emitter.go

/*
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package candiedyaml

import (
	"bytes"
)

var default_tag_directives = []yaml_tag_directive_t{
	{[]byte("!"), []byte("!")},
	{[]byte("!!"), []byte("tag:yaml.org,2002:")},
}

/*
 * Flush the buffer if needed.
 */

func flush(emitter *yaml_emitter_t) bool {
	if emitter.buffer_pos+5 >= len(emitter.buffer) {
		return yaml_emitter_flush(emitter)
	}
	return true
}

/*
 * Put a character to the output buffer.
 */
func put(emitter *yaml_emitter_t, value byte) bool {
	if !flush(emitter) {
		return false
	}

	emitter.buffer[emitter.buffer_pos] = value
	emitter.buffer_pos++
	emitter.column++
	return true
}

/*
 * Put a line break to the output buffer.
 */

func put_break(emitter *yaml_emitter_t) bool {
	if !flush(emitter) {
		return false
	}
	switch emitter.line_break {
	case yaml_CR_BREAK:
		emitter.buffer[emitter.buffer_pos] = '\r'
		emitter.buffer_pos++
	case yaml_LN_BREAK:
		emitter.buffer[emitter.buffer_pos] = '\n'
		emitter.buffer_pos++
	case yaml_CRLN_BREAK:
		emitter.buffer[emitter.buffer_pos] = '\r'
		emitter.buffer[emitter.buffer_pos] = '\n'
		emitter.buffer_pos += 2
	default:
		return false
	}
	emitter.column = 0
	emitter.line++
	return true
}

/*
 * Copy a character from a string into buffer.
 */
func write(emitter *yaml_emitter_t, src []byte, src_pos *int) bool {
	if !flush(emitter) {
		return false
	}
	copy_bytes(emitter.buffer, &emitter.buffer_pos, src, src_pos)
	emitter.column++
	return true
}

/*
 * Copy a line break character from a string into buffer.
 */

func write_break(emitter *yaml_emitter_t, src []byte, src_pos *int) bool {
	if src[*src_pos] == '\n' {
		if !put_break(emitter) {
			return false
		}
		*src_pos++
	} else {
		if !write(emitter, src, src_pos) {
			return false
		}
		emitter.column = 0
		emitter.line++
	}

	return true
}

/*
 * Set an emitter error and return 0.
 */

func yaml_emitter_set_emitter_error(emitter *yaml_emitter_t, problem string) bool {
	emitter.error = yaml_EMITTER_ERROR
	emitter.problem = problem
	return false
}

/*
 * Emit an event.
 */

func yaml_emitter_emit(emitter *yaml_emitter_t, event *yaml_event_t) bool {
	emitter.events = append(emitter.events, *event)
	for !yaml_emitter_need_more_events(emitter) {
		event := &emitter.events[emitter.events_head]
		if !yaml_emitter_analyze_event(emitter, event) {
			return false
		}
		if !yaml_emitter_state_machine(emitter, event) {
			return false
		}
		yaml_event_delete(event)
		emitter.events_head++
	}
	return true
}

/*
 * Check if we need to accumulate more events before emitting.
 *
 * We accumulate extra
 *  - 1 event for DOCUMENT-START
 *  - 2 events for SEQUENCE-START
 *  - 3 events for MAPPING-START
 */

func yaml_emitter_need_more_events(emitter *yaml_emitter_t) bool {
	if emitter.events_head == len(emitter.events) {
		return true
	}

	accumulate := 0
	switch emitter.events[emitter.events_head].event_type {
	case yaml_DOCUMENT_START_EVENT:
		accumulate = 1
	case yaml_SEQUENCE_START_EVENT:
		accumulate = 2
	case yaml_MAPPING_START_EVENT:
		accumulate = 3
	default:
		return false
	}

	if len(emitter.events)-emitter.events_head > accumulate {
		return false
	}

	level := 0
	for i := emitter.events_head; i < len(emitter.events); i++ {
		switch emitter.events[i].event_type {
		case yaml_STREAM_START_EVENT, yaml_DOCUMENT_START_EVENT, yaml_SEQUENCE_START_EVENT, yaml_MAPPING_START_EVENT:
			level++
		case yaml_STREAM_END_EVENT, yaml_DOCUMENT_END_EVENT, yaml_SEQUENCE_END_EVENT, yaml_MAPPING_END_EVENT:
			level--
		}

		if level == 0 {
			return false
		}
	}
	return true
}

/*
 * Append a directive to the directives stack.
 */

func yaml_emitter_append_tag_directive(emitter *yaml_emitter_t,
	value *yaml_tag_directive_t, allow_duplicates bool) bool {

	for i := range emitter.tag_directives {

		if bytes.Equal(value.handle, emitter.tag_directives[i].handle) {
			if allow_duplicates {
				return true
			}
			return yaml_emitter_set_emitter_error(emitter, "duplicat %TAG directive")
		}
	}

	tag_copy := yaml_tag_directive_t{
		handle: value.handle,
		prefix: value.prefix,
	}

	emitter.tag_directives = append(emitter.tag_directives, tag_copy)

	return true
}

/*
 * Increase the indentation level.
 */

func yaml_emitter_increase_indent(emitter *yaml_emitter_t, flow bool, indentless bool) bool {

	emitter.indents = append(emitter.indents, emitter.indent)

	if emitter.indent < 0 {
		if flow {
			emitter.indent = emitter.best_indent
		} else {
			emitter.indent = 0
		}
	} else if !indentless {
		emitter.indent += emitter.best_indent
	}

	return true
}

/*
 * State dispatcher.
 */

func yaml_emitter_state_machine(emitter *yaml_emitter_t, event *yaml_event_t) bool {
	switch emitter.state {
	case yaml_EMIT_STREAM_START_STATE:
		return yaml_emitter_emit_stream_start(emitter, event)

	case yaml_EMIT_FIRST_DOCUMENT_START_STATE:
		return yaml_emitter_emit_document_start(emitter, event, true)

	case yaml_EMIT_DOCUMENT_START_STATE:
		return yaml_emitter_emit_document_start(emitter, event, false)

	case yaml_EMIT_DOCUMENT_CONTENT_STATE:
		return yaml_emitter_emit_document_content(emitter, event)

	case yaml_EMIT_DOCUMENT_END_STATE:
		return yaml_emitter_emit_document_end(emitter, event)

	case yaml_EMIT_FLOW_SEQUENCE_FIRST_ITEM_STATE:
		return yaml_emitter_emit_flow_sequence_item(emitter, event, true)

	case yaml_EMIT_FLOW_SEQUENCE_ITEM_STATE:
		return yaml_emitter_emit_flow_sequence_item(emitter, event, false)

	case yaml_EMIT_FLOW_MAPPING_FIRST_KEY_STATE:
		return yaml_emitter_emit_flow_mapping_key(emitter, event, true)

