main-c.c

#include <string.h>
#include <stdio.h>
#include <tree_sitter/api.h>
#include <stdlib.h>

TSLanguage *tree_sitter_c();

struct buffer {
  char *buf;
  long len;
};

const char *read_file(void *payload, uint32_t byte_index,
                TSPoint position, uint32_t *bytes_read) {
  long len = ((struct buffer *) payload)->len;
  if (byte_index >= len) {
    *bytes_read = 0;
    return (char *) "";
  } else {
    *bytes_read = len - byte_index;
    return (char *) (((struct buffer *) payload)->buf) + byte_index;
  }
}

int main() {

  ts_set_allocator(malloc, calloc, realloc, free);

  TSParser *parser = ts_parser_new();
  ts_parser_set_language(parser, tree_sitter_c());

  /* Copy the file into BUFFER. */
  FILE *file = fopen("xdisp.c", "rb");
  fseek(file, 0, SEEK_END);
  long length = ftell (file);
  fseek(file, 0, SEEK_SET);
  char *buffer = malloc (length);
  fread(buffer, 1, length, file);
  fclose (file);

  struct buffer buf = {buffer, length};
  TSInput input = {&buf, read_file, TSInputEncodingUTF8};
  
  TSTree *tree = ts_parser_parse(parser, NULL, input);
  TSTree *new_tree = ts_parser_parse(parser, tree, input);
  
  free(buffer);
  ts_tree_delete(tree);
  ts_tree_delete(new_tree);
  ts_parser_delete(parser);

  return 0;
}