ttf.c/ttf.h/ttftest.c: TrueType parser core -- sfnt/head/maxp/loca/glyf/cmap (item 4.3.7)

Freestanding C module resolving a Unicode codepoint (cmap format 4) to a glyph index and its outline header (contour count, bounding box), verified against an independent from-scratch Python reference reader via tools/ttftest.c. Not yet wired into the boot path or capsule system. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
2026-08-10 21:41:42 -04:00
parent b9b7cb2c6a
commit 5f6cc054d4
4 changed files with 552 additions and 1 deletions
@@ -0,0 +1,126 @@
+/*
+  StarForth — Steady-State Virtual Machine Runtime
+
+  Copyright (c) 2023–2025 Robert A. James
+  All rights reserved.
+
+  Licensed under the StarForth License, Version 1.0.
+*/
+
+/**
+ * ttftest.c — Host-side unit test for src/starkernel/hal/ttf.c (FABRIC.md
+ * item 4.3.7). No QEMU needed, same pattern as tools/README.md's fbtest.c
+ * entry (that file is itself missing from tools/ — stale doc, reported
+ * separately, not fixed here).
+ *
+ * Expected values below were independently computed by a from-scratch
+ * Python/struct reference reader (not this codebase's parser), against
+ * JetBrainsMono-Regular.ttf.
+ *
+ * Usage: ./ttftest <path-to-ttf>
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "../include/starkernel/ttf.h"
+
+typedef struct {
+    uint32_t codepoint;
+    uint32_t expect_glyph;
+    int16_t expect_contours;
+    int16_t expect_xmin, expect_ymin, expect_xmax, expect_ymax;
+    uint32_t expect_glyf_offset;
+    uint32_t expect_glyf_length;
+} expect_t;
+
+static const expect_t EXPECTED[] = {
+    /*   cp     glyph   nc  xmin ymin xmax ymax    off      len */
+    {0x0041, 1, 2, 50, 0, 550, 730, 35536, 112},   /* 'A' */
+    {0x0061, 198, 2, 67, -10, 508, 560, 46968, 244}, /* 'a' */
+    {0x0030, 737, 3, 80, -10, 520, 740, 92152, 184}, /* '0' */
+    {0x002E, 908, 1, 218, -10, 382, 152, 110044, 72}, /* '.' */
+    {0x0021, 913, 2, 225, -5, 375, 730, 110632, 108}, /* '!' */
+    {0x0040, 1151, 2, 45, -180, 560, 740, 144400, 224}, /* '@' */
+    {0x0020, 821, 0, 0, 0, 0, 0, 99448, 0},         /* space, empty glyph */
+};
+
+static int failures = 0;
+
+static void check_eq_i(const char *what, uint32_t cp, long got, long want) {
+    if (got != want) {
+        printf("  FAIL U+%04X %s: got %ld want %ld\n", cp, what, got, want);
+        failures++;
+    }
+}
+
+int main(int argc, char **argv) {
+    FILE *fp;
+    long size;
+    uint8_t *buf;
+    ttf_font_t font;
+    int rc;
+    size_t i;
+
+    if (argc < 2) {
+        fprintf(stderr, "usage: %s <path-to-ttf>\n", argv[0]);
+        return 2;
+    }
+
+    fp = fopen(argv[1], "rb");
+    if (!fp) {
+        perror("fopen");
+        return 2;
+    }
+    fseek(fp, 0, SEEK_END);
+    size = ftell(fp);
+    fseek(fp, 0, SEEK_SET);
+    buf = malloc((size_t) size);
+    if (!buf || fread(buf, 1, (size_t) size, fp) != (size_t) size) {
+        fprintf(stderr, "read failed\n");
+        return 2;
+    }
+    fclose(fp);
+
+    rc = ttf_parse(buf, (uint32_t) size, &font);
+    if (rc != TTF_OK) {
+        printf("ttf_parse failed: rc=%d\n", rc);
+        return 1;
+    }
+    printf("parsed: unitsPerEm=%u numGlyphs=%u indexToLocFormat=%d has_cmap=%d\n",
+           font.units_per_em, font.num_glyphs, font.index_to_loc_format, font.has_cmap);
+
+    for (i = 0; i < sizeof(EXPECTED) / sizeof(EXPECTED[0]); i++) {
+        const expect_t *e = &EXPECTED[i];
+        uint32_t gid = ttf_codepoint_to_glyph(&font, e->codepoint);
+        ttf_glyph_header_t hdr;
+        int hrc;
+
+        printf("U+%04X -> glyph %u (want %u)\n", e->codepoint, gid, e->expect_glyph);
+        check_eq_i("glyph", e->codepoint, gid, e->expect_glyph);
+
+        hrc = ttf_glyph_header(&font, gid, &hdr);
+        if (hrc != TTF_OK) {
+            printf("  FAIL U+%04X ttf_glyph_header rc=%d\n", e->codepoint, hrc);
+            failures++;
+            continue;
+        }
+        check_eq_i("num_contours", e->codepoint, hdr.num_contours, e->expect_contours);
+        check_eq_i("x_min", e->codepoint, hdr.x_min, e->expect_xmin);
+        check_eq_i("y_min", e->codepoint, hdr.y_min, e->expect_ymin);
+        check_eq_i("x_max", e->codepoint, hdr.x_max, e->expect_xmax);
+        check_eq_i("y_max", e->codepoint, hdr.y_max, e->expect_ymax);
+        check_eq_i("glyf_offset", e->codepoint, hdr.glyf_offset, e->expect_glyf_offset);
+        check_eq_i("glyf_length", e->codepoint, hdr.glyf_length, e->expect_glyf_length);
+    }
+
+    free(buf);
+
+    if (failures) {
+        printf("%d check(s) FAILED\n", failures);
+        return 1;
+    }
+    printf("all checks passed\n");
+    return 0;
+}