feat: add examples/hello-world

1 files changed, 95 insertions, 0 deletions

diff --git a/src/Stream/BlobStream.php b/src/Stream/BlobStream.php
new file mode 100644
index 0000000..972b8f6
--- /dev/null
+++ b/src/Stream/BlobStream.php
@@ -0,0 +1,95 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Nsfisis\Waddiwasi\Stream;
+
+use function assert;
+use function ord;
+use function strlen;
+use function substr;
+
+/**
+ * Read-only blob stream.
+ */
+final class BlobStream implements StreamInterface
+{
+    /**
+     * @var int<0, max>
+     */
+    private int $pos = 0;
+
+    /**
+     * @var positive-int
+     */
+    private readonly int $len;
+
+    /**
+     * Creates a new blob stream with the given content.
+     *
+     * @param non-empty-string $content
+     *   The content of the blob.
+     */
+    public function __construct(
+        private readonly string $content,
+    ) {
+        $this->len = strlen($content);
+    }
+
+    public function close(): void
+    {
+    }
+
+    public function read(int $bytes): string
+    {
+        $this->ensureNBytesAvailable($bytes);
+        $ret = substr($this->content, $this->pos, $bytes);
+        $this->pos += $bytes;
+        assert($ret !== '');
+        return $ret;
+    }
+
+    public function readByte(): int
+    {
+        $this->ensureNBytesAvailable(1);
+        return ord($this->content[$this->pos++]);
+    }
+
+    public function peekByte(): int
+    {
+        $this->ensureNBytesAvailable(1);
+        return ord($this->content[$this->pos]);
+    }
+
+    public function seek(int $bytes): void
+    {
+        $this->ensureNBytesAvailable($bytes);
+        $this->pos += $bytes;
+    }
+
+    /**
+     * @phpstan-pure
+     */
+    public function tell(): int
+    {
+        return $this->pos;
+    }
+
+    /**
+     * @phpstan-pure
+     */
+    public function eof(): bool
+    {
+        return $this->len <= $this->pos;
+    }
+
+    /**
+     * @param positive-int $bytes
+     */
+    private function ensureNBytesAvailable(int $bytes): void
+    {
+        if ($this->len < $this->pos + $bytes) {
+            throw new UnexpectedEofException(sprintf("Unexpected EOF while reading from blob (%d bytes expected, %d bytes read)", $bytes, $this->len - $this->pos));
+        }
+    }
+}