Align distance code meaning in the brotli encoder.
Two different definitions (offset by 1) were used in
command.h and hash.h. Now they have been made the same,
also consistent with the spec (e.g. 0 means use previous dist, etc...)
diff --git a/enc/command.h b/enc/command.h
index 5600455..05eb9d0 100644
--- a/enc/command.h
+++ b/enc/command.h
@@ -24,7 +24,6 @@
static inline void GetDistCode(int distance_code,
uint16_t* code, uint32_t* extra) {
- distance_code -= 1;
if (distance_code < 16) {
*code = distance_code;
*extra = 0;
@@ -106,6 +105,7 @@
struct Command {
Command() {}
+ // distance_code is e.g. 0 for same-as-last short code, or 16 for offset 1.
Command(int insertlen, int copylen, int copylen_code, int distance_code)
: insert_len_(insertlen), copy_len_(copylen) {
GetDistCode(distance_code, &dist_prefix_, &dist_extra_);
@@ -120,12 +120,12 @@
int DistanceCode() const {
if (dist_prefix_ < 16) {
- return dist_prefix_ + 1;
+ return dist_prefix_;
}
int nbits = dist_extra_ >> 24;
int extra = dist_extra_ & 0xffffff;
int prefix = dist_prefix_ - 12 - 2 * nbits;
- return (prefix << nbits) + extra + 13;
+ return (prefix << nbits) + extra + 12;
}
int DistanceContext() const {