Generalise strbuf_catf() into put_fmt().

marshal.h now provides a macro put_fmt() which allows you to write
arbitrary printf-formatted data to an arbitrary BinarySink.

We already had this facility for strbufs in particular, in the form of
strbuf_catf(). That was able to take advantage of knowing the inner
structure of a strbuf to minimise memory allocation (it would snprintf
directly into the strbuf's existing buffer if possible). For a general
black-box BinarySink we can't do that, so instead we dupvprintf into a
temporary buffer.

For consistency, I've removed strbuf_catf, and converted all uses of
it into the new put_fmt - and I've also added an extra vtable method
in the BinarySink API, so that put_fmt can still use strbuf_catf's
more efficient memory management when talking to a strbuf, and fall
back to the simpler strategy when that's not available.

1 files changed, 12 insertions, 12 deletions

diff --git a/keygen/pockle.c b/keygen/pockle.c
index 60017e33..2a072f18 100644
--- a/keygen/pockle.c
+++ b/keygen/pockle.c
@@ -410,10 +410,10 @@ strbuf *pockle_mpu(Pockle *pockle, mp_int *p)
     memset(needed, 0, pockle->nlist * sizeof(bool));
     needed[pr->index] = true;
 
-    strbuf_catf(sb, "[MPU - Primality Certificate]\nVersion 1.0\nBase 10\n\n"
-                "Proof for:\nN  ");
+    put_fmt(sb, "[MPU - Primality Certificate]\nVersion 1.0\nBase 10\n\n"
+            "Proof for:\nN  ");
     mp_write_decimal(sb, p);
-    strbuf_catf(sb, "\n");
+    put_fmt(sb, "\n");
 
     for (size_t index = pockle->nlist; index-- > 0 ;) {
         if (!needed[index])
@@ -421,27 +421,27 @@ strbuf *pockle_mpu(Pockle *pockle, mp_int *p)
         pr = pockle->list[index];
 
         if (mp_get_nbits(pr->prime) <= 64) {
-            strbuf_catf(sb, "\nType Small\nN  ");
+            put_fmt(sb, "\nType Small\nN  ");
             mp_write_decimal(sb, pr->prime);
-            strbuf_catf(sb, "\n");
+            put_fmt(sb, "\n");
         } else {
             assert(pr->witness);
-            strbuf_catf(sb, "\nType BLS5\nN  ");
+            put_fmt(sb, "\nType BLS5\nN  ");
             mp_write_decimal(sb, pr->prime);
-            strbuf_catf(sb, "\n");
+            put_fmt(sb, "\n");
             for (size_t i = 0; i < pr->nfactors; i++) {
-                strbuf_catf(sb, "Q[%"SIZEu"]  ", i+1);
+                put_fmt(sb, "Q[%"SIZEu"]  ", i+1);
                 mp_write_decimal(sb, pr->factors[i]->prime);
                 assert(pr->factors[i]->index < index);
                 needed[pr->factors[i]->index] = true;
-                strbuf_catf(sb, "\n");
+                put_fmt(sb, "\n");
             }
             for (size_t i = 0; i < pr->nfactors + 1; i++) {
-                strbuf_catf(sb, "A[%"SIZEu"]  ", i);
+                put_fmt(sb, "A[%"SIZEu"]  ", i);
                 mp_write_decimal(sb, pr->witness);
-                strbuf_catf(sb, "\n");
+                put_fmt(sb, "\n");
             }
-            strbuf_catf(sb, "----\n");
+            put_fmt(sb, "----\n");
         }
     }
     sfree(needed);