Implement function for formatting JSON values

* src/Make.am: Add jsonfmt.c
* src/json.h (json_format): New struct.
(json_format_value): New proto.
* src/jsonfmt.c: New file.
* tests/json.c: Use json_format_value.

4 files changed, 239 insertions, 169 deletions

diff --git a/src/Make.am b/src/Make.am
index 15e0075..e39a44a 100644
--- a/src/Make.am
+++ b/src/Make.am
@@ -40,7 +40,7 @@ if GRECS_COND_GIT_PARSER
 endif
 
 if GRECS_COND_JSON
-  GRECS_JSON = json-gram.y json-lex.l
+  GRECS_JSON = json-gram.y json-lex.l jsonfmt.c
   GRECS_EXTRA_JSON = json-gram.h
 endif
 
diff --git a/src/json.h b/src/json.h
index e089692..698d56b 100644
--- a/src/json.h
+++ b/src/json.h
@@ -65,4 +65,14 @@ struct json_value *json_parse_string(char const *input, size_t len);
 struct json_value *json_value_lookup(struct json_value *obj,
 				       const char *ident);
 
+
+struct json_format
+{
+	size_t indent;
+	int precision;
+	void (*write) (void *, char const *, size_t);
+	void *data;
+};
+
+void json_format_value(struct json_value *obj, struct json_format *fmt);
 
