fix

Makefile

@@ -1,26 +1,36 @@
 
 MAKEFLAGS += -j16
 
-CFLAGS=-std=c17 -pedantic-errors -Wall -Wextra -Wconversion -g
+CFLAGS=-std=c17 -pedantic-errors -Wall -Wextra -Wconversion
 LDFLAGS=
 
 # CFLAGS+=-fsanitize=address
 
+RELEASE=0
+
+ifeq ($(RELEASE),1)
+	CFLAGS += -O3
+else
+	CFLAGS += -g
+endif
+
 build_dir = build
 obj_dir = $(build_dir)/obj
 
 sources = \
 	src/main.c \
-	src/json_parse.c \
+	src/collections.c \
 	src/json_value.c \
-	src/collections.c
+	src/json_parse.c \
+	src/json_query.c \
+	src/json_stringify.c
 
 target=$(build_dir)/jq
 
 all: $(target)
 
 debug: $(target)
-	gdb tui -ex 'b main.c:254' -ex 'b collections.c:161' -ex 'r' --args build/jq '.' data.json
+	gdb -ex 'r' --args build/jq '.' data.json
 
 $(target): $(sources:%.c=$(obj_dir)/%.o)
 	gcc -o $@ $(CFLAGS) $(LDFLAGS) $^

data.json

@@ -1,5 +0,0 @@
-{
-    "baz": false,
-    "foo": [123, "bar"]
-}
-

src/collections.c

@@ -58,6 +58,8 @@ void *array_insert_at(void **data,
     return src_ptr;
 }
 
+#define small_count_max 3
+
 void smallarray_construct(struct smallarray *a)
 {
     *a = (struct smallarray) { 0 };
@@ -77,11 +79,12 @@ static bool sa_is_big(struct smallarray const *a)
 
 static void sa_push_big(struct smallarray *a, void *value)
 {
+    if (!sa_is_big(a)) {
         size_t capacity = 8;
         void **ptr = malloc(capacity * sizeof(void *));
         size_t count = 0;
 
-    for (size_t i = 0; i < 3; ++i) {
+        for (size_t i = 0; i < small_count_max; ++i) {
             if ((a->smalldata[i] & 1) == 0)
                 break;
             ptr[i] = (void *)(a->smalldata[i] & ~1ull);
@@ -91,13 +94,15 @@ static void sa_push_big(struct smallarray *a, void *value)
         a->capacity = capacity;
         a->data = ptr;
         a->count = count;
+    }
+
     array_push(
         (void **)&a->data, &a->capacity, &a->count, &value, sizeof(void *));
 }
 
 static void sa_push_small(struct smallarray *a, void *value)
 {
-    for (size_t i = 0; i < 3; ++i) {
+    for (size_t i = 0; i < small_count_max; ++i) {
         if (a->smalldata[i] & 1)
             continue;
         a->smalldata[i] = (size_t)value | 1;
@@ -109,7 +114,7 @@ void smallarray_push(struct smallarray *a, void *value)
 {
     assert((size_t)value % 2 == 0 && "pointer must be 2 bytes aligned");
 
-    if (sa_is_big(a)) {
+    if (sa_is_big(a) || smallarray_count(a) >= small_count_max) {
         sa_push_big(a, value);
     } else {
         sa_push_small(a, value);
@@ -122,7 +127,7 @@ size_t smallarray_count(struct smallarray const *a)
         return a->count;
     } else {
         size_t count = 0;
-        for (size_t i = 0; i < 3; ++i) {
+        for (size_t i = 0; i < small_count_max; ++i) {
             if ((a->smalldata[i] & 1) == 0)
                 break;
             count += 1;
@@ -136,12 +141,17 @@ void *smallarray_get(struct smallarray *a, size_t idx)
     if (sa_is_big(a)) {
         return a->data[idx];
     } else {
-        if (idx >= 3 || (a->smalldata[idx] & 1) == 0)
+        if (idx >= small_count_max || (a->smalldata[idx] & 1) == 0)
             return NULL;
         return (void *)(a->smalldata[idx] & ~1ull);
     }
 }
 
