diff --git a/Makefile.in b/Makefile.in
index c7053639..675e4cb6 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -186,6 +186,7 @@ TESTS_UNIT := \
 	$(srcroot)test/unit/size_classes.c \
 	$(srcroot)test/unit/smoothstep.c \
 	$(srcroot)test/unit/stats.c \
+	$(srcroot)test/unit/stats_print.c \
 	$(srcroot)test/unit/ticker.c \
 	$(srcroot)test/unit/nstime.c \
 	$(srcroot)test/unit/tsd.c \
diff --git a/src/stats.c b/src/stats.c
index 6b71158b..8d579c7b 100644
--- a/src/stats.c
+++ b/src/stats.c
@@ -39,7 +39,7 @@ stats_arena_bins_print(void (*write_cb)(void *, const char *), void *cbopaque,
     bool json, bool large, bool huge, unsigned i)
 {
 	size_t page;
-	bool config_tcache, in_gap, in_gap_prev;
+	bool in_gap, in_gap_prev;
 	unsigned nbins, j;
 
 	CTL_GET("arenas.page", &page, size_t);
@@ -49,7 +49,6 @@ stats_arena_bins_print(void (*write_cb)(void *, const char *), void *cbopaque,
 		malloc_cprintf(write_cb, cbopaque,
 		    "\t\t\t\t\"bins\": [\n");
 	} else {
-		CTL_GET("config.tcache", &config_tcache, bool);
 		if (config_tcache) {
 			malloc_cprintf(write_cb, cbopaque,
 			    "bins:           size ind    allocated      nmalloc"
@@ -536,7 +535,7 @@ stats_arena_print(void (*write_cb)(void *, const char *), void *cbopaque,
 		    "\t\t\t\t\t\"allocated\": %zu\n", metadata_allocated);
 
 		malloc_cprintf(write_cb, cbopaque,
-		    "\t\t\t\t},\n");
+		    "\t\t\t\t}%s\n", (bins || large || huge) ? "," : "");
 	} else {
 		malloc_cprintf(write_cb, cbopaque,
 		    "metadata: mapped: %zu, allocated: %zu\n",
@@ -838,9 +837,11 @@ stats_general_print(void (*write_cb)(void *, const char *), void *cbopaque,
 		malloc_cprintf(write_cb, cbopaque,
 		    "\t\t\t\"nbins\": %u,\n", nbins);
 
-		CTL_GET("arenas.nhbins", &uv, unsigned);
-		malloc_cprintf(write_cb, cbopaque,
-		    "\t\t\t\"nhbins\": %u,\n", uv);
+		if (config_tcache) {
+			CTL_GET("arenas.nhbins", &uv, unsigned);
+			malloc_cprintf(write_cb, cbopaque,
+			    "\t\t\t\"nhbins\": %u,\n", uv);
+		}
 
 		malloc_cprintf(write_cb, cbopaque,
 		    "\t\t\t\"bin\": [\n");
@@ -1022,31 +1023,37 @@ stats_print_helper(void (*write_cb)(void *, const char *), void *cbopaque,
 				    narenas, bins, large, huge);
 				if (json) {
 					malloc_cprintf(write_cb, cbopaque,
-					    "\t\t\t}%s\n", (ninitialized > 1) ?
