fix: ftoa

include/sonic/dom/dynamicnode.h

@@ -269,7 +269,7 @@ class DNode : public GenericNode<DNode<Allocator>> {
 
     if (path[index].is_wildcard()) {
       if (!this->IsObject() && !this->IsArray()) {
-        return true;
+        return false;
       }
       DNode* n = (DNode*)getChildrenFirstUnsafe() + (this->IsObject() ? 1 : 0);
       size_t step = this->IsObject() ? 2 : 1;
@@ -296,11 +296,18 @@ class DNode : public GenericNode<DNode<Allocator>> {
       if (!this->IsArray()) {
         return false;
       }
-      size_t idx = path[index].index();
-      if (idx >= this->Size()) {
+
+      // index maybe negative
+      int64_t idx = path[index].index();
+      if (idx < 0) {
+        idx = this->Size() + idx;
+      }
+
+      if (idx >= int64_t(this->Size()) || idx < 0) {
         return false;
       }
-      return this->findValueImpl(idx).atJsonPathImpl(path, index + 1, res);
+      return this->findValueImpl(size_t(idx))
+          .atJsonPathImpl(path, index + 1, res);
     }
     return false;
   };

include/sonic/dom/generic_document.h

@@ -323,9 +323,18 @@ sonic_force_inline std::tuple<std::string, SonicError> GetByJsonPath(
     return std::make_tuple("", result.error);
   }
 
-  // check json path is wildcard
+  // filter the null nodes
+  result.nodes.erase(
+      std::remove_if(result.nodes.begin(), result.nodes.end(),
+                     [](const auto& node) { return node->IsNull(); }),
+      result.nodes.end());
+
+  if (result.nodes.empty()) {
+    return std::make_tuple("null", kErrorNone);
+  }
+
   WriteBuffer wb;
-  if (result.is_single) {
+  if (result.nodes.size() == 1) {
     // not serialize the single string
     auto& root = result.nodes[0];
     if (root->IsString()) {

include/sonic/dom/jsonpath.h

@@ -18,43 +18,47 @@ namespace internal {
 const char NONE = '\0';
 const char WILDCARD = '*';
 const char ROOT = '$';
+const char IS_KEY = '\x01';
+const char IS_INDEX = '\x02';
 
 class JsonPathNode {
  public:
   JsonPathNode() noexcept = default;
-  JsonPathNode(int index) noexcept : index_(index) {}
-  JsonPathNode(StringView key) noexcept : key_(key) {}
+  JsonPathNode(int64_t index) noexcept : index_(index), token_(IS_INDEX) {}
+  JsonPathNode(StringView key) noexcept : key_(key), token_(IS_KEY) {}
   JsonPathNode(char token) noexcept : token_(token) {}
   ~JsonPathNode() = default;
 
  public:
-  bool is_wildcard() const noexcept { return token_ == '*'; }
+  bool is_wildcard() const noexcept { return token_ == WILDCARD; }
 
-  bool is_key() const noexcept { return index_ == -1 && token_ == '\0'; }
+  bool is_key() const noexcept { return token_ == IS_KEY; }
 
-  bool is_index() const noexcept { return index_ != -1; }
+  bool is_index() const noexcept { return token_ == IS_INDEX; }
 
-  bool is_root() const noexcept { return token_ == '$'; }
+  bool is_none() const noexcept { return token_ == NONE; }
+
+  bool is_root() const noexcept { return token_ == ROOT; }
 
   StringView key() const noexcept {
-    sonic_assert(index_ == -1 && token_ == '\0');
+    sonic_assert(is_key());
     return key_;
   }
 
-  int index() const noexcept {
-    sonic_assert(index_ != -1 && token_ == '\0');
+  int64_t index() const noexcept {
+    sonic_assert(is_index());
     return index_;
   }
 
   char token() const noexcept {
-    sonic_assert(index_ == -1 && key_ == "");
+    sonic_assert(!is_key() && !is_index() && !is_none());
     return token_;
   }
 
  private:
-  int index_ = -1;
+  int64_t index_ = 0;
   StringView key_ = "";
-  // special tokens
+  // record special tokens, also distinguish key and index
   char token_ = '\0';
 };
 
@@ -88,15 +92,46 @@ class JsonPath : public std::vector<JsonPathNode> {
     return true;
   }
 