	case yaml_EMIT_FLOW_MAPPING_KEY_STATE:
		return yaml_emitter_emit_flow_mapping_key(emitter, event, false)

	case yaml_EMIT_FLOW_MAPPING_SIMPLE_VALUE_STATE:
		return yaml_emitter_emit_flow_mapping_value(emitter, event, true)

	case yaml_EMIT_FLOW_MAPPING_VALUE_STATE:
		return yaml_emitter_emit_flow_mapping_value(emitter, event, false)

	case yaml_EMIT_BLOCK_SEQUENCE_FIRST_ITEM_STATE:
		return yaml_emitter_emit_block_sequence_item(emitter, event, true)

	case yaml_EMIT_BLOCK_SEQUENCE_ITEM_STATE:
		return yaml_emitter_emit_block_sequence_item(emitter, event, false)

	case yaml_EMIT_BLOCK_MAPPING_FIRST_KEY_STATE:
		return yaml_emitter_emit_block_mapping_key(emitter, event, true)

	case yaml_EMIT_BLOCK_MAPPING_KEY_STATE:
		return yaml_emitter_emit_block_mapping_key(emitter, event, false)

	case yaml_EMIT_BLOCK_MAPPING_SIMPLE_VALUE_STATE:
		return yaml_emitter_emit_block_mapping_value(emitter, event, true)

	case yaml_EMIT_BLOCK_MAPPING_VALUE_STATE:
		return yaml_emitter_emit_block_mapping_value(emitter, event, false)

	case yaml_EMIT_END_STATE:
		return yaml_emitter_set_emitter_error(emitter,
			"expected nothing after STREAM-END")

	}

	panic("invalid state")
}

/*
 * Expect STREAM-START.
 */

func yaml_emitter_emit_stream_start(emitter *yaml_emitter_t, event *yaml_event_t) bool {

	if event.event_type != yaml_STREAM_START_EVENT {
		return yaml_emitter_set_emitter_error(emitter,
			"expected STREAM-START")
	}

	if emitter.encoding == yaml_ANY_ENCODING {
		emitter.encoding = event.encoding

		if emitter.encoding == yaml_ANY_ENCODING {
			emitter.encoding = yaml_UTF8_ENCODING
		}
	}

	if emitter.best_indent < 2 || emitter.best_indent > 9 {
		emitter.best_indent = 2
	}

	if emitter.best_width >= 0 && emitter.best_width <= emitter.best_indent*2 {
		emitter.best_width = 80
	}

	if emitter.best_width < 0 {
		emitter.best_width = 1<<31 - 1
	}

	if emitter.line_break == yaml_ANY_BREAK {
		emitter.line_break = yaml_LN_BREAK
	}

	emitter.indent = -1

	emitter.line = 0
	emitter.column = 0
	emitter.whitespace = true
	emitter.indention = true

	if emitter.encoding != yaml_UTF8_ENCODING {
		if !yaml_emitter_write_bom(emitter) {
			return false
		}
	}

	emitter.state = yaml_EMIT_FIRST_DOCUMENT_START_STATE

	return true
}

/*
 * Expect DOCUMENT-START or STREAM-END.
 */

func yaml_emitter_emit_document_start(emitter *yaml_emitter_t,
	event *yaml_event_t, first bool) bool {

	if event.event_type == yaml_DOCUMENT_START_EVENT {
		if event.version_directive != nil {
			if !yaml_emitter_analyze_version_directive(emitter,
				*event.version_directive) {
				return false
			}
		}

		for i := range event.tag_directives {
			tag_directive := &event.tag_directives[i]

			if !yaml_emitter_analyze_tag_directive(emitter, tag_directive) {
				return false
			}
			if !yaml_emitter_append_tag_directive(emitter, tag_directive, false) {
				return false
			}
		}

		for i := range default_tag_directives {
			if !yaml_emitter_append_tag_directive(emitter, &default_tag_directives[i], true) {
				return false
			}
		}

		implicit := event.implicit
		if !first || emitter.canonical {
			implicit = false
		}

		if (event.version_directive != nil || len(event.tag_directives) > 0) &&
			emitter.open_ended {
			if !yaml_emitter_write_indicator(emitter, []byte("..."), true, false, false) {
				return false
			}
			if !yaml_emitter_write_indent(emitter) {
				return false
			}
		}

		if event.version_directive != nil {
			implicit = false
			if !yaml_emitter_write_indicator(emitter, []byte("%YAML"), true, false, false) {
				return false
			}

			if !yaml_emitter_write_indicator(emitter, []byte("1.1"), true, false, false) {
				return false
			}

			if !yaml_emitter_write_indent(emitter) {
				return false
			}
		}

		if len(event.tag_directives) > 0 {
			implicit = false
			for i := range event.tag_directives {
				tag_directive := &event.tag_directives[i]

				if !yaml_emitter_write_indicator(emitter, []byte("%TAG"), true, false, false) {
					return false
				}
				if !yaml_emitter_write_tag_handle(emitter, tag_directive.handle) {
					return false
				}
				if !yaml_emitter_write_tag_content(emitter, tag_directive.prefix, true) {
					return false
				}
				if !yaml_emitter_write_indent(emitter) {
					return false
				}
			}
		}

		if yaml_emitter_check_empty_document(emitter) {
			implicit = false
		}

		if !implicit {
			if !yaml_emitter_write_indent(emitter) {
				return false
			}
			if !yaml_emitter_write_indicator(emitter, []byte("---"), true, false, false) {
				return false
			}

			if emitter.canonical {
				if !yaml_emitter_write_indent(emitter) {
					return false
				}
			}
		}

		emitter.state = yaml_EMIT_DOCUMENT_CONTENT_STATE

		return true
	} else if event.event_type == yaml_STREAM_END_EVENT {
		if emitter.open_ended {
			if !yaml_emitter_write_indicator(emitter, []byte("..."), true, false, false) {
				return false
			}
			if !yaml_emitter_write_indent(emitter) {
				return false
			}
		}

		if !yaml_emitter_flush(emitter) {
			return false
		}

		emitter.state = yaml_EMIT_END_STATE

		return true
	}

	return yaml_emitter_set_emitter_error(emitter,
		"expected DOCUMENT-START or STREAM-END")
}

/*
 * Expect the root node.
 */

func yaml_emitter_emit_document_content(emitter *yaml_emitter_t, event *yaml_event_t) bool {
	emitter.states = append(emitter.states, yaml_EMIT_DOCUMENT_END_STATE)

	return yaml_emitter_emit_node(emitter, event, true, false, false, false)
}

/*
 * Expect DOCUMENT-END.
 */

func yaml_emitter_emit_document_end(emitter *yaml_emitter_t, event *yaml_event_t) bool {

	if event.event_type != yaml_DOCUMENT_END_EVENT {
		return yaml_emitter_set_emitter_error(emitter,
			"expected DOCUMENT-END")
	}

	if !yaml_emitter_write_indent(emitter) {
		return false
	}
	if !event.implicit {
		if !yaml_emitter_write_indicator(emitter, []byte("..."), true, false, false) {
			return false
		}
		if !yaml_emitter_write_indent(emitter) {
			return false
		}
	}
	if !yaml_emitter_flush(emitter) {
		return false
	}

	emitter.state = yaml_EMIT_DOCUMENT_START_STATE
	emitter.tag_directives = emitter.tag_directives[:0]
	return true
}