-					    "," : "");
+					    "\t\t\t}%s\n", unmerged ?  "," :
+					    "");
 				}
 			}
 
 			/* Unmerged stats. */
-			for (i = j = 0; i < narenas; i++) {
-				if (initialized[i]) {
-					if (json) {
-						j++;
-						malloc_cprintf(write_cb,
-						    cbopaque,
-						    "\t\t\t\"%u\": {\n", i);
-					} else {
-						malloc_cprintf(write_cb,
-						    cbopaque, "\narenas[%u]:\n",
-						    i);
-					}
-					stats_arena_print(write_cb, cbopaque,
-					    json, i, bins, large, huge);
-					if (json) {
-						malloc_cprintf(write_cb,
-						    cbopaque,
-						    "\t\t\t}%s\n", (j <
-						    ninitialized) ? "," : "");
+			if (unmerged) {
+				for (i = j = 0; i < narenas; i++) {
+					if (initialized[i]) {
+						if (json) {
+							j++;
+							malloc_cprintf(write_cb,
+							    cbopaque,
+							    "\t\t\t\"%u\": {\n",
+							    i);
+						} else {
+							malloc_cprintf(write_cb,
+							    cbopaque,
+							    "\narenas[%u]:\n",
+							    i);
+						}
+						stats_arena_print(write_cb,
+						    cbopaque, json, i, bins,
+						    large, huge);
+						if (json) {
+							malloc_cprintf(write_cb,
+							    cbopaque,
+							    "\t\t\t}%s\n", (j <
+							    ninitialized) ? ","
+							    : "");
+						}
 					}
 				}
 			}
diff --git a/test/unit/stats_print.c b/test/unit/stats_print.c
new file mode 100644
index 00000000..91cfdf2d
--- /dev/null
+++ b/test/unit/stats_print.c
@@ -0,0 +1,1000 @@
+#include "test/jemalloc_test.h"
+
+typedef enum {
+	TOKEN_TYPE_NONE,
+	TOKEN_TYPE_ERROR,
+	TOKEN_TYPE_EOI,
+	TOKEN_TYPE_NULL,
+	TOKEN_TYPE_FALSE,
+	TOKEN_TYPE_TRUE,
+	TOKEN_TYPE_LBRACKET,
+	TOKEN_TYPE_RBRACKET,
+	TOKEN_TYPE_LBRACE,
+	TOKEN_TYPE_RBRACE,
+	TOKEN_TYPE_COLON,
+	TOKEN_TYPE_COMMA,
+	TOKEN_TYPE_STRING,
+	TOKEN_TYPE_NUMBER
+} token_type_t;
+
+typedef struct parser_s parser_t;
+typedef struct {
+	parser_t	*parser;
+	token_type_t	token_type;
+	size_t		pos;
+	size_t		len;
+	size_t		line;
+	size_t		col;
+} token_t;
+
+struct parser_s {
+	bool verbose;
+	char	*buf; /* '\0'-terminated. */
+	size_t	len; /* Number of characters preceding '\0' in buf. */
+	size_t	pos;
+	size_t	line;
+	size_t	col;
+	token_t	token;
+};
+
+static void
+token_init(token_t *token, parser_t *parser, token_type_t token_type,
+    size_t pos, size_t len, size_t line, size_t col)
+{
+	token->parser = parser;
+	token->token_type = token_type;
+	token->pos = pos;
+	token->len = len;
+	token->line = line;
+	token->col = col;
+}
+
+static void
+token_error(token_t *token)
+{
+	if (!token->parser->verbose) {
+		return;
+	}
+	switch (token->token_type) {
+	case TOKEN_TYPE_NONE:
+		not_reached();
+	case TOKEN_TYPE_ERROR:
+		malloc_printf("%zu:%zu: Unexpected character in token: ",
+		    token->line, token->col);
+		break;
+	default:
+		malloc_printf("%zu:%zu: Unexpected token: ", token->line,
+		    token->col);
+		break;
+	}
+	write(STDERR_FILENO, &token->parser->buf[token->pos], token->len);
+	malloc_printf("\n");
+}
+
+static void
+parser_init(parser_t *parser, bool verbose)
+{
+	parser->verbose = verbose;
+	parser->buf = NULL;
+	parser->len = 0;
+	parser->pos = 0;
+	parser->line = 1;
+	parser->col = 0;
+}
+
+static void
+parser_fini(parser_t *parser)
+{
+	if (parser->buf != NULL) {
+		dallocx(parser->buf, MALLOCX_TCACHE_NONE);
+	}
+}
+
+static bool
+parser_append(parser_t *parser, const char *str)
+{
+	size_t len = strlen(str);
+	char *buf = (parser->buf == NULL) ? mallocx(len + 1,
+	    MALLOCX_TCACHE_NONE) : rallocx(parser->buf, parser->len + len + 1,
+	    MALLOCX_TCACHE_NONE);
+	if (buf == NULL) {
+		return true;
