_padded = (dib->width * dib->depth + 7) / 8;
+
+	*bitmap_size = dib->height * width_padded;
+	*bitmap = malloc(*bitmap_size);
+
+	if (*bitmap == NULL) {
+		free(dib);
+		return 1;
+	}
+
+	strdec_jbig2(bitmap, jbig + 48, jbig_size - 48);
+
+	*bitmap_width = dib->width;
+	*bitmap_height = dib->height;
+
+	free(dib);
+
+	return 0;
+}
diff --git a/src/cnki_pdf.c b/src/cnki_pdf.c
index dcf6d30..b59b7c6 100644
--- a/src/cnki_pdf.c
+++ b/src/cnki_pdf.c
@@ -238,7 +238,7 @@ cnki_pdf(cnki_t **param)
 			if ((*param)->stat > 1)
 				printf("Generating object\n");
 
-			dictionary_size = 64 + 12 * kid[0];
+			dictionary_size = 64 + 16 * kid[0];
 			dictionary = malloc(dictionary_size);
 
 			if (dictionary == NULL) {
@@ -483,6 +483,9 @@ cnki_pdf_hn(cnki_t **param)
 		int *ids = NULL;
 		pdf_get_free_ids(&pdf, &ids, ptr->image_length + 3);
 
+		int bitmap_size;
+		char *bitmap;
+
 		int stream_size;
 		char *stream;
 
@@ -493,32 +496,34 @@ cnki_pdf_hn(cnki_t **param)
 
 		if (dim == NULL) {
 			free(root_kid);
+			free(ids);
 			return 1;
 		}
 
-		for (int i = 0; i < ptr->image_length; i++) {
-			dictionary_size = 128;
-			dictionary = malloc(dictionary_size);
+		dictionary_size = 256;
+		dictionary = malloc(dictionary_size);
 
-			if (dictionary == NULL) {
-				free(root_kid);
-				free(dim);
-				return 1;
-			}
+		if (dictionary == NULL) {
+			free(root_kid);
+			free(ids);
+			free(dim);
+			return 1;
+		}
 
+		for (int i = 0; i < ptr->image_length; i++) {
 			memset(dictionary, 0, dictionary_size);
 
 			strcat(dictionary, "<<\n/Type /XObject\n"
 				"/Subtype /Image\n");
 
 			if ((*param)->stat > 2)
-				printf("\tDecoding data, page %04d item %02d... ",
-					ptr->page, i);
+				printf("\tDecoding data, page %04d item %02d format %d... ",
+					ptr->page, i, ptr->image_data[i].format);
 
 			switch (ptr->image_data[i].format) {
 				case JBIG:
-					ret = cnki_jbig(&stream,
-						&stream_size,
+					ret = cnki_jbig(&bitmap,
+						&bitmap_size,
 						&wh[0],
 						&wh[1],
 						ptr->image_data[i].image,
@@ -530,18 +535,30 @@ cnki_pdf_hn(cnki_t **param)
 						break;
 					}
 
+					if (strdeflate(&stream, &stream_size,
+						bitmap, bitmap_size) != 0) {
+						free(root_kid);
+						free(ids);
+						free(dim);
+						free(dictionary);
+						return 1;
+					}
+
+					free(bitmap);
+
 					snprintf(buf, 64, "/Width %d\n/Height %d\n",
 						wh[0], wh[1]);
 					strcat(dictionary, buf);
 
 					strcat(dictionary, "/ColorSpace /DeviceGray\n"
 						"/BitsPerComponent 1\n");
+					strcat(dictionary, "/Decode [1.0 0.0]\n");
 
 					snprintf(buf, 64, "/Length %d\n",
 						stream_size);
 					strcat(dictionary, buf);
 
-					strcat(dictionary, "/Filter /CCITTFaxDecode\n");
+					strcat(dictionary, "/Filter /FlateDecode\n");
 
 					dim[i * 2] = wh[0];
 					dim[i * 2 + 1] = wh[1];
@@ -562,9 +579,10 @@ cnki_pdf_hn(cnki_t **param)
 					stream_size = ptr->image_data[i].size;
 					stream = malloc(stream_size);
 					if (stream == NULL) {
-						free(dictionary);
 						free(root_kid);
+						free(ids);
 						free(dim);
+						free(dictionary);
 						return 1;
 					}
 					memcpy(stream, ptr->image_data[i].image, stream_size);
@@ -573,7 +591,7 @@ cnki_pdf_hn(cnki_t **param)
 						wh[0], wh[1]);
 					strcat(dictionary, buf);
 
