1 files changed, 39 insertions, 0 deletions
diff --git a/web/server/h2o/libh2o/deps/mruby/src/crc.c b/web/server/h2o/libh2o/deps/mruby/src/crc.c
new file mode 100644
index 00000000..290b2ca0
--- /dev/null
+++ b/web/server/h2o/libh2o/deps/mruby/src/crc.c
@@ -0,0 +1,39 @@
+/*
+** crc.c - calculate CRC
+**
+** See Copyright Notice in mruby.h
+*/
+
+#include <limits.h>
+#include <stdint.h>
+#include <stddef.h>
+
+/* Calculate CRC (CRC-16-CCITT)
+**
+**  0000_0000_0000_0000_0000_0000_0000_0000
+**          ^|------- CRC -------|- work --|
+**        carry
+*/
+#define  CRC_16_CCITT       0x11021ul        /* x^16+x^12+x^5+1 */
+#define  CRC_XOR_PATTERN    (CRC_16_CCITT << 8)
+#define  CRC_CARRY_BIT      (0x01000000)
+
+uint16_t
+calc_crc_16_ccitt(const uint8_t *src, size_t nbytes, uint16_t crc)
+{
+  size_t ibyte;
+  uint32_t ibit;
+  uint32_t crcwk = crc << 8;
+
+  for (ibyte = 0; ibyte < nbytes; ibyte++) {
+    crcwk |= *src++;
+    for (ibit = 0; ibit < CHAR_BIT; ibit++) {
+      crcwk <<= 1;
+      if (crcwk & CRC_CARRY_BIT) {
+        crcwk ^= CRC_XOR_PATTERN;
+      }
+    }
+  }
+  return (uint16_t)(crcwk >> 8);
+}
+