+void const *smallarray_get_const(struct smallarray const *a, size_t idx)
+{
+    return smallarray_get((struct smallarray *)a, idx);
+}
+
 static uint64_t hash_key(char const *data)
 {
     // djb2
@@ -172,14 +182,15 @@ static uint64_t hash_key_sized(char const *data, size_t size)
 
 void hashmap_construct(struct hashmap *t)
 {
-    *t = (struct hashmap) { NULL, 0, 0 };
+    *t = (struct hashmap) { NULL, 0, 0, NULL, 0, 0 };
 }
 
 void hashmap_destroy(struct hashmap *t)
 {
-    if (t->buckets) {
+    if (t->buckets)
         free(t->buckets);
-    }
+    if (t->keys)
+        free(t->keys);
 }
 
 static struct hash_entry *find_entry(struct hashmap *m, uint64_t hash)
@@ -256,7 +267,31 @@ static struct hash_entry *make_entry(struct hashmap *m, uint64_t hash)
     assert(false);
 }
 
-static void hashmap_set_internal(struct hashmap *m, uint64_t hash, void *value)
+static void insert_key(
+    struct hashmap *m, char const *key, size_t key_size, uint64_t hash)
+{
+    key_size = key_size != 0 ? key_size : strlen(key);
+    char *key_value = malloc(key_size + 1);
+    strncpy(key_value, key, key_size);
+    key_value[key_size] = '\0';
+
+    struct hash_key_entry key_entry = {
+        .hash = hash,
+        .value = key_value,
+    };
+
+    array_push((void **)&m->keys,
+        &m->keys_capacity,
+        &m->keys_count,
+        &key_entry,
+        sizeof(key_entry));
+}
+
+static void hashmap_set_internal(struct hashmap *m,
+    char const *key,
+    size_t key_size,
+    uint64_t hash,
+    void *value)
 {
     if (m->buckets_count == 0) {
         struct hash_bucket *bucket = insert_bucket_at(m, 0);
@@ -264,6 +299,8 @@ static void hashmap_set_internal(struct hashmap *m, uint64_t hash, void *value)
         bucket->count += 1;
         bucket->first_hash = hash;
         bucket->last_hash = hash;
+
+        insert_key(m, key, key_size, hash);
         return;
     }
 
@@ -271,6 +308,8 @@ static void hashmap_set_internal(struct hashmap *m, uint64_t hash, void *value)
     if (!entry) {
         entry = make_entry(m, hash);
         entry->hash = hash;
+
+        insert_key(m, key, key_size, hash);
     }
     entry->value = value;
     return;
@@ -279,14 +318,14 @@ static void hashmap_set_internal(struct hashmap *m, uint64_t hash, void *value)
 void hashmap_set(struct hashmap *m, char const *key, void *value)
 {
     uint64_t hash = hash_key(key);
-    hashmap_set_internal(m, hash, value);
+    hashmap_set_internal(m, key, 0, hash, value);
 }
 
 void hashmap_set_sized(
     struct hashmap *m, char const *key, size_t key_size, void *value)
 {
     uint64_t hash = hash_key_sized(key, key_size);
-    hashmap_set_internal(m, hash, value);
+    hashmap_set_internal(m, key, key_size, hash, value);
 }
 
 bool hashmap_has(struct hashmap *m, char const *key)
@@ -311,6 +350,23 @@ void *hashmap_get_sized(struct hashmap *m, char const *key, size_t key_size)
     return hashmap_get_internal(m, hash);
 }
 
+void *hashmap_get_hash(struct hashmap *m, size_t hash)
+{
+    return hashmap_get_internal(m, hash);
+}
+
+void const *hashmap_get_hash_const(struct hashmap const *m, size_t hash)
+{
+    return hashmap_get_internal((struct hashmap *)m, hash);
+}
+
+void hashmap_keys(
+    struct hashmap const *m, struct hash_key_entry const **keys, size_t *count)
+{
+    *keys = m->keys;
+    *count = m->keys_count;
+}
+
 struct blockalloc_block {
     unsigned char *data;
     size_t size;

src/collections.h

@@ -34,6 +34,7 @@ void smallarray_destroy(struct smallarray *a);
 void smallarray_push(struct smallarray *a, void *value);
 size_t smallarray_count(struct smallarray const *a);
 void *smallarray_get(struct smallarray *a, size_t idx);
+void const *smallarray_get_const(struct smallarray const *a, size_t idx);
 
 struct hash_entry {
     uint64_t hash;
@@ -49,10 +50,18 @@ struct hash_bucket {
     uint64_t last_hash;
 };
 
+struct hash_key_entry {
+    uint64_t hash;
+    char *value;
+};
+
 struct hashmap {
     struct hash_bucket *buckets;
     size_t buckets_capacity;
     size_t buckets_count;
+    struct hash_key_entry *keys;
+    size_t keys_capacity;
+    size_t keys_count;
 };
 
 void hashmap_construct(struct hashmap *m);
@@ -63,6 +72,10 @@ void hashmap_set_sized(
 bool hashmap_has(struct hashmap *m, char const *key);
 void *hashmap_get(struct hashmap *m, char const *key);
 void *hashmap_get_sized(struct hashmap *m, char const *key, size_t key_size);
+void *hashmap_get_hash(struct hashmap *m, size_t hash);
+void const *hashmap_get_hash_const(struct hashmap const *m, size_t hash);
+void hashmap_keys(
+    struct hashmap const *m, struct hash_key_entry const **keys, size_t* count);
 
 #define blockalloc_default_block 4096
 

src/json.h

@@ -1,6 +1,7 @@
 #ifndef JSON_H
 #define JSON_H
 
+#include "collections.h"
 #include <stdbool.h>
 #include <stddef.h>
 #include <stdint.h>
@@ -23,29 +24,50 @@ void json_free(struct json_value *value);
 
 bool json_is(struct json_value const *value, enum json_type type);
 
+enum json_type json_get_type(struct json_value const *value);
 bool json_get_bool(struct json_value const *value);
 int64_t json_get_int(struct json_value const *value);
 double json_get_float(struct json_value const *value);
-char *json_get_string(struct json_value *value);
+char const *json_get_string(struct json_value const *value);
 
-void json_set_bool(struct json_value *value, bool val);
-void json_set_int(struct json_value *value, int64_t val);
-void json_set_float(struct json_value *value, double val);
-void json_set_string(struct json_value *value, char *val);
+void json_set_null(struct json_value **value);
+void json_set_bool(struct json_value **value, bool val);
+void json_set_int(struct json_value **value, int64_t val);
+void json_set_float(struct json_value **value, double val);
+void json_set_string(struct json_value *value, char *vaAl);
 
+struct json_value *json_new_int(int64_t val);
+struct json_value *json_new_float(double val);
+
+size_t json_array_count(struct json_value const *array);
 struct json_value *json_idx(struct json_value *array, size_t idx);
+struct json_value const *json_idx_const(struct json_value const *array, size_t idx);
 void json_push(struct json_value *array, struct json_value *value);
 
 struct json_value *json_key(struct json_value *object, char const *key);
 struct json_value *json_key_sized(
     struct json_value *object, char const *key, size_t key_size);
+struct json_value const *json_key_hash_const(
+    struct json_value const *object, size_t hash);
 void json_set(
     struct json_value *object, char const *key, struct json_value *value);
 void json_set_sized(struct json_value *object,
     char const *key,
     size_t key_size,
     struct json_value *value);
+void json_object_keys(
+    struct json_value const *object, struct hash_key_entry const **keys, size_t *count);
 
-struct json_value *json_parse(char const *text, size_t text_size);
+struct json_value *json_parse(
+    char const *text, size_t text_size, struct blockalloc* alloc);
+
+struct json_value *json_query(struct json_value *val, char const *query);
+
+typedef int JsonWriteCb(void* self, const char* data, size_t size);
+
+int json_stringify(
+    struct json_value const *node,
+    JsonWriteCb write,
+    void* self);
 
 #endif

src/json_parse.c

@@ -110,10 +110,13 @@ static struct tok t_make_ident_tok(
     struct tokenizer *t, struct loc loc, size_t *i)
 {
     char const *kws[] = { "null", "false", "true" };
+    size_t const lens[] = { 4, 5, 4 };
     enum tokty tys[] = { tt_null, tt_false, tt_true };
-    for (size_t kw_i = 0; kw_i < sizeof(kws) / sizeof(kws[0]); ++kw_i) {
-        if (strncmp(kws[kw_i], &t->text[loc.idx], *i - loc.idx)) {
-            return t_tok(t, tys[kw_i], loc);
+    for (size_t j = 0; j < sizeof(kws) / sizeof(kws[0]); ++j) {
+        size_t len = *i - loc.idx;
+        if (lens[j] == len && strncmp(kws[j], &t->text[loc.idx], len) == 0) {
+
+            return t_tok(t, tys[j], loc);
         }
     }
     report(loc, "invalid identifier", t->text, t->len);
@@ -201,7 +204,7 @@ static struct tok tokenizer_next(struct tokenizer *t)
 struct parser {
     struct tokenizer tokenizer;
     struct tok tok;
-    struct blockalloc allocator;
+    struct blockalloc* alloc;
 };
 
 static void p_step(struct parser *p)
@@ -210,14 +213,13 @@ static void p_step(struct parser *p)
 }
 
 static void parser_construct(
-    struct parser *p, char const *text, size_t text_len)
+    struct parser *p, char const *text, size_t text_len, struct blockalloc* alloc)
 {
     *p = (struct parser) {
         .tokenizer = (struct tokenizer) { text, text_len, 0, 1, 1, false },
         .tok = (struct tok) { 0 },
-        .allocator = (struct blockalloc) { 0 },
+        .alloc = alloc,
     };
-    blockalloc_construct(&p->allocator);
     p_step(p);
 }
 