/*
 *
 * Expect a flow item node.
 */

func yaml_emitter_emit_flow_sequence_item(emitter *yaml_emitter_t, event *yaml_event_t, first bool) bool {
	if first {
		if !yaml_emitter_write_indicator(emitter, []byte("["), true, true, false) {
			return false
		}
		if !yaml_emitter_increase_indent(emitter, true, false) {
			return false
		}
		emitter.flow_level++
	}

	if event.event_type == yaml_SEQUENCE_END_EVENT {
		emitter.flow_level--
		emitter.indent = emitter.indents[len(emitter.indents)-1]
		emitter.indents = emitter.indents[:len(emitter.indents)-1]
		if emitter.canonical && !first {
			if !yaml_emitter_write_indicator(emitter, []byte(","), false, false, false) {
				return false
			}
			if !yaml_emitter_write_indent(emitter) {
				return false
			}
		}
		if !yaml_emitter_write_indicator(emitter, []byte("]"), false, false, false) {
			return false
		}
		emitter.state = emitter.states[len(emitter.states)-1]
		emitter.states = emitter.states[:len(emitter.states)-1]

		return true
	}

	if !first {
		if !yaml_emitter_write_indicator(emitter, []byte(","), false, false, false) {
			return false
		}
	}

	if emitter.canonical || emitter.column > emitter.best_width {
		if !yaml_emitter_write_indent(emitter) {
			return false
		}
	}

	emitter.states = append(emitter.states, yaml_EMIT_FLOW_SEQUENCE_ITEM_STATE)
	return yaml_emitter_emit_node(emitter, event, false, true, false, false)
}

/*
 * Expect a flow key node.
 */

func yaml_emitter_emit_flow_mapping_key(emitter *yaml_emitter_t,
	event *yaml_event_t, first bool) bool {

	if first {

		if !yaml_emitter_write_indicator(emitter, []byte("{"), true, true, false) {
			return false
		}
		if !yaml_emitter_increase_indent(emitter, true, false) {
			return false
		}
		emitter.flow_level++
	}

	if event.event_type == yaml_MAPPING_END_EVENT {
		emitter.flow_level--
		emitter.indent = emitter.indents[len(emitter.indents)-1]
		emitter.indents = emitter.indents[:len(emitter.indents)-1]

		if emitter.canonical && !first {
			if !yaml_emitter_write_indicator(emitter, []byte(","), false, false, false) {
				return false
			}
			if !yaml_emitter_write_indent(emitter) {
				return false
			}
		}
		if !yaml_emitter_write_indicator(emitter, []byte("}"), false, false, false) {
			return false
		}

		emitter.state = emitter.states[len(emitter.states)-1]
		emitter.states = emitter.states[:len(emitter.states)-1]

		return true
	}

	if !first {
		if !yaml_emitter_write_indicator(emitter, []byte(","), false, false, false) {
			return false
		}
	}
	if emitter.canonical || emitter.column > emitter.best_width {
		if !yaml_emitter_write_indent(emitter) {
			return false
		}
	}

	if !emitter.canonical && yaml_emitter_check_simple_key(emitter) {
		emitter.states = append(emitter.states, yaml_EMIT_FLOW_MAPPING_SIMPLE_VALUE_STATE)
		return yaml_emitter_emit_node(emitter, event, false, false, true, true)
	} else {
		if !yaml_emitter_write_indicator(emitter, []byte("?"), true, false, false) {
			return false
		}

		emitter.states = append(emitter.states, yaml_EMIT_FLOW_MAPPING_VALUE_STATE)
		return yaml_emitter_emit_node(emitter, event, false, false, true, false)
	}
}

/*
 * Expect a flow value node.
 */

func yaml_emitter_emit_flow_mapping_value(emitter *yaml_emitter_t,
	event *yaml_event_t, simple bool) bool {

	if simple {
		if !yaml_emitter_write_indicator(emitter, []byte(":"), false, false, false) {
			return false
		}
	} else {
		if emitter.canonical || emitter.column > emitter.best_width {
			if !yaml_emitter_write_indent(emitter) {
				return false
			}
		}
		if !yaml_emitter_write_indicator(emitter, []byte(":"), true, false, false) {
			return false
		}
	}
	emitter.states = append(emitter.states, yaml_EMIT_FLOW_MAPPING_KEY_STATE)
	return yaml_emitter_emit_node(emitter, event, false, false, true, false)
}

/*
 * Expect a block item node.
 */

func yaml_emitter_emit_block_sequence_item(emitter *yaml_emitter_t,
	event *yaml_event_t, first bool) bool {

	if first {
		if !yaml_emitter_increase_indent(emitter, false,
			(emitter.mapping_context && !emitter.indention)) {
			return false
		}
	}

	if event.event_type == yaml_SEQUENCE_END_EVENT {

		emitter.indent = emitter.indents[len(emitter.indents)-1]
		emitter.indents = emitter.indents[:len(emitter.indents)-1]

		emitter.state = emitter.states[len(emitter.states)-1]
		emitter.states = emitter.states[:len(emitter.states)-1]

		return true
	}

	if !yaml_emitter_write_indent(emitter) {
		return false
	}
	if !yaml_emitter_write_indicator(emitter, []byte("-"), true, false, true) {
		return false
	}

	emitter.states = append(emitter.states, yaml_EMIT_BLOCK_SEQUENCE_ITEM_STATE)
	return yaml_emitter_emit_node(emitter, event, false, true, false, false)
}