-					strcat(dictionary, "/ColorSpace /DeviceRGB\n"
+					strcat(dictionary, "/ColorSpace /DeviceGray\n"
 						"/BitsPerComponent 8\n");
 
 					snprintf(buf, 64, "/Length %d\n",
@@ -586,6 +604,47 @@ cnki_pdf_hn(cnki_t **param)
 					dim[i * 2 + 1] = wh[1];
 					break;
 				case JBIG2:
+					ret = cnki_jbig2(&bitmap,
+						&bitmap_size,
+						&wh[0],
+						&wh[1],
+						ptr->image_data[i].image,
+						ptr->image_data[i].size);
+
+					if (ret != 0) {
+						dim[i * 2] = 0;
+						dim[i * 2 + 1] = 0;
+						break;
+					}
+
+					if (strdeflate(&stream, &stream_size,
+						bitmap, bitmap_size) != 0) {
+						free(root_kid);
+						free(ids);
+						free(dim);
+						free(dictionary);
+						return 1;
+					}
+
+					free(bitmap);
+
+					snprintf(buf, 64, "/Width %d\n/Height %d\n",
+						wh[0], wh[1]);
+					strcat(dictionary, buf);
+
+					strcat(dictionary, "/ColorSpace /DeviceGray\n"
+						"/BitsPerComponent 1\n");
+					strcat(dictionary, "/Decode [1.0 0.0]\n");
+
+					snprintf(buf, 64, "/Length %d\n",
+						stream_size);
+					strcat(dictionary, buf);
+
+					strcat(dictionary, "/Filter /FlateDecode\n");
+
+					dim[i * 2] = wh[0];
+					dim[i * 2 + 1] = wh[1];
+					break;
 				case JPX:
 				default:
 					ret = -1;
@@ -598,37 +657,26 @@ cnki_pdf_hn(cnki_t **param)
 
 			if (ret == 0) {
 				if ((*param)->stat > 2)
-					printf("Done\n");
+					printf("%6d byte(s), width %4d, height %4d.\n",
+						stream_size, wh[0], wh[1]);
 
 				pdf_obj_append(&pdf, ids[i],
 					NULL, dictionary, stream, stream_size);
 
-				free(dictionary);
 				free(stream);
 			} else if (ret == 1) {
 				if ((*param)->stat > 2)
-					printf("Failed\n");
-
-				free(dictionary);
+					printf("Not extracted.\n");
 
 				pdf_obj_append(&pdf, ids[i], NULL, NULL, NULL, 0);
 			} else {
 				if ((*param)->stat > 2)
-					printf("Unsupported format\n");
+					printf("Unsupported format.\n");
 
-				free(dictionary);
+				pdf_obj_append(&pdf, ids[i], NULL, NULL, NULL, 0);
 			}
 		}
 
-		dictionary_size = 128;
-		dictionary = malloc(dictionary_size);
-
-		if (dictionary == NULL) {
-			free(root_kid);
-			free(dim);
-			return 1;
-		}
-
 		memset(dictionary, 0, dictionary_size);
 
 		strcat(dictionary, "<<\n/XObject <<");
@@ -655,11 +703,12 @@ cnki_pdf_hn(cnki_t **param)
 		if (strncmp(ptr->text + 8, "COMPRESSTEXT", 12) == 0) {
 			cnki_zlib(&stream, &stream_size, ptr->text, ptr->text_size);
 
-			dictionary_size = stream_size / 8 + 7;
+			dictionary_size = 64 + 2 * stream_size;
 			dictionary = malloc(dictionary_size);
 
 			if (dictionary == NULL) {
 				free(root_kid);
+				free(ids);
 				free(dim);
 				return 1;
 			}
@@ -688,11 +737,12 @@ cnki_pdf_hn(cnki_t **param)
 
 			strcat(dictionary, ">");
 		} else {
-			dictionary_size = ptr->text_size;
+			dictionary_size = 64 + 2 * ptr->text_size;
 			dictionary = malloc(dictionary_size);
 
 			if (dictionary == NULL) {
 				free(root_kid);
+				free(ids);
 				free(dim);
 				return 1;
 			}
@@ -724,11 +774,12 @@ cnki_pdf_hn(cnki_t **param)
 		/* FIXME: Use the text somehow? */
 		free(dictionary);
 
