text: /* plugin_common - Routines common to several plugins
   * Copyright (C) 2002-2009  Josh Coalson
   * Copyright (C) 2011-2013  Xiph.Org Foundation
   *
   * This library is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public
   * License as published by the Free Software Foundation; either
   * version 2.1 of the License, or (at your option) any later version.
   *
   * This library is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with this library; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
   */
  
  #if HAVE_CONFIG_H
  #  include <config.h>
  #endif
  
  #include <stdio.h>
  #include <string.h>
  #include <stdlib.h>
  
  #include "tags.h"
  #include "FLAC/assert.h"
  #include "FLAC/metadata.h"
  #include "share/alloc.h"
  
  #ifndef FLaC__INLINE
  #define FLaC__INLINE
  #endif
  
  
  static FLaC__INLINE size_t local__wide_strlen(const FLAC__uint16 *s)
  {
  	size_t n = 0;
  	while(*s++)
  		n++;
  	return n;
  }
  
  /*
   * also disallows non-shortest-form encodings, c.f.
   *   http://www.unicode.org/versions/corrigendum1.html
   * and a more clear explanation at the end of this section:
   *   http://www.cl.cam.ac.uk/~mgk25/unicode.html#utf-8
   */
  static size_t local__utf8len(const FLAC__byte *utf8)
  {
  	FLAC__ASSERT(0 != utf8);
  	if ((utf8[0] & 0x80) == 0) {
  		return 1;
  	}
  	else if ((utf8[0] & 0xE0) == 0xC0 && (utf8[1] & 0xC0) == 0x80) {
  		if ((utf8[0] & 0xFE) == 0xC0) /* overlong sequence check */
  			return 0;
  		return 2;
  	}
  	else if ((utf8[0] & 0xF0) == 0xE0 && (utf8[1] & 0xC0) == 0x80 && (utf8[2] & 0xC0) == 0x80) {
  		if (utf8[0] == 0xE0 && (utf8[1] & 0xE0) == 0x80) /* overlong sequence check */
  			return 0;
  		/* illegal surrogates check (U+D800...U+DFFF and U+FFFE...U+FFFF) */
  		if (utf8[0] == 0xED && (utf8[1] & 0xE0) == 0xA0) /* D800-DFFF */
  			return 0;
  		if (utf8[0] == 0xEF && utf8[1] == 0xBF && (utf8[2] & 0xFE) == 0xBE) /* FFFE-FFFF */
  			return 0;
  		return 3;
  	}
  	else if ((utf8[0] & 0xF8) == 0xF0 && (utf8[1] & 0xC0) == 0x80 && (utf8[2] & 0xC0) == 0x80 && (utf8[3] & 0xC0) == 0x80) {
  		if (utf8[0] == 0xF0 && (utf8[1] & 0xF0) == 0x80) /* overlong sequence check */
  			return 0;
  		return 4;
  	}
  	else if ((utf8[0] & 0xFC) == 0xF8 && (utf8[1] & 0xC0) == 0x80 && (utf8[2] & 0xC0) == 0x80 && (utf8[3] & 0xC0) == 0x80 && (utf8[4] & 0xC0) == 0x80) {
  		if (utf8[0] == 0xF8 && (utf8[1] & 0xF8) == 0x80) /* overlong sequence check */
  			return 0;
  		return 5;
  	}
  	else if ((utf8[0] & 0xFE) == 0xFC && (utf8[1] & 0xC0) == 0x80 && (utf8[2] & 0xC0) == 0x80 && (utf8[3] & 0xC0) == 0x80 && (utf8[4] & 0xC0) == 0x80 && (utf8[5] & 0xC0) == 0x80) {
  		if (utf8[0] == 0xFC && (utf8[1] & 0xFC) == 0x80) /* overlong sequence check */
  			return 0;
  		return 6;
  	}
  	else {
  		return 0;
  	}
  }
  
  
  static size_t local__utf8_to_ucs2(const FLAC__byte *utf8, FLAC__uint16 *ucs2)
  {
  	const size_t len = local__utf8len(utf8);
  
  	FLAC__ASSERT(0 != ucs2);
  
  	if (len == 1)
  		*ucs2 = *utf8;
  	else if (len == 2)
  		*ucs2 = (*utf8 & 0x3F)<<6 | (*(utf8+1) & 0x3F);
  	else if (len == 3)
  		*ucs2 = (*utf8 & 0x1F)<<12 | (*(utf8+1) & 0x3F)<<6 | (*(utf8+2) & 0x3F);
  	else
  		*ucs2 = '?';
  
  	return len;
  }
  
  static FLAC__uint16 *local__convert_utf8_to_ucs2(const char *src, unsigned length)
  {
  	FLAC__uint16 *out;
  	size_t chars = 0;
  