+	}
+	memcpy(&buf[parser->len], str, len + 1);
+	parser->buf = buf;
+	parser->len += len;
+	return false;
+}
+
+static bool
+parser_tokenize(parser_t *parser)
+{
+	enum {
+		STATE_START,
+		STATE_EOI,
+		STATE_N, STATE_NU, STATE_NUL, STATE_NULL,
+		STATE_F, STATE_FA, STATE_FAL, STATE_FALS, STATE_FALSE,
+		STATE_T, STATE_TR, STATE_TRU, STATE_TRUE,
+		STATE_LBRACKET,
+		STATE_RBRACKET,
+		STATE_LBRACE,
+		STATE_RBRACE,
+		STATE_COLON,
+		STATE_COMMA,
+		STATE_CHARS,
+		STATE_CHAR_ESCAPE,
+		STATE_CHAR_U, STATE_CHAR_UD, STATE_CHAR_UDD, STATE_CHAR_UDDD,
+		STATE_STRING,
+		STATE_MINUS,
+		STATE_LEADING_ZERO,
+		STATE_DIGITS,
+		STATE_DECIMAL,
+		STATE_FRAC_DIGITS,
+		STATE_EXP,
+		STATE_EXP_SIGN,
+		STATE_EXP_DIGITS,
+		STATE_ACCEPT
+	} state = STATE_START;
+	size_t token_pos, token_line, token_col;
+
+	assert_zu_le(parser->pos, parser->len,
+	    "Position is past end of buffer");
+
+	while (state != STATE_ACCEPT) {
+		char c = parser->buf[parser->pos];
+
+		switch (state) {
+		case STATE_START:
+			token_pos = parser->pos;
+			token_line = parser->line;
+			token_col = parser->col;
+			switch (c) {
+			case ' ': case '\b': case '\n': case '\r': case '\t':
+				break;
+			case '\0':
+				state = STATE_EOI;
+				break;
+			case 'n':
+				state = STATE_N;
+				break;
+			case 'f':
+				state = STATE_F;
+				break;
+			case 't':
+				state = STATE_T;
+				break;
+			case '[':
+				state = STATE_LBRACKET;
+				break;
+			case ']':
+				state = STATE_RBRACKET;
+				break;
+			case '{':
+				state = STATE_LBRACE;
+				break;
+			case '}':
+				state = STATE_RBRACE;
+				break;
+			case ':':
+				state = STATE_COLON;
+				break;
+			case ',':
+				state = STATE_COMMA;
+				break;
+			case '"':
+				state = STATE_CHARS;
+				break;
+			case '-':
+				state = STATE_MINUS;
+				break;
+			case '0':
+				state = STATE_LEADING_ZERO;
+				break;
+			case '1': case '2': case '3': case '4':
+			case '5': case '6': case '7': case '8': case '9':
+				state = STATE_DIGITS;
+				break;
+			default:
+				token_init(&parser->token, parser,
+				    TOKEN_TYPE_ERROR, token_pos, parser->pos + 1
+				    - token_pos, token_line, token_col);
+				return true;
+			}
+			break;
+		case STATE_EOI:
+			token_init(&parser->token, parser,
+			    TOKEN_TYPE_EOI, token_pos, parser->pos -
+			    token_pos, token_line, token_col);
+			state = STATE_ACCEPT;
+			break;
+		case STATE_N:
+			switch (c) {
+			case 'u':
+				state = STATE_NU;
+				break;
+			default:
+				token_init(&parser->token, parser,
+				    TOKEN_TYPE_ERROR, token_pos, parser->pos + 1
+				    - token_pos, token_line, token_col);
+				return true;
+			}
+			break;
+		case STATE_NU:
+			switch (c) {
+			case 'l':
+				state = STATE_NUL;
+				break;
+			default:
+				token_init(&parser->token, parser,
+				    TOKEN_TYPE_ERROR, token_pos, parser->pos + 1
+				    - token_pos, token_line, token_col);
+				return true;
+			}
+			break;
+		case STATE_NUL:
+			switch (c) {
+			case 'l':
+				state = STATE_NULL;
+				break;
+			default:
+				token_init(&parser->token, parser,
+				    TOKEN_TYPE_ERROR, token_pos, parser->pos + 1
+				    - token_pos, token_line, token_col);
+				return true;
+			}
+			break;
+		case STATE_NULL:
+			switch (c) {
+			case ' ': case '\b': case '\n': case '\r': case '\t':
+			case '\0':
+			case '[': case ']': case '{': case '}': case ':':
+			case ',':
+				break;
+			default:
+				token_init(&parser->token, parser,
+				    TOKEN_TYPE_ERROR, token_pos, parser->pos + 1
+				    - token_pos, token_line, token_col);
+				return true;
+			}
