--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/extern/libmustach/mustach.c	Wed Mar 15 19:34:00 2023 +0100
@@ -0,0 +1,546 @@
+/*
+ Author: José Bollo <jobol@nonadev.net>
+
+ https://gitlab.com/jobol/mustach
+
+ SPDX-License-Identifier: ISC
+*/
+
+#define _GNU_SOURCE
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+#include <ctype.h>
+#ifdef _WIN32
+#include <malloc.h>
+#endif
+
+#include "mustach.h"
+
+struct iwrap {
+	int (*emit)(void *closure, const char *buffer, size_t size, int escape, FILE *file);
+	void *closure; /* closure for: enter, next, leave, emit, get */
+	int (*put)(void *closure, const char *name, int escape, FILE *file);
+	void *closure_put; /* closure for put */
+	int (*enter)(void *closure, const char *name);
+	int (*next)(void *closure);
+	int (*leave)(void *closure);
+	int (*get)(void *closure, const char *name, struct mustach_sbuf *sbuf);
+	int (*partial)(void *closure, const char *name, struct mustach_sbuf *sbuf);
+	void *closure_partial; /* closure for partial */
+	int flags;
+};
+
+struct prefix {
+	size_t len;
+	const char *start;
+	struct prefix *prefix;
+};
+
+#if !defined(NO_OPEN_MEMSTREAM)
+static FILE *memfile_open(char **buffer, size_t *size)
+{
+	return open_memstream(buffer, size);
+}
+static void memfile_abort(FILE *file, char **buffer, size_t *size)
+{
+	fclose(file);
+	free(*buffer);
+	*buffer = NULL;
+	*size = 0;
+}
+static int memfile_close(FILE *file, char **buffer, size_t *size)
+{
+	int rc;
+
+	/* adds terminating null */
+	rc = fputc(0, file) ? MUSTACH_ERROR_SYSTEM : 0;
+	fclose(file);
+	if (rc == 0)
+		/* removes terminating null of the length */
+		(*size)--;
+	else {
+		free(*buffer);
+		*buffer = NULL;
+		*size = 0;
+	}
+	return rc;
+}
+#else
+static FILE *memfile_open(char **buffer, size_t *size)
+{
+	/*
+	 * We can't provide *buffer and *size as open_memstream does but
+	 * at least clear them so the caller won't get bad data.
+	 */
+	*buffer = NULL;
+	*size = 0;
+
+	return tmpfile();
+}
+static void memfile_abort(FILE *file, char **buffer, size_t *size)
+{
+	fclose(file);
+	*buffer = NULL;
+	*size = 0;
+}
+static int memfile_close(FILE *file, char **buffer, size_t *size)
+{
+	int rc;
+	size_t s;
+	char *b;
+
+	s = (size_t)ftell(file);
+	b = malloc(s + 1);
+	if (b == NULL) {
+		rc = MUSTACH_ERROR_SYSTEM;
+		errno = ENOMEM;
+		s = 0;
+	} else {
+		rewind(file);
+		if (1 == fread(b, s, 1, file)) {
+			rc = 0;
+			b[s] = 0;
+		} else {
+			rc = MUSTACH_ERROR_SYSTEM;
+			free(b);
+			b = NULL;
+			s = 0;
+		}
+	}
+	*buffer = b;
+	*size = s;
+	return rc;
+}
+#endif
+
+static inline void sbuf_reset(struct mustach_sbuf *sbuf)
+{
+	sbuf->value = NULL;
+	sbuf->freecb = NULL;
+	sbuf->closure = NULL;
+	sbuf->length = 0;
+}
+
+static inline void sbuf_release(struct mustach_sbuf *sbuf)
+{
+	if (sbuf->releasecb)
+		sbuf->releasecb(sbuf->value, sbuf->closure);
+}
+
+static inline size_t sbuf_length(struct mustach_sbuf *sbuf)
+{
+	size_t length = sbuf->length;
+	if (length == 0 && sbuf->value != NULL)
+		length = strlen(sbuf->value);
+	return length;
+}
+
+static int iwrap_emit(void *closure, const char *buffer, size_t size, int escape, FILE *file)
+{
+	size_t i, j, r;
+
+	(void)closure; /* unused */
+
+	if (!escape)
+		return fwrite(buffer, 1, size, file) != size ? MUSTACH_ERROR_SYSTEM : MUSTACH_OK;
+
+	r = i = 0;
+	while (i < size) {
+		j = i;