@@ -300,18 +302,16 @@ static struct json_value *parser_parse(struct parser *p)
         return val;
     } else if (*ty == tt_int) {
         int64_t value = strtol(p->tok.ptr, NULL, 10);
-        struct json_value *val = json_new(json_int);
-        json_set_int(val, value);
+        struct json_value *val = json_new_int(value);
         p_step(p);
         return val;
     } else if (*ty == tt_float) {
         double value = strtod(p->tok.ptr, NULL);
-        struct json_value *val = json_new(json_float);
-        json_set_float(val, value);
+        struct json_value *val = json_new_float(value);
         p_step(p);
         return val;
     } else if (*ty == tt_string) {
-        char *value = blockalloc_alloc(&p->allocator, p->tok.len - 2 + 1, 2);
+        char *value = blockalloc_alloc(p->alloc, p->tok.len - 2 + 1, 2);
         strncpy(value, p->tok.ptr + 1, p->tok.len - 2);
         value[p->tok.len - 2] = '\0';
         struct json_value *val = json_new(json_string);
@@ -323,17 +323,27 @@ static struct json_value *parser_parse(struct parser *p)
     } else if (*ty == '{') {
         return parser_parse_object(p, ty);
     } else {
+        if (!p->tokenizer.failed) {
             p_report(p, loc, "expected expression");
+        }
         return NULL;
     }
 }
 
-struct json_value *json_parse(char const *text, size_t text_size)
+struct json_value *json_parse(
+    char const *text, size_t text_size, struct blockalloc* alloc)
 {
     text_size = text_size > 0 ? text_size : strlen(text);
 
     struct parser p;
-    parser_construct(&p, text, text_size);
+    parser_construct(&p, text, text_size, alloc);
 
-    return parser_parse(&p);
+    struct json_value *result = parser_parse(&p);
+
+    if (result && p.tokenizer.failed) {
+        json_free(result);
+        return NULL;
+    }
+
+    return result;
 }