+			token_init(&parser->token, parser, TOKEN_TYPE_NULL,
+			    token_pos, parser->pos - token_pos, token_line,
+			    token_col);
+			state = STATE_ACCEPT;
+			break;
+		case STATE_F:
+			switch (c) {
+			case 'a':
+				state = STATE_FA;
+				break;
+			default:
+				token_init(&parser->token, parser,
+				    TOKEN_TYPE_ERROR, token_pos, parser->pos + 1
+				    - token_pos, token_line, token_col);
+				return true;
+			}
+			break;
+		case STATE_FA:
+			switch (c) {
+			case 'l':
+				state = STATE_FAL;
+				break;
+			default:
+				token_init(&parser->token, parser,
+				    TOKEN_TYPE_ERROR, token_pos, parser->pos + 1
+				    - token_pos, token_line, token_col);
+				return true;
+			}
+			break;
+		case STATE_FAL:
+			switch (c) {
+			case 's':
+				state = STATE_FALS;
+				break;
+			default:
+				token_init(&parser->token, parser,
+				    TOKEN_TYPE_ERROR, token_pos, parser->pos + 1
+				    - token_pos, token_line, token_col);
+				return true;
+			}
+			break;
+		case STATE_FALS:
+			switch (c) {
+			case 'e':
+				state = STATE_FALSE;
+				break;
+			default:
+				token_init(&parser->token, parser,
+				    TOKEN_TYPE_ERROR, token_pos, parser->pos + 1
+				    - token_pos, token_line, token_col);
+				return true;
+			}
+			break;
+		case STATE_FALSE:
+			switch (c) {
+			case ' ': case '\b': case '\n': case '\r': case '\t':
+			case '\0':
+			case '[': case ']': case '{': case '}': case ':':
+			case ',':
+				break;
+			default:
+				token_init(&parser->token, parser,
+				    TOKEN_TYPE_ERROR, token_pos, parser->pos + 1
+				    - token_pos, token_line, token_col);
+				return true;
+			}
+			token_init(&parser->token, parser,
+			    TOKEN_TYPE_FALSE, token_pos, parser->pos -
+			    token_pos, token_line, token_col);
+			state = STATE_ACCEPT;
+			break;
+		case STATE_T:
+			switch (c) {
+			case 'r':
+				state = STATE_TR;
+				break;
+			default:
+				token_init(&parser->token, parser,
+				    TOKEN_TYPE_ERROR, token_pos, parser->pos + 1
+				    - token_pos, token_line, token_col);
+				return true;
+			}
+			break;
+		case STATE_TR:
+			switch (c) {
+			case 'u':
+				state = STATE_TRU;
+				break;
+			default:
+				token_init(&parser->token, parser,
+				    TOKEN_TYPE_ERROR, token_pos, parser->pos + 1
+				    - token_pos, token_line, token_col);
+				return true;
+			}
+			break;
+		case STATE_TRU:
+			switch (c) {
+			case 'e':
+				state = STATE_TRUE;
+				break;
+			default:
+				token_init(&parser->token, parser,
+				    TOKEN_TYPE_ERROR, token_pos, parser->pos + 1
+				    - token_pos, token_line, token_col);
+				return true;
+			}
+			break;
+		case STATE_TRUE:
+			switch (c) {
+			case ' ': case '\b': case '\n': case '\r': case '\t':
+			case '\0':
+			case '[': case ']': case '{': case '}': case ':':
+			case ',':
+				break;
+			default:
+				token_init(&parser->token, parser,
+				    TOKEN_TYPE_ERROR, token_pos, parser->pos + 1
+				    - token_pos, token_line, token_col);
+				return true;
+			}
+			token_init(&parser->token, parser, TOKEN_TYPE_TRUE,
+			    token_pos, parser->pos - token_pos, token_line,
+			    token_col);
+			state = STATE_ACCEPT;
+			break;
+		case STATE_LBRACKET:
+			token_init(&parser->token, parser, TOKEN_TYPE_LBRACKET,
+			    token_pos, parser->pos - token_pos, token_line,
+			    token_col);
+			state = STATE_ACCEPT;
+			break;
+		case STATE_RBRACKET:
+			token_init(&parser->token, parser, TOKEN_TYPE_RBRACKET,
+			    token_pos, parser->pos - token_pos, token_line,
+			    token_col);
+			state = STATE_ACCEPT;
+			break;
+		case STATE_LBRACE:
