65 lines
1.6 KiB
C
65 lines
1.6 KiB
C
/*
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* Copyright (c) 2014-2020 Pavel Kalvoda <me@pavelkalvoda.com>
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*
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* libcbor is free software; you can redistribute it and/or modify
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* it under the terms of the MIT license. See LICENSE for details.
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*/
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#include <stdio.h>
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#include <string.h>
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#include "cbor.h"
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#ifdef __GNUC__
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#define UNUSED(x) __attribute__((__unused__)) x
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#else
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#define UNUSED(x) x
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#endif
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void usage(void) {
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printf("Usage: streaming_parser [input file]\n");
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exit(1);
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}
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/*
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* Illustrates how one might skim through a map (which is assumed to have
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* string keys and values only), looking for the value of a specific key
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*
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* Use the examples/data/map.cbor input to test this.
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*/
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const char* key = "a secret key";
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bool key_found = false;
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void find_string(void* UNUSED(_ctx), cbor_data buffer, uint64_t len) {
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if (key_found) {
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printf("Found the value: %.*s\n", (int)len, buffer);
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key_found = false;
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} else if (len == strlen(key)) {
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key_found = (memcmp(key, buffer, len) == 0);
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}
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}
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int main(int argc, char* argv[]) {
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if (argc != 2) usage();
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FILE* f = fopen(argv[1], "rb");
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if (f == NULL) usage();
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fseek(f, 0, SEEK_END);
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size_t length = (size_t)ftell(f);
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fseek(f, 0, SEEK_SET);
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unsigned char* buffer = malloc(length);
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fread(buffer, length, 1, f);
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struct cbor_callbacks callbacks = cbor_empty_callbacks;
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struct cbor_decoder_result decode_result;
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size_t bytes_read = 0;
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callbacks.string = find_string;
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while (bytes_read < length) {
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decode_result = cbor_stream_decode(buffer + bytes_read, length - bytes_read,
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&callbacks, NULL);
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bytes_read += decode_result.read;
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}
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free(buffer);
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fclose(f);
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}
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