prick_darr: hard fail when unable to allocate resources

So if calloc fails, hard exit with a message.
tbh if you're working on something and I run out of memory here, I'm
doing you a favour.

prick_darr.h

@@ -45,6 +45,8 @@ void prick_darr_ensure_remaining(void **ptr, uint32_t space);
 
 #ifdef PRICK_DARR_IMPL
 
+#include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
 
 #ifndef PRICK_DARR_MULT
@@ -53,12 +55,22 @@ void prick_darr_ensure_remaining(void **ptr, uint32_t space);
 
 #define MAX(A, B) ((A) > (B) ? (A) : (B))
 #define MIN(A, B) ((A) < (B) ? (A) : (B))
+#define FAIL(...)                          \
+  do                                       \
+  {                                        \
+    fprintf(stderr, "FAIL: prick_darr: "); \
+    fprintf(stderr, __VA_ARGS__);          \
+    exit(1);                               \
+  } while (0)
 
 void prick_darr_make(void **ptr, uint32_t size)
 {
   if (!ptr)
     return;
   prick_darr_t *darr = calloc(1, sizeof(*darr) + size);
+  if (!darr)
+    FAIL("Could not allocate memory (%lu bytes) for new dynamic array.\n",
+         sizeof(*darr) + size);
   darr->size     = 0;
   darr->capacity = size;
   *ptr           = (darr + 1);
@@ -80,8 +92,14 @@ void prick_darr_ensure_remaining(void **ptr, uint32_t space)
   if (darr->capacity - darr->size < space)
   {
     void *new_darr = NULL;
-    prick_darr_make(&new_darr,
+    uint64_t new_capacity =
-                    MAX(darr->capacity * PRICK_DARR_MULT, darr->size + space));
+        MAX(darr->capacity * PRICK_DARR_MULT, darr->size + space);
+    prick_darr_make(&new_darr, new_capacity);
+
+    if (!new_darr)
+      FAIL("Could not allocate new dynamic array with %lu bytes capacity.\n",
+           new_capacity);
+
     PRICK_DARR_SIZE(new_darr) = darr->size;
     memcpy(new_darr, *ptr, darr->size);
     prick_darr_free(ptr);
@@ -91,6 +109,8 @@ void prick_darr_ensure_remaining(void **ptr, uint32_t space)
 
 void prick_darr_append_byte(void **ptr, uint8_t byte)
 {
+  if (!ptr || !*ptr)
+    return;
   prick_darr_ensure_remaining(ptr, 1);
   prick_darr_t *darr        = PRICK_DARR_GET(*ptr);
   darr->bytes[darr->size++] = byte;
@@ -98,9 +118,11 @@ void prick_darr_append_byte(void **ptr, uint8_t byte)
 
 void prick_darr_append(void **ptr, void *data, uint32_t size)
 {
+  if (!ptr || !*ptr || !data)
+    return;
   prick_darr_ensure_remaining(ptr, size);
   prick_darr_t *darr = PRICK_DARR_GET(*ptr);
-  memcpy(*ptr + darr->size, data, size);
+  memcpy(((uint8_t *)*ptr) + darr->size, data, size);
   darr->size += size;
 }
 
@@ -113,6 +135,9 @@ void prick_darr_clone(void **dest, void **src)
   PRICK_DARR_SIZE(*dest) = PRICK_DARR_SIZE(*src);
 }
 
+#undef MAX
+#undef MIN
+
 #endif
 
 #endif