stdlib: Add interior vector-ified versions of ebml and term

Author: pcwalton

src/lib/ebmlivec.rs

@@ -0,0 +1,172 @@
+
+
+// Simple Extensible Binary Markup Language (ebml) reader and writer on a
+// cursor model. See the specification here:
+//     http://www.matroska.org/technical/specs/rfc/index.html
+import option::none;
+import option::some;
+
+type ebml_tag = rec(uint id, uint size);
+
+type ebml_state = rec(ebml_tag ebml_tag, uint tag_pos, uint data_pos);
+
+
+// TODO: When we have module renaming, make "reader" and "writer" separate
+// modules within this file.
+
+// ebml reading
+type doc = rec(u8[] data, uint start, uint end);
+
+fn vint_at(&u8[] data, uint start) -> tup(uint, uint) {
+    auto a = data.(start);
+    if (a & 0x80u8 != 0u8) { ret tup(a & 0x7fu8 as uint, start + 1u); }
+    if (a & 0x40u8 != 0u8) {
+        ret tup((a & 0x3fu8 as uint) << 8u | (data.(start + 1u) as uint),
+                start + 2u);
+    } else if (a & 0x20u8 != 0u8) {
+        ret tup((a & 0x1fu8 as uint) << 16u |
+                    (data.(start + 1u) as uint) << 8u |
+                    (data.(start + 2u) as uint), start + 3u);
+    } else if (a & 0x10u8 != 0u8) {
+        ret tup((a & 0x0fu8 as uint) << 24u |
+                    (data.(start + 1u) as uint) << 16u |
+                    (data.(start + 2u) as uint) << 8u |
+                    (data.(start + 3u) as uint), start + 4u);
+    } else { log_err "vint too big"; fail; }
+}
+
+fn new_doc(&u8[] data) -> doc {
+    ret rec(data=data, start=0u, end=ivec::len[u8](data));
+}
+
+fn doc_at(&u8[] data, uint start) -> doc {
+    auto elt_tag = vint_at(data, start);
+    auto elt_size = vint_at(data, elt_tag._1);
+    auto end = elt_size._1 + elt_size._0;
+    ret rec(data=data, start=elt_size._1, end=end);
+}
+
+fn maybe_get_doc(doc d, uint tg) -> option::t[doc] {
+    auto pos = d.start;
+    while (pos < d.end) {
+        auto elt_tag = vint_at(d.data, pos);
+        auto elt_size = vint_at(d.data, elt_tag._1);
+        pos = elt_size._1 + elt_size._0;
+        if (elt_tag._0 == tg) {
+            ret some[doc](rec(data=d.data, start=elt_size._1, end=pos));
+        }
+    }
+    ret none[doc];
+}
+
+fn get_doc(doc d, uint tg) -> doc {
+    alt (maybe_get_doc(d, tg)) {
+        case (some(?d)) { ret d; }
+        case (none) {
+            log_err "failed to find block with tag " + uint::to_str(tg, 10u);
+            fail;
+        }
+    }
+}
+
+iter docs(doc d) -> tup(uint, doc) {
+    auto pos = d.start;
+    while (pos < d.end) {
+        auto elt_tag = vint_at(d.data, pos);
+        auto elt_size = vint_at(d.data, elt_tag._1);
+        pos = elt_size._1 + elt_size._0;
+        put tup(elt_tag._0, rec(data=d.data, start=elt_size._1, end=pos));
+    }
+}
+
+iter tagged_docs(doc d, uint tg) -> doc {
+    auto pos = d.start;
+    while (pos < d.end) {
+        auto elt_tag = vint_at(d.data, pos);
+        auto elt_size = vint_at(d.data, elt_tag._1);
+        pos = elt_size._1 + elt_size._0;
+        if (elt_tag._0 == tg) {
+            put rec(data=d.data, start=elt_size._1, end=pos);
+        }
+    }
+}
+
+fn doc_data(doc d) -> u8[] { ret ivec::slice[u8](d.data, d.start, d.end); }
+
+fn be_uint_from_bytes(&u8[] data, uint start, uint size) -> uint {
+    auto sz = size;
+    assert (sz <= 4u);
+    auto val = 0u;
+    auto pos = start;
+    while (sz > 0u) {
+        sz -= 1u;
+        val += (data.(pos) as uint) << sz * 8u;
+        pos += 1u;
+    }
+    ret val;
+}
+
+fn doc_as_uint(doc d) -> uint {
+    ret be_uint_from_bytes(d.data, d.start, d.end - d.start);
+}
+
+
+// ebml writing
+type writer = rec(ioivec::buf_writer writer, mutable uint[] size_positions);
+
+fn write_sized_vint(&ioivec::buf_writer w, uint n, uint size) {
+    let u8[] buf;
+    alt (size) {
+        case (1u) { buf = ~[0x80u8 | (n as u8)]; }
+        case (2u) { buf = ~[0x40u8 | (n >> 8u as u8), n & 0xffu as u8]; }
+        case (3u) {
+            buf =
+                ~[0x20u8 | (n >> 16u as u8), n >> 8u & 0xffu as u8,
+                  n & 0xffu as u8];
+        }
+        case (4u) {
+            buf =
+                ~[0x10u8 | (n >> 24u as u8), n >> 16u & 0xffu as u8,
+                  n >> 8u & 0xffu as u8, n & 0xffu as u8];
+        }
+        case (_) { log_err "vint to write too big"; fail; }
+    }
+    w.write(buf);
+}
+
+fn write_vint(&ioivec::buf_writer w, uint n) {
+    if (n < 0x7fu) { write_sized_vint(w, n, 1u); ret; }
+    if (n < 0x4000u) { write_sized_vint(w, n, 2u); ret; }
+    if (n < 0x200000u) { write_sized_vint(w, n, 3u); ret; }
+    if (n < 0x10000000u) { write_sized_vint(w, n, 4u); ret; }
+    log_err "vint to write too big";
+    fail;
+}
+
+fn create_writer(&ioivec::buf_writer w) -> writer {
+    let uint[] size_positions = ~[];
+    ret rec(writer=w, mutable size_positions=size_positions);
+}
+
+
+// TODO: Provide a function to write the standard ebml header.
+fn start_tag(&writer w, uint tag_id) {
+    // Write the tag ID:
+
+    write_vint(w.writer, tag_id);
+    // Write a placeholder four-byte size.
+
+    w.size_positions += ~[w.writer.tell()];
+    let u8[] zeroes = ~[0u8, 0u8, 0u8, 0u8];
+    w.writer.write(zeroes);
+}
+
+fn end_tag(&writer w) {
+    auto last_size_pos = ivec::pop[uint](w.size_positions);
+    auto cur_pos = w.writer.tell();
+    w.writer.seek(last_size_pos as int, ioivec::seek_set);
+    write_sized_vint(w.writer, cur_pos - last_size_pos - 4u, 4u);
+    w.writer.seek(cur_pos as int, ioivec::seek_set);
+}
+// TODO: optionally perform "relaxations" on end_tag to more efficiently
+// encode sizes; this is a fixed point iteration