-		dictionary_size = 64 + 12 * ptr->image_length;
+		dictionary_size = 64 + 64 * ptr->image_length;
 		dictionary = malloc(dictionary_size);
 
 		if (dictionary == NULL) {
 			free(root_kid);
+			free(ids);
 			free(dim);
 			return 1;
 		}
@@ -739,12 +790,27 @@ cnki_pdf_hn(cnki_t **param)
 
 		strcat(dictionary, "0.25 0 0 0.25 0 0 cm\n");
 
+		double resize_x;
+		double resize_y;
+
 		for (int i = 0; i < ptr->image_length; i++) {
 			if (dim[i * 2] <= 0 || dim[i * 2 + 1] <= 0)
 				continue;
 
+			/* Scale within bound of A4 paper */
+			resize_x = 595.276 * 4 / dim[i * 2];
+			resize_y = 841.89 * 4 / dim[i * 2 + 1];
+
+			if (resize_y < resize_x)
+				snprintf(buf, 64, "%f 0 0 %f 0 0 cm\n",
+					resize_y, resize_y);
+			else
+				snprintf(buf, 64, "%f 0 0 %f 0 0 cm\n",
+					resize_x, resize_x);
+			strcat(dictionary, buf);
+
 			/* Apply transformation matrix */
-			if (ptr->image_data[i].format == DCT_1) {
+			if (ptr->image_data[i].format == JBIG || ptr->image_data[i].format == DCT_1) {
 				snprintf(buf, 64, "1 0 0 1 0 %d cm\n",
 					dim[i * 2 + 1]);
 				strcat(dictionary, buf);
@@ -763,9 +829,10 @@ cnki_pdf_hn(cnki_t **param)
 		strcat(dictionary, "Q");
 
 		if (strdeflate(&stream, &stream_size, dictionary, strlen(dictionary)) != 0) {
-			free(dictionary);
 			free(root_kid);
+			free(ids);
 			free(dim);
+			free(dictionary);
 			return 1;
 		}
 
@@ -796,7 +863,7 @@ cnki_pdf_hn(cnki_t **param)
 		strcat(dictionary, buf);
 
 		/* A4 paper */
-		strcat(dictionary, "/MediaBox [ 0 0 595.276 841.89 ]\n");
+		strcat(dictionary, "/MediaBox [0 0 595.276 841.89]\n");
 
 		/* Add /Parent when we know root */
 		pdf_obj_append(&pdf, ids[ptr->image_length + 2], NULL, dictionary, NULL, 0);
@@ -838,7 +905,7 @@ cnki_pdf_hn(cnki_t **param)
 	if ((*param)->stat > 1)
 		printf("Generating root object\n");
 
-	dictionary_size = 64 + 12 * (*param)->file_stat->page;
+	dictionary_size = 64 + 64 * (*param)->file_stat->page;
 	dictionary = malloc(dictionary_size);
 
 	if (dictionary == NULL) {
@@ -877,7 +944,7 @@ cnki_pdf_hn(cnki_t **param)
 
 	free(dictionary);
 
-	dictionary_size = 128;
+	dictionary_size = 256;
 	dictionary = malloc(dictionary_size);
 
 	if (dictionary == NULL) {
diff --git a/src/cnki_xml.c b/src/cnki_xml.c
deleted file mode 100644
index 7f870d1..0000000
--- a/src/cnki_xml.c
+++ /dev/null
@@ -1,14 +0,0 @@
-/*
- * Copyright (c) 2020-2021, yzrh <yzrh@noema.org>
- *
- * SPDX-License-Identifier: Apache-2.0
- */
-
-#include <stdio.h>
-
-int
-cnki_xml(char **xml, FILE **fp)
-{
-	/* TODO: Extract XML and embed into `/Metadata' */
-	return 1;
-}
diff --git a/src/cnki_zlib.c b/src/cnki_zlib.c
index 7731036..edff141 100644
--- a/src/cnki_zlib.c
+++ b/src/cnki_zlib.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020-2021, yzrh <yzrh@noema.org>
+ * Copyright (c) 2020-2022, yzrh <yzrh@noema.org>
  *
  * SPDX-License-Identifier: Apache-2.0
  */
@@ -18,7 +18,7 @@ cnki_zlib(char **dst, int *dst_size,
 