diff --git a/src/jsonfmt.c b/src/jsonfmt.c
new file mode 100644
index 0000000..75c8ac7
--- /dev/null
+++ b/src/jsonfmt.c
@@ -0,0 +1,216 @@
+/* grecs - Gray's Extensible Configuration System
+   Copyright (C) 2007-2012, 2015 Sergey Poznyakoff
+
+   Grecs 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 3 of the License, or (at your
+   option) any later version.
+
+   Grecs 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 Grecs. If not, see <http://www.gnu.org/licenses/>. */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+#include <string.h>
+#include "grecs.h"
+#include "json.h"
+
+static void
+json_writez(struct json_format *fmt, char const *str)
+{
+	size_t len = strlen(str);
+	fmt->write(fmt->data, str, len);
+}
+
+static void
+json_writec(struct json_format *fmt, char c)
+{
+	fmt->write(fmt->data, &c, 1);
+}
+
+static void
+json_indent(struct json_format *fmt, size_t level)
+{
+	level *= fmt->indent;
+	while (level--)
+		json_writec(fmt, ' ');
+}
+
+static void
+json_format_delim(struct json_format *fmt, size_t level)
+{
+	json_writec(fmt, ',');
+	if (fmt->indent) {
+		json_writec(fmt, '\n');
+		json_indent(fmt, level);
+	} else
+		json_writec(fmt, ' ');
+}
+
+static int
+escape(char c, char *o)
+{
+	static char transtab[] = "\\\\\"\"//b\bf\fn\nr\rt\t";
+	char *p;
+
+	for (p = transtab; *p; p += 2) {
+		if (p[1] == c) {
+			*o = p[0];
+			return 0;
+		}
+	}
+	return -1;
+}
+
+static void
+json_format_string(struct json_format *fmt, const char *s)
+{
+	json_writec(fmt, '"');
+	for (; *s; s++) {
+		char c;
+		if (!escape(*s, &c)) {
+			json_writec(fmt, '\\');
+			json_writec(fmt, c);
+		} else
+			json_writec(fmt, *s);
+	}
+	json_writec(fmt, '"');
+}
+
+static void
+json_format_number(struct json_format *fmt, double n)
+{
+	char *buffer = NULL;
+	size_t size = 0;
+	if (fmt->precision == -1) 
+		grecs_asprintf(&buffer, &size, "%e", n);
+	else
+		grecs_asprintf(&buffer, &size, "%.*f", fmt->precision, n);
+	json_writez(fmt, buffer);
+	free(buffer);
+}
+
+static int
+collect_keypairs(void *sym, void *data)
+{
+	struct json_pair *p = sym;
+	struct json_pair ***kp = data;
+	**kp = p;
+	++*kp;
+	return 0;
+}
+
+static void json_formatter(struct json_format *fmt, struct json_value *obj,
+			   size_t level);
+
+static int
+keypair_cmp_name(const void *a, const void *b)
+{
+	struct json_pair const * const *kpa = a;
+	struct json_pair const * const *kpb = b;
+	return strcmp((*kpa)->k, (*kpb)->k);
+}
+
+static void
+json_format_obj(struct json_format *fmt, struct json_value *obj, size_t level)
+{
+	size_t count, i;
+	struct json_pair **keypairs, **kp;
+	
+	count = grecs_symtab_count_entries(obj->v.o);
+	keypairs = grecs_calloc(count, sizeof(*keypairs));
+	kp = keypairs;
+	grecs_symtab_enumerate(obj->v.o, collect_keypairs, &kp);
+	qsort(keypairs, count, sizeof(*keypairs), keypair_cmp_name);
+
+	json_writec(fmt, '{');
+	if (count) {
+		if (fmt->indent)
+			json_writec(fmt, '\n');
+		for (i = 0; i < count; i++) {
+			(i ? json_format_delim : json_indent)(fmt, level);
+			json_format_string(fmt, keypairs[i]->k);
+			json_writec(fmt, ':');
+			if (fmt->indent)
+				json_writec(fmt, ' ');
+			json_formatter(fmt, keypairs[i]->v, level);
+		}
+		if (fmt->indent) {
+			json_writec(fmt, '\n');
+			json_indent(fmt, level-1);
+		}
+	}
+	json_writec(fmt, '}');
+}
+
+static void
+json_format_array(struct json_format *fmt, struct json_value *obj,
+		  size_t level)
+{
+	size_t i;
+
+	json_writec(fmt, '[');
+	if (obj->v.a->oc) {
+		if (fmt->indent)
+			json_writec(fmt, '\n');
+		for (i = 0; i < obj->v.a->oc; i++) {
+			(i ? json_format_delim : json_indent)(fmt, level);
+			json_formatter(fmt, obj->v.a->ov[i], level);
+		}
+		if (fmt->indent) {
+			json_writec(fmt, '\n');
+			json_indent(fmt, level-1);
+		}
+	}
+	json_writec(fmt, ']');
+}
+
+static void
+json_formatter(struct json_format *fmt, struct json_value *obj, size_t level)
+{
+	if (!obj) {
+		json_writez(fmt, "null");
+		return;
+	}
+
+	++level;
+	switch (obj->type) {
+	case json_null:
+		json_writez(fmt, "null");
+		break;
+		
+	case json_bool:
+		json_writez(fmt, obj->v.b ? "true" : "false");
+		break;
+		
+	case json_number:
+		json_format_number(fmt, obj->v.n);
+		break;
+
+	case json_string:
+		json_format_string(fmt, obj->v.s);
+		break;
+		
+	case json_arr:
+		json_format_array(fmt, obj, level);
+		break;
+
+	case json_object: 
+		json_format_obj(fmt, obj, level);
+		break;
+	}
+}		
+
+void
+json_format_value(struct json_value *obj, struct json_format *fmt)
+{
+	json_formatter(fmt, obj, 0);
+}
+
+
diff --git a/tests/json.c b/tests/json.c
index f2c2380..60e264c 100644
--- a/tests/json.c
+++ b/tests/json.c
@@ -25,9 +25,14 @@
 #include "grecs.h"
 #include "json.h"
 
-size_t indent;
-int pretty_print;
-int precision = -1;
+static void
+printer(void *d, char const *buf, size_t size)
+{
+	FILE *fp = d;
+	fwrite(buf, size, 1, fp);
+}
+
+struct json_format fmt = { 0, -1, printer, NULL };
 
 static void
 usage(const char *arg, FILE *fp, int code)
@@ -38,168 +43,6 @@ usage(const char *arg, FILE *fp, int code)
 	exit(code);
 }
 
