some progress

Common/bin.c

@@ -0,0 +1,64 @@
+#include <stddef.h>
+#include <stdint.h>
+
+#include "bin.h"
+#include "bits.h"
+#include "buf.h"
+#include "def.h"
+#include "std.h"
+
+bool com_bin_read_i16(com_bin *b, int16_t *value) {
+  int16_t buf;
+  if (!b->interface.readn(b->ctx, (char *)&buf, 2))
+    return false;
+  if (COM_DEF_CPU_LITEND && (b->flags & COM_BIN_BIG_ENDIAN)) {
+    *value = __builtin_bswap16(buf);
+  } else
+    *value = buf;
+  return true;
+}
+
+/* Same thing, really. */
+bool com_bin_read_u16(com_bin *b, uint16_t *value) {
+  return (com_bin_read_i16(b, (int16_t *)value));
+}
+
+bool com_bin_read_bufb(com_bin *b, struct com_buf *buf, uint32_t bytes) {
+  com_std_assert(buf->typesz == 1);
+
+  if (!com_buf_make_room(buf, bytes))
+    return false;
+  bool s = b->interface.readn(b->ctx, (char *)&buf->data[buf->len], bytes);
+  if (s)
+    buf->len += bytes;
+  return s;
+}
+
+bool com_bin_read_bufbi(com_bin *b, struct com_buf *buf, uint32_t *index,
+                        uint32_t bytes) {
+  com_std_assert(buf->typesz == 1);
+
+  uint32_t const alignextra =
+      com_bits_nalign(buf->len, COM_DEF_ALIGNMENT) - buf->len;
+
+  if (!com_buf_make_room(buf, alignextra + sizeof(struct com_buf) + bytes))
+    return false;
+
+  buf->len += alignextra;
+  struct com_buf *in = (struct com_buf *)&buf->data[buf->len];
+  buf->len += sizeof(struct com_buf);
+  bool s = b->interface.readn(b->ctx, (char *)&buf->data[buf->len], bytes);
+  if (s) {
+    buf->len += bytes;
+    *in = (struct com_buf){.cap = bytes,
+                           .len = bytes,
+                           .typesz = 1,
+                           .flags = (buf->flags & COM_BUF_STACK) | COM_BUF_SUB};
+    *index = ((ptrdiff_t)in - (ptrdiff_t)buf->data) / sizeof(struct com_buf);
+  }
+  return s;
+}
+
+bool com_bin_skip(com_bin *b, uint32_t bytes) {
+  return b->interface.skipn(b->ctx, bytes);
+}