+		while (j < size && buffer[j] != '<' && buffer[j] != '>' && buffer[j] != '&' && buffer[j] != '"')
+			j++;
+		if (j != i && fwrite(&buffer[i], j - i, 1, file) != 1)
+			return MUSTACH_ERROR_SYSTEM;
+		if (j < size) {
+			switch(buffer[j++]) {
+			case '<':
+				r = fwrite("&lt;", 4, 1, file);
+				break;
+			case '>':
+				r = fwrite("&gt;", 4, 1, file);
+				break;
+			case '&':
+				r = fwrite("&amp;", 5, 1, file);
+				break;
+			case '"':
+				r = fwrite("&quot;", 6, 1, file);
+				break;
+			}
+			if (r != 1)
+				return MUSTACH_ERROR_SYSTEM;
+		}
+		i = j;
+	}
+	return MUSTACH_OK;
+}
+
+static int iwrap_put(void *closure, const char *name, int escape, FILE *file)
+{
+	struct iwrap *iwrap = closure;
+	int rc;
+	struct mustach_sbuf sbuf;
+	size_t length;
+
+	sbuf_reset(&sbuf);
+	rc = iwrap->get(iwrap->closure, name, &sbuf);
+	if (rc >= 0) {
+		length = sbuf_length(&sbuf);
+		if (length)
+			rc = iwrap->emit(iwrap->closure, sbuf.value, length, escape, file);
+		sbuf_release(&sbuf);
+	}
+	return rc;
+}
+
+static int iwrap_partial(void *closure, const char *name, struct mustach_sbuf *sbuf)
+{
+	struct iwrap *iwrap = closure;
+	int rc;
+	FILE *file;
+	size_t size;
+	char *result;
+
+	result = NULL;
+	file = memfile_open(&result, &size);
+	if (file == NULL)
+		rc = MUSTACH_ERROR_SYSTEM;
+	else {
+		rc = iwrap->put(iwrap->closure_put, name, 0, file);
+		if (rc < 0)
+			memfile_abort(file, &result, &size);
+		else {
+			rc = memfile_close(file, &result, &size);
+			if (rc == 0) {
+				sbuf->value = result;
+				sbuf->freecb = free;
+				sbuf->length = size;
+			}
+		}
+	}
+	return rc;
+}
+
+static int emitprefix(struct iwrap *iwrap, FILE *file, struct prefix *prefix)
+{
+	if (prefix->prefix) {
+		int rc = emitprefix(iwrap, file, prefix->prefix);
+		if (rc < 0)
+			return rc;
+	}
+	return prefix->len ? iwrap->emit(iwrap->closure, prefix->start, prefix->len, 0, file) : 0;
+}
+
+static int process(const char *template, size_t length, struct iwrap *iwrap, FILE *file, struct prefix *prefix)
+{
+	struct mustach_sbuf sbuf;
+	char opstr[MUSTACH_MAX_DELIM_LENGTH], clstr[MUSTACH_MAX_DELIM_LENGTH];
+	char name[MUSTACH_MAX_LENGTH + 1], c;
+	const char *beg, *term, *end;
+	struct { const char *name, *again; size_t length; unsigned enabled: 1, entered: 1; } stack[MUSTACH_MAX_DEPTH];
+	size_t oplen, cllen, len, l;
+	int depth, rc, enabled, stdalone;
+	struct prefix pref;
+
+	pref.prefix = prefix;
+	end = template + (length ? length : strlen(template));
+	opstr[0] = opstr[1] = '{';
+	clstr[0] = clstr[1] = '}';
+	oplen = cllen = 2;
+	stdalone = enabled = 1;
+	depth = pref.len = 0;
+	for (;;) {
+		/* search next openning delimiter */
+		for (beg = template ; ; beg++) {
+			c = beg == end ? '\n' : *beg;
+			if (c == '\n') {
+				l = (beg != end) + (size_t)(beg - template);
+				if (stdalone != 2 && enabled) {
+					if (beg != template /* don't prefix empty lines */) {
+						rc = emitprefix(iwrap, file, &pref);
+						if (rc < 0)
+							return rc;
+					}
+					rc = iwrap->emit(iwrap->closure, template, l, 0, file);
+					if (rc < 0)
+						return rc;
+				}
+				if (beg == end) /* no more mustach */
+					return depth ? MUSTACH_ERROR_UNEXPECTED_END : MUSTACH_OK;
+				template += l;
+				stdalone = 1;
+				pref.len = 0;
+			}
+			else if (!isspace(c)) {
+				if (stdalone == 2 && enabled) {
+					rc = emitprefix(iwrap, file, &pref);
