Clean up fbclock

You can't use the return value of gzerror to check if an error occurred
or not. Its implementation actually checks if the internal error is NULL
and returns the empty string if it is! This is stupid and unhelpful, so
check gzeof first since its return value actually means something.

1 files changed, 24 insertions, 16 deletions

diff --git a/bin/fbclock.c b/bin/fbclock.c
index 97d931f7..605fa4e0 100644
--- a/bin/fbclock.c
+++ b/bin/fbclock.c
@@ -44,30 +44,40 @@ static const uint32_t BG = 0x1D2021;
 static const uint32_t FG = 0xA99A84;
 
 int main() {
-    size_t count;
+    size_t len;
 
     const char *fontPath = getenv("FONT");
-    if (!fontPath) fontPath = "/usr/share/kbd/consolefonts/Lat2-Terminus16.psfu.gz";
+    if (!fontPath) {
+        fontPath = "/usr/share/kbd/consolefonts/Lat2-Terminus16.psfu.gz";
+    }
 
     gzFile font = gzopen(fontPath, "r");
     if (!font) err(EX_NOINPUT, "%s", fontPath);
 
     struct Psf2Header header;
-    count = gzfread(&header, sizeof(header), 1, font);
-    if (!count) errx(EX_IOERR, "%s: %s", fontPath, gzerror(font, NULL));
+    len = gzfread(&header, sizeof(header), 1, font);
+    if (!len && gzeof(font)) errx(EX_DATAERR, "%s: missing header", fontPath);
+    if (!len) errx(EX_IOERR, "%s", gzerror(font, NULL));
 
     if (header.magic != PSF2_MAGIC) {
-        errx(EX_DATAERR, "%s: invalid header magic %#x", fontPath, header.magic);
+        errx(
+            EX_DATAERR, "%s: invalid header magic %08x",
+            fontPath, header.magic
+        );
     }
     if (header.headerSize != sizeof(struct Psf2Header)) {
-        errx(EX_DATAERR, "%s: weird header size %d", fontPath, header.headerSize);
+        errx(
+            EX_DATAERR, "%s: weird header size %d",
+            fontPath, header.headerSize
+        );
     }
 
     uint8_t glyphs[128][header.glyphSize];
-    count = gzfread(glyphs, header.glyphSize, 128, font);
-    if (!count) errx(EX_IOERR, "%s: %s", fontPath, gzerror(font, NULL));
+    len = gzfread(glyphs, header.glyphSize, 128, font);
+    if (!len && gzeof(font)) errx(EX_DATAERR, "%s: missing glyphs", fontPath);
+    if (!len) errx(EX_IOERR, "%s", gzerror(font, NULL));
 
-    assert(Z_OK == gzclose(font));
+    gzclose(font);
 
     const char *fbPath = getenv("FRAMEBUFFER");
     if (!fbPath) fbPath = "/dev/fb0";
@@ -79,8 +89,8 @@ int main() {
     int error = ioctl(fb, FBIOGET_VSCREENINFO, &info);
     if (error) err(EX_IOERR, "%s", fbPath);
 
-    size_t len = 4 * info.xres * info.yres;
-    uint32_t *buf = mmap(NULL, len, PROT_READ | PROT_WRITE, MAP_SHARED, fb, 0);
+    size_t size = 4 * info.xres * info.yres;
+    uint32_t *buf = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fb, 0);
     if (buf == MAP_FAILED) err(EX_IOERR, "%s", fbPath);
 
     for (;;) {
@@ -90,10 +100,10 @@ int main() {
         if (!local) err(EX_OSERR, "localtime");
 
         char str[64];
-        size_t len = strftime(str, sizeof(str), "%H:%M", local);
+        len = strftime(str, sizeof(str), "%H:%M", local);
         assert(len);
 
-        for (int i = 0; i < (60 - local->tm_sec); ++i) {
+        for (int i = 0; i < (60 - local->tm_sec); ++i, sleep(1)) {
             uint32_t left = info.xres - header.glyphWidth * len;
             uint32_t bottom = header.glyphHeight;
 
@@ -105,7 +115,7 @@ int main() {
             }
 
             for (const char *s = str; *s; ++s) {
-                uint8_t *glyph = glyphs[(uint8_t)*s];
+                const uint8_t *glyph = glyphs[(unsigned)*s];
                 uint32_t stride = header.glyphSize / header.glyphHeight;
                 for (uint32_t y = 0; y < header.glyphHeight; ++y) {
                     for (uint32_t x = 0; x < header.glyphWidth; ++x) {
@@ -116,8 +126,6 @@ int main() {
                 }
                 left += header.glyphWidth;
             }
-
-            sleep(1);
         }
     }
 }