fix alloc bug

rtcore.h

@@ -215,6 +215,14 @@ RTC_API split_result S8Split(s8 s, u8 c);
 /* Creates a clone of string s on arena a */
 RTC_API s8 S8Clone(s8 s, arena *a);
 
+typedef struct { i64 i; b32 ok; } s8_parse_i64_result;
+typedef struct { i32 i; b32 ok; } s8_parse_i32_result;
+
+/* Parses a integer from string s */
+RTC_API s8_parse_i64_result S8ParseI64(s8 s, int base);
+/* Parses an integer from string s */
+RTC_API s8_parse_i32_result S8ParseI32(s8 s, int base);
+
 /* Basic file io */
 typedef struct file_buffer
 {
@@ -285,7 +293,7 @@ RTC_API void *
 ArenaAlloc(arena *a, isize size, isize align, isize n, int flags)
 {
 	isize padding = -(usize)a->begin & (align - 1);
-	isize available = a->end - a->begin - padding;
+	isize available = (isize)(a->end - a->begin) - padding;
 	if (available < 0 || n > available / size)
 	{
 		if (!(flags & ALLOC_SOFTFAIL))
@@ -293,7 +301,7 @@ ArenaAlloc(arena *a, isize size, isize align, isize n, int flags)
 		return NULL;
 	}
 	void *p = a->begin + padding;
-	a->begin += padding - n * size;
+	a->begin += padding + n * size;
 	return (flags & ALLOC_NOZERO) ? p : memset(p, 0, n * size);
 }
 
@@ -392,6 +400,84 @@ S8Clone(s8 s, arena *a)
 	memcpy(c.data, s.data, s.length);
 	return s;
 }
+RTC_API s8_parse_i64_result
+S8ParseI64(s8 s, int base)
+{
+  isize at = s.length - 1;
+  i64 exp = 1;
+  i64 val = 0;
+  while (at >= 0)
+  {
+    u8 c = s.data[at];
+    int digit = 0;
+    if (c >= '0' && c <= '9')
+      digit = c - '0';
+    else if (c >= 'A' && c <= 'Z')
+      digit = c - 'A';
+    else if (c >= 'a' && c <= 'z')
+      digit = c - 'a';
+    else if (c == '-')
+    {
+      val *= -1;
+      break;
+    }
+    else if (c == '+')
+    {
+      break;
+    }
+    else
+      return (s8_parse_i64_result){0};
+    if (digit >= base)
+    	return (s8_parse_i64_result){0};
+    
+    val += digit * exp;
+    exp *= base;
+    --at;
+  }
+  return (s8_parse_i64_result){
+		.i = val,
+		.ok = 1,
+	};
+}
+RTC_API s8_parse_i32_result
+S8ParseI32(s8 s, int base)
+{
+  isize at = s.length - 1;
+  i32 exp = 1;
+  i32 val = 0;
+  while (at >= 0)
+  {
+    u8 c = s.data[at];
+    int digit = 0;
+    if (c >= '0' && c <= '9')
+      digit = c - '0';
+    else if (c >= 'A' && c <= 'Z')
+      digit = c - 'A';
+    else if (c >= 'a' && c <= 'z')
+      digit = c - 'a';
+    else if (c == '-')
+    {
+      val *= -1;
+      break;
+    }
+    else if (c == '+')
+    {
+      break;
+    }
+    else
+      return (s8_parse_i32_result){0};
+    if (digit >= base)
+    	return (s8_parse_i32_result){0};
+    
+    val += digit * exp;
+    exp *= base;
+    --at;
+  }
+  return (s8_parse_i32_result){
+		.i = val,
+		.ok = 1,
+	};
+}
 
 /* Basic file io */
 RTC_API file_buffer

test.c

@@ -47,6 +47,20 @@ ThreadTest(void)
   return AtomicLoad(&p) == 42;
 }
 
+internal int
+ParseIntTest(void)
+{
+  if (S8ParseI32(S8("123"), 10).i != 123)
+    return 0;
+  if (S8ParseI32(S8("-124"), 10).i != -124)
+    return 0;
+  if (S8ParseI64(S8("9223372036854775807"), 10).i != 9223372036854775807)
+    return 0;
+  if (S8ParseI32(S8("Not a number"), 10).ok)
+    return 0;
+  return 1;
+}
+
 int
 main()
 {
@@ -56,5 +70,7 @@ main()
     return 2;
   if (!ThreadTest())
     return 3;
+  if (!ParseIntTest())
+    return 4;
   return 0;
 }