src/lib/std.rc

@@ -90,6 +90,8 @@ mod smallintmap;
 mod ptr;
 mod test;
 mod unsafe;
+mod ebmlivec;
+mod termivec;
 
 // Local Variables:
 // mode: rust;

src/lib/termivec.rs

@@ -0,0 +1,81 @@
+
+
+
+// Simple ANSI color library.
+//
+// TODO: Windows support.
+const u8 color_black = 0u8;
+
+const u8 color_red = 1u8;
+
+const u8 color_green = 2u8;
+
+const u8 color_yellow = 3u8;
+
+const u8 color_blue = 4u8;
+
+const u8 color_magenta = 5u8;
+
+const u8 color_cyan = 6u8;
+
+const u8 color_light_gray = 7u8;
+
+const u8 color_light_grey = 7u8;
+
+const u8 color_dark_gray = 8u8;
+
+const u8 color_dark_grey = 8u8;
+
+const u8 color_bright_red = 9u8;
+
+const u8 color_bright_green = 10u8;
+
+const u8 color_bright_yellow = 11u8;
+
+const u8 color_bright_blue = 12u8;
+
+const u8 color_bright_magenta = 13u8;
+
+const u8 color_bright_cyan = 14u8;
+
+const u8 color_bright_white = 15u8;
+
+fn esc(ioivec::buf_writer writer) { writer.write(~[0x1bu8, '[' as u8]); }
+
+fn reset(ioivec::buf_writer writer) {
+    esc(writer);
+    writer.write(~['0' as u8, 'm' as u8]);
+}
+
+fn color_supported() -> bool {
+    auto supported_terms = ["xterm-color", "xterm", "screen-bce"];
+    ret alt (generic_os::getenv("TERM")) {
+            case (option::some(?env)) { vec::member(env, supported_terms) }
+            case (option::none) { false }
+        };
+}
+
+fn set_color(ioivec::buf_writer writer, u8 first_char, u8 color) {
+    assert (color < 16u8);
+    esc(writer);
+    if (color >= 8u8) { writer.write(~['1' as u8, ';' as u8]); color -= 8u8; }
+    writer.write(~[first_char, ('0' as u8) + color, 'm' as u8]);
+}
+
+fn fg(ioivec::buf_writer writer, u8 color) {
+    ret set_color(writer, '3' as u8, color);
+}
+
+fn bg(ioivec::buf_writer writer, u8 color) {
+    ret set_color(writer, '4' as u8, color);
+}
+// export fg;
+// export bg;
+
+// Local Variables:
+// 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: