kernel settings file

1 files changed, 91 insertions, 0 deletions

diff --git a/src/kernel/settings.c b/src/kernel/settings.c
new file mode 100644
index 0000000..699196b
--- /dev/null
+++ b/src/kernel/settings.c
@@ -0,0 +1,91 @@
+#include "window.h"
+#include "drive.h"
+#include "panic.h"
+#include "util.h"
+
+#include <stdint.h>
+
+#define SETTINGS_FILE "sys/settings.pls"
+
+static struct {
+  uint32_t main_start;
+  uint32_t main_entries;
+  uint32_t names_start;
+  uint32_t data_start;
+} settings_header;
+
+enum {
+  ST_SZ_STRING = 0x00,
+  ST_COLOR     = 0x01
+};
+
+struct main_entry {
+  uint32_t name_offset;
+  uint8_t name_len;
+  uint8_t type;
+  uint16_t pad;
+  union {
+    struct {
+      uint32_t data_offset;
+      uint32_t length;
+    } as_string;
+    struct pixel as_pixel;
+  };
+} __attribute__ ((__packed__));
+
+static file_id_t fid;
+static uint32_t main_end;
+
+void init_settings() {
+  fid = drives->get_file(drives, SETTINGS_FILE);
+  if (!fid)
+    PANIC("could not open settings file at \"" SETTINGS_FILE "\".");
+
+  fmcpy(&settings_header, drives, fid, 0, 16);
+
+  main_end = settings_header.main_start + settings_header.main_entries * sizeof(struct main_entry);
+}
+
+bool try_find_setting(const char *name, struct main_entry *entry_out) {
+  uint16_t name_len = 0;
+  while (name[name_len])
+    if (++name_len == 256)
+      return false;
+
+  for (uint32_t i = settings_header.main_start; i < main_end; i += sizeof(struct main_entry)) {
+    fmcpy(entry_out, drives, fid, i, sizeof(struct main_entry));
+    if (entry_out->name_len != name_len)
+      continue;
+    char found_name[255];
+    fmcpy(found_name, drives, fid, settings_header.names_start + entry_out->name_offset, name_len);
+    for (uint8_t j = 0; j < name_len; ++j)
+      if (found_name[j] != name[j])
+        goto lc;
+    return true;
+  lc:
+    ;
+  }
+
+  return false;
+}
+
+bool try_get_sz_setting(const char *name, char *out, uint32_t max_len, uint32_t *len_out) {
+  struct main_entry entry;
+  if (!try_find_setting(name, &entry) || (entry.type != ST_SZ_STRING))
+    return false;
+
+  const uint32_t len = entry.as_string.length > max_len ? max_len : entry.as_string.length;
+  fmcpy(out, drives, fid, settings_header.data_start + entry.as_string.data_offset, len);
+  out[len] = '\0';
+  *len_out = len;
+  return true;
+}
+
+bool try_get_color_setting(const char *name, struct pixel *out) {
+  struct main_entry entry;
+  if (!try_find_setting(name, &entry) || (entry.type != ST_COLOR))
+    return false;
+
+  *out = entry.as_pixel;
+  return true;
+}
\ No newline at end of file