1 files changed, 119 insertions, 0 deletions
diff --git a/src/jp2.c b/src/jp2.c
new file mode 100644
index 0000000..9420b48
--- /dev/null
+++ b/src/jp2.c
@@ -0,0 +1,119 @@
+/*
+ * Copyright (c) 2022, yzrh <yzrh@noema.org>
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <string.h>
+
+#ifdef __linux__
+#include <openjpeg.h>
+#else
+#include <openjpeg-2.5/openjpeg.h>
+#endif
+
+typedef struct _stream_user_data {
+	OPJ_SIZE_T pos;
+	OPJ_SIZE_T size;
+	const unsigned char *data;
+} stream_user_data;
+
+static OPJ_SIZE_T
+_opj_stream_read(void *p_buffer, OPJ_SIZE_T p_nb_bytes, void *p_user_data)
+{
+	stream_user_data *d = (stream_user_data *) p_user_data;
+
+	if (d->pos >= d->size)
+		return (OPJ_SIZE_T) - 1;
+
+	OPJ_SIZE_T ret_size = p_nb_bytes;
+
+	if (d->pos + ret_size > d->size)
+		ret_size = d->size - d->pos;
+
+	memcpy(p_buffer, d->data + d->pos, ret_size);
+
+	d->pos += ret_size;
+
+	return ret_size;
+}
+
+static OPJ_OFF_T
+_opj_stream_skip(OPJ_OFF_T p_nb_bytes, void *p_user_data)
+{
+	stream_user_data *d = (stream_user_data *) p_user_data;
+
+	if (d->pos + p_nb_bytes <= d->size)
+		d->pos += p_nb_bytes;
+	else
+		d->pos = d->size;
+
+	return d->pos;
+}
+
+static OPJ_BOOL
+_opj_stream_seek(OPJ_OFF_T p_nb_bytes, void *p_user_data)
+{
+	stream_user_data *d = (stream_user_data *) p_user_data;
+
+	if (p_nb_bytes <= (OPJ_OFF_T) d->size) {
+		d->pos = p_nb_bytes;
+		return OPJ_TRUE;
+	}
+
+	return OPJ_FALSE;
+}
+
+int
+strinfo_jp2_dim(int *jp2_width, int *jp2_height,
+	const char * restrict data, int data_size)
+{
+	opj_codec_t *codec;
+	opj_dparameters_t param;
+	opj_stream_t *stream;
+	opj_image_t *image;
+	stream_user_data d;
+
+	if (data_size < 2)
+		return 1;
+
+	opj_set_default_decoder_parameters(&param);
+
+	if ((unsigned char) data[0] == 0xff && (unsigned char) data[1] == 0x4f)
+		codec = opj_create_decompress(OPJ_CODEC_J2K);
+	else
+		codec = opj_create_decompress(OPJ_CODEC_JP2);
+
+	if (!opj_setup_decoder(codec, &param)) {
+		opj_destroy_codec(codec);
+		return 1;
+	}
+
+	stream = opj_stream_default_create(OPJ_TRUE);
+
+	d.pos = 0;
+	d.size = data_size;
+	d.data = (unsigned char *) data;
+
+	opj_stream_set_read_function(stream, _opj_stream_read);
+	opj_stream_set_skip_function(stream, _opj_stream_skip);
+	opj_stream_set_seek_function(stream, _opj_stream_seek);
+	opj_stream_set_user_data(stream, &d, NULL);
+	opj_stream_set_user_data_length(stream, data_size);
+
+	if (!opj_read_header(stream, codec, &image)) {
+		opj_destroy_codec(codec);
+		opj_stream_destroy(stream);
+		return 1;
+	}
+
+	opj_destroy_codec(codec);
+	opj_stream_destroy(stream);
+
+	*jp2_width = image->x1 - image->x0;
+	*jp2_height = image->y1 - image->y0;
+
+	opj_image_destroy(image);
+
+	return 0;
+}