 	*dst_size = size;
 
-	if (strinflate(dst, size, src + 24, size - 24) != 0)
+	if (strinflate(dst, size, src + 24, src_size - 24) != 0)
 		return 1;
 
 	return 0;
diff --git a/src/jbig.c b/src/jbig.c
index 8e3dbaf..09a3d92 100644
--- a/src/jbig.c
+++ b/src/jbig.c
@@ -1,41 +1,303 @@
 /*
- * Copyright (c) 2020-2022, yzrh <yzrh@noema.org>
+ * Copyright (c) 2022, yzrh <yzrh@noema.org>
  *
  * SPDX-License-Identifier: Apache-2.0
  */
 
-#include <stdio.h> /* FIXME: test */
+#include <stdbool.h>
+#include <stdint.h>
 #include <stdlib.h>
 #include <string.h>
 
-#include <jbig.h>
+static const uint16_t _LSZ[256] = {
+	0x5a1d,
+	0x2586, 0x1114, 0x080b, 0x03d8, 0x01da, 0x00e5, 0x006f, 0x0036,
+	0x001a, 0x000d, 0x0006, 0x0003, 0x0001, 0x5a7f, 0x3f25, 0x2cf2,
+	0x207c, 0x17b9, 0x1182, 0x0cef, 0x09a1, 0x072f, 0x055c, 0x0406,
+	0x0303, 0x0240, 0x01b1, 0x0144, 0x00f5, 0x00b7, 0x008a, 0x0068,
+	0x004e, 0x003b, 0x002c, 0x5ae1, 0x484c, 0x3a0d, 0x2ef1, 0x261f,
+	0x1f33, 0x19a8, 0x1518, 0x1177, 0x0e74, 0x0bfb, 0x09f8, 0x0861,
+	0x0706, 0x05cd, 0x04de, 0x040f, 0x0363, 0x02d4, 0x025c, 0x01f8,
 