/*
 * Expect a block key node.
 */

func yaml_emitter_emit_block_mapping_key(emitter *yaml_emitter_t,
	event *yaml_event_t, first bool) bool {

	if first {
		if !yaml_emitter_increase_indent(emitter, false, false) {
			return false
		}
	}

	if event.event_type == yaml_MAPPING_END_EVENT {
		emitter.indent = emitter.indents[len(emitter.indents)-1]
		emitter.indents = emitter.indents[:len(emitter.indents)-1]

		emitter.state = emitter.states[len(emitter.states)-1]
		emitter.states = emitter.states[:len(emitter.states)-1]

		return true
	}

	if !yaml_emitter_write_indent(emitter) {
		return false
	}

	if yaml_emitter_check_simple_key(emitter) {
		emitter.states = append(emitter.states, yaml_EMIT_BLOCK_MAPPING_SIMPLE_VALUE_STATE)

		return yaml_emitter_emit_node(emitter, event, false, false, true, true)
	} else {
		if !yaml_emitter_write_indicator(emitter, []byte("?"), true, false, true) {
			return false
		}
		emitter.states = append(emitter.states, yaml_EMIT_BLOCK_MAPPING_VALUE_STATE)

		return yaml_emitter_emit_node(emitter, event, false, false, true, false)
	}
}

/*
 * Expect a block value node.
 */

func yaml_emitter_emit_block_mapping_value(emitter *yaml_emitter_t,
	event *yaml_event_t, simple bool) bool {

	if simple {
		if !yaml_emitter_write_indicator(emitter, []byte(":"), false, false, false) {
			return false
		}
	} else {
		if !yaml_emitter_write_indent(emitter) {
			return false
		}
		if !yaml_emitter_write_indicator(emitter, []byte(":"), true, false, true) {
			return false
		}
	}
	emitter.states = append(emitter.states, yaml_EMIT_BLOCK_MAPPING_KEY_STATE)

	return yaml_emitter_emit_node(emitter, event, false, false, true, false)
}

/*
 * Expect a node.
 */

func yaml_emitter_emit_node(emitter *yaml_emitter_t, event *yaml_event_t,
	root bool, sequence bool, mapping bool, simple_key bool) bool {
	emitter.root_context = root
	emitter.sequence_context = sequence
	emitter.mapping_context = mapping
	emitter.simple_key_context = simple_key

	switch event.event_type {
	case yaml_ALIAS_EVENT:
		return yaml_emitter_emit_alias(emitter, event)

	case yaml_SCALAR_EVENT:
		return yaml_emitter_emit_scalar(emitter, event)

	case yaml_SEQUENCE_START_EVENT:
		return yaml_emitter_emit_sequence_start(emitter, event)

	case yaml_MAPPING_START_EVENT:
		return yaml_emitter_emit_mapping_start(emitter, event)

	default:
		return yaml_emitter_set_emitter_error(emitter,
			"expected SCALAR, SEQUENCE-START, MAPPING-START, or ALIAS")
	}

	return false
}

/*
 * Expect ALIAS.
 */

func yaml_emitter_emit_alias(emitter *yaml_emitter_t, event *yaml_event_t) bool {
	if !yaml_emitter_process_anchor(emitter) {
		return false
	}

	emitter.state = emitter.states[len(emitter.states)-1]
	emitter.states = emitter.states[:len(emitter.states)-1]

	return true
}

/*
 * Expect SCALAR.
 */

func yaml_emitter_emit_scalar(emitter *yaml_emitter_t, event *yaml_event_t) bool {
	if !yaml_emitter_select_scalar_style(emitter, event) {
		return false
	}
	if !yaml_emitter_process_anchor(emitter) {
		return false
	}
	if !yaml_emitter_process_tag(emitter) {
		return false
	}
	if !yaml_emitter_increase_indent(emitter, true, false) {
		return false
	}
	if !yaml_emitter_process_scalar(emitter) {
		return false
	}
	emitter.indent = emitter.indents[len(emitter.indents)-1]
	emitter.indents = emitter.indents[:len(emitter.indents)-1]

	emitter.state = emitter.states[len(emitter.states)-1]
	emitter.states = emitter.states[:len(emitter.states)-1]

	return true
}

/*
 * Expect SEQUENCE-START.
 */

func yaml_emitter_emit_sequence_start(emitter *yaml_emitter_t, event *yaml_event_t) bool {
	if !yaml_emitter_process_anchor(emitter) {
		return false
	}
	if !yaml_emitter_process_tag(emitter) {
		return false
	}

	if emitter.flow_level > 0 || emitter.canonical ||
		event.style == yaml_style_t(yaml_FLOW_SEQUENCE_STYLE) ||
		yaml_emitter_check_empty_sequence(emitter) {
		emitter.state = yaml_EMIT_FLOW_SEQUENCE_FIRST_ITEM_STATE
	} else {
		emitter.state = yaml_EMIT_BLOCK_SEQUENCE_FIRST_ITEM_STATE
	}

	return true
}

/*
 * Expect MAPPING-START.
 */

func yaml_emitter_emit_mapping_start(emitter *yaml_emitter_t, event *yaml_event_t) bool {
	if !yaml_emitter_process_anchor(emitter) {
		return false
	}
	if !yaml_emitter_process_tag(emitter) {
		return false
	}

	if emitter.flow_level > 0 || emitter.canonical ||
		event.style == yaml_style_t(yaml_FLOW_MAPPING_STYLE) ||
		yaml_emitter_check_empty_mapping(emitter) {
		emitter.state = yaml_EMIT_FLOW_MAPPING_FIRST_KEY_STATE
	} else {
		emitter.state = yaml_EMIT_BLOCK_MAPPING_FIRST_KEY_STATE
	}

	return true
}

/*
 * Check if the document content is an empty scalar.
 */

func yaml_emitter_check_empty_document(emitter *yaml_emitter_t) bool {
	return false
}

/*
 * Check if the next events represent an empty sequence.
 */

func yaml_emitter_check_empty_sequence(emitter *yaml_emitter_t) bool {
	if len(emitter.events)-emitter.events_head < 2 {
		return false
	}

	return (emitter.events[emitter.events_head].event_type == yaml_SEQUENCE_START_EVENT &&
		emitter.events[emitter.events_head+1].event_type == yaml_SEQUENCE_END_EVENT)
}

/*
 * Check if the next events represent an empty mapping.
 */

func yaml_emitter_check_empty_mapping(emitter *yaml_emitter_t) bool {
	if len(emitter.events)-emitter.events_head < 2 {
		return false
	}

	return (emitter.events[emitter.events_head].event_type == yaml_MAPPING_START_EVENT &&
		emitter.events[emitter.events_head+1].event_type == yaml_MAPPING_END_EVENT)
}

