Add int return values to RIPEMD-160 function calls

The following function calls are being deprecated to introduce int
return values.
    * mbedtls_ripemd160()
    * mbedtls_ripemd160_starts()
    * mbedtls_ripemd160_update()
    * mbedtls_ripemd160_finish()
    * mbedtls_ripemd160_process()
The return codes can be used to return error values. This is important
when using hardware accelerators.
diff --git a/library/ripemd160.c b/library/ripemd160.c
index cdb0a63..f1d1f1e 100644
--- a/library/ripemd160.c
+++ b/library/ripemd160.c
@@ -96,7 +96,7 @@
 /*
  * RIPEMD-160 context setup
  */
-void mbedtls_ripemd160_starts( mbedtls_ripemd160_context *ctx )
+int mbedtls_ripemd160_starts_ext( mbedtls_ripemd160_context *ctx )
 {
     ctx->total[0] = 0;
     ctx->total[1] = 0;
@@ -106,13 +106,16 @@
     ctx->state[2] = 0x98BADCFE;
     ctx->state[3] = 0x10325476;
     ctx->state[4] = 0xC3D2E1F0;
+
+    return( 0 );
 }
 
 #if !defined(MBEDTLS_RIPEMD160_PROCESS_ALT)
 /*
  * Process one block
  */
-void mbedtls_ripemd160_process( mbedtls_ripemd160_context *ctx, const unsigned char data[64] )
+int mbedtls_ripemd160_process_ext( mbedtls_ripemd160_context *ctx,
+                                   const unsigned char data[64] )
 {
     uint32_t A, B, C, D, E, Ap, Bp, Cp, Dp, Ep, X[16];
 
@@ -287,20 +290,24 @@
     ctx->state[3] = ctx->state[4] + A + Bp;
     ctx->state[4] = ctx->state[0] + B + Cp;
     ctx->state[0] = C;
+
+    return( 0 );
 }
 #endif /* !MBEDTLS_RIPEMD160_PROCESS_ALT */
 
 /*
  * RIPEMD-160 process buffer
  */
-void mbedtls_ripemd160_update( mbedtls_ripemd160_context *ctx,
-                       const unsigned char *input, size_t ilen )
+int mbedtls_ripemd160_update_ext( mbedtls_ripemd160_context *ctx,
+                                  const unsigned char *input,
+                                  size_t ilen )
 {
+    int ret;
     size_t fill;
     uint32_t left;
 
     if( ilen == 0 )
-        return;
+        return( 0 );
 
     left = ctx->total[0] & 0x3F;
     fill = 64 - left;
@@ -314,7 +321,10 @@
     if( left && ilen >= fill )
     {
         memcpy( (void *) (ctx->buffer + left), input, fill );
-        mbedtls_ripemd160_process( ctx, ctx->buffer );
+
+        if( ( ret = mbedtls_ripemd160_process_ext( ctx, ctx->buffer ) ) != 0 )
+            return( ret );
+
         input += fill;
         ilen  -= fill;
         left = 0;
@@ -322,7 +332,9 @@
 
     while( ilen >= 64 )
     {
-        mbedtls_ripemd160_process( ctx, input );
+        if( ( ret = mbedtls_ripemd160_process_ext( ctx, input ) ) != 0 )
+            return( ret );
+
         input += 64;
         ilen  -= 64;
     }
@@ -331,6 +343,8 @@
     {
         memcpy( (void *) (ctx->buffer + left), input, ilen );
     }
+
+    return( 0 );
 }
 
 static const unsigned char ripemd160_padding[64] =
@@ -344,8 +358,10 @@
 /*
  * RIPEMD-160 final digest
  */
-void mbedtls_ripemd160_finish( mbedtls_ripemd160_context *ctx, unsigned char output[20] )
+int mbedtls_ripemd160_finish_ext( mbedtls_ripemd160_context *ctx,
+                                  unsigned char output[20] )
 {
+    int ret;
     uint32_t last, padn;
     uint32_t high, low;
     unsigned char msglen[8];
@@ -360,29 +376,47 @@
     last = ctx->total[0] & 0x3F;
     padn = ( last < 56 ) ? ( 56 - last ) : ( 120 - last );
 
-    mbedtls_ripemd160_update( ctx, ripemd160_padding, padn );
-    mbedtls_ripemd160_update( ctx, msglen, 8 );
+    ret = mbedtls_ripemd160_update_ext( ctx, ripemd160_padding, padn );
+    if( ret != 0 )
+            return( ret );
+
+    ret = mbedtls_ripemd160_update_ext( ctx, msglen, 8 );
+    if( ret != 0 )
+            return( ret );
 
     PUT_UINT32_LE( ctx->state[0], output,  0 );
     PUT_UINT32_LE( ctx->state[1], output,  4 );
     PUT_UINT32_LE( ctx->state[2], output,  8 );
     PUT_UINT32_LE( ctx->state[3], output, 12 );
     PUT_UINT32_LE( ctx->state[4], output, 16 );
+
+    return( 0 );
 }
 
 /*
  * output = RIPEMD-160( input buffer )
  */
-void mbedtls_ripemd160( const unsigned char *input, size_t ilen,
-                unsigned char output[20] )
+int mbedtls_ripemd160_ext( const unsigned char *input,
+                           size_t ilen,
+                           unsigned char output[20] )
 {
+    int ret;
     mbedtls_ripemd160_context ctx;
 
     mbedtls_ripemd160_init( &ctx );
-    mbedtls_ripemd160_starts( &ctx );
-    mbedtls_ripemd160_update( &ctx, input, ilen );
-    mbedtls_ripemd160_finish( &ctx, output );
+
+    if( ( ret = mbedtls_ripemd160_starts_ext( &ctx ) ) != 0 )
+            return( ret );
+
+    if( ( ret = mbedtls_ripemd160_update_ext( &ctx, input, ilen ) ) != 0 )
+            return( ret );
+
+    if( ( ret = mbedtls_ripemd160_finish_ext( &ctx, output ) ) != 0 )
+            return( ret );
+
     mbedtls_ripemd160_free( &ctx );
+
+    return( 0 );
 }
 
 #if defined(MBEDTLS_SELF_TEST)
@@ -430,7 +464,7 @@
  */
 int mbedtls_ripemd160_self_test( int verbose )
 {
-    int i;
+    int i, ret;
     unsigned char output[20];
 
     memset( output, 0, sizeof output );
@@ -440,17 +474,14 @@
         if( verbose != 0 )
             mbedtls_printf( "  RIPEMD-160 test #%d: ", i + 1 );
 
-        mbedtls_ripemd160( (const unsigned char *) ripemd160_test_input[i],
-                   strlen( ripemd160_test_input[i] ),
-                   output );
+        ret = mbedtls_ripemd160_ext(
+                                (const unsigned char *)ripemd160_test_input[i],
+                                strlen( ripemd160_test_input[i] ), output );
+        if( ret != 0 )
+            goto fail;
 
         if( memcmp( output, ripemd160_test_md[i], 20 ) != 0 )
-        {
-            if( verbose != 0 )
-                mbedtls_printf( "failed\n" );
-
-            return( 1 );
-        }
+            goto fail;
 
         if( verbose != 0 )
             mbedtls_printf( "passed\n" );
@@ -460,6 +491,12 @@
         mbedtls_printf( "\n" );
 
     return( 0 );
+
+fail:
+    if( verbose != 0 )
+        mbedtls_printf( "failed\n" );
+
+    return( 1 );
 }
 
 #endif /* MBEDTLS_SELF_TEST */