osmpbf-parser's Introduction

osmpbf-parser

parse open street map protobuf files and scan for records with explicit file offsets

This crate differs from osmpbf mainly in that you get explicit u64 file offsets for jumping and scanning and can bring your own concurrency strategy by creating many file handles and parser instances for the same file to fan out operations in parallel.

This example loops over all the blobs in an osmpbf file and prints diagnostic info such as the element type (node, way, or relation), the file offset and byte length of each blob, the number of items, and the range of ids.

use std::fs::File;
use osmpbf_parser::{Parser,Element};

type Error = Box<dyn std::error::Error+Send+Sync+'static>;

fn main() -> Result<(),Error> {
  let args = std::env::args().collect::<Vec<String>>();
  let h = File::open(&args[1])?;
  let file_len = h.metadata()?.len();
  let mut opd = Parser::new(Box::new(h));
  let mut offset = 0;
  while offset < file_len {
    let (byte_len,items) = opd.read(offset)?;
    let mut etype = "";
    let mut min_id = i64::MAX;
    let mut max_id = i64::MIN;
    for item in items.iter() {
      match item {
        Element::Node(node) => {
          etype = "node";
          min_id = node.id.min(min_id);
          max_id = node.id.max(max_id);
        },
        Element::Way(way) => {
          etype = "way";
          min_id = way.id.min(min_id);
          max_id = way.id.max(max_id);
        },
        Element::Relation(relation) => {
          etype = "relation";
          min_id = relation.id.min(min_id);
          max_id = relation.id.max(max_id);
        },
      }
    }
    if !items.is_empty() {
      println!["{}: offset={} byte_len={} items.len()={} id range {}..{}",
        etype, offset, byte_len, items.len(), min_id, max_id];
    }
    offset += byte_len;
  }
  Ok(())
}