From: Orit Wasserman <owasserm@redhat.com>
Date: Mon, 6 Aug 2012 18:42:51 +0000 (+0300)
Subject: Add uleb encoding/decoding functions
X-Git-Tag: v1.2.0-rc0~29^2~7
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=e6546bb938f5326269b6669d6cbb44d72458caa4;p=thirdparty%2Fqemu.git

Add uleb encoding/decoding functions

Implement Unsigned Little Endian Base 128.

Signed-off-by: Orit Wasserman <owasserm@redhat.com>

Reviewed-by: Luiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---

diff --git a/cutils.c b/cutils.c
index 35e2e2bf448..ee4614d3786 100644
--- a/cutils.c
+++ b/cutils.c
@@ -391,3 +391,36 @@ int64_t pow2floor(int64_t value)
     }
     return value;
 }
+
+/*
+ * Implementation of  ULEB128 (http://en.wikipedia.org/wiki/LEB128)
+ * Input is limited to 14-bit numbers
+ */
+int uleb128_encode_small(uint8_t *out, uint32_t n)
+{
+    g_assert(n <= 0x3fff);
+    if (n < 0x80) {
+        *out++ = n;
+        return 1;
+    } else {
+        *out++ = (n & 0x7f) | 0x80;
+        *out++ = n >> 7;
+        return 2;
+    }
+}
+
+int uleb128_decode_small(const uint8_t *in, uint32_t *n)
+{
+    if (!(*in & 0x80)) {
+        *n = *in++;
+        return 1;
+    } else {
+        *n = *in++ & 0x7f;
+        /* we exceed 14 bit number */
+        if (*in & 0x80) {
+            return -1;
+        }
+        *n |= *in++ << 7;
+        return 2;
+    }
+}
diff --git a/qemu-common.h b/qemu-common.h
index ff7026e3778..9c1b95551bb 100644
--- a/qemu-common.h
+++ b/qemu-common.h
@@ -443,4 +443,12 @@ int64_t pow2floor(int64_t value);
 
 #include "module.h"
 
+/*
+ * Implementation of ULEB128 (http://en.wikipedia.org/wiki/LEB128)
+ * Input is limited to 14-bit numbers
+ */
+
+int uleb128_encode_small(uint8_t *out, uint32_t n);
+int uleb128_decode_small(const uint8_t *in, uint32_t *n);
+
 #endif