/*
 * 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.
 */

#include "jsmn.h"

#define JSMN_STRICT     // force strict mode

const uint32_t JSMN_START_MAX = (1U << JSMN_START_B) - 1;
const uint32_t JSMN_LEN_MAX   = (1U << JSMN_LEN_B) - 1;

/**
 * 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 = JSMN_START_MAX;
  tok->len = JSMN_LEN_MAX;
  tok->size = 0;
  return tok;
}

/**
 * Fills token type and boundaries.
 */
static void jsmn_fill_token(jsmntok_t *token, const jsmntype_t type,
                            const int start, const int len) {
  token->type = type;
  token->start = start;
  token->len = len;
  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 - start);
  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 - start - 1);
      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++;
      }
      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);
      for (i = parser->toknext - 1; i >= 0; i--) {
        token = &tokens[i];
        if ((token->start != JSMN_START_MAX) && (token->len == JSMN_LEN_MAX)) {
          if (token->type != type) {
            return JSMN_ERROR_INVAL;
          }
          parser->toksuper = -1;
          token->len = parser->pos + 1 - token->start;
          break;
        }
      }
      /* Error if unmatched closing bracket */
      if (i == -1) {
        return JSMN_ERROR_INVAL;
      }
      for (; i >= 0; i--) {
        token = &tokens[i];
        if ((token->start != JSMN_START_MAX) && (token->len == JSMN_LEN_MAX)) {
          parser->toksuper = i;
          break;
        }
      }
      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) {
        for (i = parser->toknext - 1; i >= 0; i--) {
          if (tokens[i].type == JSMN_ARRAY || tokens[i].type == JSMN_OBJECT) {
            if ((tokens[i].start != JSMN_START_MAX) && (tokens[i].len == JSMN_LEN_MAX)) {
              parser->toksuper = i;
              break;
            }
          }
        }
      }
      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':
// Add uppercase variants
    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 != JSMN_START_MAX) && (tokens[i].len == JSMN_LEN_MAX)) {
        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;
}

//
// Json in-place string unescape
// inpired from https://github.com/mjansson/json/blob/master/json.h
//
//! Define a bitmask with the given number of bits set to 1
#define JSON_BITMASK(numbits) ((1U << (numbits)) - 1)

static uint32_t json_get_num_bytes_as_utf8(uint32_t val) {
	if (val >= 0x04000000) return 6;
	else if (val >= 0x00200000) return 5;
	else if (val >= 0x00010000) return 4;
	else if (val >= 0x00000800) return 3;
	else if (val >= 0x00000080) return 2;
	return 1;
}

static uint32_t json_encode_utf8(char* str, uint32_t val) {
	if (val < 0x80) {
		*str = (char)val;
		return 1;
	}

	//Get number of _extra_ bytes
	uint32_t num = json_get_num_bytes_as_utf8(val) - 1;

	*str++ = (char)((0x80U | (JSON_BITMASK(num) << (7U - num))) |
	         ((val >> (6U * num)) & JSON_BITMASK(6U - num)));
	for (uint32_t j = 1; j <= num; ++j)
		*str++ = (char)(0x80U | ((val >> (6U * (num - j))) & 0x3F));

	return num + 1;
}

void json_unescape(char* string) {
	size_t outlength = 0;
	uint32_t hexval, numbytes;

  char c;
	for (uint32_t i = 0; (c = string[i]) != 0; i++) {
		if ('\\' == c) {
			c = string[++i];
			switch (c) {
        case 0:
          return;   // end of stream
        case '\"':
        case '/':
        case '\\':
          string[outlength++] = c;
          break;

        case 'b':
          string[outlength++] = '\b';
          break;
        case 'f':
          string[outlength++] = '\f';
          break;
        case 'r':
          string[outlength++] = '\r';
          break;
        case 'n':
          string[outlength++] = '\n';
          break;
        case 't':
          string[outlength++] = '\t';
          break;

        case 'u':
          {
            uint32_t hexval = 0;
            for (uint32_t j = 0; j < 4; ++j) {
              char val = string[++i];
              if (0 == val) { return; }   // we reached end of string
              uint32_t uival = 0;
              if ((val >= 'a') && (val <= 'f'))
                uival = 10 + (val - 'a');
              else if ((val >= 'A') && (val <= 'F'))
                uival = 10 + (val - 'A');
              else if ((val >= '0') && (val <= '9'))
                uival = val - '0';
              hexval |= uival << (3 - j);
            }
            numbytes = json_get_num_bytes_as_utf8(hexval);
            outlength += json_encode_utf8(string + outlength, hexval);
          }
          break;

        default:
          break;
			}
		}
		else {
			string[outlength++] = c;
		}
	}
}