-int
-strdec_jbig(char **bitmap, int *bitmap_size,
-	const char * restrict data, int data_size)
+	0x01a4, 0x0160, 0x0125, 0x00f6, 0x00cb, 0x00ab, 0x008f, 0x5b12,
+	0x4d04, 0x412c, 0x37d8, 0x2fe8, 0x293c, 0x2379, 0x1edf, 0x1aa9,
+	0x174e, 0x1424, 0x119c, 0x0f6b, 0x0d51, 0x0bb6, 0x0a40, 0x5832,
+	0x4d1c, 0x438e, 0x3bdd, 0x34ee, 0x2eae, 0x299a, 0x2516, 0x5570,
+	0x4ca9, 0x44d9, 0x3e22, 0x3824, 0x32b4, 0x2e17, 0x56a8, 0x4f46,
+	0x47e5, 0x41cf, 0x3c3d, 0x375e, 0x5231, 0x4c0f, 0x4639, 0x415e,
+	0x5627, 0x50e7, 0x4b85, 0x5597, 0x504f, 0x5a10, 0x5522, 0x59eb
+};
+
+static const uint8_t _NLPS[256] = {
+	1,
+	14, 16, 18, 20, 23, 25, 28, 30,
+	33, 35, 9, 10, 12, 15, 36, 38,
+	39, 40, 42, 43, 45, 46, 48, 49,
+	51, 52, 54, 56, 57, 59, 60, 62,
+	63, 32, 33, 37, 64, 65, 67, 68,
+	69, 70, 72, 73, 74, 75, 77, 78,
+	79, 48, 50, 50, 51, 52, 53, 54,
+
+	55, 56, 57, 58, 59, 61, 61, 65,
+	80, 81, 82, 83, 84, 86, 87, 87,
+	72, 72, 74, 74, 75, 77, 77, 80,
+	88, 89, 90, 91, 92, 93, 86, 88,
+	95, 96, 97, 99, 99, 93, 95, 101,
+	102, 103, 104, 99, 105, 106, 107, 103,
+	105, 108, 109, 110, 111, 110, 112, 112
+};
+
+static const uint8_t _NMPS[256] = {
+	1,
+	2, 3, 4, 5, 6, 7, 8, 9,
+	10, 11, 12, 13, 13, 15, 16, 17,
+	18, 19, 20, 21, 22, 23, 24, 25,
+	26, 27, 28, 29, 30, 31, 32, 33,
+	34, 35, 9, 37, 38, 39, 40, 41,
+	42, 43, 44, 45, 46, 47, 48, 49,
+	50, 51, 52, 53, 54, 55, 56, 57,
+
+	58, 59, 60, 61, 62, 63, 32, 65,
+	66, 67, 68, 69, 70, 71, 72, 73,
+	74, 75, 76, 77, 78, 79, 48, 81,
+	82, 83, 84, 85, 86, 87, 71, 89,
+	90, 91, 92, 93, 94, 86, 96, 97,
+	98, 99, 100, 93, 102, 103, 104, 99,
+	106, 107, 103, 109, 107, 111, 109, 111
+};
+
+static const bool _SWTCH[256] = {
+	1,
+	0, 0, 0, 0, 0, 0, 0, 0,
+	0, 0, 0, 0, 0, 1, 0, 0,
+	0, 0, 0, 0, 0, 0, 0, 0,
+	0, 0, 0, 0, 0, 0, 0, 0,
+	0, 0, 0, 1, 0, 0, 0, 0,
+	0, 0, 0, 0, 0, 0, 0, 0,
+	0, 0, 0, 0, 0, 0, 0, 0,
+
+	0, 0, 0, 0, 0, 0, 0, 1,
+	0, 0, 0, 0, 0, 0, 0, 0,
+	0, 0, 0, 0, 0, 0, 0, 1,
+	0, 0, 0, 0, 0, 0, 0, 1,
+	0, 0, 0, 0, 0, 0, 1, 0,
+	0, 0, 0, 0, 0, 0, 0, 0,
+	1, 0, 0, 0, 0, 1, 0, 1
+};
+
+static uint8_t _ct;
+static uint8_t _pix;
+
+static uint16_t _reg_a;
+static uint32_t _reg_c;
+static uint8_t _mps[0x1000];
+static uint8_t _st[0x1000];
+
+static int _width;
+static int _height;
+
+static int _width_padded;
+
+static int _ret_pos;
+static char *_ret;
+
+static int _scd_size;
+static unsigned char *_scd;
+
+static void
+_bytein(void)
 {
-	struct jbg_dec_state sd;
+	if (_ret_pos < _scd_size)
+		_reg_c += *(_scd + _ret_pos++) << 8;
 
-	jbg_dec_init(&sd);
+	_ct = 8;
+}
 
-	unsigned char *data_ptr[1] = {(unsigned char *) data};
+static void
+_initdec(void)
+{
+	memset(_mps, 0, 0x1000);
+	memset(_st, 0, 0x1000);
 