-static void
-json_indent(FILE *fp, size_t level)
-{
-	level *= indent;
-	while (level--)
-		fputc(' ', fp);
-}
-
-static void
-json_format_delim(FILE *fp, size_t level)
-{
-	fputc(',', fp);
-	if (indent) {
-		fputc('\n', fp);
-		json_indent(fp, level);
-	} else
-		fputc(' ', fp);
-}
-
-static int
-escape(char c, char *o)
-{
-	static char transtab[] = "\\\\\"\"//b\bf\fn\nr\rt\t";
-	char *p;
-
-	for (p = transtab; *p; p += 2) {
-		if (p[1] == c) {
-			*o = p[0];
-			return 0;
-		}
-	}
-	return -1;
-}
-
-static void
-json_format_string(FILE *fp, const char *s)
-{
-	fputc('"', fp);
-	for (; *s; s++) {
-		char c;
-		if (!escape(*s, &c)) {
-			fputc('\\', fp);
-			fputc(c, fp);
-		} else
-			fputc(*s, fp);
-	}
-	fputc('"', fp);
-}
-
-static int
-collect_keypairs(void *sym, void *data)
-{
-	struct json_pair *p = sym;
-	struct json_pair ***kp = data;
-	**kp = p;
-	++*kp;
-	return 0;
-}
-
-static void json_format_value(FILE *fp, struct json_value *obj, size_t level);
-
-static int
-keypair_cmp_name(const void *a, const void *b)
-{
-	struct json_pair const * const *kpa = a;
-	struct json_pair const * const *kpb = b;
-	return strcmp((*kpa)->k, (*kpb)->k);
-}
-
-static void
-json_format_obj(FILE *fp, struct json_value *obj, size_t level)
-{
-	size_t count, i;
-	struct json_pair **keypairs, **kp;
-	
-	count = grecs_symtab_count_entries(obj->v.o);
-	keypairs = grecs_calloc(count, sizeof(*keypairs));
-	kp = keypairs;
-	grecs_symtab_enumerate(obj->v.o, collect_keypairs, &kp);
-	qsort(keypairs, count, sizeof(*keypairs), keypair_cmp_name);
-
-	fputc('{', fp);
-	if (count) {
-		if (indent)
-			fputc('\n', fp);
-		for (i = 0; i < count; i++) {
-			(i ? json_format_delim : json_indent)(fp, level);
-			json_format_string(fp, keypairs[i]->k);
-			fputc(':', fp);
-			if (indent)
-				fputc(' ', fp);
-			json_format_value(fp, keypairs[i]->v, level);
-		}
-		if (indent) {
-			fputc('\n', fp);
-			json_indent(fp, level-1);
-		}
-	}
-	fputc('}', fp);
-}
-
-static void
-json_format_array(FILE *fp, struct json_value *obj, size_t level)
-{
-	size_t i;
-
-	fputc('[', fp);
-	if (obj->v.a->oc) {
-		if (indent)
-			fputc('\n', fp);
-		for (i = 0; i < obj->v.a->oc; i++) {
-			(i ? json_format_delim : json_indent)(fp, level);
-			json_format_value(fp, obj->v.a->ov[i], level);
-		}
-		if (indent) {
-			fputc('\n', fp);
-			json_indent(fp, level-1);
-		}
-	}
-	fputc(']', fp);
-}
-
-static void
-json_format_value(FILE *fp, struct json_value *obj, size_t level)
-{
-	if (!obj) {
-		fprintf(fp, "null");
-		return;
-	}
-
-	++level;
-	switch (obj->type) {
-	case json_null:
-		fprintf(fp, "null");
-		break;
-		
-	case json_bool:
-		fprintf(fp, "%s", obj->v.b ? "true" : "false");
-		break;
-		
-	case json_number:
-		if (precision == -1) 
-			fprintf(fp, "%e", obj->v.n);
-		else
-			fprintf(fp, "%.*f", precision, obj->v.n);
-		break;
-
-	case json_string:
-		json_format_string(fp, obj->v.s);
-		break;
-		
-	case json_arr:
-		json_format_array(fp, obj, level);
-		break;
-
-	case json_object: 
-		json_format_obj(fp, obj, level);
-		break;
-	}
-}		
-	
-
 int
 main(int argc, char **argv)
 {
@@ -215,11 +58,11 @@ main(int argc, char **argv)
 		if (strncmp(arg, "-file=", 6) == 0)
 			file = arg + 6;
 		else if (strncmp(arg, "-indent=", 8) == 0)
-			indent = atoi(arg + 8);
+			fmt.indent = atoi(arg + 8);
 		else if (strncmp(arg, "-search=", 8) == 0)
 			key = arg + 8;
 		else if (strncmp(arg, "-precision=", 11) == 0)
-			precision = atoi(arg + 11);
+			fmt.precision = atoi(arg + 11);
 		else if (arg[0] == '-')
 			usage(progname, stderr, 1);
 		else
@@ -280,7 +123,8 @@ main(int argc, char **argv)
 			return 4;
 		obj = p;
 	}
-	json_format_value(stdout, obj, 0);
+	fmt.data = stdout;
+	json_format_value(obj, &fmt);
 	putchar('\n');
 	return 0;
 }