1 files changed, 117 insertions, 0 deletions
diff --git a/mem.c b/mem.c
new file mode 100644
index 0000000..11c1c8c
--- /dev/null
+++ b/mem.c
@@ -0,0 +1,117 @@
+#include "common.h"
+#include <stdlib.h>
+#include <errno.h>
+#include <stdint.h>
+
+#define ALLOCERR(f) do {                  \
+   efmt("%s: %s\n", f, strerror(errno)); \
+   ioflush(&bstdout);                    \
+   ioflush(&bstderr);                    \
+   abort();                              \
+} while (0)
+
+static void *
+xcalloc(size_t n, const char *f)
+{
+   void *p = calloc(n, 1);
+   if (!p) ALLOCERR(f);
+   return p;
+}
+
+static void *
+xrealloc(void *p, size_t n, const char *f)
+{
+   p = p ? realloc(p, n) : malloc(n);
+   if (!p) ALLOCERR(f);
+   return p;
+}
+
+/* vec: when _cap < 0, buf is dynamic allocated, otherwise an user provided buf */
+
+void
+vinit_(void **p, int *pcap, void *inlbuf, int cap, uint siz)
+{
+   assert(!*p);
+   *pcap = cap;
+   if (inlbuf) {
+      *p = inlbuf; 
+   } else if (cap) {
+      *p = xrealloc(0, cap*siz, "vinit");
+      *pcap = -cap;
+   }
+}
+
+void
+vpush_(void **p, int *pcap, uint *pn, uint siz)
+{
+   if (*pn == *pcap) { /* empty or inline buffer */
+      int cap = *pcap ? *pcap * 2 : 8;
+      *p = xrealloc(NULL, cap * siz, "vpush");
+      *pcap = -cap;
+   } else if (*pn == -*pcap) { /* dyn buf */
+      *p = xrealloc(*p, -(*pcap *= 2) * siz, "vpush");
+   }
+   assert(-(volatile int)*pcap > *pn && "overflow");
+}
+
+void *
+vpushn_(void **p, int *pcap, uint *pn, uint siz, const void *dat, uint ndat)
+{
+   void *beg;
+
+   for (uint i = 0; i < ndat; ++i)
+      vpush_(p, pcap, pn, siz);
+   beg = (char *)*p + *pn * siz;
+   memcpy(beg, dat, ndat * siz);
+   *pn += ndat;
+   return beg;
+}
+
+struct arena *
+newarena(uint chunksiz)
+{
+   struct arena *ar = xcalloc(offsetof(struct arena, mem) + chunksiz, "newarena");
+   assert(chunksiz < 1u<<31 && "toobig");
+   ar->cap = chunksiz;
+   ar->dyn = 1;
+   return ar;
+}
+
+void *
+alloc(struct arena **par, uint siz, uint align)
+{
+   uint idx;
+   struct arena *new;
+   
+   if (siz > (*par)->cap) {
+      new = newarena(siz);
+      new->n = siz;
+      new->prev = (*par)->prev;
+      (*par)->prev = new;
+      return new->mem;
+   }
+   align = align ? align : sizeof(void *);
+   idx = (uchar *)alignup((uintptr_t)&(*par)->mem[(*par)->n], align) - (*par)->mem;
+   if ((*par)->cap - idx >= siz) {
+      (*par)->n = idx + siz;
+      return (*par)->mem + idx;
+   }
+   new = newarena((*par)->cap);
+   new->prev = *par;
+   *par = new;
+   new->n = siz;
+   return new->mem;
+}
+
+void
+freearena(struct arena *ar)
+{
+   struct arena *prev;
+   for (; ar; ar = prev) {
+      prev = ar->prev;
+      if (ar->dyn)
+         free(ar);
+   }
+}
+
+/* vim:set ts=3 sw=3 expandtab: */