Fix how zipEntry returns values

zipEntry was returning a struct, but that caused some
problems with tests under 32 bit builds.

The tests run better if we operate on structs allocated in the
caller without worrying about copying on return.

src/ziplist.c

@@ -404,14 +404,12 @@ static int64_t zipLoadInteger(unsigned char *p, unsigned char encoding) {
 }
 
 /* Return a struct with all information about an entry. */
-static zlentry zipEntry(unsigned char *p) {
-    zlentry e;
-
-    ZIP_DECODE_PREVLEN(p, e.prevrawlensize, e.prevrawlen);
-    ZIP_DECODE_LENGTH(p + e.prevrawlensize, e.encoding, e.lensize, e.len);
-    e.headersize = e.prevrawlensize + e.lensize;
-    e.p = p;
-    return e;
+static void zipEntry(unsigned char *p, zlentry *e) {
+
+    ZIP_DECODE_PREVLEN(p, e->prevrawlensize, e->prevrawlen);
+    ZIP_DECODE_LENGTH(p + e->prevrawlensize, e->encoding, e->lensize, e->len);
+    e->headersize = e->prevrawlensize + e->lensize;
+    e->p = p;
 }
 
 /* Create a new empty ziplist. */
@@ -460,13 +458,13 @@ static unsigned char *__ziplistCascadeUpdate(unsigned char *zl, unsigned char *p
     zlentry cur, next;
 
     while (p[0] != ZIP_END) {
-        cur = zipEntry(p);
+        zipEntry(p, &cur);
         rawlen = cur.headersize + cur.len;
         rawlensize = zipPrevEncodeLength(NULL,rawlen);
 
         /* Abort if there is no next entry. */
         if (p[rawlen] == ZIP_END) break;
-        next = zipEntry(p+rawlen);
+        zipEntry(p+rawlen, &next);
 
         /* Abort when "prevlen" has not changed. */
         if (next.prevrawlen == rawlen) break;
@@ -521,7 +519,7 @@ static unsigned char *__ziplistDelete(unsigned char *zl, unsigned char *p, unsig
     int nextdiff = 0;
     zlentry first, tail;
 
-    first = zipEntry(p);
+    zipEntry(p, &first);
     for (i = 0; p[0] != ZIP_END && i < num; i++) {
         p += zipRawEntryLength(p);
         deleted++;
@@ -545,7 +543,7 @@ static unsigned char *__ziplistDelete(unsigned char *zl, unsigned char *p, unsig
             /* When the tail contains more than one entry, we need to take
              * "nextdiff" in account as well. Otherwise, a change in the
              * size of prevlen doesn't have an effect on the *tail* offset. */
-            tail = zipEntry(p);
+            zipEntry(p, &tail);
             if (p[tail.headersize+tail.len] != ZIP_END) {
                 ZIPLIST_TAIL_OFFSET(zl) =
                    intrev32ifbe(intrev32ifbe(ZIPLIST_TAIL_OFFSET(zl))+nextdiff);
@@ -635,7 +633,7 @@ static unsigned char *__ziplistInsert(unsigned char *zl, unsigned char *p, unsig
         /* When the tail contains more than one entry, we need to take
          * "nextdiff" in account as well. Otherwise, a change in the
          * size of prevlen doesn't have an effect on the *tail* offset. */
-        tail = zipEntry(p+reqlen);
+        zipEntry(p+reqlen, &tail);
         if (p[reqlen+tail.headersize+tail.len] != ZIP_END) {
             ZIPLIST_TAIL_OFFSET(zl) =
                 intrev32ifbe(intrev32ifbe(ZIPLIST_TAIL_OFFSET(zl))+nextdiff);
@@ -748,7 +746,7 @@ unsigned int ziplistGet(unsigned char *p, unsigned char **sstr, unsigned int *sl
     if (p == NULL || p[0] == ZIP_END) return 0;
     if (sstr) *sstr = NULL;
 
-    entry = zipEntry(p);
+    zipEntry(p, &entry);
     if (ZIP_IS_STR(entry.encoding)) {
         if (sstr) {
             *slen = entry.len;
@@ -796,7 +794,7 @@ unsigned int ziplistCompare(unsigned char *p, unsigned char *sstr, unsigned int
     long long zval, sval;
     if (p[0] == ZIP_END) return 0;
 
-    entry = zipEntry(p);
+    zipEntry(p, &entry);
     if (ZIP_IS_STR(entry.encoding)) {
         /* Raw compare */
         if (entry.len == slen) {
@@ -913,7 +911,7 @@ void ziplistRepr(unsigned char *zl) {
         intrev32ifbe(ZIPLIST_TAIL_OFFSET(zl)));
     p = ZIPLIST_ENTRY_HEAD(zl);
     while(*p != ZIP_END) {
-        entry = zipEntry(p);
+        zipEntry(p, &entry);
         printf(
             "{"
                 "addr 0x%08lx, "
@@ -1076,10 +1074,10 @@ static void verify(unsigned char *zl, zlentry *e) {
 
     for (i = 0; i < len; i++) {
         memset(&e[i], 0, sizeof(zlentry));
-        e[i] = zipEntry(ziplistIndex(zl, i));
+        zipEntry(ziplistIndex(zl, i), &e[i]);
 
         memset(&_e, 0, sizeof(zlentry));
-        _e = zipEntry(ziplistIndex(zl, -len+i));
+        zipEntry(ziplistIndex(zl, -len+i), &_e);
 
         assert(memcmp(&e[i], &_e, sizeof(zlentry)) == 0);
     }