add function fast_buffer_set_capacity

src/fast_buffer.c

@@ -42,32 +42,42 @@ void fast_buffer_destroy(FastBuffer *buffer)
     }
 }
 
-int fast_buffer_check_capacity(FastBuffer *buffer, const int capacity)
+int fast_buffer_set_capacity(FastBuffer *buffer, const int capacity)
 {
     int alloc_size;
+    int new_capacity;
     char *buff;
 
-    if (buffer->alloc_size >= capacity)
-    {
-        return 0;
+    new_capacity = (capacity > buffer->length) ?
+        capacity : (buffer->length + 1);
+    if (buffer->alloc_size >= new_capacity) {
+        if (new_capacity > 1024) {
+            alloc_size = 2048;
+        } else if (new_capacity > 512) {
+            alloc_size = 1024;
+        } else if (new_capacity > 256) {
+            alloc_size = 512;
+        } else {
+            alloc_size = 256;
         }
+    } else {
         alloc_size = buffer->alloc_size * 2;
-    while (alloc_size <= capacity)
-    {
+    }
+
+    while (alloc_size < new_capacity) {
         alloc_size *= 2;
     }
 
     buff = (char *)malloc(alloc_size);
-    if (buff == NULL)
-    {
+    if (buff == NULL) {
         logError("file: "__FILE__", line: %d, "
              "malloc %d bytes fail", __LINE__, alloc_size);
         return ENOMEM;
     }
 
-    if (buffer->length > 0)
-    {
+    if (buffer->length > 0) {
         memcpy(buff, buffer->data, buffer->length);
+        *(buff + buffer->length) = '\0';
     }
 
     free(buffer->data);

src/fast_buffer.h

@@ -44,7 +44,18 @@ void fast_buffer_destroy(FastBuffer *buffer);
 #define fast_buffer_check(buffer, inc_len) \
     fast_buffer_check_inc_size(buffer, inc_len)
 
-int fast_buffer_check_capacity(FastBuffer *buffer, const int capacity);
+int fast_buffer_set_capacity(FastBuffer *buffer, const int capacity);
+
+static inline int fast_buffer_check_capacity(FastBuffer *buffer,
+        const int capacity)
+{
+    if (buffer->alloc_size >= capacity)
+    {
+        return 0;
+    }
+
+    return fast_buffer_set_capacity(buffer, capacity);
+}
 
 static inline int fast_buffer_check_inc_size(FastBuffer *buffer,
         const int inc_size)