term: move the term core to subprojects/term

The core now builds, tests, and benchmarks alone, as a Meson subproject
with no dependency on the main tree.

- include/term/ holds term.h and the header-only unicode/. src/ holds
  the core and its private headers. The main tree gets only
  include/term through term_dep, so it cannot reach a private header.
- The term tests, the term benchmarks, the Kitty parser suite, and
  tools/amalgamate.py and tools/generate_unicode.py move with it. The
  tests run as term:<name>.
- The main build passes its -march (arch_flag) and b_ndebug to the
  subproject. A directory configured before this commit needs
  meson configure -Dterm:arch_flag=-march=... once.
- The term tests compile with -UNDEBUG. They do work inside assert.
- The subproject exports term_test_dep with term_api.h, for the main
  tree's render, thumbnail, color, and selection tests.
- The Kitty bridge used struct vector2i and has not compiled since the
  public API redesign. It builds again. 2 of its 14 tests fail: REP
  after a tab, and a cursor report after a resize.
- dirgraph.py drops the term and unicode layers. Its self-test uses pty.
- The symbols test ignores the __odr_asan symbols that ASan adds.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

1 files changed, 60 insertions, 0 deletions

diff --git a/src/hist_view.h b/src/hist_view.h
new file mode 100644
index 0000000..0214c0b
--- /dev/null
+++ b/src/hist_view.h
@@ -0,0 +1,60 @@
+#ifndef TERM_HIST_VIEW_H
+#define TERM_HIST_VIEW_H
+
+#include "hist.h"
+
+struct line_pos {
+    uint64_t id;
+    uint32_t seg;
+};
+
+struct view_anchor {
+    uint64_t line_id;
+    uint64_t cell;
+    uint64_t base_cell;
+    uint32_t seg;
+    bool active;
+};
+
+struct hist_view {
+    struct view_anchor anchor;
+
+    /* Line ids map to circular slots. Tree sums use physical slot order. */
+    uint64_t *fenwick;
+    uint32_t *counts;
+    uint64_t total_rows;
+    uint64_t first_id, end_id;
+    uint64_t epoch, head, tail, last_cells;
+    int cols;
+    uint32_t cap;
+    int index_cols;
+};
+
+void term_hist_view_init(struct hist_view *v);
+void term_hist_view_free(struct hist_view *v);
+void term_hist_view_clear(struct hist_view *v);
+
+/* Update the index during snapshot capture. Reads do not change it. */
+bool term_hist_view_sync(struct hist_view *v, const struct hist *h, int cols);
+void term_hist_view_refine(struct hist_view *v, struct hist *h, int cols, int rows);
+uint64_t term_hist_view_rows(const struct hist_view *v, const struct hist *h, int cols);
+bool term_hist_view_find_row(const struct hist_view *v, const struct hist *h, int row,
+                        int cols, uint64_t *id, int *seg);
+
+/* Read the offset from the anchor at the current width. */
+int term_hist_view_scroll_offset(const struct hist_view *v, const struct hist *h, int cols);
+void term_hist_view_scroll(struct hist_view *v, const struct hist *h, int cols,
+                      struct line_pos screen_top, int lines);
+void term_hist_view_scroll_to(struct hist_view *v, const struct hist *h, int cols,
+                         struct line_pos screen_top, int offset);
+void term_hist_view_reset_bottom(struct hist_view *v);
+
+/* Clamp an evicted anchor. This does not update the index on the write path. */
+void term_hist_view_note_push(struct hist_view *v, const struct hist *h, int cols);
+void term_hist_view_rewrap(struct hist_view *v, const struct hist *h, int cols);
+
+bool term_hist_view_row_pos(const struct hist_view *v, const struct hist *h, int cols,
+                       int screen_rows, struct line_pos screen_top, int y,
+                       uint64_t *out_id, int *out_seg, int *out_screen_y);
+
+#endif