1 files changed, 89 insertions, 0 deletions
diff --git a/src/cnki_jbig.c b/src/cnki_jbig.c
new file mode 100644
index 0000000..02040be
--- /dev/null
+++ b/src/cnki_jbig.c
@@ -0,0 +1,89 @@
+/*
+ * Copyright (c) 2020-2021, yzrh <yzrh@noema.org>
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <stdlib.h>
+#include <string.h>
+
+#include "cnki_jbig.h"
+#include "jbig.h"
+
+int
+cnki_jbig(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);
+
+	bih_t *bih = malloc(sizeof(bih_t));
+
+	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;
+
+	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) {
+		free(dib);
+		free(bih);
+		return 1;
+	}
+
+	memcpy(bie, bih, 20);
+	memcpy(bie + 20, 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;
+	}
+
+	free(dib);
+	free(bih);
+	free(bie);
+
+	if (ret != 0)
+		return 1;
+
+	return 0;
+}