--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/extern/libmustach/mustach.h	Wed Mar 15 19:34:00 2023 +0100
@@ -0,0 +1,313 @@
+/*
+ Author: José Bollo <jobol@nonadev.net>
+
+ https://gitlab.com/jobol/mustach
+
+ SPDX-License-Identifier: ISC
+*/
+
+#ifndef _mustach_h_included_
+#define _mustach_h_included_
+
+struct mustach_sbuf; /* see below */
+
+/**
+ * Current version of mustach and its derivates
+ */
+#define MUSTACH_VERSION 102
+#define MUSTACH_VERSION_MAJOR (MUSTACH_VERSION / 100)
+#define MUSTACH_VERSION_MINOR (MUSTACH_VERSION % 100)
+
+/**
+ * Maximum nested imbrications supported
+ */
+#define MUSTACH_MAX_DEPTH  256
+
+/**
+ * Maximum length of tags in mustaches {{...}}
+ */
+#define MUSTACH_MAX_LENGTH 4096
+
+/**
+ * Maximum length of delimitors (2 normally but extended here)
+ */
+#define MUSTACH_MAX_DELIM_LENGTH 8
+
+/**
+ * Flags specific to mustach core
+ */
+#define Mustach_With_NoExtensions   0
+#define Mustach_With_Colon          1
+#define Mustach_With_EmptyTag       2
+#define Mustach_With_AllExtensions  3
+
+/*
+ * Definition of error codes returned by mustach
+ */
+#define MUSTACH_OK                       0
+#define MUSTACH_ERROR_SYSTEM            -1
+#define MUSTACH_ERROR_UNEXPECTED_END    -2
+#define MUSTACH_ERROR_EMPTY_TAG         -3
+#define MUSTACH_ERROR_TAG_TOO_LONG      -4
+#define MUSTACH_ERROR_BAD_SEPARATORS    -5
+#define MUSTACH_ERROR_TOO_DEEP          -6
+#define MUSTACH_ERROR_CLOSING           -7
+#define MUSTACH_ERROR_BAD_UNESCAPE_TAG  -8
+#define MUSTACH_ERROR_INVALID_ITF       -9
+#define MUSTACH_ERROR_ITEM_NOT_FOUND    -10
+#define MUSTACH_ERROR_PARTIAL_NOT_FOUND -11
+#define MUSTACH_ERROR_UNDEFINED_TAG     -12
+
+/*
+ * You can use definition below for user specific error
+ *
+ * The macro MUSTACH_ERROR_USER is involutive so for any value
+ *   value = MUSTACH_ERROR_USER(MUSTACH_ERROR_USER(value))
+ */
+#define MUSTACH_ERROR_USER_BASE         -100
+#define MUSTACH_ERROR_USER(x)           (MUSTACH_ERROR_USER_BASE-(x))
+#define MUSTACH_IS_ERROR_USER(x)        (MUSTACH_ERROR_USER(x) >= 0)
+
+/**
+ * mustach_itf - pure abstract mustach - interface for callbacks
+ *
+ * The functions enter and next should return 0 or 1.
+ *
+ * All other functions should normally return MUSTACH_OK (zero).
+ *
+ * If any function returns a negative value, it means an error that
+ * stop the processing and that is reported to the caller. Mustach
+ * also has its own error codes. Using the macros MUSTACH_ERROR_USER
+ * and MUSTACH_IS_ERROR_USER could help to avoid clashes.
+ *
+ * @start: If defined (can be NULL), starts the mustach processing
+ *         of the closure, called at the very beginning before any
+ *         mustach processing occurs.
+ *
+ * @put: If defined (can be NULL), writes the value of 'name'
+ *       to 'file' with 'escape' or not.
+ *       As an extension (see NO_ALLOW_EMPTY_TAG), the 'name' can be
+ *       the empty string. In that later case an implementation can
+ *       return MUSTACH_ERROR_EMPTY_TAG to refuse empty names.
+ *       If NULL and 'get' NULL the error MUSTACH_ERROR_INVALID_ITF
+ *       is returned.
+ *
+ * @enter: Enters the section of 'name' if possible.
+ *         Musts return 1 if entered or 0 if not entered.
+ *         When 1 is returned, the function 'leave' will always be called.
+ *         Conversely 'leave' is never called when enter returns 0 or
+ *         a negative value.
+ *         When 1 is returned, the function must activate the first
+ *         item of the section.
+ *
+ * @next: Activates the next item of the section if it exists.
+ *        Musts return 1 when the next item is activated.
+ *        Musts return 0 when there is no item to activate.