/*
 * Check if the next node can be expressed as a simple key.
 */

func yaml_emitter_check_simple_key(emitter *yaml_emitter_t) bool {
	length := 0

	switch emitter.events[emitter.events_head].event_type {
	case yaml_ALIAS_EVENT:
		length += len(emitter.anchor_data.anchor)

	case yaml_SCALAR_EVENT:
		if emitter.scalar_data.multiline {
			return false
		}
		length += len(emitter.anchor_data.anchor) +
			len(emitter.tag_data.handle) +
			len(emitter.tag_data.suffix) +
			len(emitter.scalar_data.value)

	case yaml_SEQUENCE_START_EVENT:
		if !yaml_emitter_check_empty_sequence(emitter) {
			return false
		}

		length += len(emitter.anchor_data.anchor) +
			len(emitter.tag_data.handle) +
			len(emitter.tag_data.suffix)

	case yaml_MAPPING_START_EVENT:
		if !yaml_emitter_check_empty_mapping(emitter) {
			return false
		}

		length += len(emitter.anchor_data.anchor) +
			len(emitter.tag_data.handle) +
			len(emitter.tag_data.suffix)

	default:
		return false
	}

	if length > 128 {
		return false
	}

	return true
}

/*
 * Determine an acceptable scalar style.
 */

func yaml_emitter_select_scalar_style(emitter *yaml_emitter_t, event *yaml_event_t) bool {
	no_tag := len(emitter.tag_data.handle) == 0 && len(emitter.tag_data.suffix) == 0

	if no_tag && !event.implicit && !event.quoted_implicit {
		return yaml_emitter_set_emitter_error(emitter,
			"neither tag nor implicit flags are specified")
	}

	style := yaml_scalar_style_t(event.style)

	if style == yaml_ANY_SCALAR_STYLE {
		style = yaml_PLAIN_SCALAR_STYLE
	}

	if emitter.canonical {
		style = yaml_DOUBLE_QUOTED_SCALAR_STYLE
	}

	if emitter.simple_key_context && emitter.scalar_data.multiline {
		style = yaml_DOUBLE_QUOTED_SCALAR_STYLE
	}

	if style == yaml_PLAIN_SCALAR_STYLE {
		if (emitter.flow_level > 0 && !emitter.scalar_data.flow_plain_allowed) ||
			(emitter.flow_level == 0 && !emitter.scalar_data.block_plain_allowed) {
			style = yaml_SINGLE_QUOTED_SCALAR_STYLE
		}
		if len(emitter.scalar_data.value) == 0 &&
			(emitter.flow_level > 0 || emitter.simple_key_context) {
			style = yaml_SINGLE_QUOTED_SCALAR_STYLE
		}
		if no_tag && !event.implicit {
			style = yaml_SINGLE_QUOTED_SCALAR_STYLE
		}
	}

	if style == yaml_SINGLE_QUOTED_SCALAR_STYLE {
		if !emitter.scalar_data.single_quoted_allowed {
			style = yaml_DOUBLE_QUOTED_SCALAR_STYLE
		}
	}

	if style == yaml_LITERAL_SCALAR_STYLE || style == yaml_FOLDED_SCALAR_STYLE {
		if !emitter.scalar_data.block_allowed ||
			emitter.flow_level > 0 || emitter.simple_key_context {
			style = yaml_DOUBLE_QUOTED_SCALAR_STYLE
		}
	}

	if no_tag && !event.quoted_implicit &&
		style != yaml_PLAIN_SCALAR_STYLE {
		emitter.tag_data.handle = []byte("!")
	}

	emitter.scalar_data.style = style

	return true
}

/*
 * Write an achor.
 */

func yaml_emitter_process_anchor(emitter *yaml_emitter_t) bool {
	if emitter.anchor_data.anchor == nil {
		return true
	}

	indicator := "*"
	if !emitter.anchor_data.alias {
		indicator = "&"
	}
	if !yaml_emitter_write_indicator(emitter, []byte(indicator), true, false, false) {
		return false
	}

	return yaml_emitter_write_anchor(emitter, emitter.anchor_data.anchor)
}

/*
 * Write a tag.
 */

func yaml_emitter_process_tag(emitter *yaml_emitter_t) bool {
	if len(emitter.tag_data.handle) == 0 && len(emitter.tag_data.suffix) == 0 {
		return true
	}

	if len(emitter.tag_data.handle) > 0 {
		if !yaml_emitter_write_tag_handle(emitter, emitter.tag_data.handle) {
			return false
		}

		if len(emitter.tag_data.suffix) > 0 {
			if !yaml_emitter_write_tag_content(emitter, emitter.tag_data.suffix, false) {
				return false
			}

		}
	} else {
		if !yaml_emitter_write_indicator(emitter, []byte("!<"), true, false, false) {
			return false
		}

		if !yaml_emitter_write_tag_content(emitter, emitter.tag_data.suffix, false) {
			return false
		}

		if !yaml_emitter_write_indicator(emitter, []byte(">"), false, false, false) {
			return false
		}

	}

	return true
}

/*
 * Write a scalar.
 */

func yaml_emitter_process_scalar(emitter *yaml_emitter_t) bool {
	switch emitter.scalar_data.style {
	case yaml_PLAIN_SCALAR_STYLE:
		return yaml_emitter_write_plain_scalar(emitter,
			emitter.scalar_data.value,
			!emitter.simple_key_context)

	case yaml_SINGLE_QUOTED_SCALAR_STYLE:
		return yaml_emitter_write_single_quoted_scalar(emitter,
			emitter.scalar_data.value,
			!emitter.simple_key_context)

	case yaml_DOUBLE_QUOTED_SCALAR_STYLE:
		return yaml_emitter_write_double_quoted_scalar(emitter,
			emitter.scalar_data.value,
			!emitter.simple_key_context)

	case yaml_LITERAL_SCALAR_STYLE:
		return yaml_emitter_write_literal_scalar(emitter,
			emitter.scalar_data.value)

	case yaml_FOLDED_SCALAR_STYLE:
		return yaml_emitter_write_folded_scalar(emitter,
			emitter.scalar_data.value)

	default:
		panic("unknown scalar")
	}

	return false
}

/*
 * Check if a %YAML directive is valid.
 */

func yaml_emitter_analyze_version_directive(emitter *yaml_emitter_t,
	version_directive yaml_version_directive_t) bool {
	if version_directive.major != 1 || version_directive.minor != 1 {
		return yaml_emitter_set_emitter_error(emitter,
			"incompatible %YAML directive")
	}

	return true
}

/*
 * Check if a %TAG directive is valid.
 */

func yaml_emitter_analyze_tag_directive(emitter *yaml_emitter_t,
	tag_directive *yaml_tag_directive_t) bool {
	handle := tag_directive.handle
	prefix := tag_directive.prefix

	if len(handle) == 0 {
		return yaml_emitter_set_emitter_error(emitter,
			"tag handle must not be empty")
	}

	if handle[0] != '!' {
		return yaml_emitter_set_emitter_error(emitter,
			"tag handle must start with '!'")
	}

	if handle[len(handle)-1] != '!' {
		return yaml_emitter_set_emitter_error(emitter,
			"tag handle must end with '!'")
	}

	for i := 1; i < len(handle)-1; width(handle[i]) {
		if !is_alpha(handle[i]) {
			return yaml_emitter_set_emitter_error(emitter,
				"tag handle must contain alphanumerical characters only")
		}
	}

	if len(prefix) == 0 {
		return yaml_emitter_set_emitter_error(emitter,
			"tag prefix must not be empty")
	}

