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, 76 insertions, 0 deletions

diff --git a/src/osc/clipboard.c b/src/osc/clipboard.c
new file mode 100644
index 0000000..a5ac59d
--- /dev/null
+++ b/src/osc/clipboard.c
@@ -0,0 +1,76 @@
+#include "osc.h"
+#include "../internal.h"
+#include <stdlib.h>
+#include <string.h>
+
+static int b64_val(char c)
+{
+    if (c >= 'A' && c <= 'Z') return c - 'A';
+    if (c >= 'a' && c <= 'z') return c - 'a' + 26;
+    if (c >= '0' && c <= '9') return c - '0' + 52;
+    if (c == '+') return 62;
+    if (c == '/') return 63;
+    return -1;
+}
+
+static bool b64_decode(const char *s, size_t n, char *out, size_t *out_len)
+{
+    size_t pad = 0;
+    while (pad < n && s[n - pad - 1] == '=')
+        pad++;
+    n -= pad;
+    if (pad > 2 || (pad && n % 4 + pad != 4))
+        return false;
+    size_t rem = n % 4;
+    if (rem == 1)
+        return false;
+    size_t i = 0, o = 0;
+    for (; i + 4 <= n; i += 4) {
+        int a = b64_val(s[i]), b = b64_val(s[i + 1]);
+        int c = b64_val(s[i + 2]), d = b64_val(s[i + 3]);
+        if ((a | b | c | d) < 0)
+            return false;
+        out[o++] = (char)(a << 2 | b >> 4);
+        out[o++] = (char)(b << 4 | c >> 2);
+        out[o++] = (char)(c << 6 | d);
+    }
+    if (rem >= 2) {
+        int a = b64_val(s[i]), b = b64_val(s[i + 1]);
+        if ((a | b) < 0)
+            return false;
+        out[o++] = (char)(a << 2 | b >> 4);
+        if (rem == 3) {
+            int c = b64_val(s[i + 2]);
+            if (c < 0)
+                return false;
+            out[o++] = (char)(b << 4 | c >> 2);
+        }
+    }
+    *out_len = o;
+    return true;
+}
+
+void term_osc52(struct term *t, const char *params)
+{
+    const char *sep = strchr(params, ';');
+    if (!sep || sep == params)
+        return;
+    const char *pd = sep + 1;
+    if (!strcmp(pd, "?") || !t->cb.clipboard)
+        return;
+    size_t sel_len = (size_t)(sep - params);
+    char sel[64];
+    if (sel_len >= sizeof(sel))
+        return;
+    memcpy(sel, params, sel_len);
+    sel[sel_len] = '\0';
+    if (!*pd) {
+        t->cb.clipboard(t->cb.ud, sel, "", 0);
+        return;
+    }
+    size_t enc_len = strlen(pd);
+    char *dec = (char *)pd;
+    size_t dec_len;
+    if (b64_decode(pd, enc_len, dec, &dec_len))
+        t->cb.clipboard(t->cb.ud, sel, dec, dec_len);
+}