Move uzlib_gzip_wrapper, utils, and fallback_log to local libs

uzlib_gzip_wrapper changes:
 * Move to local lib.
 * Add callback style decompression support.
 * Add four native decompression unit tests. These need python3 to be
installed.
 * Add workaround for uzlib output buffer needing to be one byte larger
than decompressed file.
 * Add function to check the number of already decompressed bytes.
 * Add function to check whether the decompression is finished.
 * Move to gzip namespace.

Other changes:
 * Move utils and fallback log to local libs.
 * Change utils namespace from "utility" to "utils".

TODO.md

@@ -10,6 +10,8 @@ Not all of these are necessarily going to be implemented at all.
  * Merge wifissid.txt and wifipass.txt into wificreds.txt and merge mqttuser.txt and mqttpass.txt into mqttcreds.txt
  * Improve log messages for when measurements fail
  * Use an asynchronous DHT library(for example https://github.com/bertmelis/esp32DHT/)?
+ * Add (stream?) compression to uzlib_gzip_wrapper
+ * Change callback based uzlib_ungzip_wrapper to use C++ function objects instead of C function pointers
 
 ## Web Interface
  * Add error message to web interface if measurement fails
@@ -19,6 +21,7 @@ Not all of these are necessarily going to be implemented at all.
  * Allow caching of static resources using a hash of their content as an ETag
  * Add theme switcher to web interface(clientside setting)
  * Web server IPv6 support
+ * Add current commit to prometheus info and HTTP Server header
 
 ## Integration
  * Find a way to make the kubernetes service(for prometheus) automatically point to the esp(mDNS?)
@@ -28,3 +31,5 @@ Not all of these are necessarily going to be implemented at all.
  * Add MQTT state json
  * Cleanup MQTT code
  * Add MQTT discovery support(https://www.home-assistant.io/docs/mqtt/discovery/)
+ * Add WiFi info to prometheus metrics
+ * Dynamically gzip compress metrics page?

lib/fallback_log/README.md

@@ -0,0 +1,2 @@
+# Fallback Log
+This is a simple header-only library, containing fallback logging(log_X) macros to use if the framework for the given board doesn't include them.

lib/fallback_log/library.json

@@ -0,0 +1,12 @@
+{
+	"name": "FallbackLog",
+	"description": "A header only library containing fallback definitions of the log_X macros.",
+	"version": "1.0.0",
+	"license": "MIT",
+	"dependencies": [
+		{
+			"name": "utils",
+			"version": "utils"
+		}
+	]
+}

lib/utils/README.md

@@ -0,0 +1,2 @@
+# Utils
+This library contains common utilities required for other parts of this project.

src/utils.h → lib/utils/include/utils.h

@@ -15,7 +15,7 @@
 
 #include <string>
 
-namespace utility {
+namespace utils {
 /**
  * A method to get the index of the Most Significant Bit set in a number.
  *
@@ -58,28 +58,28 @@ struct const_expr_value {
 constexpr size_t strlen(const char *str) {
 	return (*str == 0) ? 0 : strlen(str + 1) + 1;
 }
-}
+} /* namespace utils */
 
 /**
  * CONST_EXPR_VALUE is an utility macro to get force compile time evaluation of a constexpr value.
  */
-#define CONST_EXPR_VALUE(exp) utility::const_expr_value<decltype(exp), exp>::value
+#define CONST_EXPR_VALUE(exp) utils::const_expr_value<decltype(exp), exp>::value
 
 /**
  * FILE_BASE_NAME is a macro that represents the base name of the current file.
  */
 #ifdef __FILE_NAME__
 #define FILE_BASE_NAME __FILE_NAME__
 #else
-#define FILE_BASE_NAME &__FILE__[CONST_EXPR_VALUE(utility::get_base_name_offset(__FILE__))]
+#define FILE_BASE_NAME &__FILE__[CONST_EXPR_VALUE(utils::get_base_name_offset(__FILE__))]
 #endif
 
 /**
  * EXPAND_MACRO is a utility macro to expand a macro to its string form.
  */
 #define EXPAND_MACRO(macro) #macro
 
-namespace utility {
+namespace utils {
 /**
  * Converts the given temperature from degrees celsius to degrees fahrenheit.
  *
@@ -115,6 +115,6 @@ std::string float_to_string(const float measurement,
  * @return	The newly created string.
  */
 std::string timespan_to_string(const int64_t time_ms);
-}
+} /* namespace utils */
 
 #endif /* SRC_UTILS_H_ */

src/utils.cpp → lib/utils/src/utils.cpp

@@ -13,7 +13,7 @@
 #include <cmath>
 #include <sstream>
 
-namespace utility {
+namespace utils {
 
 uint8_t get_msb(const uint32_t number) {
 	uint8_t idx = 0;
@@ -65,4 +65,4 @@ std::string timespan_to_string(const int64_t time_ms) {
 	return stream.str();
 }
 
-} /* namespace utility */
+} /* namespace utils */

lib/uzlib_gzip_wrapper/README.md

@@ -0,0 +1,10 @@
+# UZLib GZIP Wrapper
+This is a [UZLib](https://github.com/pfalcon/uzlib.git) wrapper specifically used to (de)compress GZIP files.
+
+**IMPORTANT:** The current version of this library cannot handle compression yet.
+
+This wrapper can handle both decompressing a file from a constant byte array, as well as from a callback.
+
+This wrapper can handle a custom window size.
+
+There are no usage examples at this point in time.

