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authorDwight <dmerriman@gmail.com>2007-10-28 14:42:59 -0400
committerDwight <dmerriman@gmail.com>2007-10-28 14:42:59 -0400
commit5380b6e5911e50f2e89bdc0226e5526f58f6cab2 (patch)
tree8407fcf619cb19de8232b6ebfacd0865632c8f9a /util/builder.h
parent9e1541367984bcc5fd9a8c709b311ef309af3954 (diff)
downloadmongo-5380b6e5911e50f2e89bdc0226e5526f58f6cab2.tar.gz
stuff
Diffstat (limited to 'util/builder.h')
-rw-r--r--util/builder.h60
1 files changed, 54 insertions, 6 deletions
diff --git a/util/builder.h b/util/builder.h
index 886ea230c7a..c048b8a6807 100644
--- a/util/builder.h
+++ b/util/builder.h
@@ -6,10 +6,58 @@
class BufBuilder {
public:
- void skip(int n) { }
- char* buf() { return 0; }
- void decouple() { }
- void append(int) { }
- void append(void *, int len) { }
- int len() { return 0; }
+ BufBuilder(int initsize = 32768) : size(initsize) {
+ data = (char *) malloc(size);
+ l = 0;
+ }
+ ~BufBuilder() {
+ if( data ) {
+ free(data);
+ data = 0;
+ }
+ }
+
+ /* leave room for some stuff later */
+ void skip(int n) { grow(n); }
+
+ /* note this may be deallocated (realloced) if you keep writing. */
+ char* buf() { return data; }
+
+ /* assume ownership of the buffer - you must then free it */
+ void decouple() { data = 0; }
+
+ template<class T> void append(T j) { *((T*)grow(sizeof(T))) = j; }
+ void append(short j) { append<short>(j); }
+ void append(int j) { append<int>(j); }
+ void append(unsigned j) { append<unsigned>(j); }
+ void append(bool j) { append<bool>(j); }
+ void append(double j) { append<double>(j); }
+
+ void append(void *src, int len) { memcpy(grow(len), src, len); }
+
+ void append(const char *str) {
+ append((void*) str, strlen(str)+1);
+ }
+
+ int len() { return l; }
+
+private:
+ /* returns the pre-grow write position */
+ char* grow(int by) {
+ int oldlen = l;
+ l += by;
+ if( l > size ) {
+ int a = size * 2;
+ if( l > a )
+ a = l + 16 * 1024;
+ assert( a < 64 * 1024 * 1024 );
+ data = (char *) realloc(data, a);
+ size= a;
+ }
+ return data + oldlen;
+ }
+
+ char *data;
+ int l;
+ int size;
};