vendor/libcbor/0.8.0

1 files changed, 58 insertions, 0 deletions

diff --git a/examples/streaming_parser.c b/examples/streaming_parser.c
new file mode 100644
index 000000000000..fe3ab853d978
--- /dev/null
+++ b/examples/streaming_parser.c
@@ -0,0 +1,58 @@
+/*
+ * Copyright (c) 2014-2020 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 <stdio.h>
+#include <string.h>
+#include "cbor.h"
+
+void usage() {
+  printf("Usage: streaming_parser [input file]\n");
+  exit(1);
+}
+
+/*
+ * Illustrates how one might skim through a map (which is assumed to have
+ * string keys and values only), looking for the value of a specific key
+ *
+ * Use the examples/data/map.cbor input to test this.
+ */
+
+const char* key = "a secret key";
+bool key_found = false;
+
+void find_string(void* _ctx, cbor_data buffer, size_t len) {
+  if (key_found) {
+    printf("Found the value: %.*s\n", (int)len, buffer);
+    key_found = false;
+  } else if (len == strlen(key)) {
+    key_found = (memcmp(key, buffer, len) == 0);
+  }
+}
+
+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);
+
+  struct cbor_callbacks callbacks = cbor_empty_callbacks;
+  struct cbor_decoder_result decode_result;
+  size_t bytes_read = 0;
+  callbacks.string = find_string;
+  while (bytes_read < length) {
+    decode_result = cbor_stream_decode(buffer + bytes_read, length - bytes_read,
+                                       &callbacks, NULL);
+    bytes_read += decode_result.read;
+  }
+
+  free(buffer);
+  fclose(f);
+}