-	/* FIXME: test */
-	int ret;
-	if ((ret = jbg_dec_in(&sd, (unsigned char *) data_ptr,
-		data_size, NULL)) != JBG_EOK) {
-		printf("[%s] ", jbg_strerror(ret));
-		jbg_dec_free(&sd);
-		return 1;
+	_reg_c = 0;
+	_bytein();
+	_reg_c <<= 8;
+	_bytein();
+	_reg_c <<= 8;
+	_bytein();
+	_reg_a = 0x0000;
+}
+
+static void
+_exchange_lps(uint16_t cx)
+{
+	uint8_t st_cx = _st[cx];
+	uint16_t lsz_st_cx = _LSZ[_st[cx]];
+
+	if (_reg_a < lsz_st_cx) {
+		_pix = _mps[cx];
+		_st[cx] = _NMPS[st_cx];
+	} else {
+		_pix = 1 - _mps[cx];
+
+		if (_SWTCH[st_cx])
+			_mps[cx] = _pix;
+
+		_st[cx] = _NLPS[st_cx];
+	}
+
+	_reg_c -= _reg_a << 16;
+	_reg_a = lsz_st_cx;
+}
+
+static void
+_exchange_mps(uint16_t cx)
+{
+	uint8_t st_cx = _st[cx];
+	uint16_t lsz_st_cx = _LSZ[_st[cx]];
+
+	if (_reg_a < lsz_st_cx) {
+		_pix = 1 - _mps[cx];
+
+		if (_SWTCH[st_cx])
+			_mps[cx] = _pix;
+
+		_st[cx] = _NLPS[st_cx];
+	} else {
+		_pix = _mps[cx];
+		_st[cx] = _NMPS[st_cx];
+	}
+}
+
+static void
+_renormd(void)
+{
+	do {
+		if (_ct == 0)
+			_bytein();
+
+		_reg_a <<= 1;
+		_reg_c <<= 1;
+		_ct--;
+	} while (_reg_a < 0x8000);
+
+	if (_ct == 0)
+		_bytein();
+}
+
+static void
+_decode(uint16_t cx)
+{
+	_reg_a -= _LSZ[_st[cx]];
+
+	if (_reg_a > _reg_c >> 16) {
+		if (_reg_a < 0x8000) {
+			_exchange_mps(cx);
+			_renormd();
+		} else {
+			_pix = _mps[cx];
+		}
+	} else {
+		_exchange_lps(cx);
+		_renormd();
+	}
+}
+
+static void
+_procline(int line, char *a, char *b, char *c)
+{
+	/* The encoder must be erroneous */
+	uint16_t cx = (*b & 0x01) << 2;
+
+	for (int i = 0; i < _width; i++) {
+		_decode(cx);
+
+		cx >>= 1;
+
+		if (_pix == 1) {
+			*(_ret + _width_padded * (_height - line - 1) + i / 8) |= _pix << (7 - (i & 0x07));
+			*(c + i) = 1;
+			cx |= 0x0200;
+		} else {
+			cx &= 0xfdff;
+		}
+
+		if (i + 2 < _width && *(a + i + 2) == 1)
+			cx |= 0x0004;
+		else
+			cx &= 0xfffb;
+
+		if (i + 3 < _width && *(b + i + 3) == 1)
+			cx |= 0x0080;
+		else
+			cx &= 0xff7f;
 	}
+}
+
+static int
+_procstripe(void)
+{
+	if (_height <= 0 || _width_padded <= 0)
+		return 1;
 
-	*bitmap_size = jbg_dec_getsize(&sd);
-	*bitmap = malloc(*bitmap_size);
+	int pix_size = 8 * _width_padded;
 
-	if (*bitmap != NULL)
-		memcpy(*bitmap, jbg_dec_getimage(&sd, 0), *bitmap_size);
+	char *buf = malloc(3 * pix_size);
 
-	jbg_dec_free(&sd);
+	if (buf == NULL)
+		return 1;
+
+	memset(buf, 0, 3 * pix_size);
+
+	char *a = buf;
+	char *b = a + pix_size;
+	char *c = b + pix_size;
+	char *z;
+
+	for (int i = 0; i < _height; i++) {
+		_decode(0x029c);
+
+		if (_pix == 1) {
+			if (i > 0)
+				memcpy(_ret + _width_padded * (_height - i - 1),
+					_ret + _width_padded * (_height - i),
+					_width_padded);
+
+			memcpy(c, b, pix_size);
+		} else {
+			/* line atypical */
+			memset(c, 0, pix_size);
+			_procline(i, a, b, c);
+		}
+
+		z = a;
+		a = b;
+		b = c;
+		c = z;
+	}
+
+	free(buf);
 
 	return 0;
 }
+
+int
+strdec_jbig(char **bitmap, int width, int height,
+	const char * restrict jbig, int jbig_size)
+{
+	_width = width;
+	_height = height;
+
+	_width_padded = (_width + 7) / 8;
+
+	memset(*bitmap, 0, _height * _width_padded);
+
+	_ret_pos = 0;
+	_ret = *bitmap;
+
+	_scd_size = jbig_size;
+	_scd = (unsigned char *) jbig;
+
+	_initdec();
+	return _procstripe();
+}
diff --git a/src/jbig.h b/src/jbig.h
index 170eda1..1919f3e 100644
--- a/src/jbig.h
+++ b/src/jbig.h
@@ -1,8 +1,8 @@
 /*
- * Copyright (c) 2020-2021, yzrh <yzrh@noema.org>
+ * Copyright (c) 2022, yzrh <yzrh@noema.org>
  *
  * SPDX-License-Identifier: Apache-2.0
  */
 