src/json_query.c

@@ -0,0 +1,252 @@
+#include "json.h"
+#include <assert.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+static void report(
+    size_t idx, char const *message, char const *text, size_t text_len)
+{
+    fprintf(stderr, "error: %s\n", message);
+    if (!text)
+        return;
+    static char const *spaces = "                        ";
+    printf("|%.*s\n"
+           "|%.*s^\n",
+        (int)text_len,
+        text,
+        (int)idx,
+        spaces);
+}
+
+enum tokty {
+    tt_eof,
+    tt_string,
+    tt_ident,
+    tt_int = '0',
+    tt_dot = '.',
+    tt_lbracket = '[',
+    tt_rbracket = ']',
+};
+
+struct tok {
+    enum tokty ty;
+    char const *ptr;
+    size_t idx;
+    size_t len;
+};
+
+struct tokenizer {
+    char const *text;
+    size_t len;
+    size_t idx;
+    bool failed;
+};
+
+static void t_step(struct tokenizer *t)
+{
+    if (t->idx >= t->len)
+        return;
+    t->idx += 1;
+}
+
+static struct tok t_tok(struct tokenizer *t, enum tokty ty, size_t idx)
+{
+    return (struct tok) { ty, &t->text[idx], idx, t->idx - idx };
+}
+static struct tok tokenizer_next(struct tokenizer *t);
+
+static struct tok t_make_number_tok(
+    struct tokenizer *t, size_t idx, size_t *i)
+{
+    while (*i < t->len && t->text[*i] >= '0' && t->text[*i] <= '9') {
+        t_step(t);
+    }
+    return t_tok(t, tt_int, idx);
+}
+
+static struct tok t_make_string_tok(
+    struct tokenizer *t, size_t idx, size_t *i)
+{
+    t_step(t);
+    while (*i < t->len && t->text[*i] != '\"') {
+        if (t->text[*i] == '\\') {
+            t_step(t);
+            if (*i >= t->len)
+                break;
+        }
+        t_step(t);
+    }
+    if (*i >= t->len && t->text[*i] != '\"') {
+        report(idx, "malformed string", t->text, t->len);
+        t->failed = true;
+        return tokenizer_next(t);
+    }
+    t_step(t);
+    return t_tok(t, tt_string, idx);
+}
+
+static struct tok tokenizer_next(struct tokenizer *t)
+{
+    size_t idx = t->idx;
+    size_t *i = &t->idx;
+    if (*i >= t->len) {
+        return t_tok(t, tt_eof, idx);
+    }
+    bool matched = false;
+    while (*i < t->len && strchr(" \t\r\n", t->text[*i]) != NULL) {
+        matched = true;
+        t_step(t);
+    }
+    if (matched) {
+        return tokenizer_next(t);
+    }
+    if (strchr(".[]0", t->text[*i]) != NULL) {
+        enum tokty ty = (enum tokty)t->text[*i];
+        t_step(t);
+        return t_tok(t, ty, idx);
+    }
+    while (*i < t->len && t->text[*i] >= 'a' && t->text[*i] <= 'z') {
+        matched = true;
+        t_step(t);
+    }
+    if (matched) {
+        return t_tok(t, tt_ident, idx);
+    }
+    if (t->text[*i] >= '1' && t->text[*i] <= '9') {
+        return t_make_number_tok(t, idx, i);
+    }
+    if (t->text[*i] == '\"') {
+        return t_make_string_tok(t, idx, i);
+    }
+    report(idx, "illegal character", t->text, t->len);
+    t->failed = true;
+    t_step(t);
+    return tokenizer_next(t);
+}
+
+enum path_seg_ty {
+    pt_error,
+    pt_eof,
+    pt_ident_key,
+    pt_string_key,
+    pt_idx,
+};
+
+struct path_seg {
+    enum path_seg_ty ty;
+    struct tok tok;
+};
+
+struct parser {
+    struct tokenizer tokenizer;
+    struct tok tok;
+};
+
+static void p_step(struct parser *p)
+{
+    p->tok = tokenizer_next(&p->tokenizer);
+}
+
+static void p_report(struct parser *p, size_t idx, char const *message)
+{
+    report(idx, message, p->tokenizer.text, p->tokenizer.len);
+}
+
+static struct path_seg parse_next(struct parser *p)
+{
+    size_t idx = p->tok.idx;
+    enum tokty *ty = &p->tok.ty;
+
+    if (*ty == tt_eof) {
+        return (struct path_seg) { .ty = pt_eof, .tok = p->tok };
+    } else if (*ty == '.') {
+        p_step(p);
+        struct tok tok = p->tok;
+        if (*ty == tt_eof || *ty != tt_ident) {
+            p_report(p, p->tok.idx, "expected identifier");
+            return (struct path_seg) { .ty = pt_error, .tok = p->tok };
+        }
+        p_step(p);
+        return (struct path_seg) { .ty = pt_ident_key, .tok = tok };
+    } else if (*ty == '[') {
+        p_step(p);
+        struct tok tok = p->tok;
+        enum path_seg_ty seg_ty;
+        if (tok.ty == tt_int) {
+            seg_ty = pt_idx;
+        } else if (tok.ty == tt_string) {
+            seg_ty = pt_string_key;
+        } else {
+            p_report(p, p->tok.idx, "expected string or integer");
+            return (struct path_seg) { .ty = pt_error, .tok = p->tok };
+        }
+        p_step(p);
+        if (*ty == tt_eof || *ty != ']') {
+            p_report(p, p->tok.idx, "expected ']'");
+            return (struct path_seg) { .ty = pt_error, .tok = p->tok };
+        }
+        p_step(p);
+        return (struct path_seg) { .ty = seg_ty, .tok = tok };
+    } else {
+        if (!p->tokenizer.failed) {
+            p_report(p, idx, "expected expression");
+        }
+        return (struct path_seg) { .ty = pt_error, .tok = p->tok };
+    }
+}
+
+struct json_value *resolve_next_path_seg(
+    struct parser *p, struct json_value* node)
+{
+    struct path_seg seg = parse_next(p);
+    switch (seg.ty){
+        case pt_error:
+            return NULL;
+        case pt_eof:
+            return node;
+        case pt_ident_key: {
+            if (!json_is(node, json_object))
+                return NULL;
+            struct json_value *child =
+                json_key_sized(node, seg.tok.ptr, seg.tok.len);
+            return resolve_next_path_seg(p, child);
+        }
+        case pt_string_key: {
+            if (!json_is(node, json_object))
+                return NULL;
+            struct json_value *child =
+                json_key_sized(node, seg.tok.ptr + 1, seg.tok.len - 2);
+            return resolve_next_path_seg(p, child);
+        }
+        case pt_idx: {
+            if (!json_is(node, json_array))
+                return NULL;
+            struct json_value *child =
+                json_idx(node, strtoull(seg.tok.ptr, NULL, 10));
+            return resolve_next_path_seg(p, child);
+        }
+    }
+    assert(false);
+}
+
+struct json_value *json_query(struct json_value *val, char const *query)
+{
+    size_t query_len = strlen(query);
+
+    struct parser p = {
+        .tokenizer = (struct tokenizer) {
+            .text = query,
+            .len = query_len,
+            .idx = 0,
+            .failed = false,
+        },
+        .tok = (struct tok){0},
+    };
+    p_step(&p);
+
+    return resolve_next_path_seg(&p, val);
+}
+
+

