githubmirror/libcbor

examples/readfile.c
83 строки2 KB
PJK
Happy new year!
01 янв 2017, 21:01
01 янв 2017, 21:011e80f4a
/*
 * Copyright (c) 2014-2017 Pavel Kalvoda <me@pavelkalvoda.com>
 *
 * libcbor is free software; you can redistribute it and/or modify
 * it under the terms of the MIT license. See LICENSE for details.
 */

#include "cbor.h"
#include <stdio.h>

void usage()
{
	printf("Usage: readfile [input file]\n");
	exit(1);
}

/*
 * Reads data from a file. Example usage:
 * $ ./examples/readfile examples/data/nested_array.cbor
 */

int main(int argc, char * argv[])
{
	if (argc != 2)
		usage();
	FILE * f = fopen(argv[1], "rb");
	if (f == NULL)
		usage();
	fseek(f, 0, SEEK_END);
	size_t length = (size_t)ftell(f);
	fseek(f, 0, SEEK_SET);
	unsigned char * buffer = malloc(length);
	fread(buffer, length, 1, f);

	/* Assuming `buffer` contains `length` bytes of input data */
	struct cbor_load_result result;
	cbor_item_t * item = cbor_load(buffer, length, &result);

	if (result.error.code != CBOR_ERR_NONE) {
		printf("There was an error while reading the input near byte %zu (read %zu bytes in total): ", result.error.position, result.read);
		switch (result.error.code) {
			case CBOR_ERR_MALFORMATED:
			{
				printf("Malformed data\n");
				break;
			}
			case CBOR_ERR_MEMERROR:
			{
				printf("Memory error -- perhaps the input is too large?\n");
				break;
			}
			case CBOR_ERR_NODATA:
			{
				printf("The input is empty\n");
				break;
			}
			case CBOR_ERR_NOTENOUGHDATA:
			{
				printf("Data seem to be missing -- is the input complete?\n");
				break;
			}
			case CBOR_ERR_SYNTAXERROR:
			{
				printf("Syntactically malformed data -- see http://tools.ietf.org/html/rfc7049\n");
				break;
			}
			case CBOR_ERR_NONE:
			{
				// GCC's cheap dataflow analysis gag
				break;
			}
		}
		exit(1);
	}

	/* Pretty-print the result */
	cbor_describe(item, stdout);
	fflush(stdout);
	/* Deallocate the result */
	cbor_decref(&item);

	fclose(f);
}