// SPDX-License-Identifier: MIT
/*
 * MIT License
 *
 * Copyright (c) 2010 Serge Zaitsev
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
#ifndef JSMN_H
#define JSMN_H

#include <stddef.h>

#ifdef __cplusplus
extern "C"
{
#endif

#ifdef JSMN_STATIC
#define JSMN_API static
#else
#define JSMN_API extern
#endif

/**
 * JSON type identifier. Basic types are:
 * 	o Object
 * 	o Array
 * 	o String
 * 	o Other primitive: number, boolean (true/false) or null
 */
  typedef enum
  {
    JSMN_UNDEFINED = 0,
    JSMN_OBJECT = 1,
    JSMN_ARRAY = 2,
    JSMN_STRING = 3,
    JSMN_PRIMITIVE = 4
  } jsmntype_t;

  enum jsmnerr
  {
    /* Not enough tokens were provided */
    JSMN_ERROR_NOMEM = -1,
    /* Invalid character inside JSON string */
    JSMN_ERROR_INVAL = -2,
    /* The string is not a full JSON packet, more bytes expected */
    JSMN_ERROR_PART = -3
  };

/**
 * JSON token description.
 * type		type (object, array, string etc.)
 * start	start position in JSON data string
 * end		end position in JSON data string
 */
  typedef struct
  {
    jsmntype_t type;
    int start;
    int end;
    int size;
#ifdef JSMN_PARENT_LINKS
    int parent;
#endif
  } jsmntok_t;

/**
 * JSON parser. Contains an array of token blocks available. Also stores
 * the string being parsed now and current position in that string.
 */
  typedef struct
  {
    unsigned int pos;		/* offset in the JSON string */
    unsigned int toknext;	/* next token to allocate */
    int toksuper;		/* superior token node, e.g. parent object or array */
  } jsmn_parser;

/**
 * Create JSON parser over an array of tokens
 */
  JSMN_API void jsmn_init (jsmn_parser * parser);

/**
 * Run JSON parser. It parses a JSON data string into and array of tokens, each
 * describing
 * a single JSON object.
 */
  JSMN_API int jsmn_parse (jsmn_parser * parser, const char *js,
			   const size_t len, jsmntok_t * tokens,
			   const unsigned int num_tokens);

#ifndef JSMN_HEADER
/**
 * Allocates a fresh unused token from the token pool.
 */
  static jsmntok_t *jsmn_alloc_token (jsmn_parser * parser,
				      jsmntok_t * tokens,
				      const size_t num_tokens)
  {
    jsmntok_t *tok;
    if (parser->toknext >= num_tokens)
      {
	return NULL;
      }
    tok = &tokens[parser->toknext++];
    tok->start = tok->end = -1;
    tok->size = 0;
#ifdef JSMN_PARENT_LINKS
    tok->parent = -1;
#endif
    return tok;
  }

/**
 * Fills token type and boundaries.
 */
  static void jsmn_fill_token (jsmntok_t * token, const jsmntype_t type,
			       const int start, const int end)
  {
    token->type = type;
    token->start = start;
    token->end = end;
    token->size = 0;
  }

/**
 * Fills next available token with JSON primitive.
 */
  static int jsmn_parse_primitive (jsmn_parser * parser, const char *js,
				   const size_t len, jsmntok_t * tokens,
				   const size_t num_tokens)
  {
    jsmntok_t *token;
    int start;

    start = parser->pos;

    for (; parser->pos < len && js[parser->pos] != '\0'; parser->pos++)
      {
	switch (js[parser->pos])
	  {
#ifndef JSMN_STRICT
	    /* In strict mode primitive must be followed by "," or "}" or "]" */
	  case ':':
#endif
	  case '\t':
	  case '\r':
	  case '\n':
	  case ' ':
	  case ',':
	  case ']':
	  case '}':
	    goto found;
	  default:
	    /* to quiet a warning from gcc */
	    break;
	  }
	if (js[parser->pos] < 32 || js[parser->pos] >= 127)
	  {
	    parser->pos = start;
	    return JSMN_ERROR_INVAL;
	  }
      }
#ifdef JSMN_STRICT
    /* In strict mode primitive must be followed by a comma/object/array */
    parser->pos = start;
    return JSMN_ERROR_PART;
#endif

  found:
    if (tokens == NULL)
      {
	parser->pos--;
	return 0;
      }
    token = jsmn_alloc_token (parser, tokens, num_tokens);
    if (token == NULL)
      {
	parser->pos = start;
	return JSMN_ERROR_NOMEM;
      }
    jsmn_fill_token (token, JSMN_PRIMITIVE, start, parser->pos);
#ifdef JSMN_PARENT_LINKS
    token->parent = parser->toksuper;
#endif
    parser->pos--;
    return 0;
  }