-int strdec_jbig(char **bitmap, int *bitmap_size,
-	const char * restrict data, int data_size);
+int strdec_jbig(char **bitmap, int width, int height,
+	const char * restrict jbig, int jbig_size);
diff --git a/src/jbig2.c b/src/jbig2.c
new file mode 100644
index 0000000..9b3a9be
--- /dev/null
+++ b/src/jbig2.c
@@ -0,0 +1,35 @@
+/*
+ * Copyright (c) 2022, yzrh <yzrh@noema.org>
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <jbig2.h>
+
+int
+strdec_jbig2(char **bitmap,
+	const char * restrict jbig2, int jbig2_size)
+{
+	Jbig2Ctx *ctx = jbig2_ctx_new(NULL, JBIG2_OPTIONS_EMBEDDED, NULL, NULL, NULL);
+
+	jbig2_data_in(ctx, (unsigned char *) jbig2, jbig2_size);
+
+	jbig2_complete_page(ctx);
+
+	Jbig2Image *image = jbig2_page_out(ctx);
+
+	int width_padded = (image->width + 7) / 8;
+	unsigned char *data = image->data;
+
+	for (unsigned int i = 0; i < image->height; i++) {
+		memcpy(*bitmap + i * width_padded, data, width_padded);
+		data += image->stride;
+	}
+
+	jbig2_release_page(ctx, image);
+	return 0;
+}
diff --git a/src/jbig2.h b/src/jbig2.h
new file mode 100644
index 0000000..11249cf
--- /dev/null
+++ b/src/jbig2.h
@@ -0,0 +1,7 @@
+/*
+ * Copyright (c) 2022, yzrh <yzrh@noema.org>
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+int strdec_jbig2(char **bitmap, const char * restrict jbig2, int jbig2_size);
diff --git a/src/melon.c b/src/melon.c
index 8741989..af6aaf4 100644
--- a/src/melon.c
+++ b/src/melon.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020-2021, yzrh <yzrh@noema.org>
+ * Copyright (c) 2020-2022, yzrh <yzrh@noema.org>
  *
  * SPDX-License-Identifier: Apache-2.0
  */
@@ -82,7 +82,7 @@ main(int argc, char **argv)
 
 		if (param->stat > 0)
 			printf("Melon " VERSION "." RELEASE "." PATCH EXTRA "\n"
-				"Copyright (c) 2020-2021, yzrh <yzrh@noema.org>\n\n");
+				"Copyright (c) 2020-2022, yzrh <yzrh@noema.org>\n\n");
 
 		cnki_info(&param);
 
diff --git a/src/pdf.c b/src/pdf.c
index de98706..bf9da5c 100644
--- a/src/pdf.c
+++ b/src/pdf.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020-2021, yzrh <yzrh@noema.org>
+ * Copyright (c) 2020-2022, yzrh <yzrh@noema.org>
  *
  * SPDX-License-Identifier: Apache-2.0
  */
diff --git a/src/pdf_cnki.c b/src/pdf_cnki.c
index a1c7a09..e8e2f90 100644
--- a/src/pdf_cnki.c
+++ b/src/pdf_cnki.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020-2021, yzrh <yzrh@noema.org>
+ * Copyright (c) 2020-2022, yzrh <yzrh@noema.org>
  *
  * SPDX-License-Identifier: Apache-2.0
  */
diff --git a/src/pdf_get.c b/src/pdf_get.c
index 4e1ec56..a72c68d 100644
--- a/src/pdf_get.c
+++ b/src/pdf_get.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020-2021, yzrh <yzrh@noema.org>
+ * Copyright (c) 2020-2022, yzrh <yzrh@noema.org>
  *
  * SPDX-License-Identifier: Apache-2.0
  */
diff --git a/src/version.h b/src/version.h
index 4731e6a..4e5cfa6 100644
--- a/src/version.h
+++ b/src/version.h
@@ -1,10 +1,10 @@
 /*
- * Copyright (c) 2020-2021, yzrh <yzrh@noema.org>
+ * Copyright (c) 2020-2022, yzrh <yzrh@noema.org>
  *
  * SPDX-License-Identifier: Apache-2.0
  */
 
 #define VERSION	"0"
-#define RELEASE	"1"
+#define RELEASE	"2"
 #define PATCH	"0"
 #define EXTRA	""