Merge pull request #707 from NanXiao/patch-1

[redis.git] / src / zipmap.c

diff --git a/src/zipmap.c b/src/zipmap.c
index 35faeabefa78434046e9cc6d922389255ec6d04d..d9b7c8b31e075393eff0e5410ecc8f9444bb9ebd 100644 (file)
--- a/src/zipmap.c
+++ b/src/zipmap.c
@@ -52,15 +52,15 @@
  * <len> lengths are encoded in a single value or in a 5 bytes value.
  * If the first byte value (as an unsigned 8 bit value) is between 0 and
  * 252, it's a single-byte length. If it is 253 then a four bytes unsigned
- * integer follows (in the host byte ordering). A value fo 255 is used to
+ * integer follows (in the host byte ordering). A value of 255 is used to
  * signal the end of the hash. The special value 254 is used to mark
  * empty space that can be used to add new key/value pairs.
  *
- * <free> is the number of free unused bytes
- * after the string, resulting from modification of values associated to a
- * key (for instance if "foo" is set to "bar', and later "foo" will be se to
- * "hi", I'll have a free byte to use if the value will enlarge again later,
- * or even in order to add a key/value pair if it fits.
+ * <free> is the number of free unused bytes after the string, resulting 
+ * from modification of values associated to a key. For instance if "foo"
+ * is set to "bar", and later "foo" will be set to "hi", it will have a
+ * free byte to use if the value will enlarge again later, or even in
+ * order to add a key/value pair if it fits.
  *
  * <free> is always an unsigned 8 bit number, because if after an
  * update operation there are more than a few free bytes, the zipmap will be
@@ -80,6 +80,7 @@
 #include <string.h>
 #include <assert.h>
 #include "zmalloc.h"
+#include "endianconv.h"
 
 #define ZIPMAP_BIGLEN 254
 #define ZIPMAP_END 255
@@ -108,6 +109,7 @@ static unsigned int zipmapDecodeLength(unsigned char *p) {
 
     if (len < ZIPMAP_BIGLEN) return len;
     memcpy(&len,p+1,sizeof(unsigned int));
+    memrev32ifbe(&len);
     return len;
 }
 
@@ -123,6 +125,7 @@ static unsigned int zipmapEncodeLength(unsigned char *p, unsigned int len) {
         } else {
             p[0] = ZIPMAP_BIGLEN;
             memcpy(p+1,&len,sizeof(len));
+            memrev32ifbe(p+1);
             return 1+sizeof(len);
         }
     }
@@ -144,7 +147,7 @@ static unsigned char *zipmapLookupRaw(unsigned char *zm, unsigned char *key, uns
         /* Match or skip the key */
         l = zipmapDecodeLength(p);
         llen = zipmapEncodeLength(NULL,l);
-        if (k == NULL && l == klen && !memcmp(p+llen,key,l)) {
+        if (key != NULL && k == NULL && l == klen && !memcmp(p+llen,key,l)) {
             /* Only return when the user doesn't care
              * for the total length of the zipmap. */
             if (totlen != NULL) {
@@ -295,7 +298,7 @@ unsigned char *zipmapDel(unsigned char *zm, unsigned char *key, unsigned int kle
     return zm;
 }
 
-/* Call it before to iterate trought elements via zipmapNext() */
+/* Call before iterating through elements via zipmapNext() */
 unsigned char *zipmapRewind(unsigned char *zm) {
     return zm+1;
 }
@@ -360,6 +363,16 @@ unsigned int zipmapLen(unsigned char *zm) {
     return len;
 }
 
+/* Return the raw size in bytes of a zipmap, so that we can serialize
+ * the zipmap on disk (or everywhere is needed) just writing the returned
+ * amount of bytes of the C array starting at the zipmap pointer. */
+size_t zipmapBlobLen(unsigned char *zm) {
+    unsigned int totlen;
+    zipmapLookupRaw(zm,NULL,0,&totlen);
+    return totlen;
+}
+
+#ifdef ZIPMAP_TEST_MAIN
 void zipmapRepr(unsigned char *p) {
     unsigned int l;
 
@@ -374,14 +387,14 @@ void zipmapRepr(unsigned char *p) {
             l = zipmapDecodeLength(p);
             printf("{key %u}",l);
             p += zipmapEncodeLength(NULL,l);
-            fwrite(p,l,1,stdout);
+            if (l != 0 && fwrite(p,l,1,stdout) == 0) perror("fwrite");
             p += l;
 
             l = zipmapDecodeLength(p);
             printf("{value %u}",l);
             p += zipmapEncodeLength(NULL,l);
             e = *p++;
-            fwrite(p,l,1,stdout);
+            if (l != 0 && fwrite(p,l,1,stdout) == 0) perror("fwrite");
             p += l+e;
             if (e) {
                 printf("[");
@@ -393,7 +406,6 @@ void zipmapRepr(unsigned char *p) {
     printf("\n");
 }
 
-#ifdef ZIPMAP_TEST_MAIN
 int main(void) {
     unsigned char *zm;
 
@@ -440,7 +452,7 @@ int main(void) {
                 vlen, vlen, value);
         }
     }
-    printf("\nIterate trought elements:\n");
+    printf("\nIterate through elements:\n");
     {
         unsigned char *i = zipmapRewind(zm);
         unsigned char *key, *value;