fix: optimize sse chunk reading off-by-one error (#31)

Author: stainless-app[bot]

src/internal/decoders/line.ts

@@ -147,3 +147,34 @@ function findNewlineIndex(
 
   return null;
 }
+
+export function findDoubleNewlineIndex(buffer: Uint8Array): number {
+  // This function searches the buffer for the end patterns (\r\r, \n\n, \r\n\r\n)
+  // and returns the index right after the first occurrence of any pattern,
+  // or -1 if none of the patterns are found.
+  const newline = 0x0a; // \n
+  const carriage = 0x0d; // \r
+
+  for (let i = 0; i < buffer.length - 1; i++) {
+    if (buffer[i] === newline && buffer[i + 1] === newline) {
+      // \n\n
+      return i + 2;
+    }
+    if (buffer[i] === carriage && buffer[i + 1] === carriage) {
+      // \r\r
+      return i + 2;
+    }
+    if (
+      buffer[i] === carriage &&
+      buffer[i + 1] === newline &&
+      i + 3 < buffer.length &&
+      buffer[i + 2] === carriage &&
+      buffer[i + 3] === newline
+    ) {
+      // \r\n\r\n
+      return i + 4;
+    }
+  }
+
+  return -1;
+}