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introduce macros STORE_OFFSET() and STORE_REPCODE()

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this meant to abstract the sumtype representation required
to transfert `offcode` to `ZSTD_storeSeq()`.

Unfortunately, the sumtype numeric representation is currently a leaky abstraction
that has permeated many other parts of the code,
especially within `zstd_lazy.c` and also within `zstd_opt.c` and `zstd_compress.c`.

While this PR makes a good job a transfering a large nb of call sites
to using the new macros, there are still a few sites where this transformation is more complex,
or where the numeric representation itself it used "as is".

One of the problematics area is the decision to use the numeric format of the sumtype
within the match finders of `zstd_lazy`.

This commit doesn't change the behavior, it only introduces and employes the macros,
but eventually the resulting code remains identical.

At target, if the numeric representation of the sumtype can be completely abstracted
and no other part of the code depends on it,
it will be possible to move it towards something slightly more efficient.
This commit is contained in:
Yann Collet
2021-12-23 22:03:30 -08:00
parent bec7bbb5a4
commit 1aed962216
8 changed files with 158 additions and 137 deletions
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tests/decodecorpus.c
+16 -19
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@@ -633,17 +633,16 @@ static inline void initSeqStore(seqStore_t *seqStore) {
}
/* Randomly generate sequence commands */
static U32 generateSequences(U32* seed, frame_t* frame, seqStore_t* seqStore,
size_t contentSize, size_t literalsSize, dictInfo info)
static U32
generateSequences(U32* seed, frame_t* frame, seqStore_t* seqStore,
size_t contentSize, size_t literalsSize, dictInfo info)
{
/* The total length of all the matches */
size_t const remainingMatch = contentSize - literalsSize;
size_t excessMatch = 0;
U32 numSequences = 0;
U32 i;
const BYTE* literals = LITERAL_BUFFER;
BYTE* srcPtr = frame->src;
@@ -703,32 +702,31 @@ static U32 generateSequences(U32* seed, frame_t* frame, seqStore_t* seqStore,
lenPastStart = MIN(lenPastStart+MIN_SEQ_LEN, (U32)info.dictContentSize);
offset = (U32)((BYTE*)srcPtr - (BYTE*)frame->srcStart) + lenPastStart;
}
{
U32 const matchLenBound = MIN(frame->header.windowSize, lenPastStart);
{ U32 const matchLenBound = MIN(frame->header.windowSize, lenPastStart);
matchLen = MIN(matchLen, matchLenBound);
}
}
}
offsetCode = offset + ZSTD_REP_MOVE;
offsetCode = STORE_OFFSET(offset);
repIndex = 2;
} else {
/* do a repeat offset */
offsetCode = RAND(seed) % 3;
U32 const randomRepIndex = RAND(seed) % 3;
offsetCode = STORE_REPCODE(randomRepIndex + 1); /* expects values between 1 & 3 */
if (literalLen > 0) {
offset = frame->stats.rep[offsetCode];
repIndex = offsetCode;
offset = frame->stats.rep[randomRepIndex];
repIndex = randomRepIndex;
} else {
/* special case */
offset = offsetCode == 2 ? frame->stats.rep[0] - 1
: frame->stats.rep[offsetCode + 1];
repIndex = MIN(2, offsetCode + 1);
/* special case : literalLen == 0 */
offset = randomRepIndex == 2 ? frame->stats.rep[0] - 1
: frame->stats.rep[randomRepIndex + 1];
repIndex = MIN(2, randomRepIndex + 1);
}
}
} while (((!info.useDict) && (offset > (size_t)((BYTE*)srcPtr - (BYTE*)frame->srcStart))) || offset == 0);
{
{ BYTE* const dictEnd = info.dictContent + info.dictContentSize;
size_t j;
BYTE* const dictEnd = info.dictContent + info.dictContentSize;
for (j = 0; j < matchLen; j++) {
if ((U32)((BYTE*)srcPtr - (BYTE*)frame->srcStart) < offset) {
/* copy from dictionary instead of literals */
@@ -739,8 +737,7 @@ static U32 generateSequences(U32* seed, frame_t* frame, seqStore_t* seqStore,
*srcPtr = *(srcPtr-offset);
}
srcPtr++;
}
}
} }
{ int r;
for (r = repIndex; r > 0; r--) {
@@ -754,7 +751,7 @@ static U32 generateSequences(U32* seed, frame_t* frame, seqStore_t* seqStore,
DISPLAYLEVEL(7, " srcPos: %8u seqNb: %3u",
(unsigned)((BYTE*)srcPtr - (BYTE*)frame->srcStart), (unsigned)i);
DISPLAYLEVEL(6, "\n");
if (offsetCode < 3) {
if (offsetCode < ZSTD_REP_NUM) { /* expects @offsetCode to use 0-2 to represents repCodes */
DISPLAYLEVEL(7, " repeat offset: %d\n", (int)repIndex);
}
/* use libzstd sequence handling */