1 files changed, 112 insertions, 0 deletions
diff --git a/vec.h b/vec.h
new file mode 100644
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--- /dev/null
+++ b/vec.h
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+/* Copyright (C) 2024 Aryadev Chavali
+
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the Unlicense
+ * for details.
+
+ * You may distribute and modify this code under the terms of the
+ * Unlicense, which you should have received a copy of along with this
+ * program.  If not, please go to <https://unlicense.org/>.
+
+ * Created: 2024-10-01
+ * Author: Aryadev Chavali
+ * Description: A dynamically sized container.
+ */
+
+#ifndef VEC_H
+#define VEC_H
+
+#include <stdint.h>
+
+typedef struct
+{
+  uint32_t size, capacity;
+  uint8_t bytes[];
+} vec_t;
+
+#define VEC_GET(P)  (((vec_t *)(P)) - 1)
+#define VEC_SIZE(P) (VEC_GET(P)->size)
+#define VEC_CAP(P)  (VEC_GET(P)->capacity)
+
+void vec_make(void **ptr, uint32_t size);
+void vec_free(void **ptr);
+void vec_append_byte(void **ptr, uint8_t byte);
+void vec_append(void **ptr, void *data, uint32_t size);
+void vec_clone(void **dest, void **src);
+void vec_ensure_remaining(void **ptr, uint32_t space);
+
+#define VEC_IMPL
+#ifdef VEC_IMPL
+
+#include <malloc.h>
+#include <string.h>
+
+#ifndef MAX
+#define MAX(A, B) ((A) > (B) ? (A) : (B))
+#endif
+
+#ifndef MIN
+#define MIN(A, B) ((A) < (B) ? (A) : (B))
+#endif
+
+void vec_make(void **ptr, uint32_t size)
+{
+  if (!ptr)
+    return;
+  vec_t *vector    = calloc(1, sizeof(*vector) + size);
+  vector->size     = 0;
+  vector->capacity = size;
+  *ptr             = (vector + 1);
+}
+
+void vec_free(void **data)
+{
+  if (!data || !*data)
+    return;
+  free(VEC_GET(*data));
+  *data = NULL;
+}
+
+void vec_ensure_remaining(void **ptr, uint32_t space)
+{
+  if (!ptr || !*ptr)
+    return;
+  vec_t *vec = VEC_GET(*ptr);
+  if (vec->capacity - vec->size < space)
+  {
+    void *new_vec = NULL;
+    vec_make(&new_vec, MAX(vec->capacity * 2, vec->size + space));
+    VEC_SIZE(new_vec) = vec->size;
+    memcpy(new_vec, *ptr, vec->size);
+    vec_free(ptr);
+    *ptr = new_vec;
+  }
+}
+
+void vec_append_byte(void **ptr, uint8_t byte)
+{
+  vec_ensure_remaining(ptr, 1);
+  vec_t *vec              = VEC_GET(*ptr);
+  vec->bytes[vec->size++] = byte;
+}
+
+void vec_append(void **ptr, void *data, uint32_t size)
+{
+  vec_ensure_remaining(ptr, size);
+  vec_t *vec = VEC_GET(*ptr);
+  memcpy(vec->bytes + vec->size, data, size);
+  vec->size += size;
+}
+
+void vec_clone(void **dest, void **src)
+{
+  if (!dest || !src || !*src)
+    return;
+  vec_make(dest, VEC_SIZE(*src));
+  memcpy(*dest, *src, VEC_SIZE(*src));
+  VEC_SIZE(*dest) = VEC_SIZE(*src);
+}
+#endif
+
+#endif