lib/uzlib_gzip_wrapper/include/uzlib_gzip_wrapper.h

@@ -0,0 +1,141 @@
+/*
+ * uzlib_gzip_wrapper.h
+ *
+ *  Created on: May 26, 2023
+ *
+ * Copyright (C) 2023 ToMe25.
+ * This project is licensed under the MIT License.
+ * The MIT license can be found in the project root and at https://opensource.org/licenses/MIT.
+ */
+
+#ifndef SRC_HTML_UZLIB_GZIP_WRAPPER_H_
+#define SRC_HTML_UZLIB_GZIP_WRAPPER_H_
+
+#include <uzlib.h>
+#include <functional>
+
+namespace gzip {
+
+/**
+ * Initializes the static variables used by uzlib.
+ */
+void init();
+
+/**
+ * A wrapper to help with storing the data associated with decompressing a gzip file using uzlib.
+ * Can currently only handle the entire compressed file being accessible as a single pointer block.
+ */
+class uzlib_ungzip_wrapper {
+private:
+	/**
+	 * The internal data store used by uzlib.
+	 */
+	uzlib_uncomp *decomp;
+
+	/**
+	 * The number of already decompressed bytes.
+	 */
+	size_t index = 0;
+
+	/**
+	 * The decompressed filesize in bytes module 2^32, if available.
+	 * Or -1 if the filesize is not available.
+	 */
+	int32_t dlen = -1;
+
+	/**
+	 * A single decompressed byte, decompressed in advance to work around the incorrect file end detection of uzlib.
+	 */
+	int16_t dcbuf = -1;
+
+public:
+	/**
+	 * Creates a new gzip wrapper to decompress the gzip file in the given memory block.
+	 *
+	 * For this the entire compressed file has to be in a single continuous memory block.
+	 *
+	 * With this constructor the uncompressed size is available immediately.
+	 *
+	 * @param cmp_start	A pointer to the first byte of the gzip file.
+	 * @param cmp_end	A pointer to the first byte after the gzip file.
+	 * @param wsize		The window size used for decompression.
+	 * 					Has to be at least as much as the window size used for compression.
+	 * 					A pow(2, -wsize) byte buffer is allocated for decompression.
+	 * 					The range of valid values is from -8 to -15.
+	 * 					Values outside of this range will be clamped to this range.
+	 */
+	uzlib_ungzip_wrapper(const uint8_t *cmp_start, const uint8_t *cmp_end,
+			int8_t wsize);
+
+	/**
+	 * Creates a new gzip wrapper to decompress a gzip file from a callback.
+	 *
+	 * This callback will be called each time `uzlib_uncomp->source` is empty.
+	 * This means by default it will be called for every byte to read.
+	 *
+	 * It is however allowed to modify `uzlib_uncomp->source` and `uzlib_uncomp->source_limit`
+	 * in this callback to allow reading a chunk of data at once.
+	 * In this case the callback still has to return the **FIRST** read byte.
+	 * If `uzlib_uncomp->source` is modified, it must point to the next byte after the returned byte.
+	 *
+	 * Once all bytes are read the callback must return -1.
+	 *
+	 * **WARNING:** This callback **MUST NOT** return the last four bytes of a gzip file, since those can't be decompressed.
+	 *
+	 * With this constructor the uncompressed size is only available once the file is read in its entirety.
+	 *
+	 * @param callback	The callback to get the compressed data from.
+	 * @param wsize		The window size used for decompression.
+	 * 					Has to be at least as much as the window size used for compression.
+	 * 					A pow(2, -wsize) byte buffer is allocated for decompression.
+	 * 					The range of valid values is from -8 to -15.
+	 * 					Values outside of this range will be clamped to this range.
+	 */
+	uzlib_ungzip_wrapper(int (*callback)(uzlib_uncomp*), int8_t wsize);
+
+	/**
+	 * Destroys this gzip wrapper, and removes its internal memory buffer.
+	 */
+	~uzlib_ungzip_wrapper();
+
+	/**
+	 * Decompresses the next segment of the gzip file to the given memory buffer.
+	 *
+	 * Attempts to decompress a single additional byte in advance,
+	 * to work around uzlib not detecting the file end when the buffer size exactly matches the uncompressed size.
+	 *
+	 * @param buf		The memory buffer to write to.
+	 * @param buf_size	The max number of bytes to write to the buffer.
+	 * @return	The number of bytes written to the buffer.
+	 */
+	size_t decompress(uint8_t *buf, const size_t buf_size);
+
+	/**
+	 * Gets the uncompressed size of the file to be decompressed, if available.
+	 *
+	 * The uncompressed size is always available once decompression is finished.
+	 * If this wrapper was initialized with a memory block, rather than a callback,
+	 * the uncompressed size is immediately available.
+	 *
+	 * @return	The uncompressed file size.
+	 */
+	int32_t getDecompressedSize() const;
+
+	/**
+	 * Gets the number of bytes that were already decompressed.
+	 *
+	 * @return	The number of already decompressed bytes.
+	 */
+	uint32_t getDecompressed() const;
+
+	/**
+	 * Checks whether the file was decompressed in its entirety.
+	 *
+	 * @return	Whether the decompression is done.
+	 */
+	bool done() const;
+};
+
+} /* namespace gzip */
+
+#endif /* SRC_HTML_UZLIB_GZIP_WRAPPER_H_ */

lib/uzlib_gzip_wrapper/library.json

@@ -0,0 +1,16 @@
+{
+	"name": "UZLibGzipWrapper",
+	"description": "A wrapper to help with storing the data associated with (de)compressing a GZIP file using UZLib. Can't handle compressing yet.",
+	"version": "1.0.0",
+	"license": "MIT",
+	"dependencies": [
+		{
+			"name": "uzlib",
+			"version": "https://github.com/pfalcon/uzlib.git"
+		},
+		{
+			"name": "FallbackLog",
+			"version": "FallbackLog"
+		}
+	]
+}