IcyMetaDataParser: move to tag/

2021-12-03 16:05:57 +01:00
parent 9262b24504
commit 3452682a42
6 changed files with 4 additions and 4 deletions
@@ -0,0 +1,281 @@
+/*
+ * Copyright 2003-2021 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "IcyMetaDataParser.hxx"
+#include "tag/Builder.hxx"
+#include "util/AllocatedString.hxx"
+#include "util/StringView.hxx"
+
+#include <algorithm>
+#include <cassert>
+
+#include <string.h>
+
+#ifdef HAVE_ICU_CONVERTER
+
+void
+IcyMetaDataParser::SetCharset(const char *charset)
+{
+	icu_converter = IcuConverter::Create(charset);
+}
+
+#endif
+
+void
+IcyMetaDataParser::Reset() noexcept
+{
+	if (!IsDefined())
+		return;
+
+	if (data_rest == 0 && meta_size > 0)
+		delete[] meta_data;
+
+	tag.reset();
+
+	data_rest = data_size;
+	meta_size = 0;
+}
+
+size_t
+IcyMetaDataParser::Data(size_t length) noexcept
+{
+	assert(length > 0);
+
+	if (!IsDefined())
+		return length;
+
+	if (data_rest == 0)
+		return 0;
+
+	if (length >= data_rest) {
+		length = data_rest;
+		data_rest = 0;
+	} else
+		data_rest -= length;
+
+	return length;
+}
+
+static void
+icy_add_item(TagBuilder &tag, TagType type, StringView value) noexcept
+{
+	if (value.size >= 2 && value.front() == '\'' && value.back() == '\'') {
+		/* strip the single quotes */
+		++value.data;
+		value.size -= 2;
+	}
+
+	if (value.size > 0)
+		tag.AddItem(type, value);
+}
+
+static void
+icy_parse_tag_item(TagBuilder &tag,
+#ifdef HAVE_ICU_CONVERTER
+		   const IcuConverter *icu_converter,
+#endif
+		   const char *name, const char *value) noexcept
+{
+	if (strcmp(name, "StreamTitle") == 0) {
+#ifdef HAVE_ICU_CONVERTER
+		if (icu_converter != nullptr) {
+			try {
+				icy_add_item(tag, TAG_TITLE,
+					     icu_converter->ToUTF8(value).c_str());
+			} catch (...) {
+			}
+
+			return;
+		}
+#endif
+
+		icy_add_item(tag, TAG_TITLE, value);
+	}
+}
+
+/**
+ * Find a single quote that is followed by a semicolon (or by the end
+ * of the string).  If that fails, return the first single quote.  If
+ * that also fails, return #end.
+ */
+static char *
+find_end_quote(char *p, char *const end) noexcept
+{
+	char *fallback = std::find(p, end, '\'');
+	if (fallback >= end - 1 || fallback[1] == ';')
+		return fallback;
+
+	p = fallback + 1;
+	while (true) {
+		p = std::find(p, end, '\'');
+		if (p == end)
+			return fallback;
+
+		if (p == end - 1 || p[1] == ';')
+			return p;
+
+		++p;
+	}
+}
+
+static std::unique_ptr<Tag>
+icy_parse_tag(
+#ifdef HAVE_ICU_CONVERTER
+	      const IcuConverter *icu_converter,
+#endif
+	      char *p, char *const end) noexcept
+{
+	assert(p != nullptr);
+	assert(end != nullptr);
+	assert(p <= end);
+
+	TagBuilder tag;
+
+	while (p != end) {
+		const char *const name = p;
+		char *eq = std::find(p, end, '=');
+		if (eq == end)
+			break;
+
+		*eq = 0;
+		p = eq + 1;
+
+		if (*p != '\'') {
+			/* syntax error; skip to the next semicolon,
+			   try to recover */
+			char *semicolon = std::find(p, end, ';');
+			if (semicolon == end)
+				break;
+			p = semicolon + 1;
+			continue;
+		}
+
+		++p;
+
+		const char *const value = p;
+		char *quote = find_end_quote(p, end);
+		if (quote == end)
+			break;
+
+		*quote = 0;
+		p = quote + 1;
+
+		icy_parse_tag_item(tag,
+#ifdef HAVE_ICU_CONVERTER
+				   icu_converter,
+#endif
+				   name, value);
+
+		char *semicolon = std::find(p, end, ';');
+		if (semicolon == end)
+			break;
+		p = semicolon + 1;
+	}
+
+	return tag.CommitNew();
+}
+
+size_t
+IcyMetaDataParser::Meta(const void *data, size_t length) noexcept
+{
+	const auto *p = (const unsigned char *)data;
+
+	assert(IsDefined());
+	assert(data_rest == 0);
