--format=csv: increase default buffer size

Input is percent-encoded when colon separated values mode is
enabled. Account for the percent encoding overhead (each character is
encoded as 3 characters) in the default buffer size.

Work around for message boundary bugs in csv mode, e.g.,
* only the first lihe delimited value is read: multiple lines may be in
  the buffer
* a buffer may contain a partial message

src/xmppipe.c

@@ -89,7 +89,7 @@ int main(int argc, char **argv) {
   state = xmppipe_calloc(1, sizeof(xmppipe_state_t));
 
   xmppipe_next_state(state, XMPPIPE_S_CONNECTING);
-  state->bufsz = 2049;
+  state->bufsz = -1;
   state->poll = 10;
   state->keepalive = 60 * 1000;
   state->keepalive_limit = 3;
@@ -240,6 +240,17 @@ int main(int argc, char **argv) {
     exit(2);
   }
 
+  if (state->bufsz == -1) {
+    switch (state->format) {
+    case XMPPIPE_FMT_CSV:
+      state->bufsz = 6144 + 1;
+      break;
+    default:
+      state->bufsz = 2048 + 1;
+      break;
+    }
+  }
+
   if (state->encode && BASE64_LENGTH(state->bufsz) + 1 > 0xffff) {
     usage(state);
     exit(2);

src/xmppipe.h

@@ -85,7 +85,7 @@ typedef struct {
       keepalive_fail; /* number of consecutive keepalives without a reply */
   u_int32_t keepalive_limit; /* number of keepalives without a reply */
   u_int32_t interval;        /* time since last keepalive (milliseconds) */
-  size_t bufsz;              /* size of read buffer */
+  ssize_t bufsz;             /* size of read buffer */
 
   int sm_enabled; /* stanzas: iq, message, presence */