Merge #45: Allow fields to be opt-in rather than opt-out

67f5160 Add convenience defines for enabling byte sizes (Cory Fields)
812d428 Allow field opt-in (Cory Fields)

Pull request description:

  This addresses the integration concern seen here: https://github.com/theuni/bitcoin/blob/minisketch-split/src/Makefile.minisketch.include#L4

  If a field is explicitly enabled and disabled, disable takes precedence.
  Defines are intended to work as such:
  ```
  Default: All fields enabled
  -DDISABLE_FIELD_3: All fields except 3 are enabled
  -DENABLE_FIELD_3: All fields enabled
  -DDISABLE_DEFAULT_FIELDS: Logical error, no fields enabled
  -DDISABLE_DEFAULT_FIELDS -DENABLE_FIELD_3: Only field 3 enabled
  -DDISABLE_DEFAULT_FIELDS -DENABLE_FIELD_2 -DENABLE_FIELD_3: Fields 2 and 3 are enabled
  -DDISABLE_DEFAULT_FIELDS -DENABLE_FIELD_2 -DENABLE_FIELD_3 -DDISABLE_FIELD_3: Only field 2 enabled
  ```

ACKs for top commit:
  sipa:
    utACK 67f5160

Tree-SHA512: b9e719450dd91089a74f7c59918372f1a36ff7fe3e1b6969d0db257e475ac8df56be650526a29ba8e50db8e63f20be005fa872890dbd84c616ccee4462b6d3dc

Author: sipa

doc/gen_params.sage

@@ -315,14 +315,14 @@ def print_result(bits, style):
         assert(False)
 
 for bits in range(2, 65):
-    print("#ifndef DISABLE_FIELD_%i" % bits)
+    print("#ifdef ENABLE_FIELD_INT_%i" % bits)
     print("// %i bit field" % bits)
     print_result(bits, INT)
     print("#endif")
     print("")
 
 for bits in range(2, 65):
-    print("#ifndef DISABLE_FIELD_%i" % bits)
+    print("#ifdef ENABLE_FIELD_INT_%i" % bits)
     print("// %i bit field" % bits)
     print_result(bits, CLMUL)
     print_result(bits, CLMUL_TRI)

sources.mk

@@ -13,6 +13,7 @@ MINISKETCH_DIST_HEADERS_INT += %reldir%/include/minisketch.h
 
 MINISKETCH_LIB_HEADERS_INT =
 MINISKETCH_LIB_HEADERS_INT += %reldir%/src/false_positives.h
+MINISKETCH_LIB_HEADERS_INT += %reldir%/src/fielddefines.h
 MINISKETCH_LIB_HEADERS_INT += %reldir%/src/int_utils.h
 MINISKETCH_LIB_HEADERS_INT += %reldir%/src/lintrans.h
 MINISKETCH_LIB_HEADERS_INT += %reldir%/src/sketch.h