	return true
}

/*
 * Check if an anchor is valid.
 */

func yaml_emitter_analyze_anchor(emitter *yaml_emitter_t,
	anchor []byte, alias bool) bool {
	if len(anchor) == 0 {
		errmsg := "alias value must not be empty"
		if !alias {
			errmsg = "anchor value must not be empty"
		}
		return yaml_emitter_set_emitter_error(emitter, errmsg)
	}

	for i := 0; i < len(anchor); i += width(anchor[i]) {
		if !is_alpha(anchor[i]) {
			errmsg := "alias value must contain alphanumerical characters only"
			if !alias {
				errmsg = "anchor value must contain alphanumerical characters only"
			}
			return yaml_emitter_set_emitter_error(emitter, errmsg)
		}
	}

	emitter.anchor_data.anchor = anchor
	emitter.anchor_data.alias = alias

	return true
}

/*
 * Check if a tag is valid.
 */

func yaml_emitter_analyze_tag(emitter *yaml_emitter_t, tag []byte) bool {
	if len(tag) == 0 {
		return yaml_emitter_set_emitter_error(emitter,
			"tag value must not be empty")
	}

	for i := range emitter.tag_directives {
		tag_directive := &emitter.tag_directives[i]
		if bytes.HasPrefix(tag, tag_directive.prefix) {
			emitter.tag_data.handle = tag_directive.handle
			emitter.tag_data.suffix = tag[len(tag_directive.prefix):]
			return true
		}
	}

	emitter.tag_data.suffix = tag

	return true
}

/*
 * Check if a scalar is valid.
 */

func yaml_emitter_analyze_scalar(emitter *yaml_emitter_t, value []byte) bool {
	block_indicators := false
	flow_indicators := false
	line_breaks := false
	special_characters := false

	leading_space := false
	leading_break := false
	trailing_space := false
	trailing_break := false
	break_space := false
	space_break := false

	preceeded_by_whitespace := false
	followed_by_whitespace := false
	previous_space := false
	previous_break := false

	emitter.scalar_data.value = value

	if len(value) == 0 {
		emitter.scalar_data.multiline = false
		emitter.scalar_data.flow_plain_allowed = false
		emitter.scalar_data.block_plain_allowed = true
		emitter.scalar_data.single_quoted_allowed = true
		emitter.scalar_data.block_allowed = false

		return true
	}

	if len(value) >= 3 && ((value[0] == '-' && value[1] == '-' && value[2] == '-') ||
		(value[0] == '.' && value[1] == '.' && value[2] == '.')) {
		block_indicators = true
		flow_indicators = true
	}

	preceeded_by_whitespace = true

	for i, w := 0, 0; i < len(value); i += w {
		w = width(value[i])
		followed_by_whitespace = i+w >= len(value) || is_blankz_at(value, i+w)

		if i == 0 {
			switch value[i] {
			case '#', ',', '[', ']', '{', '}', '&', '*', '!', '|', '>', '\'', '"', '%', '@', '`':
				flow_indicators = true
				block_indicators = true
			case '?', ':':
				flow_indicators = true
				if followed_by_whitespace {
					block_indicators = true
				}
			case '-':
				if followed_by_whitespace {
					flow_indicators = true
					block_indicators = true
				}
			}
		} else {
			switch value[i] {
			case ',', '?', '[', ']', '{', '}':
				flow_indicators = true
			case ':':
				flow_indicators = true
				if followed_by_whitespace {
					block_indicators = true
				}
			case '#':
				if preceeded_by_whitespace {
					flow_indicators = true
					block_indicators = true
				}
			}
		}

		if !is_printable_at(value, i) || (!is_ascii(value[i]) && !emitter.unicode) {
			special_characters = true
		}

		if is_break_at(value, i) {
			line_breaks = true
		}

		if is_space(value[i]) {
			if i == 0 {
				leading_space = true
			}
			if i+w == len(value) {
				trailing_space = true
			}
			if previous_break {
				break_space = true
			}
			previous_space = true
			previous_break = false
		} else if is_break_at(value, i) {
			if i == 0 {
				leading_break = true
			}
			if i+width(value[i]) == len(value) {
				trailing_break = true
			}
			if previous_space {
				space_break = true
			}
			previous_space = false
			previous_break = true
		} else {
			previous_space = false
			previous_break = false
		}

		preceeded_by_whitespace = is_blankz_at(value, i)
	}

	emitter.scalar_data.multiline = line_breaks

	emitter.scalar_data.flow_plain_allowed = true
	emitter.scalar_data.block_plain_allowed = true
	emitter.scalar_data.single_quoted_allowed = true
	emitter.scalar_data.block_allowed = true

	if leading_space || leading_break || trailing_space || trailing_break {
		emitter.scalar_data.flow_plain_allowed = false
		emitter.scalar_data.block_plain_allowed = false
	}

	if trailing_space {
		emitter.scalar_data.block_allowed = false
	}

	if break_space {
		emitter.scalar_data.flow_plain_allowed = false
		emitter.scalar_data.block_plain_allowed = false
		emitter.scalar_data.single_quoted_allowed = false
	}

	if space_break || special_characters {
		emitter.scalar_data.flow_plain_allowed = false
		emitter.scalar_data.block_plain_allowed = false
		emitter.scalar_data.single_quoted_allowed = false
		emitter.scalar_data.block_allowed = false
	}

	if line_breaks {
		emitter.scalar_data.flow_plain_allowed = false
		emitter.scalar_data.block_plain_allowed = false
	}

	if flow_indicators {
		emitter.scalar_data.flow_plain_allowed = false
	}

	if block_indicators {
		emitter.scalar_data.block_plain_allowed = false
	}

	return true
}

/*
 * Check if the event data is valid.
 */

func yaml_emitter_analyze_event(emitter *yaml_emitter_t, event *yaml_event_t) bool {
	emitter.anchor_data.anchor = nil
	emitter.tag_data.handle = nil
	emitter.tag_data.suffix = nil
	emitter.scalar_data.value = nil

	switch event.event_type {
	case yaml_ALIAS_EVENT:
		if !yaml_emitter_analyze_anchor(emitter,
			event.anchor, true) {
			return false
		}

	case yaml_SCALAR_EVENT:
		if len(event.anchor) > 0 {
			if !yaml_emitter_analyze_anchor(emitter,
				event.anchor, false) {
				return false
			}
		}
		if len(event.tag) > 0 && (emitter.canonical ||
			(!event.implicit &&
				!event.quoted_implicit)) {
			if !yaml_emitter_analyze_tag(emitter, event.tag) {
				return false
			}
		}
		if !yaml_emitter_analyze_scalar(emitter, event.value) {
			return false
		}
	case yaml_SEQUENCE_START_EVENT:
		if len(event.anchor) > 0 {
			if !yaml_emitter_analyze_anchor(emitter,
				event.anchor, false) {
				return false
			}
		}
		if len(event.tag) > 0 && (emitter.canonical ||
			!event.implicit) {
			if !yaml_emitter_analyze_tag(emitter,
				event.tag) {
				return false
			}
		}
	case yaml_MAPPING_START_EVENT:
		if len(event.anchor) > 0 {
			if !yaml_emitter_analyze_anchor(emitter,
				event.anchor, false) {
				return false
			}
		}
		if len(event.tag) > 0 && (emitter.canonical ||
			!event.implicit) {
			if !yaml_emitter_analyze_tag(emitter,
				event.tag) {
				return false
			}
		}

