BigInt::get_substring really shouldn't return size_t. Revert to

u32bit.  Maybe should be word? But that would restrict window sizes
more than might be desirable (we couldn't use more than 8 bit window
on the assumption that the lib might be using byte limbs). Messy.

3 files changed, 5 insertions, 7 deletions

diff --git a/src/math/numbertheory/point_gfp.cpp b/src/math/numbertheory/point_gfp.cpp
index 5da1959bc..8cb40270c 100644
--- a/src/math/numbertheory/point_gfp.cpp
+++ b/src/math/numbertheory/point_gfp.cpp
@@ -324,12 +324,12 @@ PointGFp operator*(const BigInt& scalar, const PointGFp& point)
 
    while(bits_left >= window_size)
       {
-      size_t nibble = scalar.get_substring(bits_left - window_size,
-                                           window_size);
-
       for(size_t i = 0; i != window_size; ++i)
          H.mult2(ws);
 
+      const u32bit nibble = scalar.get_substring(bits_left - window_size,
+                                                 window_size);
+
       if(nibble)
          H.add(Ps[nibble-1], ws);
 
diff --git a/src/math/numbertheory/powm_fw.cpp b/src/math/numbertheory/powm_fw.cpp
index afc53f233..3348e55cd 100644
--- a/src/math/numbertheory/powm_fw.cpp
+++ b/src/math/numbertheory/powm_fw.cpp
@@ -45,8 +45,7 @@ BigInt Fixed_Window_Exponentiator::execute() const
       for(size_t k = 0; k != window_bits; ++k)
          x = reducer.square(x);
 
-      size_t nibble = exp.get_substring(window_bits*(j-1), window_bits);
-      if(nibble)
+      if(u32bit nibble = exp.get_substring(window_bits*(j-1), window_bits))
          x = reducer.multiply(x, g[nibble-1]);
       }
    return x;
diff --git a/src/math/numbertheory/powm_mnt.cpp b/src/math/numbertheory/powm_mnt.cpp
index 038ce14da..4f626ac9d 100644
--- a/src/math/numbertheory/powm_mnt.cpp
+++ b/src/math/numbertheory/powm_mnt.cpp
@@ -90,8 +90,7 @@ BigInt Montgomery_Exponentiator::execute() const
          x.get_reg().set(&z[0], mod_words + 1);
          }
 
-      size_t nibble = exp.get_substring(window_bits*(i-1), window_bits);
-      if(nibble)
+      if(u32bit nibble = exp.get_substring(window_bits*(i-1), window_bits))
          {
          const BigInt& y = g[nibble-1];