+					if (rc < 0)
+						return rc;
+					pref.len = 0;
+					stdalone = 0;
+				}
+				if (c == *opstr && end - beg >= (ssize_t)oplen) {
+					for (l = 1 ; l < oplen && beg[l] == opstr[l] ; l++);
+					if (l == oplen)
+						break;
+				}
+				stdalone = 0;
+			}
+		}
+
+		pref.start = template;
+		pref.len = enabled ? (size_t)(beg - template) : 0;
+		beg += oplen;
+
+		/* search next closing delimiter */
+		for (term = beg ; ; term++) {
+			if (term == end)
+				return MUSTACH_ERROR_UNEXPECTED_END;
+			if (*term == *clstr && end - term >= (ssize_t)cllen) {
+				for (l = 1 ; l < cllen && term[l] == clstr[l] ; l++);
+				if (l == cllen)
+					break;
+			}
+		}
+		template = term + cllen;
+		len = (size_t)(term - beg);
+		c = *beg;
+		switch(c) {
+		case ':':
+			stdalone = 0;
+			if (iwrap->flags & Mustach_With_Colon)
+				goto exclude_first;
+			goto get_name;
+		case '!':
+		case '=':
+			break;
+		case '{':
+			for (l = 0 ; l < cllen && clstr[l] == '}' ; l++);
+			if (l < cllen) {
+				if (!len || beg[len-1] != '}')
+					return MUSTACH_ERROR_BAD_UNESCAPE_TAG;
+				len--;
+			} else {
+				if (term[l] != '}')
+					return MUSTACH_ERROR_BAD_UNESCAPE_TAG;
+				template++;
+			}
+			c = '&';
+			/*@fallthrough@*/
+		case '&':
+			stdalone = 0;
+			/*@fallthrough@*/
+		case '^':
+		case '#':
+		case '/':
+		case '>':
+exclude_first:
+			beg++;
+			len--;
+			goto get_name;
+		default:
+			stdalone = 0;
+get_name:
+			while (len && isspace(beg[0])) { beg++; len--; }
+			while (len && isspace(beg[len-1])) len--;
+			if (len == 0 && !(iwrap->flags & Mustach_With_EmptyTag))
+				return MUSTACH_ERROR_EMPTY_TAG;
+			if (len > MUSTACH_MAX_LENGTH)
+				return MUSTACH_ERROR_TAG_TOO_LONG;
+			memcpy(name, beg, len);
+			name[len] = 0;
+			break;
+		}
+		if (stdalone)
+			stdalone = 2;
+		else if (enabled) {
+			rc = emitprefix(iwrap, file, &pref);
+			if (rc < 0)
+				return rc;
+			pref.len = 0;
+		}
+		switch(c) {
+		case '!':
+			/* comment */
+			/* nothing to do */
+			break;
+		case '=':
+			/* defines delimiters */
+			if (len < 5 || beg[len - 1] != '=')
+				return MUSTACH_ERROR_BAD_SEPARATORS;
+			beg++;
+			len -= 2;
+			while (len && isspace(*beg))
+				beg++, len--;
+			while (len && isspace(beg[len - 1]))
+				len--;
+			for (l = 0; l < len && !isspace(beg[l]) ; l++);
+			if (l == len || l > MUSTACH_MAX_DELIM_LENGTH)
+				return MUSTACH_ERROR_BAD_SEPARATORS;
+			oplen = l;
+			memcpy(opstr, beg, l);
+			while (l < len && isspace(beg[l])) l++;
+			if (l == len || len - l > MUSTACH_MAX_DELIM_LENGTH)
+				return MUSTACH_ERROR_BAD_SEPARATORS;
+			cllen = len - l;
+			memcpy(clstr, beg + l, cllen);
+			break;
+		case '^':
+		case '#':
+			/* begin section */
+			if (depth == MUSTACH_MAX_DEPTH)
+				return MUSTACH_ERROR_TOO_DEEP;
+			rc = enabled;
+			if (rc) {
+				rc = iwrap->enter(iwrap->closure, name);
+				if (rc < 0)
+					return rc;
+			}
+			stack[depth].name = beg;
+			stack[depth].again = template;
+			stack[depth].length = len;
+			stack[depth].enabled = enabled != 0;
+			stack[depth].entered = rc != 0;
+			if ((c == '#') == (rc == 0))
+				enabled = 0;
+			depth++;
+			break;
+		case '/':
+			/* end section */
+			if (depth-- == 0 || len != stack[depth].length || memcmp(stack[depth].name, name, len))
+				return MUSTACH_ERROR_CLOSING;
+			rc = enabled && stack[depth].entered ? iwrap->next(iwrap->closure) : 0;