+			token_init(&parser->token, parser, TOKEN_TYPE_LBRACE,
+			    token_pos, parser->pos - token_pos, token_line,
+			    token_col);
+			state = STATE_ACCEPT;
+			break;
+		case STATE_RBRACE:
+			token_init(&parser->token, parser, TOKEN_TYPE_RBRACE,
+			    token_pos, parser->pos - token_pos, token_line,
+			    token_col);
+			state = STATE_ACCEPT;
+			break;
+		case STATE_COLON:
+			token_init(&parser->token, parser, TOKEN_TYPE_COLON,
+			    token_pos, parser->pos - token_pos, token_line,
+			    token_col);
+			state = STATE_ACCEPT;
+			break;
+		case STATE_COMMA:
+			token_init(&parser->token, parser, TOKEN_TYPE_COMMA,
+			    token_pos, parser->pos - token_pos, token_line,
+			    token_col);
+			state = STATE_ACCEPT;
+			break;
+		case STATE_CHARS:
+			switch (c) {
+			case '\\':
+				state = STATE_CHAR_ESCAPE;
+				break;
+			case '"':
+				state = STATE_STRING;
+				break;
+			case 0x00: case 0x01: case 0x02: case 0x03: case 0x04:
+			case 0x05: case 0x06: case 0x07: case 0x08: case 0x09:
+			case 0x0a: case 0x0b: case 0x0c: case 0x0d: case 0x0e:
+			case 0x0f: case 0x10: case 0x11: case 0x12: case 0x13:
+			case 0x14: case 0x15: case 0x16: case 0x17: case 0x18:
+			case 0x19: case 0x1a: case 0x1b: case 0x1c: case 0x1d:
+			case 0x1e: case 0x1f:
+				token_init(&parser->token, parser,
+				    TOKEN_TYPE_ERROR, token_pos, parser->pos + 1
+				    - token_pos, token_line, token_col);
+				return true;
+			default:
+				break;
+			}
+			break;
+		case STATE_CHAR_ESCAPE:
+			switch (c) {
+			case '"': case '\\': case '/': case 'b': case 'n':
+			case 'r': case 't':
+				state = STATE_CHARS;
+				break;
+			case 'u':
+				state = STATE_CHAR_U;
+				break;
+			default:
+				token_init(&parser->token, parser,
+				    TOKEN_TYPE_ERROR, token_pos, parser->pos + 1
+				    - token_pos, token_line, token_col);
+				return true;
+			}
+			break;
+		case STATE_CHAR_U:
+			switch (c) {
+			case '0': case '1': case '2': case '3': case '4':
+			case '5': case '6': case '7': case '8': case '9':
+			case 'a': case 'b': case 'c': case 'd': case 'e':
+			case 'f':
+			case 'A': case 'B': case 'C': case 'D': case 'E':
+			case 'F':
+				state = STATE_CHAR_UD;
+				break;
+			default:
+				token_init(&parser->token, parser,
+				    TOKEN_TYPE_ERROR, token_pos, parser->pos + 1
+				    - token_pos, token_line, token_col);
+				return true;
+			}
+			break;
+		case STATE_CHAR_UD:
+			switch (c) {
+			case '0': case '1': case '2': case '3': case '4':
+			case '5': case '6': case '7': case '8': case '9':
+			case 'a': case 'b': case 'c': case 'd': case 'e':
+			case 'f':
+			case 'A': case 'B': case 'C': case 'D': case 'E':
+			case 'F':
+				state = STATE_CHAR_UDD;
+				break;
+			default:
+				token_init(&parser->token, parser,
+				    TOKEN_TYPE_ERROR, token_pos, parser->pos + 1
+				    - token_pos, token_line, token_col);
+				return true;
+			}
+			break;
+		case STATE_CHAR_UDD:
+			switch (c) {
+			case '0': case '1': case '2': case '3': case '4':
+			case '5': case '6': case '7': case '8': case '9':
+			case 'a': case 'b': case 'c': case 'd': case 'e':
+			case 'f':
+			case 'A': case 'B': case 'C': case 'D': case 'E':
+			case 'F':
+				state = STATE_CHAR_UDDD;
+				break;
+			default:
+				token_init(&parser->token, parser,
+				    TOKEN_TYPE_ERROR, token_pos, parser->pos + 1
+				    - token_pos, token_line, token_col);
+				return true;
+			}
+			break;
+		case STATE_CHAR_UDDD:
+			switch (c) {
+			case '0': case '1': case '2': case '3': case '4':
+			case '5': case '6': case '7': case '8': case '9':