+ *
+ * @leave: Leaves the last entered section
+ *
+ * @partial: If defined (can be NULL), returns in 'sbuf' the content of the
+ *           partial of 'name'. @see mustach_sbuf
+ *           If NULL but 'get' not NULL, 'get' is used instead of partial.
+ *           If NULL and 'get' NULL and 'put' not NULL, 'put' is called with
+ *           a true FILE.
+ *
+ * @emit: If defined (can be NULL), writes the 'buffer' of 'size' with 'escape'.
+ *        If NULL the standard function 'fwrite' is used with a true FILE.
+ *        If not NULL that function is called instead of 'fwrite' to output
+ *        text.
+ *        It implies that if you define either 'partial' or 'get' callback,
+ *        the meaning of 'FILE *file' is abstract for mustach's process and
+ *        then you can use 'FILE*file' pass any kind of pointer (including NULL)
+ *        to the function 'fmustach'. An example of a such behaviour is given by
+ *        the implementation of 'mustach_json_c_write'.
+ *
+ * @get: If defined (can be NULL), returns in 'sbuf' the value of 'name'.
+ *       As an extension (see NO_ALLOW_EMPTY_TAG), the 'name' can be
+ *       the empty string. In that later case an implementation can
+ *       return MUSTACH_ERROR_EMPTY_TAG to refuse empty names.
+ *       If 'get' is NULL and 'put' NULL the error MUSTACH_ERROR_INVALID_ITF
+ *       is returned.
+ *
+ * @stop: If defined (can be NULL), stops the mustach processing
+ *        of the closure, called at the very end after all mustach
+ *        processing occurered. The status returned by the processing
+ *        is passed to the stop.
+ *
+ * The array below summarize status of callbacks:
+ *
+ *    FULLY OPTIONAL:   start partial
+ *    MANDATORY:        enter next leave
+ *    COMBINATORIAL:    put emit get
+ *
+ * Not definig a MANDATORY callback returns error MUSTACH_ERROR_INVALID_ITF.
+ *
+ * For COMBINATORIAL callbacks the array below summarize possible combinations:
+ *
+ *  combination  : put     : emit    : get     : abstract FILE
+ *  -------------+---------+---------+---------+-----------------------
+ *  HISTORIC     : defined : NULL    : NULL    : NO: standard FILE
+ *  MINIMAL      : NULL    : NULL    : defined : NO: standard FILE
+ *  CUSTOM       : NULL    : defined : defined : YES: abstract FILE
+ *  DUCK         : defined : NULL    : defined : NO: standard FILE
+ *  DANGEROUS    : defined : defined : any     : YES or NO, depends on 'partial'
+ *  INVALID      : NULL    : any     : NULL    : -
+ *
+ * The DUCK case runs on one leg. 'get' is not used if 'partial' is defined
+ * but is used for 'partial' if 'partial' is NULL. Thus for clarity, do not use
+ * it that way but define 'partial' and let 'get' be NULL.
+ *
+ * The DANGEROUS case is special: it allows abstract FILE if 'partial' is defined
+ * but forbids abstract FILE when 'partial' is NULL.
+ *
+ * The INVALID case returns error MUSTACH_ERROR_INVALID_ITF.
+ */
+struct mustach_itf {
+	int (*start)(void *closure);
+	int (*put)(void *closure, const char *name, int escape, FILE *file);
+	int (*enter)(void *closure, const char *name);
+	int (*next)(void *closure);
+	int (*leave)(void *closure);
+	int (*partial)(void *closure, const char *name, struct mustach_sbuf *sbuf);
+	int (*emit)(void *closure, const char *buffer, size_t size, int escape, FILE *file);
+	int (*get)(void *closure, const char *name, struct mustach_sbuf *sbuf);
+	void (*stop)(void *closure, int status);
+};
+
+/**
+ * mustach_sbuf - Interface for handling zero terminated strings
+ *
+ * That structure is used for returning zero terminated strings -in 'value'-
+ * to mustach. The callee can provide a function for releasing the returned
+ * 'value'. Three methods for releasing the string are possible.
+ *
+ *  1. no release: set either 'freecb' or 'releasecb' with NULL (done by default)
+ *  2. release without closure: set 'freecb' to its expected value
+ *  3. release with closure: set 'releasecb' and 'closure' to their expected values
+ *
+ * @value: The value of the string. That value is not changed by mustach -const-.
+ *
+ * @freecb: The function to call for freeing the value without closure.
+ *          For convenience, signature of that callback is compatible with 'free'.
+ *          Can be NULL.
+ *
+ * @releasecb: The function to release with closure.
+ *             Can be NULL.
+ *
+ * @closure: The closure to use for 'releasecb'.
+ *
+ * @length: Length of the value or zero if unknown and value null terminated.
+ *          To return the empty string, let it to zero and let value to NULL.