src/json_stringify.c

@@ -0,0 +1,100 @@
+#include "collections.h"
+#include "json.h"
+#include <stdio.h>
+#include <string.h>
+
+#define TRY(EXPR) do {int result = (EXPR); if (result != 0) { return result; }} while(0)
+
+static int write_indent(JsonWriteCb write, void *self, int depth)
+{
+    for (int i = 0; i < depth; ++i) {
+        TRY(write(self, "    ", 4));
+    }
+    return 0;
+}
+
+static int stringify_pretty_rec(
+    struct json_value const *node, JsonWriteCb write, void *self, int depth)
+{
+    static const char* kws[] = {
+        [json_null] = "null",
+        [json_false] = "false",
+        [json_true] = "true",
+    };
+    enum json_type ty = json_get_type(node);
+    switch (ty) {
+        case json_null:
+        case json_false:
+        case json_true:
+            TRY(write(self, kws[ty], strlen(kws[ty])));
+            break;
+        case json_int: {
+            char buf[25] = "";
+            int len = snprintf(buf, sizeof(buf) - 1, "%ld", json_get_int(node));
+            TRY(write(self, buf, (size_t)len));
+            break;
+        }
+        case json_float: {
+            char buf[32] = "";
+            int len = snprintf(buf, sizeof(buf) - 1, "%f", json_get_float(node));
+            TRY(write(self, buf, (size_t)len));
+            break;
+        }
+        case json_string: {
+            const char* str = json_get_string(node);
+            TRY(write(self, "\"", 1));
+            TRY(write(self, str, strlen(str)));
+            TRY(write(self, "\"", 1));
+            break;
+        }
+        case json_array: {
+            size_t count = json_array_count(node);
+            TRY(write(self, "[", 1));
+            for (size_t i = 0; i < count; ++i) {
+                struct json_value const *child = json_idx_const(node, i);
+
+                if (i != 0) {
+                    TRY(write(self, ",", 1));
+                }
+                TRY(write(self, "\n", 1));
+                TRY(write_indent(write, self, depth + 1));
+                TRY(stringify_pretty_rec(child, write, self, depth + 1));
+            }
+            TRY(write(self, "\n", 1));
+            TRY(write_indent(write, self, depth));
+            TRY(write(self, "]", 1));
+            break;
+        }
+        case json_object: {
+            struct hash_key_entry const *keys;
+            size_t count;
+            json_object_keys(node, &keys, &count);
+            TRY(write(self, "{", 1));
+            for (size_t i = 0; i < count; ++i) {
+                struct json_value const *child =
+                    json_key_hash_const(node, keys[i].hash);
+
+                if (i != 0) {
+                    TRY(write(self, ",", 1));
+                }
+                TRY(write(self, "\n", 1));
+                TRY(write_indent(write, self, depth + 1));
+                TRY(write(self, "\"", 1));
+                TRY(write(self, keys[i].value, strlen(keys[i].value)));
+                TRY(write(self, "\": ", 3));
+                TRY(stringify_pretty_rec(child, write, self, depth + 1));
+            }
+            TRY(write(self, "\n", 1));
+            TRY(write_indent(write, self, depth));
+            TRY(write(self, "}", 1));
+            break;
+        }
+    }
+    return 0;
+}
+
+int json_stringify(
+    struct json_value const *node, JsonWriteCb write, void *self)
+{
+    return stringify_pretty_rec(node, write, self, 0);
+}

src/json_value.c

@@ -19,7 +19,43 @@ struct json_value {
     };
 };
 