+	assert(length > 0);
+
+	if (meta_size == 0) {
+		/* read meta_size from the first byte of a meta
+		   block */
+		meta_size = *p++ * 16;
+		if (meta_size == 0) {
+			/* special case: no metadata */
+			data_rest = data_size;
+			return 1;
+		}
+
+		/* 1 byte was consumed (must be re-added later for the
+		   return value */
+		--length;
+
+		/* initialize metadata reader, allocate enough
+		   memory (+1 for the null terminator) */
+		meta_position = 0;
+		meta_data = new char[meta_size + 1];
+	}
+
+	assert(meta_position < meta_size);
+
+	if (length > meta_size - meta_position)
+		length = meta_size - meta_position;
+
+	memcpy(meta_data + meta_position, p, length);
+	meta_position += length;
+
+	if (p != data)
+		/* re-add the first byte (which contained meta_size) */
+		++length;
+
+	if (meta_position == meta_size) {
+		/* parse */
+
+		tag = icy_parse_tag(
+#ifdef HAVE_ICU_CONVERTER
+				    icu_converter.get(),
+#endif
+				    meta_data, meta_data + meta_size);
+		delete[] meta_data;
+
+		/* change back to normal data mode */
+
+		meta_size = 0;
+		data_rest = data_size;
+	}
+
+	return length;
+}
+
+size_t
+IcyMetaDataParser::ParseInPlace(void *data, size_t length) noexcept
+{
+	auto *const dest0 = (uint8_t *)data;
+	uint8_t *dest = dest0;
+	const uint8_t *src = dest0;
+
+	while (length > 0) {
+		size_t chunk = Data(length);
+		if (chunk > 0) {
+			memmove(dest, src, chunk);
+			dest += chunk;
+			src += chunk;
+			length -= chunk;
+
+			if (length == 0)
+				break;
+		}
+
+		chunk = Meta(src, length);
+		if (chunk > 0) {
+			src += chunk;
+			length -= chunk;
+		}
+	}
+
+	return dest - dest0;
+}
@@ -0,0 +1,103 @@
+/*
+ * Copyright 2003-2021 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifndef MPD_ICY_META_DATA_PARSER_HXX
+#define MPD_ICY_META_DATA_PARSER_HXX
+
+#include "lib/icu/Converter.hxx"
+#include "tag/Tag.hxx"
+#include "config.h"
+
+#include <cstddef>
+#include <memory>
+
+class IcyMetaDataParser {
+	size_t data_size = 0, data_rest;
+
+	size_t meta_size, meta_position;
+	char *meta_data;
+
+#ifdef HAVE_ICU_CONVERTER
+	std::unique_ptr<IcuConverter> icu_converter;
+#endif
+
+	std::unique_ptr<Tag> tag;
+
+public:
+	~IcyMetaDataParser() noexcept {
+		Reset();
+	}
+
+#ifdef HAVE_ICU_CONVERTER
+	/**
+	 * Throws on error.
+	 */
+	void SetCharset(const char *charset);
+#endif
+
+	/**
+	 * Initialize an enabled icy_metadata object with the specified
+	 * data_size (from the icy-metaint HTTP response header).
+	 */
+	void Start(size_t _data_size) noexcept {
+		data_size = data_rest = _data_size;
+		meta_size = 0;
+		tag = nullptr;
+	}
+
+	/**
+	 * Resets the icy_metadata.  Call this after rewinding the stream.
+	 */
+	void Reset() noexcept;
+
+	/**
+	 * Checks whether the icy_metadata object is enabled.
+	 */
+	bool IsDefined() const noexcept {
+		return data_size > 0;
+	}
+
+	/**
+	 * Evaluates data.  Returns the number of bytes of normal data which
+	 * can be read by the caller, but not more than "length".  If the
+	 * return value is smaller than "length", the caller should invoke
+	 * icy_meta().
+	 */
+	size_t Data(size_t length) noexcept;
+
+	/**
+	 * Reads metadata from the stream.  Returns the number of bytes
+	 * consumed.  If the return value is smaller than "length", the caller
+	 * should invoke icy_data().
+	 */
+	size_t Meta(const void *data, size_t length) noexcept;
+
+	/**
+	 * Parse data and eliminate metadata.
+	 *
+	 * @return the number of data bytes remaining in the buffer
+	 */
+	size_t ParseInPlace(void *data, size_t length) noexcept;
+
+	std::unique_ptr<Tag> ReadTag() noexcept {
+		return std::exchange(tag, nullptr);
+	}
+};
+
+#endif