maraiah: use Read for shapes

maraiah/shp.rs

@@ -7,6 +7,7 @@ pub mod fram;
 pub mod sequ;
 
 use crate::{bin::usize_from_u32, err::*};
+use std::io::prelude::*;
 
 /// Reads a collection at an offset provided by the Shapes header.
 pub fn read_coll_at_offset(b: &[u8],
@@ -23,14 +24,17 @@ pub fn read_coll_at_offset(b: &[u8],
 }
 
 /// Read all of the collections in a Shapes file.
-pub fn read(b: &[u8]) -> ResultS<Vec<CollectionDef>>
+pub fn read(fp: &mut impl Read) -> ResultS<Collections>
 {
-   let mut cl = Vec::with_capacity(32);
+   let mut b = Vec::new();
-   let mut p  = 0;
+   fp.read_to_end(&mut b)?;
 
-   for _ in 0..32 {
+   // hush little rustc, don't say a word...
+   let mut collections: Collections = unsafe {std::mem::uninitialized()};
+
+   for (i, co) in collections.iter_mut().enumerate() {
       read_data! {
-         endian: BIG, buf: b, size: 32, start: p, data {
+         endian: BIG, buf: &b, size: 32, start: i * 32, data {
             let lo_ofs = u32[4];
             let lo_len = u32[8] usize;
             let hi_ofs = u32[12];
@@ -38,18 +42,19 @@ pub fn read(b: &[u8]) -> ResultS<Vec<CollectionDef>>
          }
       }
 
-      let lo = read_coll_at_offset(b, lo_ofs, lo_len)?;
+      let lo = read_coll_at_offset(&b, lo_ofs, lo_len)?;
-      let hi = read_coll_at_offset(b, hi_ofs, hi_len)?;
+      let hi = read_coll_at_offset(&b, hi_ofs, hi_len)?;
 
-      cl.push((lo, hi));
+      *co = (lo, hi);
-
-      p += 32;
    }
 
-   Ok(cl)
+   Ok(collections)
 }
 
 /// A collection, which may have low- and high-definition variations, or none.
 pub type CollectionDef = (Option<coll::Collection>, Option<coll::Collection>);
 
+/// The set of all collections in a Shapes file.
+pub type Collections = [CollectionDef; 32];
+
 // EOF

tests/shp.rs

@@ -10,7 +10,9 @@ fn shp_must_not_process()
       assert!(shp::coll::read(inp).is_err());
       assert!(shp::fram::read(inp).is_err());
       assert!(shp::sequ::read(inp).is_err());
-      assert!(shp::read(inp).is_err());
+
+      let mut inp = std::io::BufReader::new(&inp[..]);
+      assert!(shp::read(&mut inp).is_err());
    }
 }