some progress

2026-10-07 11:21:21 +03:00
parent 14062e9d00
commit 8d502173a2
26 changed files with 705 additions and 212 deletions
@@ -0,0 +1,57 @@
+/*
+    Generic buffer structure, both dynamic and static.
+
+    Underlying implementation is very simplistic, but it's done so
+    in assumption that we always bulk allocate, with no fragmentation.
+*/
+
+#ifndef COM_BUF_H
+#define COM_BUF_H
+
+#include "def.h"
+#include "str.h"
+#include <stdbool.h>
+#include <stdint.h>
+
+#define COM_BUF_GROWABLE (1 << 0) /* Potentially growable. */
+#define COM_BUF_STACK (1 << 1)    /* Stack residing. */
+#define COM_BUF_RING (1 << 2)     /* Cycling memory. */
+#define COM_BUF_SUB (1 << 3)      /* Buffer inside of a buffer. */
+
+typedef struct com_buf {
+  uint32_t len; /* Length in typed number of elements. */
+  uint32_t cap; /* Capacity in typed number of elements. */
+  uint32_t flags;
+  union {
+    uint32_t needle; /* Present for ring type. */
+  } type;
+  uint8_t typesz;
+  char data[] __attribute__((aligned(COM_DEF_ALIGNMENT)));
+} com_buf;
+
+/* Creates a stack local buffer. It can grow if is set growable, one must still
+ * free it. */
+#define com_buf_make_on_stack(p_t, p_v, p_c, p_f)                              \
+  char p_v##_buf[sizeof(p_t) * (p_c)]                                          \
+      __attribute__((aligned(COM_DEF_ALIGNMENT)));                             \
+  struct com_buf *p_v = (struct com_buf *)&p_v##_buf;                          \
+  p_v->cap = (p_c);                                                            \
+  p_v->flags = p_f | COM_BUF_STACK;                                            \
+  p_v->typesz = sizeof(p_t);
+
+#define com_buf_index(p_t, p_v, p_i)                                           \
+  (p_t *)(&(p_v)->data[(p_v)->typesz * (p_i)])
+
+/* Dynamic allocation to persist no matter the function flow. */
+struct com_buf *com_buf_make(uint32_t cap, uint32_t flags);
+
+/* Makes sure there's N elements of capacity at least. Returns false if it
+ * cannot do so. */
+bool com_buf_make_room(struct com_buf *b, uint32_t n);
+
+/* Drops the memory, not touching the cap. */
+static inline void com_buf_clear(struct com_buf *b) { b->len = 0; }
+
+void com_buf_free(struct com_buf *b);
+
+#endif