	}
	return true
}

/*
 * Write the BOM character.
 */

func yaml_emitter_write_bom(emitter *yaml_emitter_t) bool {
	if !flush(emitter) {
		return false
	}

	pos := emitter.buffer_pos
	emitter.buffer[pos] = '\xEF'
	emitter.buffer[pos+1] = '\xBB'
	emitter.buffer[pos+2] = '\xBF'
	emitter.buffer_pos += 3
	return true
}

func yaml_emitter_write_indent(emitter *yaml_emitter_t) bool {
	indent := emitter.indent
	if indent < 0 {
		indent = 0
	}

	if !emitter.indention || emitter.column > indent ||
		(emitter.column == indent && !emitter.whitespace) {
		if !put_break(emitter) {
			return false
		}
	}

	for emitter.column < indent {
		if !put(emitter, ' ') {
			return false
		}
	}

	emitter.whitespace = true
	emitter.indention = true

	return true
}

func yaml_emitter_write_indicator(emitter *yaml_emitter_t,
	indicator []byte, need_whitespace bool,
	is_whitespace bool, is_indention bool) bool {
	if need_whitespace && !emitter.whitespace {
		if !put(emitter, ' ') {
			return false
		}
	}

	ind_pos := 0
	for ind_pos < len(indicator) {
		if !write(emitter, indicator, &ind_pos) {
			return false
		}
	}

	emitter.whitespace = is_whitespace
	emitter.indention = (emitter.indention && is_indention)
	emitter.open_ended = false

	return true
}

func yaml_emitter_write_anchor(emitter *yaml_emitter_t, value []byte) bool {
	pos := 0
	for pos < len(value) {
		if !write(emitter, value, &pos) {
			return false
		}
	}

	emitter.whitespace = false
	emitter.indention = false

	return true
}

func yaml_emitter_write_tag_handle(emitter *yaml_emitter_t, value []byte) bool {
	if !emitter.whitespace {
		if !put(emitter, ' ') {
			return false
		}
	}

	pos := 0
	for pos < len(value) {
		if !write(emitter, value, &pos) {
			return false
		}
	}

	emitter.whitespace = false
	emitter.indention = false

	return true
}

func yaml_emitter_write_tag_content(emitter *yaml_emitter_t, value []byte,
	need_whitespace bool) bool {
	if need_whitespace && !emitter.whitespace {
		if !put(emitter, ' ') {
			return false
		}
	}

	for i := 0; i < len(value); {
		write_it := false
		switch value[i] {
		case ';', '/', '?', ':', '@', '&', '=', '+', '$', ',', '_',
			'.', '!', '~', '*', '\'', '(', ')', '[', ']':
			write_it = true
		default:
			write_it = is_alpha(value[i])
		}
		if write_it {
			if !write(emitter, value, &i) {
				return false
			}
		} else {
			w := width(value[i])
			for j := 0; j < w; j++ {
				val := value[i]
				i++

				if !put(emitter, '%') {
					return false
				}
				c := val >> 4
				if c < 10 {
					c += '0'
				} else {
					c += 'A' - 10
				}
				if !put(emitter, c) {
					return false
				}

				c = val & 0x0f
				if c < 10 {
					c += '0'
				} else {
					c += 'A' - 10
				}
				if !put(emitter, c) {
					return false
				}

			}
		}
	}

	emitter.whitespace = false
	emitter.indention = false

	return true
}

func yaml_emitter_write_plain_scalar(emitter *yaml_emitter_t, value []byte,
	allow_breaks bool) bool {
	spaces := false
	breaks := false

	if !emitter.whitespace {
		if !put(emitter, ' ') {
			return false
		}
	}

	for i := 0; i < len(value); {
		if is_space(value[i]) {
			if allow_breaks && !spaces &&
				emitter.column > emitter.best_width &&
				!is_space(value[i+1]) {
				if !yaml_emitter_write_indent(emitter) {
					return false
				}
				i += width(value[i])
			} else {
				if !write(emitter, value, &i) {
					return false
				}
			}
			spaces = true
		} else if is_break_at(value, i) {
			if !breaks && value[i] == '\n' {
				if !put_break(emitter) {
					return false
				}
			}
			if !write_break(emitter, value, &i) {
				return false
			}
			emitter.indention = true
			breaks = true
		} else {
			if breaks {
				if !yaml_emitter_write_indent(emitter) {
					return false
				}
			}
			if !write(emitter, value, &i) {
				return false
			}
			emitter.indention = false
			spaces = false
			breaks = false
		}
	}

	emitter.whitespace = false
	emitter.indention = false
	if emitter.root_context {
		emitter.open_ended = true
	}

	return true
}

func yaml_emitter_write_single_quoted_scalar(emitter *yaml_emitter_t, value []byte,
	allow_breaks bool) bool {
	spaces := false
	breaks := false

	if !yaml_emitter_write_indicator(emitter, []byte("'"), true, false, false) {
		return false
	}

	for i := 0; i < len(value); {
		if is_space(value[i]) {
			if allow_breaks && !spaces &&
				emitter.column > emitter.best_width &&
				i > 0 && i < len(value)-1 &&
				!is_space(value[i+1]) {
				if !yaml_emitter_write_indent(emitter) {
					return false
				}
				i += width(value[i])
			} else {
				if !write(emitter, value, &i) {
					return false
				}
			}
			spaces = true
		} else if is_break_at(value, i) {
			if !breaks && value[i] == '\n' {
				if !put_break(emitter) {
					return false
				}
			}
			if !write_break(emitter, value, &i) {
				return false
			}
			emitter.indention = true
			breaks = true
		} else {
			if breaks {
				if !yaml_emitter_write_indent(emitter) {
					return false
				}
			}
			if value[i] == '\'' {
				if !put(emitter, '\'') {
					return false
				}
			}
			if !write(emitter, value, &i) {
				return false
			}
			emitter.indention = false
			spaces = false
			breaks = false
		}
	}

	if !yaml_emitter_write_indicator(emitter, []byte("'"), false, false, false) {
		return false
	}

	emitter.whitespace = false
	emitter.indention = false

	return true
}

func yaml_emitter_write_double_quoted_scalar(emitter *yaml_emitter_t, value []byte,
	allow_breaks bool) bool {

	spaces := false

	if !yaml_emitter_write_indicator(emitter, []byte("\""), true, false, false) {
		return false
	}

