From b05cf56b1a51b0c178c606ca41f6fb0c0208da27 Mon Sep 17 00:00:00 2001
From: Kyle Isom <kyle@imap.cc>
Date: Mon, 9 Oct 2023 05:00:38 -0700
Subject: [PATCH] start buffer test

---
 Buffer.cc     | 58 ++++++++++++++++++++++++++-------------------------
 Buffer.h      |  4 ++--
 BufferTest.cc |  6 +++++-
 3 files changed, 37 insertions(+), 31 deletions(-)

diff --git a/Buffer.cc b/Buffer.cc
index b799c0f..8ed0632 100644
--- a/Buffer.cc
+++ b/Buffer.cc
@@ -2,6 +2,7 @@
 // Created by kyle on 2023-10-09.
 //
 
+#include <cassert>
 #include <cstring>
 #include "Buffer.h"
 
@@ -12,6 +13,26 @@ constexpr size_t	defaultCapacity = 32;
 constexpr size_t	maxReasonableLine = 8192;
 
 
+static size_t
+nearestPower(size_t x)
+{
+	if (x == 0) {
+		return 0;
+	}
+
+	x--;
+
+	x |= x >> 1;
+	x |= x >> 2;
+	x |= x >> 4;
+	x |= x >> 8;
+	x |= x >> 16;
+	x |= x >> 32;
+
+	return x;
+}
+
+
 Buffer::Buffer()
     : contents(nullptr), length(0), capacity(0)
 {
@@ -31,16 +52,10 @@ Buffer::Buffer(const char *data)
 {
 	size_t	datalen = strnlen(data, maxReasonableLine);
 
-	this->Append(data, datalen);
+	this->Append((uint8_t *)data, datalen);
 }
 
 
-uint8_t *
-Buffer::Contents()
-{
-	return this->contents;
-}
-
 bool
 Buffer::Append(uint8_t *data, size_t datalen)
 {
@@ -68,11 +83,6 @@ Buffer::Insert(size_t index, uint8_t *data, size_t datalen)
 {
 	auto	resized = this->shift(index, datalen);
 
-	if (newCap > 0) {
-		this->Resize(newCap);
-		resized = true;
-	}
-
 	memcpy(this->contents + index, data, datalen);
 	return resized;
 }
@@ -83,11 +93,6 @@ Buffer::Insert(size_t index, uint8_t c)
 	return this->Insert(index, &c, 1);
 }
 
-size_t
-Buffer::Size()
-{
-	return this->length;
-}
 
 void
 Buffer::Resize(size_t newCapacity)
@@ -113,11 +118,16 @@ Buffer::Resize(size_t newCapacity)
 size_t
 Buffer::Trim()
 {
-	size_t	projectedCapacity = this->capacity * 2;
+	size_t	projectedCapacity = nearestPower(this->length);
+
+	assert(projectedCapacity >= length);
 
 	if (projectedCapacity < this->capacity) {
 		this->Resize(projectedCapacity);
+		return this->Capacity();
 	}
+
+	return 0;
 }
 
 void
@@ -143,20 +153,12 @@ Buffer::mustGrow(size_t delta)
 	}
 
 	auto newCapacity = delta + this->length;
-	newCapacity--;
-
-	newCapacity |= newCapacity >> 1;
-	newCapacity |= newCapacity >> 2;
-	newCapacity |= newCapacity >> 4;
-	newCapacity |= newCapacity >> 8;
-	newCapacity |= newCapacity >> 16;
-	newCapacity |= newCapacity >> 32;
-	return newCapacity;
+	return nearestPower(newCapacity);
 }
 
 
 bool
-Buffer:shift(size_t offset, size_t delta)
+Buffer::shift(size_t offset, size_t delta)
 {
 	auto	resized = false;
 	auto	newCap = this->mustGrow(delta);
diff --git a/Buffer.h b/Buffer.h
index 8e6045c..f7fd291 100644
--- a/Buffer.h
+++ b/Buffer.h
@@ -18,7 +18,7 @@ public:
 	Buffer(const char *);
 
 	uint8_t	*Contents() { return this->contents; }
-	size_t	 Size() { return this->size; };
+	size_t	 Size() { return this->length; };
 	size_t	 Capacity() { return this->capacity; }
 
 	bool	 Append(uint8_t *data, size_t datalen);
@@ -35,7 +35,7 @@ public:
 	void	 Reclaim();
 
 private:
-	bool	 mustGrow(size_t delta);
+	size_t	 mustGrow(size_t delta);
 	bool	 shift(size_t offset, size_t delta);
 
 	uint8_t	*contents;
diff --git a/BufferTest.cc b/BufferTest.cc
index 37359cf..858322b 100644
--- a/BufferTest.cc
+++ b/BufferTest.cc
@@ -6,7 +6,11 @@
 int
 main()
 {
-	Buffer	buffer("hlo, world");
+	kge::Buffer	buffer("hlo, world");
+
+	std::cout << buffer.Contents() << std::endl;
+
+	buffer.Insert(1, (uint8_t *)"el", 2);
 
 	std::cout << buffer.Contents() << std::endl;
 }