  	FLAC__ASSERT(0 != src);
  
  	/* calculate length */
  	{
  		const unsigned char *s, *end;
  		for (s=(const unsigned char *)src, end=s+length; s<end; chars++) {
  			const unsigned n = local__utf8len(s);
  			if (n == 0)
  				return 0;
  			s += n;
  		}
  		FLAC__ASSERT(s == end);
  	}
  
  	/* allocate */
  	out = safe_malloc_mul_2op_(chars, /*times*/sizeof(FLAC__uint16));
  	if (0 == out) {
  		FLAC__ASSERT(0);
  		return 0;
  	}
  
  	/* convert */
  	{
  		const unsigned char *s = (const unsigned char *)src;
  		FLAC__uint16 *u = out;
  		for ( ; chars; chars--)
  			s += local__utf8_to_ucs2(s, u++);
  	}
  
  	return out;
  }
  
  static FLaC__INLINE size_t local__ucs2len(FLAC__uint16 ucs2)
  {
  	if (ucs2 < 0x0080)
  		return 1;
  	else if (ucs2 < 0x0800)
  		return 2;
  	else
  		return 3;
  }
  
  static size_t local__ucs2_to_utf8(FLAC__uint16 ucs2, FLAC__byte *utf8)
  {
  	if (ucs2 < 0x080) {
  		utf8[0] = (FLAC__byte)ucs2;
  		return 1;
  	}
  	else if (ucs2 < 0x800) {
  		utf8[0] = 0xc0 | (ucs2 >> 6);
  		utf8[1] = 0x80 | (ucs2 & 0x3f);
  		return 2;
  	}
  	else {
  		utf8[0] = 0xe0 | (ucs2 >> 12);
  		utf8[1] = 0x80 | ((ucs2 >> 6) & 0x3f);
  		utf8[2] = 0x80 | (ucs2 & 0x3f);
  		return 3;
  	}
  }
  
  static char *local__convert_ucs2_to_utf8(const FLAC__uint16 *src, unsigned length)
  {
  	char *out;
  	size_t len = 0, n;
  
  	FLAC__ASSERT(0 != src);
  
  	/* calculate length */
  	{
  		unsigned i;
  		for (i = 0; i < length; i++) {
  			n = local__ucs2len(src[i]);
  			if(len + n < len) /* overflow check */
  				return 0;
  			len += n;
  		}
  	}
  
  	/* allocate */
  	out = safe_malloc_mul_2op_(len, /*times*/sizeof(char));
  	if (0 == out)
  		return 0;
  
  	/* convert */
  	{
  		unsigned char *u = (unsigned char *)out;
  		for ( ; *src; src++)
  			u += local__ucs2_to_utf8(*src, u);
  		local__ucs2_to_utf8(*src, u);
  	}
  
  	return out;
  }
  
  
  FLAC__bool FLAC_plugin__tags_get(const char *filename, FLAC__StreamMetadata **tags)
  {
  	if(!FLAC__metadata_get_tags(filename, tags))
  		if(0 == (*tags = FLAC__metadata_object_new(FLAC__METADATA_TYPE_VORBIS_COMMENT)))
  			return false;
  	return true;
  }
  
  FLAC__bool FLAC_plugin__tags_set(const char *filename, const FLAC__StreamMetadata *tags)
  {
  	FLAC__Metadata_Chain *chain;
  	FLAC__Metadata_Iterator *iterator;
  	FLAC__StreamMetadata *block;
  	FLAC__bool got_vorbis_comments = false;
  	FLAC__bool ok;
  
  	if(0 == (chain = FLAC__metadata_chain_new()))
  		return false;
  
  	if(!FLAC__metadata_chain_read(chain, filename)) {
  		FLAC__metadata_chain_delete(chain);
  		return false;
  	}
  
  	if(0 == (iterator = FLAC__metadata_iterator_new())) {
  		FLAC__metadata_chain_delete(chain);
  		return false;
  	}
  
  	FLAC__metadata_iterator_init(iterator, chain);
  
  	do {
  		if(FLAC__metadata_iterator_get_block_type(iterator) == FLAC__METADATA_TYPE_VORBIS_COMMENT)
  			got_vorbis_comments = true;
  	} while(!got_vorbis_comments && FLAC__metadata_iterator_next(iterator));
  
  	if(0 == (block = FLAC__metadata_object_clone(tags))) {
  		FLAC__metadata_chain_delete(chain);
  		FLAC__metadata_iterator_delete(iterator);
  		return false;
  	}
  
  	if(got_vorbis_comments)
  		ok = FLAC__metadata_iterator_set_block(iterator, block);
  	else
  		ok = FLAC__metadata_iterator_insert_block_after(iterator, block);
  