	for i := 0; i < len(value); {
		if !is_printable_at(value, i) || (!emitter.unicode && !is_ascii(value[i])) ||
			is_bom_at(value, i) || is_break_at(value, i) ||
			value[i] == '"' || value[i] == '\\' {
			octet := value[i]

			var w int
			var v rune
			switch {
			case octet&0x80 == 0x00:
				w, v = 1, rune(octet&0x7F)
			case octet&0xE0 == 0xC0:
				w, v = 2, rune(octet&0x1F)
			case octet&0xF0 == 0xE0:
				w, v = 3, rune(octet&0x0F)
			case octet&0xF8 == 0xF0:
				w, v = 4, rune(octet&0x07)
			}

			for k := 1; k < w; k++ {
				octet = value[i+k]
				v = (v << 6) + (rune(octet) & 0x3F)
			}
			i += w

			if !put(emitter, '\\') {
				return false
			}

			switch v {
			case 0x00:
				if !put(emitter, '0') {
					return false
				}
			case 0x07:
				if !put(emitter, 'a') {
					return false
				}
			case 0x08:
				if !put(emitter, 'b') {
					return false
				}
			case 0x09:
				if !put(emitter, 't') {
					return false
				}

			case 0x0A:
				if !put(emitter, 'n') {
					return false
				}

			case 0x0B:
				if !put(emitter, 'v') {
					return false
				}

			case 0x0C:
				if !put(emitter, 'f') {
					return false
				}

			case 0x0D:
				if !put(emitter, 'r') {
					return false
				}

			case 0x1B:
				if !put(emitter, 'e') {
					return false
				}
			case 0x22:
				if !put(emitter, '"') {
					return false
				}
			case 0x5C:
				if !put(emitter, '\\') {
					return false
				}
			case 0x85:
				if !put(emitter, 'N') {
					return false
				}

			case 0xA0:
				if !put(emitter, '_') {
					return false
				}

			case 0x2028:
				if !put(emitter, 'L') {
					return false
				}

			case 0x2029:
				if !put(emitter, 'P') {
					return false
				}
			default:
				if v <= 0xFF {
					if !put(emitter, 'x') {
						return false
					}
					w = 2
				} else if v <= 0xFFFF {
					if !put(emitter, 'u') {
						return false
					}
					w = 4
				} else {
					if !put(emitter, 'U') {
						return false
					}
					w = 8
				}
				for k := (w - 1) * 4; k >= 0; k -= 4 {
					digit := byte((v >> uint(k)) & 0x0F)
					var c byte
					if digit > 9 {
						c = digit + 'A' - 10
					} else {
						c = digit + '0'
					}
					if !put(emitter, c) {
						return false
					}
				}
			}
			spaces = false
		} else if is_space(value[i]) {
			if allow_breaks && !spaces &&
				emitter.column > emitter.best_width &&
				i > 0 && i < len(value)-1 {
				if !yaml_emitter_write_indent(emitter) {
					return false
				}
				if is_space(value[i+1]) {
					if !put(emitter, '\\') {
						return false
					}
				}
				i += width(value[i])
			} else {
				if !write(emitter, value, &i) {
					return false
				}
			}
			spaces = true
		} else {
			if !write(emitter, value, &i) {
				return false
			}
			spaces = false
		}
	}

	if !yaml_emitter_write_indicator(emitter, []byte("\""), false, false, false) {
		return false
	}

	emitter.whitespace = false
	emitter.indention = false

	return true
}

func yaml_emitter_write_block_scalar_hints(emitter *yaml_emitter_t, value []byte) bool {

	if is_space(value[0]) || is_break_at(value, 0) {
		indent_hint := []byte{'0' + byte(emitter.best_indent)}
		if !yaml_emitter_write_indicator(emitter, indent_hint, false, false, false) {
			return false
		}
	}

	emitter.open_ended = false

	var chomp_hint [1]byte
	if len(value) == 0 {
		chomp_hint[0] = '-'
	} else {
		i := len(value) - 1
		for value[i]&0xC0 == 0x80 {
			i--
		}

		if !is_break_at(value, i) {
			chomp_hint[0] = '-'
		} else if i == 0 {
			chomp_hint[0] = '+'
			emitter.open_ended = true
		} else {
			for value[i]&0xC0 == 0x80 {
				i--
			}

			if is_break_at(value, i) {
				chomp_hint[0] = '+'
				emitter.open_ended = true
			}
		}
	}

	if chomp_hint[0] != 0 {
		if !yaml_emitter_write_indicator(emitter, chomp_hint[:], false, false, false) {
			return false
		}
	}

	return true
}

func yaml_emitter_write_literal_scalar(emitter *yaml_emitter_t, value []byte) bool {

	breaks := true

	if !yaml_emitter_write_indicator(emitter, []byte("|"), true, false, false) {
		return false
	}

	if !yaml_emitter_write_block_scalar_hints(emitter, value) {
		return false
	}

	if !put_break(emitter) {
		return false
	}

	emitter.indention = true
	emitter.whitespace = true

	for i := 0; i < len(value); {
		if is_break_at(value, i) {
			if !write_break(emitter, value, &i) {
				return false
			}
			emitter.indention = true
			breaks = true
		} else {
			if breaks {
				if !yaml_emitter_write_indent(emitter) {
					return false
				}
			}
			if !write(emitter, value, &i) {
				return false
			}
			emitter.indention = false
			breaks = false
		}
	}

	return true
}

func yaml_emitter_write_folded_scalar(emitter *yaml_emitter_t, value []byte) bool {
	breaks := true
	leading_spaces := true

	if !yaml_emitter_write_indicator(emitter, []byte(">"), true, false, false) {
		return false
	}
	if !yaml_emitter_write_block_scalar_hints(emitter, value) {
		return false
	}
	if !put_break(emitter) {
		return false
	}
	emitter.indention = true
	emitter.whitespace = true

	for i := 0; i < len(value); {
		if is_break_at(value, i) {
			if !breaks && !leading_spaces && value[i] == '\n' {
				k := i
				for is_break_at(value, k) {
					k += width(value[k])
				}
				if !is_blankz_at(value, k) {
					if !put_break(emitter) {
						return false
					}
				}
			}
			if !write_break(emitter, value, &i) {
				return false
			}
			emitter.indention = true
			breaks = true
		} else {
			if breaks {
				if !yaml_emitter_write_indent(emitter) {
					return false
				}
				leading_spaces = is_blank(value[i])
			}
			if !breaks && is_space(value[i]) && !is_space(value[i+1]) &&
				emitter.column > emitter.best_width {
				if !yaml_emitter_write_indent(emitter) {
					return false
				}
				i += width(value[i])
			} else {
				if !write(emitter, value, &i) {
					return false
				}
			}
			emitter.indention = false
			breaks = false
		}
	}

	return true
}