+ */
+struct mustach_sbuf {
+	const char *value;
+	union {
+		void (*freecb)(void*);
+		void (*releasecb)(const char *value, void *closure);
+	};
+	void *closure;
+	size_t length;
+};
+
+/**
+ * mustach_file - Renders the mustache 'template' in 'file' for 'itf' and 'closure'.
+ *
+ * @template: the template string to instantiate
+ * @length:   length of the template or zero if unknown and template null terminated
+ * @itf:      the interface to the functions that mustach calls
+ * @closure:  the closure to pass to functions called
+ * @file:     the file where to write the result
+ *
+ * Returns 0 in case of success, -1 with errno set in case of system error
+ * a other negative value in case of error.
+ */
+extern int mustach_file(const char *template, size_t length, const struct mustach_itf *itf, void *closure, int flags, FILE *file);
+
+/**
+ * mustach_fd - Renders the mustache 'template' in 'fd' for 'itf' and 'closure'.
+ *
+ * @template: the template string to instantiate
+ * @length:   length of the template or zero if unknown and template null terminated
+ * @itf:      the interface to the functions that mustach calls
+ * @closure:  the closure to pass to functions called
+ * @fd:       the file descriptor number where to write the result
+ *
+ * Returns 0 in case of success, -1 with errno set in case of system error
+ * a other negative value in case of error.
+ */
+extern int mustach_fd(const char *template, size_t length, const struct mustach_itf *itf, void *closure, int flags, int fd);
+
+/**
+ * mustach_mem - Renders the mustache 'template' in 'result' for 'itf' and 'closure'.
+ *
+ * @template: the template string to instantiate
+ * @length:   length of the template or zero if unknown and template null terminated
+ * @itf:      the interface to the functions that mustach calls
+ * @closure:  the closure to pass to functions called
+ * @result:   the pointer receiving the result when 0 is returned
+ * @size:     the size of the returned result
+ *
+ * Returns 0 in case of success, -1 with errno set in case of system error
+ * a other negative value in case of error.
+ */
+extern int mustach_mem(const char *template, size_t length, const struct mustach_itf *itf, void *closure, int flags, char **result, size_t *size);
+
+/***************************************************************************
+* compatibility with version before 1.0
+*/
+#ifdef __GNUC__
+#define DEPRECATED_MUSTACH(func) func __attribute__ ((deprecated))
+#elif defined(_MSC_VER)
+#define DEPRECATED_MUSTACH(func) __declspec(deprecated) func
+#elif !defined(DEPRECATED_MUSTACH)
+#pragma message("WARNING: You need to implement DEPRECATED_MUSTACH for this compiler")
+#define DEPRECATED_MUSTACH(func) func
+#endif
+/**
+ * OBSOLETE use mustach_file
+ *
+ * fmustach - Renders the mustache 'template' in 'file' for 'itf' and 'closure'.
+ *
+ * @template: the template string to instantiate, null terminated
+ * @itf:      the interface to the functions that mustach calls
+ * @closure:  the closure to pass to functions called
+ * @file:     the file where to write the result
+ *
+ * Returns 0 in case of success, -1 with errno set in case of system error
+ * a other negative value in case of error.
+ */
+DEPRECATED_MUSTACH(extern int fmustach(const char *template, const struct mustach_itf *itf, void *closure, FILE *file));
+
+/**
+ * OBSOLETE use mustach_fd
+ *
+ * fdmustach - Renders the mustache 'template' in 'fd' for 'itf' and 'closure'.
+ *
+ * @template: the template string to instantiate, null terminated
+ * @itf:      the interface to the functions that mustach calls
+ * @closure:  the closure to pass to functions called
+ * @fd:       the file descriptor number where to write the result
+ *
+ * Returns 0 in case of success, -1 with errno set in case of system error
+ * a other negative value in case of error.
+ */
+DEPRECATED_MUSTACH(extern int fdmustach(const char *template, const struct mustach_itf *itf, void *closure, int fd));
+
+/**
+ * OBSOLETE use mustach_mem
+ *
+ * mustach - Renders the mustache 'template' in 'result' for 'itf' and 'closure'.
+ *
+ * @template: the template string to instantiate, null terminated
+ * @itf:      the interface to the functions that mustach calls
+ * @closure:  the closure to pass to functions called
+ * @result:   the pointer receiving the result when 0 is returned
+ * @size:     the size of the returned result
+ *
+ * Returns 0 in case of success, -1 with errno set in case of system error
+ * a other negative value in case of error.
+ */
+DEPRECATED_MUSTACH(extern int mustach(const char *template, const struct mustach_itf *itf, void *closure, char **result, size_t *size));
+
+#endif
+