diff --git a/miniz.c b/miniz.c
index 696f8a2..bfc234a 100644
--- a/miniz.c
+++ b/miniz.c
@@ -552,19 +552,18 @@ int mz_inflateEnd(mz_streamp pStream)
     }
     return MZ_OK;
 }
-
-int mz_uncompress(unsigned char *pDest, mz_ulong *pDest_len, const unsigned char *pSource, mz_ulong source_len)
+int mz_uncompress2(unsigned char *pDest, mz_ulong *pDest_len, const unsigned char *pSource, mz_ulong *pSource_len)
 {
     mz_stream stream;
     int status;
     memset(&stream, 0, sizeof(stream));
 
     /* In case mz_ulong is 64-bits (argh I hate longs). */
-    if ((source_len | *pDest_len) > 0xFFFFFFFFU)
+    if ((*pSource_len | *pDest_len) > 0xFFFFFFFFU)
         return MZ_PARAM_ERROR;
 
     stream.next_in = pSource;
-    stream.avail_in = (mz_uint32)source_len;
+    stream.avail_in = (mz_uint32)*pSource_len;
     stream.next_out = pDest;
     stream.avail_out = (mz_uint32)*pDest_len;
 
@@ -573,6 +572,7 @@ int mz_uncompress(unsigned char *pDest, mz_ulong *pDest_len, const unsigned char
         return status;
 
     status = mz_inflate(&stream, MZ_FINISH);
+    *pSource_len = *pSource_len - stream.avail_in;
     if (status != MZ_STREAM_END)
     {
         mz_inflateEnd(&stream);
@@ -583,6 +583,11 @@ int mz_uncompress(unsigned char *pDest, mz_ulong *pDest_len, const unsigned char
     return mz_inflateEnd(&stream);
 }
 
+int mz_uncompress(unsigned char *pDest, mz_ulong *pDest_len, const unsigned char *pSource, mz_ulong source_len)
+{
+    return mz_uncompress2(pDest, pDest_len, pSource, &source_len);
+}
+
 const char *mz_error(int err)
 {
     static struct
diff --git a/miniz.h b/miniz.h
index 3018dae..7789be9 100644
--- a/miniz.h
+++ b/miniz.h
@@ -388,6 +388,7 @@ MINIZ_EXPORT int mz_inflateEnd(mz_streamp pStream);
 /* Single-call decompression. */
 /* Returns MZ_OK on success, or one of the error codes from mz_inflate() on failure. */
 MINIZ_EXPORT int mz_uncompress(unsigned char *pDest, mz_ulong *pDest_len, const unsigned char *pSource, mz_ulong source_len);
+MINIZ_EXPORT int mz_uncompress2(unsigned char *pDest, mz_ulong *pDest_len, const unsigned char *pSource, mz_ulong *pSource_len);
 
 /* Returns a string description of the specified error code, or NULL if the error code is invalid. */
 MINIZ_EXPORT const char *mz_error(int err);
@@ -453,6 +454,7 @@ typedef void *const voidpc;
 #define inflate mz_inflate
 #define inflateEnd mz_inflateEnd
 #define uncompress mz_uncompress
+#define uncompress2 mz_uncompress2
 #define crc32 mz_crc32
 #define adler32 mz_adler32
 #define MAX_WBITS 15