+			if (rc < 0)
+				return rc;
+			if (rc) {
+				template = stack[depth++].again;
+			} else {
+				enabled = stack[depth].enabled;
+				if (enabled && stack[depth].entered)
+					iwrap->leave(iwrap->closure);
+			}
+			break;
+		case '>':
+			/* partials */
+			if (enabled) {
+				sbuf_reset(&sbuf);
+				rc = iwrap->partial(iwrap->closure_partial, name, &sbuf);
+				if (rc >= 0) {
+					rc = process(sbuf.value, sbuf_length(&sbuf), iwrap, file, &pref);
+					sbuf_release(&sbuf);
+				}
+				if (rc < 0)
+					return rc;
+			}
+			break;
+		default:
+			/* replacement */
+			if (enabled) {
+				rc = iwrap->put(iwrap->closure_put, name, c != '&', file);
+				if (rc < 0)
+					return rc;
+			}
+			break;
+		}
+	}
+}
+
+int mustach_file(const char *template, size_t length, const struct mustach_itf *itf, void *closure, int flags, FILE *file)
+{
+	int rc;
+	struct iwrap iwrap;
+
+	/* check validity */
+	if (!itf->enter || !itf->next || !itf->leave || (!itf->put && !itf->get))
+		return MUSTACH_ERROR_INVALID_ITF;
+
+	/* init wrap structure */
+	iwrap.closure = closure;
+	if (itf->put) {
+		iwrap.put = itf->put;
+		iwrap.closure_put = closure;
+	} else {
+		iwrap.put = iwrap_put;
+		iwrap.closure_put = &iwrap;
+	}
+	if (itf->partial) {
+		iwrap.partial = itf->partial;
+		iwrap.closure_partial = closure;
+	} else if (itf->get) {
+		iwrap.partial = itf->get;
+		iwrap.closure_partial = closure;
+	} else {
+		iwrap.partial = iwrap_partial;
+		iwrap.closure_partial = &iwrap;
+	}
+	iwrap.emit = itf->emit ? itf->emit : iwrap_emit;
+	iwrap.enter = itf->enter;
+	iwrap.next = itf->next;
+	iwrap.leave = itf->leave;
+	iwrap.get = itf->get;
+	iwrap.flags = flags;
+
+	/* process */
+	rc = itf->start ? itf->start(closure) : 0;
+	if (rc == 0)
+		rc = process(template, length, &iwrap, file, 0);
+	if (itf->stop)
+		itf->stop(closure, rc);
+	return rc;
+}
+
+int mustach_fd(const char *template, size_t length, const struct mustach_itf *itf, void *closure, int flags, int fd)
+{
+	int rc;
+	FILE *file;
+
+	file = fdopen(fd, "w");
+	if (file == NULL) {
+		rc = MUSTACH_ERROR_SYSTEM;
+		errno = ENOMEM;
+	} else {
+		rc = mustach_file(template, length, itf, closure, flags, file);
+		fclose(file);
+	}
+	return rc;
+}
+
+int mustach_mem(const char *template, size_t length, const struct mustach_itf *itf, void *closure, int flags, char **result, size_t *size)
+{
+	int rc;
+	FILE *file;
+	size_t s;
+
+	*result = NULL;
+	if (size == NULL)
+		size = &s;
+	file = memfile_open(result, size);
+	if (file == NULL)
+		rc = MUSTACH_ERROR_SYSTEM;
+	else {
+		rc = mustach_file(template, length, itf, closure, flags, file);
+		if (rc < 0)
+			memfile_abort(file, result, size);
+		else
+			rc = memfile_close(file, result, size);
+	}
+	return rc;
+}
+
+int fmustach(const char *template, const struct mustach_itf *itf, void *closure, FILE *file)
+{
+	return mustach_file(template, 0, itf, closure, Mustach_With_AllExtensions, file);
+}
+
+int fdmustach(const char *template, const struct mustach_itf *itf, void *closure, int fd)
+{
+	return mustach_fd(template, 0, itf, closure, Mustach_With_AllExtensions, fd);
+}
+
+int mustach(const char *template, const struct mustach_itf *itf, void *closure, char **result, size_t *size)
+{
+	return mustach_mem(template, 0, itf, closure, Mustach_With_AllExtensions, result, size);
+}
+