From dfad8a8016426d7fe198dc32973b01a1e075142e Mon Sep 17 00:00:00 2001
From: dec05eba <dec05eba@protonmail.com>
Date: Sun, 12 Jul 2020 21:32:44 +0200
Subject: Starting on conversion to c. Program exec, buffers..

---
 buffer.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 54 insertions(+)
 create mode 100644 buffer.c

(limited to 'buffer.c')

diff --git a/buffer.c b/buffer.c
new file mode 100644
index 0000000..879a62b
--- /dev/null
+++ b/buffer.c
@@ -0,0 +1,54 @@
+#include "buffer.h"
+#include "alloc.h"
+#include <stdio.h>
+#include <string.h>
+#include <assert.h>
+
+void buffer_init(Buffer *self) {
+    self->data = NULL;
+    self->size = 0;
+    self->capacity = 0;
+}
+
+void buffer_deinit(Buffer *self) {
+    free(self->data);
+    self->size = 0;
+    self->capacity = 0;
+}
+
+static void buffer_ensure_capacity(Buffer *self, size_t new_size) {
+    size_t new_capacity = self->capacity;
+    if(new_size <= self->capacity)
+        return;
+
+    if(new_capacity == 0)
+        new_capacity = 8;
+    
+    while(new_capacity < new_size) {
+        /* new_capacity *= 1.5 */
+        new_capacity += (new_capacity >> 1);
+    }
+
+    self->data = realloc_or_crash(self->data, new_capacity);
+    self->capacity = new_capacity;
+}
+
+void buffer_append(Buffer *self, const void *data, size_t size) {
+    buffer_ensure_capacity(self, self->size + size);
+    memcpy((char*)self->data + self->size, data, size);
+    self->size += size;
+}
+
+void* buffer_pop(Buffer *self, size_t size) {
+    assert(self->size >= size);
+    self->size -= size;
+    return (char*)self->data + self->size;
+}
+
+void* buffer_begin(Buffer *self) {
+    return self->data;
+}
+
+void* buffer_end(Buffer *self) {
+    return (char*)self->data + self->size;
+}
-- 
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