/**
 * Fills next token with JSON string.
 */
  static int jsmn_parse_string (jsmn_parser * parser, const char *js,
				const size_t len, jsmntok_t * tokens,
				const size_t num_tokens)
  {
    jsmntok_t *token;

    int start = parser->pos;

    parser->pos++;

    /* Skip starting quote */
    for (; parser->pos < len && js[parser->pos] != '\0'; parser->pos++)
      {
	char c = js[parser->pos];

	/* Quote: end of string */
	if (c == '\"')
	  {
	    if (tokens == NULL)
	      {
		return 0;
	      }
	    token = jsmn_alloc_token (parser, tokens, num_tokens);
	    if (token == NULL)
	      {
		parser->pos = start;
		return JSMN_ERROR_NOMEM;
	      }
	    jsmn_fill_token (token, JSMN_STRING, start + 1, parser->pos);
#ifdef JSMN_PARENT_LINKS
	    token->parent = parser->toksuper;
#endif
	    return 0;
	  }

	/* Backslash: Quoted symbol expected */
	if (c == '\\' && parser->pos + 1 < len)
	  {
	    int i;
	    parser->pos++;
	    switch (js[parser->pos])
	      {
		/* Allowed escaped symbols */
	      case '\"':
	      case '/':
	      case '\\':
	      case 'b':
	      case 'f':
	      case 'r':
	      case 'n':
	      case 't':
		break;
		/* Allows escaped symbol \uXXXX */
	      case 'u':
		parser->pos++;
		for (i = 0;
		     i < 4 && parser->pos < len && js[parser->pos] != '\0';
		     i++)
		  {
		    /* If it isn't a hex character we have an error */
		    if (!((js[parser->pos] >= 48 && js[parser->pos] <= 57) ||	/* 0-9 */
			  (js[parser->pos] >= 65 && js[parser->pos] <= 70) ||	/* A-F */
			  (js[parser->pos] >= 97 && js[parser->pos] <= 102)))
		      {		/* a-f */
			parser->pos = start;
			return JSMN_ERROR_INVAL;
		      }
		    parser->pos++;
		  }
		parser->pos--;
		break;
		/* Unexpected symbol */
	      default:
		parser->pos = start;
		return JSMN_ERROR_INVAL;
	      }
	  }
      }
    parser->pos = start;
    return JSMN_ERROR_PART;
  }

/**
 * Parse JSON string and fill tokens.
 */
  JSMN_API int jsmn_parse (jsmn_parser * parser, const char *js,
			   const size_t len, jsmntok_t * tokens,
			   const unsigned int num_tokens)
  {
    int r;
    int i;
    jsmntok_t *token;
    int count = parser->toknext;

    for (; parser->pos < len && js[parser->pos] != '\0'; parser->pos++)
      {
	char c;
	jsmntype_t type;

