From 55a7d656c76167f889bf2cdf478f9581422a74ea Mon Sep 17 00:00:00 2001
From: lovyan03 <42724151+lovyan03@users.noreply.github.com>
Date: Sun, 3 May 2020 10:57:05 +0900
Subject: [PATCH] Add: Return error if data is too big.

---
 src/qrcode.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/src/qrcode.c b/src/qrcode.c
index 940c06e..d0fb124 100755
--- a/src/qrcode.c
+++ b/src/qrcode.c
@@ -209,7 +209,9 @@ static void bb_initGrid(BitBucket *bitGrid, uint8_t *data, uint8_t size) {
 static void bb_appendBits(BitBucket *bitBuffer, uint32_t val, uint8_t length) {
     uint32_t offset = bitBuffer->bitOffsetOrWidth;
     for (int8_t i = length - 1; i >= 0; i--, offset++) {
-        bitBuffer->data[offset >> 3] |= ((val >> i) & 1) << (7 - (offset & 7));
+        if (bitBuffer->capacityBytes > offset >> 3) {
+            bitBuffer->data[offset >> 3] |= ((val >> i) & 1) << (7 - (offset & 7));
+        }
     }
     bitBuffer->bitOffsetOrWidth = offset;
 }
@@ -771,7 +773,7 @@ uint16_t qrcode_getBufferSize(uint8_t version) {
     return bb_getGridSizeBytes(4 * version + 17);
 }
 
-// @TODO: Return error if data is too big.
+
 int8_t qrcode_initBytes(QRCode *qrcode, uint8_t *modules, uint8_t version, uint8_t ecc, uint8_t *data, uint16_t length) {
     uint8_t size = version * 4 + 17;
     qrcode->version = version;
@@ -801,7 +803,8 @@ int8_t qrcode_initBytes(QRCode *qrcode, uint8_t *modules, uint8_t version, uint8
     qrcode->mode = mode;
     
     // Add terminator and pad up to a byte if applicable
-    uint32_t padding = (dataCapacity * 8) - codewords.bitOffsetOrWidth;
+    int32_t padding = (dataCapacity * 8) - codewords.bitOffsetOrWidth;
+    if (padding < 0) { return -1; }
     if (padding > 4) { padding = 4; }
     bb_appendBits(&codewords, 0, padding);
     bb_appendBits(&codewords, 0, (8 - codewords.bitOffsetOrWidth % 8) % 8);