+			case 'a': case 'b': case 'c': case 'd': case 'e':
+			case 'f':
+			case 'A': case 'B': case 'C': case 'D': case 'E':
+			case 'F':
+				state = STATE_CHARS;
+				break;
+			default:
+				token_init(&parser->token, parser,
+				    TOKEN_TYPE_ERROR, token_pos, parser->pos + 1
+				    - token_pos, token_line, token_col);
+				return true;
+			}
+			break;
+		case STATE_STRING:
+			token_init(&parser->token, parser, TOKEN_TYPE_STRING,
+			    token_pos, parser->pos - token_pos, token_line,
+			    token_col);
+			state = STATE_ACCEPT;
+			break;
+		case STATE_MINUS:
+			switch (c) {
+			case '0':
+				state = STATE_LEADING_ZERO;
+				break;
+			case '1': case '2': case '3': case '4':
+			case '5': case '6': case '7': case '8': case '9':
+				state = STATE_DIGITS;
+				break;
+			default:
+				token_init(&parser->token, parser,
+				    TOKEN_TYPE_ERROR, token_pos, parser->pos + 1
+				    - token_pos, token_line, token_col);
+				return true;
+			}
+			break;
+		case STATE_LEADING_ZERO:
+			switch (c) {
+			case '.':
+				state = STATE_DECIMAL;
+				break;
+			default:
+				token_init(&parser->token, parser,
+				    TOKEN_TYPE_NUMBER, token_pos, parser->pos -
+				    token_pos, token_line, token_col);
+				state = STATE_ACCEPT;
+				break;
+			}
+			break;
+		case STATE_DIGITS:
+			switch (c) {
+			case '0': case '1': case '2': case '3': case '4':
+			case '5': case '6': case '7': case '8': case '9':
+				break;
+			case '.':
+				state = STATE_DECIMAL;
+				break;
+			default:
+				token_init(&parser->token, parser,
+				    TOKEN_TYPE_NUMBER, token_pos, parser->pos -
+				    token_pos, token_line, token_col);
+				state = STATE_ACCEPT;
+				break;
+			}
+			break;
+		case STATE_DECIMAL:
+			switch (c) {
+			case '0': case '1': case '2': case '3': case '4':
+			case '5': case '6': case '7': case '8': case '9':
+				state = STATE_FRAC_DIGITS;
+				break;
+			default:
+				token_init(&parser->token, parser,
+				    TOKEN_TYPE_ERROR, token_pos, parser->pos + 1
+				    - token_pos, token_line, token_col);
+				return true;
+			}
+			break;
+		case STATE_FRAC_DIGITS:
+			switch (c) {
+			case '0': case '1': case '2': case '3': case '4':
+			case '5': case '6': case '7': case '8': case '9':
+				break;
+			case 'e': case 'E':
+				state = STATE_EXP;
+				break;
+			default:
+				token_init(&parser->token, parser,
+				    TOKEN_TYPE_NUMBER, token_pos, parser->pos -
+				    token_pos, token_line, token_col);
+				state = STATE_ACCEPT;
+				break;
+			}
+			break;
+		case STATE_EXP:
+			switch (c) {
+			case '-': case '+':
+				state = STATE_EXP_SIGN;
+				break;
+			case '0': case '1': case '2': case '3': case '4':
+			case '5': case '6': case '7': case '8': case '9':
+				state = STATE_EXP_DIGITS;
+				break;
+			default:
+				token_init(&parser->token, parser,
+				    TOKEN_TYPE_ERROR, token_pos, parser->pos + 1
+				    - token_pos, token_line, token_col);
+				return true;
+			}
+			break;
+		case STATE_EXP_SIGN:
+			switch (c) {
+			case '0': case '1': case '2': case '3': case '4':
+			case '5': case '6': case '7': case '8': case '9':
+				state = STATE_EXP_DIGITS;
+				break;
+			default:
+				token_init(&parser->token, parser,
+				    TOKEN_TYPE_ERROR, token_pos, parser->pos + 1
+				    - token_pos, token_line, token_col);
+				return true;
+			}
+			break;
+		case STATE_EXP_DIGITS:
+			switch (c) {
+			case '0': case '1': case '2': case '3': case '4':
+			case '5': case '6': case '7': case '8': case '9':
+				break;
+			default:
+				token_init(&parser->token, parser,
+				    TOKEN_TYPE_NUMBER, token_pos, parser->pos -
