Merge branch 'master' of github.com:omnisci3nce/celeritas-core

4 files changed, 122 insertions, 7 deletions

diff --git a/src/std/mem.c b/src/std/mem.c
new file mode 100644
index 0000000..f5b92d4
--- /dev/null
+++ b/src/std/mem.c
@@ -0,0 +1,32 @@
+#include "mem.h"
+#include <stddef.h>
+#include <stdint.h>
+#include <string.h>
+#include "log.h"
+
+#ifndef DEFAULT_ALIGNMENT
+#define DEFAULT_ALIGNMENT (2 * sizeof(void*))
+#endif
+
+void* arena_alloc_align(arena* a, size_t size, size_t align) {
+  ptrdiff_t padding = -(uintptr_t)a->curr & (align - 1);
+  ptrdiff_t available = a->end - a->curr - padding;
+  TRACE("Padding %td available %td", padding, available);
+  if (available < 0 || (ptrdiff_t)size > available) {
+    ERROR_EXIT("Arena ran out of memory\n");
+  }
+  void* p = a->begin + padding;
+  a->begin += padding + size;
+  return memset(p, 0, size);
+}
+void* arena_alloc(arena* a, size_t size) { return arena_alloc_align(a, size, DEFAULT_ALIGNMENT); }
+
+arena arena_create(void* backing_buffer, size_t capacity) {
+  return (arena){ .begin = backing_buffer,
+                  .curr = backing_buffer,
+                  .end = backing_buffer + (ptrdiff_t)capacity };
+}
+
+void arena_free_all(arena* a) {
+  a->curr = a->begin;  // pop everything at once and reset to the start.
+}
\ No newline at end of file
diff --git a/src/std/mem.h b/src/std/mem.h
index 74222a7..c3ec61d 100644
--- a/src/std/mem.h
+++ b/src/std/mem.h
@@ -9,6 +9,17 @@
  */
 #pragma once
 
-#include "defines.h"
+#include <stddef.h>
 
-typedef void* (*alloc)(size_t amount);
\ No newline at end of file
+// Inspired by https://nullprogram.com/blog/2023/09/27/
+typedef struct arena {
+  char* begin;
+  char* curr;
+  char* end;
+} arena;
+
+arena arena_create(void* backing_buffer, size_t capacity);
+void* arena_alloc(arena* a, size_t size);
+void* arena_alloc_align(arena* a, size_t size, size_t align);
+void arena_free_all(arena* a);
+// TODO: arena_resize
\ No newline at end of file
diff --git a/src/std/str.c b/src/std/str.c
index 27f8f68..3b2770e 100644
--- a/src/std/str.c
+++ b/src/std/str.c
@@ -1,4 +1,9 @@
 #include "str.h"
+#include <string.h>
+
+#include "mem.h"
+
+str8 str8_create(u8* buf, size_t len) { return (str8){ .buf = buf, .len = len }; }
 
 bool str8_equals(str8 a, str8 b) {
   if (a.len != b.len) {
@@ -11,4 +16,29 @@ bool str8_equals(str8 a, str8 b) {
     }
   }
   return true;
+}
+
+char* str8_to_cstr(arena* a, str8 s) {
+  bool is_null_terminated = s.buf[s.len - 1] == 0;
+  size_t n_bytes = is_null_terminated ? s.len : s.len + 1;
+
+  u8* dest = arena_alloc(a, n_bytes);
+
+  memcpy(dest, s.buf, s.len);
+  if (is_null_terminated) {
+    dest[s.len] = '\0';
+  }
+  return (char*)dest;
+}
+
+str8 str8_concat(arena* a, str8 left, str8 right) {
+  size_t n_bytes = left.len + right.len + 1;
+
+  u8* dest = arena_alloc(a, n_bytes);
+  memcpy(dest, left.buf, left.len);
+  memcpy(dest + right.len, right.buf, right.len);
+
+  dest[n_bytes - 1] = '\0';
+
+  return str8_create(dest, n_bytes);
 }
\ No newline at end of file
diff --git a/src/std/str.h b/src/std/str.h
index f3ade5a..735b88e 100644
--- a/src/std/str.h
+++ b/src/std/str.h
@@ -1,10 +1,17 @@
 /**
+ * @file str.h
+ * @author your name (you@domain.com)
  * @brief
+ * @version 0.1
+ * @date 2024-02-25
+ *
+ * @copyright Copyright (c) 2024
  *
  */
 #pragma once
 
 #include "defines.h"
+#include "mem.h"
 
 /**
  * @brief Fat pointer representing a UTF8 (TODO some APIs supporting utf8) encoded string
@@ -12,20 +19,55 @@
          print routines are written. alternatively wrap in `cstr()` and pass to `%s`.
  */
 typedef struct {
-  u8 *buf;
+  u8* buf;
   size_t len;
 } str8;
 
+// --- Constructors
+
+/** @brief Take a string literal and turn it into a `str8` */
+#define str8lit(s) \
+  (str8) { (u8*)s, ((sizeof(s) / sizeof(*(s)) - 1)) }
+
+str8 str8_create(u8* buf, size_t len);
+
+/** @brief Return a null-terminated C string cloned onto an arena */
+char* str8_to_cstr(arena* a, str8 s);
+
+#define cstr(a, s) (str8_to_cstr(a, s))  // Shorthand
+
+// --- Comparisons
+
 /** @brief Compare two strings for exact equality */
 bool str8_equals(str8 a, str8 b);
 
 /**
  * @brief Compare the first `first_nchars` of each string for equality
-          If either of the strings are shorter than the number only the characters up until the end
- of the shorter string will be compared.
+ * @details If either of the strings are shorter than the number only the characters up until the
+ end of the shorter string will be compared.
  * @returns 0 if they are fully equal up until `first_nchars`, i.e they never differed, else it
- returns the index at which the first string differed from the second string.
+            returns the index at which the first string differed from the second string.
 */
 size_t str8_nequals(str8 a, str8 b, size_t first_nchars);
 
-bool str8_ends_with(str8 input_str, str8 suffix);
\ No newline at end of file
+bool str8_ends_with(str8 input_str, str8 suffix);
+
+/// --- Subviews
+
+str8 str8_substr(str8 s, u64 min, u64 max);
+/** @brief Keeps only the `first_n` chars of `s` */
+str8 str8_take(str8 s, u64 first_n);
+/** @brief Keeps only the `last_n` chars of `s` */
+str8 str8_drop(str8 s, u64 last_n);
+/** @brief Keeps everything after the first `n` chars of `s` */
+str8 str8_skip(str8 s, u64 n);
+/** @brief Keeps everything before the last `n` chars of `s` */
+str8 str8_chop(str8 s, u64 n);
+
+str8 str8_concat(arena* a, str8 left, str8 right);
+
+/// --- Misc
+
+static inline bool str8_is_null_term(str8 a) {
+  return a.buf[a.len] == 0;  // This doesn't seem safe. YOLO
+}
\ No newline at end of file