JSMN_Verify.cpp

#include "jsmn.h"

struct JSMN_Verify_Stack_Element
{
	int offset;
	int num_tokens;
};

int JSMN_Verify(const jsmntok_t* tokens, const JSMN_Verify_Stack_Element param)
{
	if (!tokens || param.num_tokens < 0)
	{
		return -1;
	}

	if (param.num_tokens == 0)
	{
		return 0;
	}

	const auto& t = tokens[param.offset];

	const auto type = t.type;
	const int num_children = t.size;
	if (type == JSMN_OBJECT)
	{
		int n = 0;
		for (int i = 0; i < num_children; ++i)
		{
			if (n + 2 >= param.num_tokens)
			{
				return -1;
			}

			const auto key_index = param.offset + 1 + n;
			const auto& key = tokens[key_index];
			if (key.type != JSMN_STRING)
			{
				return -1;
			}

			int num_value_tokens = JSMN_Verify(
				tokens, { key_index + 1, param.num_tokens - n - 1 });
			if (num_value_tokens < 0)
			{
				return -1;
			}

			n += num_value_tokens + 1;
		}

		return n + 1;
	}
	else if (type == JSMN_ARRAY)
	{
		int n = 0;
		for (int i = 0; i < num_children; ++i)
		{
			if (n + 1 >= param.num_tokens)
			{
				return -1;
			}

			int num_value_tokens = JSMN_Verify(
				tokens, { param.offset + 1 + n, param.num_tokens - n });
			if (num_value_tokens < 0)
			{
				return -1;
			}

			n += num_value_tokens;
		}

		return n + 1;
	}
	else if (type == JSMN_STRING)
	{
		return 1;
	}
	else if (type == JSMN_PRIMITIVE)
	{
		return 1;
	}

	return -1;
}