From 1af3174fe3b565371a5978381f604ea9c01e86d3 Mon Sep 17 00:00:00 2001
From: Marijn Haverbeke <marijnh@gmail.com>
Date: Fri, 8 Apr 2011 18:44:20 +0200
Subject: Move to single-uint file-position representation.

This makes passing them around cheaper. There is now a table (see
front/codemap.rs) that is needed to transform such an uint into an
actual filename/line/col location.

Also cleans up the span building in the parser a bit.
---
 src/comp/front/codemap.rs | 65 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 65 insertions(+)
 create mode 100644 src/comp/front/codemap.rs

(limited to 'src/comp/front/codemap.rs')

diff --git a/src/comp/front/codemap.rs b/src/comp/front/codemap.rs
new file mode 100644
index 00000000..20b4e2ee
--- /dev/null
+++ b/src/comp/front/codemap.rs
@@ -0,0 +1,65 @@
+import std._vec;
+
+/* A codemap is a thing that maps uints to file/line/column positions
+ * in a crate. This to make it possible to represent the positions
+ * with single-word things, rather than passing records all over the
+ * compiler.
+ */
+
+type filemap = @rec(str name,
+                    uint start_pos,
+                    mutable vec[uint] lines);
+type codemap = @rec(mutable vec[filemap] files);
+type loc = rec(str filename, uint line, uint col);
+
+fn new_codemap() -> codemap {
+    let vec[filemap] files = vec();
+    ret @rec(mutable files=files);
+}
+
+fn new_filemap(str filename, uint start_pos) -> filemap {
+    let vec[uint] lines = vec();
+    ret @rec(name=filename,
+             start_pos=start_pos,
+             mutable lines=lines);
+}
+
+fn next_line(filemap file, uint pos) {
+    _vec.push[uint](file.lines, pos);
+}
+
+fn lookup_pos(codemap map, uint pos) -> loc {
+    for (filemap f in map.files) {
+        if (f.start_pos < pos) {
+            auto line_num = 1u;
+            auto line_start = 0u;
+            // FIXME this can be a binary search if we need to be faster
+            for (uint line_start_ in f.lines) {
+                // FIXME duplicate code due to lack of working break
+                if (line_start_ > pos) {
+                    ret rec(filename=f.name,
+                            line=line_num,
+                            col=pos-line_start);
+                }
+                line_start = line_start_;
+                line_num += 1u;
+            }
+            ret rec(filename=f.name,
+                    line=line_num,
+                    col=pos-line_start);
+        }
+    }
+    log #fmt("Failed to find a location for character %u", pos);
+    fail;
+}
+
+//
+// Local Variables:
+// mode: rust
+// fill-column: 78;
+// indent-tabs-mode: nil
+// c-basic-offset: 4
+// buffer-file-coding-system: utf-8-unix
+// compile-command: "make -k -C $RBUILD 2>&1 | sed -e 's/\\/x\\//x:\\//g'";
+// End:
+//
-- 
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