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/*
* event-streaming.c - Event-based streaming parser example
*
* Demonstrates:
* - Event-based (streaming) YAML parsing
* - Processing different event types
* - Memory-efficient parsing of large files
* - Getting values from scalar events
*
* Copyright (c) 2019-2025 Pantelis Antoniou <pantelis.antoniou@konsulko.com>
*
* SPDX-License-Identifier: MIT
*/
#include <stdlib.h>
#include <stdio.h>
#include <libfyaml.h>
int main(int argc, char *argv[])
{
struct fy_parser *fyp = NULL;
struct fy_event *fye = NULL;
const char *input_file = (argc > 1) ? argv[1] : "config.yaml";
int indent = 0;
int ret = EXIT_FAILURE;
// Create parser
fyp = fy_parser_create(NULL);
if (!fyp) {
fprintf(stderr, "Failed to create parser\n");
return EXIT_FAILURE;
}
// Set input file
if (fy_parser_set_input_file(fyp, input_file)) {
fprintf(stderr, "Failed to set input file: %s\n", input_file);
fprintf(stderr, "Note: Create config.yaml or pass file as argument\n");
goto cleanup;
}
printf("Parsing events from: %s\n\n", input_file);
// Process events
while ((fye = fy_parser_parse(fyp)) != NULL) {
enum fy_event_type type = fye->type;
// Print indentation
for (int i = 0; i < indent; i++)
printf(" ");
switch (type) {
case FYET_STREAM_START:
printf("STREAM-START\n");
break;
case FYET_STREAM_END:
printf("STREAM-END\n");
break;
case FYET_DOCUMENT_START:
printf("DOCUMENT-START\n");
indent++;
break;
case FYET_DOCUMENT_END:
indent--;
printf("DOCUMENT-END\n");
break;
case FYET_MAPPING_START:
printf("MAPPING-START\n");
indent++;
break;
case FYET_MAPPING_END:
indent--;
printf("MAPPING-END\n");
break;
case FYET_SEQUENCE_START:
printf("SEQUENCE-START\n");
indent++;
break;
case FYET_SEQUENCE_END:
indent--;
printf("SEQUENCE-END\n");
break;
case FYET_SCALAR: {
// Get the scalar value
const char *value = fy_token_get_text0(fy_event_get_token(fye));
printf("SCALAR: \"%s\"\n", value ? value : "(null)");
break;
}
case FYET_ALIAS: {
const char *anchor = fy_token_get_text0(fy_event_get_token(fye));
printf("ALIAS: *%s\n", anchor ? anchor : "(null)");
break;
}
default:
printf("OTHER-EVENT (type=%d)\n", type);
break;
}
fy_parser_event_free(fyp, fye);
}
printf("\nParsing completed successfully\n");
ret = EXIT_SUCCESS;
cleanup:
fy_parser_destroy(fyp);
return ret;
}
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