  	FLAC__metadata_iterator_delete(iterator);
  
  	if(ok) {
  		FLAC__metadata_chain_sort_padding(chain);
  		ok = FLAC__metadata_chain_write(chain, /*use_padding=*/true, /*preserve_file_stats=*/true);
  	}
  
  	FLAC__metadata_chain_delete(chain);
  
  	return ok;
  }
  
  void FLAC_plugin__tags_destroy(FLAC__StreamMetadata **tags)
  {
  	FLAC__metadata_object_delete(*tags);
  	*tags = 0;
  }
  
  const char *FLAC_plugin__tags_get_tag_utf8(const FLAC__StreamMetadata *tags, const char *name)
  {
  	const int i = FLAC__metadata_object_vorbiscomment_find_entry_from(tags, /*offset=*/0, name);
  	return (i < 0? 0 : strchr((const char *)tags->data.vorbis_comment.comments[i].entry, '=')+1);
  }
  
  FLAC__uint16 *FLAC_plugin__tags_get_tag_ucs2(const FLAC__StreamMetadata *tags, const char *name)
  {
  	const char *utf8 = FLAC_plugin__tags_get_tag_utf8(tags, name);
  	if(0 == utf8)
  		return 0;
  	return local__convert_utf8_to_ucs2(utf8, strlen(utf8)+1); /* +1 for terminating null */
  }
  
  int FLAC_plugin__tags_delete_tag(FLAC__StreamMetadata *tags, const char *name)
  {
  	return FLAC__metadata_object_vorbiscomment_remove_entries_matching(tags, name);
  }
  
  int FLAC_plugin__tags_delete_all(FLAC__StreamMetadata *tags)
  {
  	int n = (int)tags->data.vorbis_comment.num_comments;
  	if(n > 0) {
  		if(!FLAC__metadata_object_vorbiscomment_resize_comments(tags, 0))
  			n = -1;
  	}
  	return n;
  }
  
  FLAC__bool FLAC_plugin__tags_add_tag_utf8(FLAC__StreamMetadata *tags, const char *name, const char *value, const char *separator)
  {
  	int i;
  
  	FLAC__ASSERT(0 != tags);
  	FLAC__ASSERT(0 != name);
  	FLAC__ASSERT(0 != value);
  
  	if(separator && (i = FLAC__metadata_object_vorbiscomment_find_entry_from(tags, /*offset=*/0, name)) >= 0) {
  		FLAC__StreamMetadata_VorbisComment_Entry *entry = tags->data.vorbis_comment.comments+i;
  		const size_t value_len = strlen(value);
  		const size_t separator_len = strlen(separator);
  		FLAC__byte *new_entry;
  		if(0 == (new_entry = safe_realloc_add_4op_(entry->entry, entry->length, /*+*/value_len, /*+*/separator_len, /*+*/1)))
  			return false;
  		memcpy(new_entry+entry->length, separator, separator_len);
  		entry->length += separator_len;
  		memcpy(new_entry+entry->length, value, value_len);
  		entry->length += value_len;
  		new_entry[entry->length] = '\0';
  		entry->entry = new_entry;
  	}
  	else {
  		FLAC__StreamMetadata_VorbisComment_Entry entry;
  		if(!FLAC__metadata_object_vorbiscomment_entry_from_name_value_pair(&entry, name, value))
  			return false;
  		FLAC__metadata_object_vorbiscomment_append_comment(tags, entry, /*copy=*/false);
  	}
  	return true;
  }
  
  FLAC__bool FLAC_plugin__tags_set_tag_ucs2(FLAC__StreamMetadata *tags, const char *name, const FLAC__uint16 *value, FLAC__bool replace_all)
  {
  	FLAC__StreamMetadata_VorbisComment_Entry entry;
  
  	FLAC__ASSERT(0 != tags);
  	FLAC__ASSERT(0 != name);
  	FLAC__ASSERT(0 != value);
  
  	{
  		char *utf8 = local__convert_ucs2_to_utf8(value, local__wide_strlen(value)+1); /* +1 for the terminating null */
  		if(0 == utf8)
  			return false;
  		if(!FLAC__metadata_object_vorbiscomment_entry_from_name_value_pair(&entry, name, utf8)) {
  			free(utf8);
  			return false;
  		}
  		free(utf8);
  	}
  	if(!FLAC__metadata_object_vorbiscomment_replace_comment(tags, entry, replace_all, /*copy=*/false))
  		return false;
  	return true;
  }
  