-  // case as .123
-  sonic_force_inline bool parseRawIndex(StringView path, size_t& index,
-                                        JsonPathNode& node) {
-    int sum = 0;
+  // case as [123] or [-123]
+  sonic_force_inline bool parseBracktedIndex(StringView path, size_t& index,
+                                             JsonPathNode& node) {
+    uint64_t sum = 0;
+    int sign = 1;
+
+    // check negative
+    if (index < path.size() && path[index] == '-') {
+      index++;
+      sign = -1;
+    }
+
+    // check leading zero
+    if (index < path.size() && path[index] == '0') {
+      index++;
+      goto end;
+    }
+
     while (index < path.size() && path[index] >= '0' && path[index] <= '9') {
-      sum = sum * 10 + (path[index] - '0');
+      auto last = sum * 10 + (path[index] - '0');
+      // check overflow
+      if (last < sum) {
+        return false;
+      }
+      sum = last;
       index++;
     }
-    node = JsonPathNode(sum);
+
+    // check overflow
+    if (sum > INT64_MAX) {
+      return false;
+    }
+
+  end:
+    // match ']'
+    if (index >= path.size() || path[index] != ']') {
+      return false;
+    }
+    index++;
+    node = JsonPathNode(int64_t(sum) * sign);
     return true;
   }
 
@@ -146,8 +181,9 @@ class JsonPath : public std::vector<JsonPathNode> {
   }
 
   // case as [abc]
-  sonic_force_inline bool parseBrackedUnquotedKey(StringView path, size_t& index,
-                                          JsonPathNode& node) {
+  sonic_force_inline bool parseBrackedUnquotedKey(StringView path,
+                                                  size_t& index,
+                                                  JsonPathNode& node) {
     size_t start = index;
     while (index < path.size() && path[index] != ']') {
       index++;
@@ -160,18 +196,6 @@ class JsonPath : public std::vector<JsonPathNode> {
     return true;
   }
 
-  // case as [123]
-  sonic_force_inline bool parseBracktedIndex(StringView path, size_t& index,
-                                             JsonPathNode& node) {
-    if (!parseRawIndex(path, index, node)) {
-      return false;
-    }
-    if (path[index++] != ']') {
-      return false;
-    }
-    return true;
-  }
-
   sonic_force_inline bool parseWildcard(StringView path, size_t& index,
                                         JsonPathNode& node) {
     if (index + 1 < path.size() && path[index] == '*' &&
@@ -211,12 +235,7 @@ class JsonPath : public std::vector<JsonPathNode> {
           i++;
           continue;
         }
-
-        if (path[i] >= '0' && path[i] <= '9') {
-          valid = parseRawIndex(path, i, node);
-        } else {
-          valid = parseUnquotedKey(path, i, node);
-        }
+        valid = parseUnquotedKey(path, i, node);
       } else if (path[i] == '[') {
         if (i + 1 >= path.size()) {
           return false;
@@ -235,13 +254,9 @@ class JsonPath : public std::vector<JsonPathNode> {
 
         if (path[i] == '\'' || path[i] == '"') {
           valid = parseQuotedName(path, i, node);
-        } else if (path[i] >= '0' && path[i] <= '9') {
+        } else if ((path[i] >= '0' && path[i] <= '9') || path[i] == '-') {
           valid = parseBracktedIndex(path, i, node);
-        } else {
-          valid = false;
         }
-      } else {
-        valid = false;
       }
 
       if (!valid) {

include/sonic/internal/ftoa.h

@@ -1035,9 +1035,22 @@ sonic_static_noinline int F64toa(char* out, double fp) {
     /* fast path for integer */
     if (q <= 0 && q >= -F64_SIG_BITS && IsDivPow2(c, -q)) {
       uint64_t u = c >> -q;
+#if SONIC_UES_EXPONENT
+      uint64_t exp = 0;
+      while ((u % 10) == 0) {
+        u /= 10;
+        exp += 1;
+      }
+#endif
       p = U64toa(p, u);
       *p++ = '.';
       *p++ = '0';
+#if SONIC_UES_EXPONENT
+      if (exp != 0) {
+        *p++ = 'E';
+        p = U64toa(p, exp);
+      }
+#endif
       return p - out;
     }
 
@@ -1050,7 +1063,11 @@ sonic_static_noinline int F64toa(char* out, double fp) {
   int cnt = Ctz10(dec.sig);
   int dot = cnt + dec.exp;
   int sci_exp = dot - 1;
+#if SONIC_UES_EXPONENT
+  bool exp_fmt = sci_exp != 0;
+#else
   bool exp_fmt = sci_exp < -6 || sci_exp > 20;
+#endif
   bool has_dot = dot < cnt;
 
   if (exp_fmt) {

include/sonic/macro.h

@@ -80,6 +80,7 @@
 #define SONIC_EXPONENT_ALWAYS_DOT 1
 #define SONIC_EXPONENT_UPPERCASE 1
 #define SONIC_EXPONENT_ALWAYS_SIGN 0
+#define SONIC_UES_EXPONENT 1
 #endif
 
 #ifdef SONIC_DEFAULT_FORMAT
@@ -103,3 +104,8 @@
 // print exponent with sign, including '+', like 1.0E+2
 #define SONIC_EXPONENT_ALWAYS_SIGN 1
 #endif
+
+#ifndef SONIC_UES_EXPONENT
+// use exponent format for float point number
+#define SONIC_UES_EXPONENT 0
+#endif