	c = js[parser->pos];
	switch (c)
	  {
	  case '{':
	  case '[':
	    count++;
	    if (tokens == NULL)
	      {
		break;
	      }
	    token = jsmn_alloc_token (parser, tokens, num_tokens);
	    if (token == NULL)
	      {
		return JSMN_ERROR_NOMEM;
	      }
	    if (parser->toksuper != -1)
	      {
		jsmntok_t *t = &tokens[parser->toksuper];
#ifdef JSMN_STRICT
		/* In strict mode an object or array can't become a key */
		if (t->type == JSMN_OBJECT)
		  {
		    return JSMN_ERROR_INVAL;
		  }
#endif
		t->size++;
#ifdef JSMN_PARENT_LINKS
		token->parent = parser->toksuper;
#endif
	      }
	    token->type = (c == '{' ? JSMN_OBJECT : JSMN_ARRAY);
	    token->start = parser->pos;
	    parser->toksuper = parser->toknext - 1;
	    break;
	  case '}':
	  case ']':
	    if (tokens == NULL)
	      {
		break;
	      }
	    type = (c == '}' ? JSMN_OBJECT : JSMN_ARRAY);
#ifdef JSMN_PARENT_LINKS
	    if (parser->toknext < 1)
	      {
		return JSMN_ERROR_INVAL;
	      }
	    token = &tokens[parser->toknext - 1];
	    for (;;)
	      {
		if (token->start != -1 && token->end == -1)
		  {
		    if (token->type != type)
		      {
			return JSMN_ERROR_INVAL;
		      }
		    token->end = parser->pos + 1;
		    parser->toksuper = token->parent;
		    break;
		  }
		if (token->parent == -1)
		  {
		    if (token->type != type || parser->toksuper == -1)
		      {
			return JSMN_ERROR_INVAL;
		      }
		    break;
		  }
		token = &tokens[token->parent];
	      }
#else
	    for (i = parser->toknext - 1; i >= 0; i--)
	      {
		token = &tokens[i];
		if (token->start != -1 && token->end == -1)
		  {
		    if (token->type != type)
		      {
			return JSMN_ERROR_INVAL;
		      }
		    parser->toksuper = -1;
		    token->end = parser->pos + 1;
		    break;
		  }
	      }
	    /* Error if unmatched closing bracket */
	    if (i == -1)
	      {
		return JSMN_ERROR_INVAL;
	      }
	    for (; i >= 0; i--)
	      {
		token = &tokens[i];
		if (token->start != -1 && token->end == -1)
		  {
		    parser->toksuper = i;
		    break;
		  }
	      }
#endif
	    break;
	  case '\"':
	    r = jsmn_parse_string (parser, js, len, tokens, num_tokens);
	    if (r < 0)
	      {
		return r;
	      }
	    count++;
	    if (parser->toksuper != -1 && tokens != NULL)
	      {
		tokens[parser->toksuper].size++;
	      }
	    break;
	  case '\t':
	  case '\r':
	  case '\n':
	  case ' ':
	    break;
	  case ':':
	    parser->toksuper = parser->toknext - 1;
	    break;
	  case ',':
	    if (tokens != NULL && parser->toksuper != -1 &&
		tokens[parser->toksuper].type != JSMN_ARRAY &&
		tokens[parser->toksuper].type != JSMN_OBJECT)
	      {
#ifdef JSMN_PARENT_LINKS
		parser->toksuper = tokens[parser->toksuper].parent;
#else
		for (i = parser->toknext - 1; i >= 0; i--)
		  {
		    if (tokens[i].type == JSMN_ARRAY
			|| tokens[i].type == JSMN_OBJECT)
		      {
			if (tokens[i].start != -1 && tokens[i].end == -1)
			  {
			    parser->toksuper = i;
			    break;
			  }
		      }
		  }
#endif
	      }
	    break;
#ifdef JSMN_STRICT
	    /* In strict mode primitives are: numbers and booleans */
	  case '-':
	  case '0':
	  case '1':
	  case '2':
	  case '3':
	  case '4':
	  case '5':
	  case '6':
	  case '7':
	  case '8':
	  case '9':
	  case 't':
	  case 'f':
	  case 'n':
	    /* And they must not be keys of the object */
	    if (tokens != NULL && parser->toksuper != -1)
	      {
		const jsmntok_t *t = &tokens[parser->toksuper];
		if (t->type == JSMN_OBJECT ||
		    (t->type == JSMN_STRING && t->size != 0))
		  {
		    return JSMN_ERROR_INVAL;
		  }
	      }
#else
	    /* In non-strict mode every unquoted value is a primitive */
	  default:
#endif
	    r = jsmn_parse_primitive (parser, js, len, tokens, num_tokens);
	    if (r < 0)
	      {
		return r;
	      }
	    count++;
	    if (parser->toksuper != -1 && tokens != NULL)
	      {
		tokens[parser->toksuper].size++;
	      }
	    break;

#ifdef JSMN_STRICT
	    /* Unexpected char in strict mode */
	  default:
	    return JSMN_ERROR_INVAL;
#endif
	  }
      }

    if (tokens != NULL)
      {
	for (i = parser->toknext - 1; i >= 0; i--)
	  {
	    /* Unmatched opened object or array */
	    if (tokens[i].start != -1 && tokens[i].end == -1)
	      {
		return JSMN_ERROR_PART;
	      }
	  }
      }

    return count;
  }

/**
 * Creates a new parser based over a given buffer with an array of tokens
 * available.
 */
  JSMN_API void jsmn_init (jsmn_parser * parser)
  {
    parser->pos = 0;
    parser->toknext = 0;
    parser->toksuper = -1;
  }

#endif /* JSMN_HEADER */

#ifdef __cplusplus
}
#endif

#endif /* JSMN_H */