-struct json_value *json_new(enum json_type ty)
+#define shallow_int_min (-144115188075855872ll)
+#define shallow_int_max 144115188075855871ll
+
+static bool is_shallow(struct json_value const *ptr)
+{
+    return ((size_t)ptr >> 1 & 1) != 0;
+}
+
+static enum json_type shallow_ty(struct json_value const *ptr)
+{
+    return (enum json_type)((size_t)ptr >> 2 & 0xf);
+}
+
+static void set_shallow_ty(struct json_value **ptr, enum json_type ty)
+{
+    *(size_t *)ptr |= (ty & 0xf) << 2;
+}
+
+static size_t shallow_val(struct json_value const *ptr)
+{
+    return (size_t)ptr >> 6;
+}
+
+static void set_shallow_val(struct json_value **ptr, size_t val)
+{
+    *(size_t *)ptr |= val << 6;
+}
+
+static struct json_value *new_shallow(enum json_type ty)
+{
+    struct json_value *shallow_val = 0;
+    *(size_t *)&shallow_val |= 0x2;
+    set_shallow_ty(&shallow_val, ty);
+    return shallow_val;
+}
+
+static struct json_value *new_deep(enum json_type ty)
 {
     struct json_value *v = malloc(sizeof(struct json_value));
     *v = (struct json_value) { .ty = ty };
@@ -41,8 +77,28 @@ struct json_value *json_new(enum json_type ty)
     return v;
 }
 
+struct json_value *json_new(enum json_type ty)
+{
+    switch (ty) {
+        case json_null:
+        case json_false:
+        case json_true:
+        case json_int:
+        case json_float:
+            return new_shallow(ty);
+        case json_string:
+        case json_array:
+        case json_object:
+            return new_deep(ty);
+    }
+    assert(false);
+}
+
 void json_free(struct json_value *v)
 {
+    if (is_shallow(v))
+        return;
+
     switch (v->ty) {
         case json_null:
         case json_false:
@@ -66,57 +122,151 @@ void json_free(struct json_value *v)
 
 bool json_is(struct json_value const *value, enum json_type type)
 {
+    if (is_shallow(value))
+        return shallow_ty(value) == type;
+
     return value->ty == type;
 }
 
+enum json_type json_get_type(struct json_value const *value)
+{
+    if (is_shallow(value))
+        return shallow_ty(value);
+
+    return value->ty;
+}
+
 bool json_get_bool(struct json_value const *value)
 {
-    assert(value->ty == json_true || value->ty == json_false);
-    return value->ty == json_true;
+    enum json_type ty;
+
+    if (is_shallow(value)) {
+        ty = shallow_ty(value);
+    } else {
+        ty = value->ty;
+    }
+
+    assert(ty == json_true || ty == json_false);
+    return ty == json_true;
 }
 int64_t json_get_int(struct json_value const *value)
 {
+    if (is_shallow(value)) {
+        assert(shallow_ty(value) == json_int);
+        return (int64_t)shallow_val(value);
+    }
+
     assert(value->ty == json_int);
     return value->int_val;
 }
 double json_get_float(struct json_value const *value)
 {
+    if (is_shallow(value)) {
+        assert(shallow_ty(value) == json_float);
+        size_t raw_val = shallow_val(value) << 6;
+        return *(double *)&raw_val;
+    }
+
     assert(value->ty == json_float);
     return value->float_val;
 }
-char *json_get_string(struct json_value *value)
+char const *json_get_string(struct json_value const *value)
 {
     assert(value->ty == json_string);
     return value->string_val;
 }
 
-void json_set_bool(struct json_value *value, bool val)
+void json_set_null(struct json_value **value)
 {
-    assert(value->ty == json_true || value->ty == json_false);
-    value->ty = val ? json_true : json_false;
+    if (is_shallow(*value)) {
+        set_shallow_ty(value, json_null);
+        return;
+    }
+
+    (*value)->ty = json_null;
 }
-void json_set_int(struct json_value *value, int64_t val)
+
+void json_set_bool(struct json_value **value, bool val)
 {
-    assert(value->ty == json_int);
-    value->int_val = val;
+    if (is_shallow(*value)) {
+        set_shallow_ty(value, val ? json_true : json_false);
+    }
+
+    (*value)->ty = val ? json_true : json_false;
 }
-void json_set_float(struct json_value *value, double val)
+void json_set_int(struct json_value **value, int64_t val)
 {
-    assert(value->ty == json_float);
-    value->float_val = val;
+    if (is_shallow(*value)) {
+        if (val >= shallow_int_min && val <= shallow_int_max) {
+            set_shallow_ty(value, json_int);
+            set_shallow_val(value, (size_t)val);
+            return;
+        } else {
+            *value = new_deep(json_int);
+        }
+    }
+
+    (*value)->ty = json_int;
+    (*value)->int_val = val;
+}
+void json_set_float(struct json_value **value, double val)
+{
+    if (is_shallow(*value)) {
+        size_t raw_val = *(size_t *)&val;
+        if ((raw_val & 0x7f) == 0) {
+            set_shallow_ty(value, json_float);
+            set_shallow_val(value, raw_val >> 6);
+            return;
+        } else {
+            *value = new_deep(json_float);
+        }
+    }
+
+    (*value)->ty = json_float;
+    (*value)->float_val = val;
 }
 void json_set_string(struct json_value *value, char *val)
 {
-    assert(value->ty == json_string);
+    value->ty = json_string;
     value->string_val = val;
 }
 
