Json.h

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/* ========================================
 
  Copyright (C) 2024-2025, Amlal El Mahrouss, licensed under the Apache 2.0 license.
 
======================================== */
 
#pragma once

 
#include <CompilerKit/CompilerKit.h>
#include <NeKit/Config.h>
#include <NeKit/KString.h>
#include <NeKit/Stream.h>
#include <NeKit/Utils.h>
 
#define kNeJsonMaxLen (8196)
#define kNeJsonLen (256)
#define kNeJsonNullArr "[]"
#define kNeJsonNullObj "{}"
#define kNeJsonNullKey "null"
#define kNeJsonNullValue kNeJsonNullKey
 
namespace Kernel {
template <typename CharKind = Char>
class JsonObject final {
 public:
  explicit JsonObject() : fUndefined(NO) {
    KBasicString<CharKind> key = KString(kNeJsonMaxLen);
    key += kNeJsonNullValue;
 
    this->AsKey()   = key;
    this->AsValue() = key;
  }
 
  explicit JsonObject(SizeT lhsLen, SizeT rhsLen) : fUndefined(NO), fKey(lhsLen), fValue(rhsLen) {
    KBasicString<CharKind> key = KString(lhsLen);
    this->AsKey()              = key;
 
    KBasicString<CharKind> value = KString(rhsLen);
    this->AsValue()              = value;
  }
 
  ~JsonObject() = default;
 
  NE_COPY_DEFAULT(JsonObject)
  NE_MOVE_DEFAULT(JsonObject)
 
  Bool& IsUndefined() { return fUndefined; }
 
 private:
  Bool                   fUndefined;  // is this instance undefined?
  KBasicString<CharKind> fKey;
  KBasicString<CharKind> fValue;
 
 public:
  KBasicString<CharKind>& AsKey() { return fKey; }

  KBasicString<CharKind>& AsValue() { return fValue; }
 
  STATIC JsonObject<CharKind> kNull;
};

struct AsciiJsonStreamReader final {
  STATIC JsonObject<Char> In(const Char* full_array) {
    auto    start_val   = '{';
    auto    end_val     = '}';
    Boolean probe_value = false;
 
    if (full_array[0] != start_val) {
      if (full_array[0] != '[') return JsonObject<Char>{0, 0};
 
      start_val = '[';
      end_val   = ']';
 
      probe_value = true;
    }
 
    SizeT len = rt_string_len(full_array);
 
    SizeT key_len   = 0;
    SizeT value_len = 0;
 
    JsonObject<Char> type(kNeJsonMaxLen, kNeJsonMaxLen);
 
    for (SizeT i = 1; i < len; ++i) {
      if (full_array[i] == '\r' || full_array[i] == '\n') continue;
 
      if (probe_value) {
        if (full_array[i] == end_val || full_array[i] == ',') {
          probe_value = false;
 
          ++value_len;
        } else {
          if (full_array[i] == '\'') {
            type.AsValue().Data()[value_len] = 0;
            break;
          }
 
          type.AsValue().Data()[value_len] = full_array[i];
 
          ++value_len;
        }
      } else {
        if (start_val == '[') continue;
 
        if (full_array[i] == ':') {
          type.AsKey().Data()[key_len] = 0;
          ++key_len;
 
          ++i;
 
          while (full_array[i] == ' ' || full_array[i] == '\t') ++i;
 
          probe_value = true;
        } else {
          type.AsKey().Data()[key_len] = full_array[i];
 
          ++key_len;
        }
      }
    }
 
    type.AsValue().Data()[value_len] = 0;
 
    return type;
  }
};

using AsciiJsonStream = Stream<AsciiJsonStreamReader, JsonObject<Char>>;
}  // namespace Kernel