+				    token_pos, token_line, token_col);
+				state = STATE_ACCEPT;
+				break;
+			}
+			break;
+		default:
+			not_reached();
+		}
+
+		if (state != STATE_ACCEPT) {
+			if (c == '\n') {
+				parser->line++;
+				parser->col = 0;
+			} else {
+				parser->col++;
+			}
+			parser->pos++;
+		}
+	}
+	return false;
+}
+
+static bool	parser_parse_array(parser_t *parser);
+static bool	parser_parse_object(parser_t *parser);
+
+static bool
+parser_parse_value(parser_t *parser)
+{
+	switch (parser->token.token_type) {
+	case TOKEN_TYPE_NULL:
+	case TOKEN_TYPE_FALSE:
+	case TOKEN_TYPE_TRUE:
+	case TOKEN_TYPE_STRING:
+	case TOKEN_TYPE_NUMBER:
+		return false;
+	case TOKEN_TYPE_LBRACE:
+		return parser_parse_object(parser);
+	case TOKEN_TYPE_LBRACKET:
+		return parser_parse_array(parser);
+	default:
+		return true;
+	}
+	not_reached();
+}
+
+static bool
+parser_parse_pair(parser_t *parser)
+{
+	assert_d_eq(parser->token.token_type, TOKEN_TYPE_STRING,
+	    "Pair should start with string");
+	if (parser_tokenize(parser)) {
+		return true;
+	}
+	switch (parser->token.token_type) {
+	case TOKEN_TYPE_COLON:
+		if (parser_tokenize(parser)) {
+			return true;
+		}
+		return parser_parse_value(parser);
+	default:
+		return true;
+	}
+}
+
+static bool
+parser_parse_values(parser_t *parser)
+{
+	if (parser_parse_value(parser)) {
+		return true;
+	}
+
+	while (true) {
+		if (parser_tokenize(parser)) {
+			return true;
+		}
+		switch (parser->token.token_type) {
+		case TOKEN_TYPE_COMMA:
+			if (parser_tokenize(parser)) {
+				return true;
+			}
+			if (parser_parse_value(parser)) {
+				return true;
+			}
+			break;
+		case TOKEN_TYPE_RBRACKET:
+			return false;
+		default:
+			return true;
+		}
+	}
+}
+
+static bool
+parser_parse_array(parser_t *parser)
+{
+	assert_d_eq(parser->token.token_type, TOKEN_TYPE_LBRACKET,
+	    "Array should start with [");
+	if (parser_tokenize(parser)) {
+		return true;
+	}
+	switch (parser->token.token_type) {
+	case TOKEN_TYPE_RBRACKET:
+		return false;
+	default:
+		return parser_parse_values(parser);
+	}
+	not_reached();
+}
+
+static bool
+parser_parse_pairs(parser_t *parser)
+{
+	assert_d_eq(parser->token.token_type, TOKEN_TYPE_STRING,
+	    "Object should start with string");
+	if (parser_parse_pair(parser)) {
+		return true;
+	}
+
+	while (true) {
+		if (parser_tokenize(parser)) {
+			return true;
+		}
+		switch (parser->token.token_type) {
+		case TOKEN_TYPE_COMMA:
+			if (parser_tokenize(parser)) {
+				return true;
+			}
+			switch (parser->token.token_type) {
+			case TOKEN_TYPE_STRING:
+				if (parser_parse_pair(parser)) {
+					return true;
+				}
+				break;
+			default:
+				return true;
+			}
+			break;
+		case TOKEN_TYPE_RBRACE:
+			return false;
+		default:
+			return true;
+		}
+	}
+}
+
+static bool
+parser_parse_object(parser_t *parser)
+{
+	assert_d_eq(parser->token.token_type, TOKEN_TYPE_LBRACE,
+	    "Object should start with {");
+	if (parser_tokenize(parser)) {
+		return true;
+	}
+	switch (parser->token.token_type) {
+	case TOKEN_TYPE_STRING:
+		return parser_parse_pairs(parser);
+	case TOKEN_TYPE_RBRACE:
+		return false;
+	default:
+		return true;
+	}
+	not_reached();
+}
+
+static bool
+parser_parse(parser_t *parser)
+{
+	if (parser_tokenize(parser)) {
+		goto label_error;
+	}
+	if (parser_parse_value(parser)) {
+		goto label_error;
+	}
+
+	if (parser_tokenize(parser)) {
+		goto label_error;
+	}
+	switch (parser->token.token_type) {
+	case TOKEN_TYPE_EOI:
+		return false;
+	default:
+		goto label_error;
+	}
+	not_reached();
+
+label_error:
