nbtvis/nbt/nbt/read.c

#include "nbt.h"
#include "lib.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

static bool nbt_read_data(tag_t *tag, const stream_t *stream);

static bool nbt_read_header(tag_t *tag, const stream_t *stream, bool named) {
	bool ok = true;

	if (stream_read_i8(stream, &tag->type) == false)
		return false;

	if (tag->type == TAG_END)
		named = false;

	if (named) {
		if (stream_read_u16(stream, &tag->name_len) == false)
			return false;
	} else {
		tag->name_len = 0;
	}

	if (tag->name_len < 1) {
		tag->name = "";
	} else {
		tag->name = xalloc(tag->name_len);
		ok = stream_read(stream, tag->name, tag->name_len);
	}

	if (!ok)
		return false;

	return true;
}


static bool nbt_read_byte_array(tagdata_t *data, const stream_t *stream) {
	if (stream_read_i32(stream, &data->b_arr.size) == false)
		return false;
	if (data->b_arr.size == 0) {
		data->b_arr.data = NULL;
		return true;
	}
	data->b_arr.data = xalloc(data->b_arr.size * sizeof(int8_t));
	for (int32_t i = 0; i < data->b_arr.size; i++)
		if (stream_read_i8(stream, &data->b_arr.data[i]) == false)
			return false;
	return true;
}

static bool nbt_read_int_array(tagdata_t *data, const stream_t *stream) {
	if (stream_read_i32(stream, &data->i_arr.size) == false)
		return false;
	if (data->i_arr.size == 0) {
		data->i_arr.data = NULL;
		return true;
	}
	data->i_arr.data = xalloc(data->i_arr.size * sizeof(int32_t));
	for (int32_t i = 0; i < data->i_arr.size; i++)
		if (stream_read_i32(stream, &data->i_arr.data[i]) == false)
			return false;
	return true;
}

static bool nbt_read_long_array(tagdata_t *data, const stream_t *stream) {
	if (stream_read_i32(stream, &data->l_arr.size) == false)
		return false;
	if (data->l_arr.size == 0) {
		data->l_arr.data = NULL;
		return true;
	}
	data->l_arr.data = xalloc(data->l_arr.size * sizeof(int64_t));
	for (int32_t i = 0; i < data->l_arr.size; i++)
		if (stream_read_i64(stream, &data->l_arr.data[i]) == false)
			return false;
	return true;
}

static bool nbt_read_string(tagdata_t *data, const stream_t *stream) {
	if (stream_read_u16(stream, &data->string.size) == false)
		return false;
	if (data->string.size < 1) {
		data->string.data = NULL;
		return true;
	}
	data->string.data = xalloc(data->string.size);
	if (stream_read(stream, data->string.data, data->string.size) == false)
		return false;
	return true;
}

static bool nbt_read_list(tagdata_t *data, const stream_t *stream) {
	if (stream_read_i8(stream, &data->list.type) == false)
		return false;
	if (stream_read_i32(stream, &data->list.size) == false)
		return false;
	if (data->list.size <= 0) {
		data->list.tags = NULL;
		return true;
	} else if (data->list.type == 0) {
		// tag end is not allowed to be used with non empty list
		return false;
	}
	data->list.tags = xalloc(data->list.size * sizeof(tag_t));
	for (int32_t i = 0; i < data->list.size; i++) {
		tag_t tag;
		tag.type = data->list.type;
		tag.name = "";
		tag.name_len = 0;
		if (nbt_read_data(&tag, stream) == false)
			return false;
		data->list.tags[i] = tag;
	}
	return true;
}

static bool nbt_read_compound(tagdata_t *data, const stream_t *stream) {

	map_t map;
	map_init(&map);

	while (1) {

		tag_t tag;

		if (nbt_read_header(&tag, stream, true) == false) {
			map_free(&map);
			return false;
		}
		
		if (tag.type == TAG_END)
			break;
		
		if (tag.name_len < 1) {
			map_free(&map);
			return false;
		}

		if (nbt_read_data(&tag, stream) == false) {
			map_free(&map);
			return false;
		}

		map_put(&map, &tag);
	}

	data->compound = map;

	return true;
}

static bool nbt_read_data(tag_t *tag, const stream_t *stream) {
	bool ok = true;

	switch (tag->type) {
        case TAG_END:
			// tag has no data
			break;
        case TAG_BYTE:
			ok = stream_read_i8(stream, &tag->data.b);
			break;
        case TAG_SHORT:
			ok = stream_read_i16(stream, &tag->data.s);
			break;
        case TAG_FLOAT:
        case TAG_INT:
			ok = stream_read_i32(stream, &tag->data.i);
			break;
        case TAG_DOUBLE:
        case TAG_LONG:
			ok = stream_read_i64(stream, &tag->data.l);
			break;
        case TAG_BYTE_ARRAY:
			ok = nbt_read_byte_array(&tag->data, stream);
			break;
        case TAG_STRING:
			ok = nbt_read_string(&tag->data, stream);
			break;
        case TAG_LIST:
			ok = nbt_read_list(&tag->data, stream);
			break;
        case TAG_COMPOUND:
			ok = nbt_read_compound(&tag->data, stream);
			break;
        case TAG_INT_ARRAY:
			ok = nbt_read_int_array(&tag->data, stream);
			break;
        case TAG_LONG_ARRAY:
			ok = nbt_read_long_array(&tag->data, stream);
			break;
          break;
        };
    return ok;
}

bool nbt_read(tag_t *tag, const stream_t *stream) {
	memset(tag, 0, sizeof(tag_t));
	if (nbt_read_header(tag, stream, true) == false)
		return false;
	if (nbt_read_data(tag, stream) == false)
		return false;
	return true;
}