+struct json_value *json_new_int(int64_t val)
+{
+    struct json_value *node = json_new(json_int);
+    json_set_int(&node, val);
+    return node;
+}
+
+struct json_value *json_new_float(double val)
+{
+    struct json_value *node = json_new(json_float);
+    json_set_float(&node, val);
+    return node;
+}
+
+size_t json_array_count(struct json_value const *array)
+{
+    assert(array->ty == json_array);
+    return smallarray_count(&array->array_vals);
+}
+
 struct json_value *json_idx(struct json_value *array, size_t idx)
 {
     assert(array->ty == json_array);
+    if (idx >= smallarray_count(&array->array_vals))
+        return NULL;
     return smallarray_get(&array->array_vals, idx);
 }
 
+struct json_value const *json_idx_const(struct json_value const *array, size_t idx)
+{
+    assert(array->ty == json_array);
+    if (idx >= smallarray_count(&array->array_vals))
+        return NULL;
+    return smallarray_get_const(&array->array_vals, idx);
+}
+
 void json_push(struct json_value *array, struct json_value *value)
 {
     assert(array->ty == json_array);
@@ -136,6 +286,14 @@ struct json_value *json_key_sized(
     return hashmap_get_sized(&object->object_fields, key, key_size);
 }
 
+struct json_value const *json_key_hash_const(
+    struct json_value const *object, size_t hash)
+{
+    assert(object->ty == json_object);
+    return hashmap_get_hash_const(&object->object_fields, hash);
+}
+
+
 void json_set(
     struct json_value *object, char const *key, struct json_value *value)
 {
@@ -151,3 +309,12 @@ void json_set_sized(struct json_value *object,
     assert(object->ty == json_object);
     hashmap_set_sized(&object->object_fields, key, key_size, value);
 }
+
+void json_object_keys(
+    struct json_value const *object, struct hash_key_entry const **keys, size_t *count)
+{
+    assert(object->ty == json_object);
+    *keys = object->object_fields.keys;
+    *count = object->object_fields.keys_count;
+}
+

src/main.c

@@ -9,13 +9,20 @@
 #include <stdlib.h>
 #include <string.h>
 
+static int stringify_cb(void *self, char const *data, unsigned long size)
+{
+    (void)self;
+    fwrite(data, size, 1, stdout);
+    return 0;
+}
+
 int main(int argc, char *argv[])
 {
     if (argc < 3) {
         fprintf(stderr, "error: incorrect arguments\n");
         return EXIT_FAILURE;
     }
-    char const *pattern = argv[1];
+    char const *query = argv[1];
     char const *filename = argv[2];
 
     FILE *file = fopen(filename, "r");
@@ -48,16 +55,23 @@ int main(int argc, char *argv[])
     }
     fclose(file);
 
-    struct json_value *val = json_parse(text, file_size);
+    struct blockalloc alloc = { 0 };
+    blockalloc_construct(&alloc);
+
+    struct json_value *parsed = json_parse(text, file_size, &alloc);
+    if (!parsed) {
+        fprintf(stderr, "something went wrong\n");
+        return EXIT_FAILURE;
+    }
     free(text);
 
-    typedef struct json_value V;
+    struct json_value *result = json_query(parsed, query);
+    if (!result) {
+        return EXIT_FAILURE;
+    }
+    json_stringify(result, stringify_cb, NULL);
+    fputc('\n', stdout);
 
-    V *a = json_key(val, "foo");
-    V *b = json_idx(a, 0);
-    V *c = json_idx(a, 1);
-    printf(".foo[0] = %ld\n", json_get_int(b));
-    printf(".foo[1] = %s\n", json_get_string(c));
-
-    json_free(val);
+    json_free(parsed);
+    blockalloc_destroy(&alloc);
 }