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Add a patch disassembler to the undocumented features, also shut up some printf warnings in there

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Alcaro
2018-09-27 18:20:54 +02:00
parent 49851a2972
commit a9fccd1485
1 changed files with 92 additions and 7 deletions
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99
libbps.cpp
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@@ -495,9 +495,90 @@ struct bpsinfo bps_get_info(file* patch, bool changefrac)
#include <stdio.h>
//Congratulations, you found the undocumented feature! It compares two equivalent BPS patches and
// tells where each one is more compact. (It crashes or gives bogus answers on invalid or
// non-equivalent patches.) Have fun.
//Congratulations, you found the undocumented features! They disassemble a patch, telling what it
// does; compare two equivalent BPS patches and tells where each one is more compact.
//They crash or give bogus answers on invalid patches, latter also misbehaves on non-equivalent ones.
//Have fun.
void bps_dump(struct mem patch)
{
#define read8() (*(patchat++))
#define decodeto(var) decodenum(patchat, var)
const uint8_t * patchat=patch.ptr;
const uint8_t * patchend=patch.ptr+patch.len-12;
read8();
read8();
read8();
read8();
size_t inreadat = 0;
size_t inlen;
decodeto(inlen);
size_t outat = 0;
size_t outreadat = 0;
size_t outlen;
decodeto(outlen);
size_t metadatalen;
decodeto(metadatalen);
patchat += metadatalen;
while (patchat<patchend)
{
size_t thisinstr;
decodeto(thisinstr);
size_t length=(thisinstr>>2)+1;
int action=(thisinstr&3);
switch (action)
{
case SourceRead:
{
printf("SourceRead %zu from %zu to %zu (0)\n", length, outat, outat);
outat += length;
}
break;
case TargetRead:
{
printf("TargetRead %zu to %zu\n", length, outat);
patchat += length;
outat += length;
}
break;
case SourceCopy:
{
size_t encodeddistance;
decodeto(encodeddistance);
size_t distance=encodeddistance>>1;
if ((encodeddistance&1)==0) inreadat+=distance;
else inreadat-=distance;
printf("SourceCopy %zu from %zu to %zu (%+zi)\n", length, inreadat, outat, inreadat-outat);
inreadat += length;
outat += length;
}
break;
case TargetCopy:
{
size_t encodeddistance;
decodeto(encodeddistance);
size_t distance=encodeddistance>>1;
if ((encodeddistance&1)==0) outreadat+=distance;
else outreadat-=distance;
printf("TargetCopy %zu from %zu to %zu\n", length, outreadat, outat);
outreadat += length;
outat += length;
}
break;
}
}
#undef read8
#undef decodeto
}
void bps_compare(struct mem patch1mem, struct mem patch2mem)
{
const uint8_t * patch[2]={patch1mem.ptr, patch2mem.ptr};
@@ -557,10 +638,10 @@ void bps_compare(struct mem patch1mem, struct mem patch2mem)
int delta = tempuint>>1;
if (tempuint&1) delta=-delta;
patchcopypos[i][action]+=delta;
sprintf(describe[i], "%s from %i (%+i) for %i in %i", actionnames[action], patchcopypos[i][action], delta, len, patchpos[i]-patchposstart);
sprintf(describe[i], "%s from %zu (%+i) for %zu in %zu", actionnames[action], patchcopypos[i][action], delta, len, patchpos[i]-patchposstart);
patchcopypos[i][action]+=len;
}
else sprintf(describe[i], "%s from %i for %i in %i", actionnames[action], patchoutpos[i], len, patchpos[i]-patchposstart);
else sprintf(describe[i], "%s from %zu for %zu in %zu", actionnames[action], patchoutpos[i], len, patchpos[i]-patchposstart);
if (!step[i^1])
{
printf("%i: %s\n", i+1, describe[i]);
@@ -585,7 +666,7 @@ void bps_compare(struct mem patch1mem, struct mem patch2mem)
if (used[0]>used[1]) which='-';
if (show)
{
printf("%c: %i,%i bytes since last match (%i)\n", which, used[0], used[1], patchoutpos[0]);
printf("%c: %zu,%zu bytes since last match (%zu)\n", which, used[0], used[1], patchoutpos[0]);
show=false;
}
patchposatmatch[0]=patchpos[0];
@@ -593,6 +674,8 @@ void bps_compare(struct mem patch1mem, struct mem patch2mem)
lastmatch=patchoutpos[0];
}
}
#undef read8
#undef decodeto
}
static struct mem ReadWholeFile(const char * filename)
@@ -618,6 +701,8 @@ static struct mem ReadWholeFile(const char * filename)
}
int main(int argc,char**argv)
{
bps_compare(ReadWholeFile(argv[1]),ReadWholeFile(argv[2]));
if (argc==1) puts("bad arguments");
if (argc==2) bps_dump(ReadWholeFile(argv[1]));
if (argc==3) bps_compare(ReadWholeFile(argv[1]),ReadWholeFile(argv[2]));
}
#endif