+	token_error(&parser->token);
+	return true;
+}
+
+TEST_BEGIN(test_json_parser)
+{
+	size_t i;
+	const char *invalid_inputs[] = {
+		/* Tokenizer error case tests. */
+		"{ \"string\": X }",
+		"{ \"string\": nXll }",
+		"{ \"string\": nuXl }",
+		"{ \"string\": nulX }",
+		"{ \"string\": nullX }",
+		"{ \"string\": fXlse }",
+		"{ \"string\": faXse }",
+		"{ \"string\": falXe }",
+		"{ \"string\": falsX }",
+		"{ \"string\": falseX }",
+		"{ \"string\": tXue }",
+		"{ \"string\": trXe }",
+		"{ \"string\": truX }",
+		"{ \"string\": trueX }",
+		"{ \"string\": \"\n\" }",
+		"{ \"string\": \"\\z\" }",
+		"{ \"string\": \"\\uX000\" }",
+		"{ \"string\": \"\\u0X00\" }",
+		"{ \"string\": \"\\u00X0\" }",
+		"{ \"string\": \"\\u000X\" }",
+		"{ \"string\": -X }",
+		"{ \"string\": 0.X }",
+		"{ \"string\": 0.0eX }",
+		"{ \"string\": 0.0e+X }",
+
+		/* Parser error test cases. */
+		"{\"string\": }",
+		"{\"string\" }",
+		"{\"string\": [ 0 }",
+		"{\"string\": {\"a\":0, 1 } }",
+		"{\"string\": {\"a\":0: } }",
+		"{",
+		"{}{",
+	};
+	const char *valid_inputs[] = {
+		/* Token tests. */
+		"null",
+		"false",
+		"true",
+		"{}",
+		"{\"a\": 0}",
+		"[]",
+		"[0, 1]",
+		"0",
+		"1",
+		"10",
+		"-10",
+		"10.23",
+		"10.23e4",
+		"10.23e-4",
+		"10.23e+4",
+		"10.23E4",
+		"10.23E-4",
+		"10.23E+4",
+		"-10.23",
+		"-10.23e4",
+		"-10.23e-4",
+		"-10.23e+4",
+		"-10.23E4",
+		"-10.23E-4",
+		"-10.23E+4",
+		"\"value\"",
+		"\" \\\" \\/ \\b \\n \\r \\t \\u0abc \\u1DEF \"",
+
+		/* Parser test with various nesting. */
+		"{\"a\":null, \"b\":[1,[{\"c\":2},3]], \"d\":{\"e\":true}}",
+	};
+
+	for (i = 0; i < sizeof(invalid_inputs)/sizeof(const char *); i++) {
+		const char *input = invalid_inputs[i];
+		parser_t parser;
+		parser_init(&parser, false);
+		assert_false(parser_append(&parser, input),
+		    "Unexpected input appending failure");
+		assert_true(parser_parse(&parser),
+		    "Unexpected parse success for input: %s", input);
+		parser_fini(&parser);
+	}
+
+	for (i = 0; i < sizeof(valid_inputs)/sizeof(const char *); i++) {
+		const char *input = valid_inputs[i];
+		parser_t parser;
+		parser_init(&parser, true);
+		assert_false(parser_append(&parser, input),
+		    "Unexpected input appending failure");
+		assert_false(parser_parse(&parser),
+		    "Unexpected parse error for input: %s", input);
+		parser_fini(&parser);
+	}
+}
+TEST_END
+
+void
+write_cb(void *opaque, const char *str)
+{
+	parser_t *parser = (parser_t *)opaque;
+	if (parser_append(parser, str)) {
+		test_fail("Unexpected input appending failure");
+	}
+}
+
+TEST_BEGIN(test_stats_print_json)
+{
+	const char *opts[] = {
+		"J",
+		"Jg",
+		"Jm",
+		"Jgm",
+		"Ja",
+		"Jb",
+		"Jab",
+		"Jl",
+		"Jal",
+		"Jbl",
+		"Jabl",
+		"Jh",
+		"Jah",
+		"Jbh",
+		"Jabh",
+		"Jlh",
+		"Jalh",
+		"Jblh",
+		"Jablh",
+		"Jgmablh",
+	};
+	unsigned arena_ind, i;
+
+	for (i = 0; i < 2; i++) {
+		unsigned j;
+
+		switch (i) {
+		case 0:
+			break;
+		case 1: {
+			size_t sz = sizeof(arena_ind);
+			assert_d_eq(mallctl("arenas.extend", (void *)&arena_ind,
+			    &sz, NULL, 0), 0, "Unexpected mallctl failure");
+			break;
+		} default:
+			not_reached();
+		}
+
+		for (j = 0; j < sizeof(opts)/sizeof(const char *); j++) {
+			parser_t parser;
+
+			parser_init(&parser, true);
+			malloc_stats_print(write_cb, (void *)&parser, opts[j]);
+			assert_false(parser_parse(&parser),
+			    "Unexpected parse error, opts=\"%s\"", opts[j]);
+			parser_fini(&parser);
+		}
+	}
+}
+TEST_END
+
+int
+main(void)
+{
+	return (test(
+	    test_json_parser,
+	    test_stats_print_json));
+}