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Rewrite this one to Arlib API, and wipe out moremem

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Alcaro
2016-12-20 22:19:58 +01:00
parent 8d1780bb29
commit 0e31df85fd
6 changed files with 101 additions and 111 deletions
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#include "patch.h"
//These two give minor performance penalties and will print some random stuff to stdout.
//The former will verify the correctness of the output patch, the latter will print some performance data.
//Can be useful for debugging, but should be disabled for release builds.
#ifdef BPS_STANDALONE
#endif
//#define TEST_CORRECT
//#define TEST_PERF
//If the suffix array of [0, 0, 0, 0] is [3, 2, 1, 0], set to true. If it's [0, 1, 2, 3], this is false.
//If it's [4, 3, 2, 1, 0] or [0, 1, 2, 3, 4], remove the 4 (easily done with some pointer math), and follow the above.
//If it's something else, get a non-broken array calculator.
#define EOF_IS_LAST false
//Algorithm description:
//
//This is heavily built upon suffix sorting; the implementation I use, libdivsufsort, claims
// O(n log n) complexity, so I'll believe that. There is also SA-IS, which claims O(n), but if that
// is true, its constant factors are ridiculously high.
//
//The program starts by taking an equal amount of the source file and target file, concatenates that
// with target first, and suffix sorts it.
//
//To find a match, it finds the sortpos where sorted[sortpos]==outpos. This is a binary search; it's
// called O(n) times, with O(log n) comparisons per iteration. Each comparison is potentially O(n),
// but for each matched byte, another iteration is removed from the outer loop, so the comparisons
// can be considered O(1) each; the sum is O(n log n).
//
//After it's found sortpos, it scans sorted[] up and down for the closest entry that either starts
// before the current output position, or is somewhere in the source file.
//As the source file comes last, the end-of-file marker (whose value is outside the range of a byte)
// is guaranteed to not be in the way for a better match.
//This is called O(n) times, and averages O(1) as at least 50% of sorted[] is in range. However, it
// is worst-case O(n) for sorted inputs, giving a total of O(n^2).
//
//It then checks which of the two candidates are superior, by checking how far they match each
// other, and then checking if the upper one has another correct byte.
//This is potentially O(n), but like the binary search, long matches reduce the outer loop. The sum
// is O(n).
//
//When the program approaches the end of the sorted area, it re-sorts twice as much as last time.
// This gives O(log n) calls to the suffix sorter.
//Given O(n log n) for one sorting step, the time taken is O(n/1 log n/1 + n/2 log n/2 +
// n/4 log n/4 + ...), which is strictly less than O(n/1 log n + n/2 log n + n/4 log n + ...), which
// equals O(2n log n), which is O(n log n). (The exact value of that infinite sum is 2n*log(n/2).)
//
//Many details were omitted from the above, but that's the basic setup.
//
//Thus, the program is O(max(n log n, n log n, n, n) = n log n) average and O(max(n log n, n log n,
// n^2, n) = n^2) worst case.
//
//I conclude that the task of finding, understanding and implementing a sub-O(n^2) algorithm for
// delta patching is resolved.
//Known cases where this function does not emit the optimal encoding:
//If a match in the target file would extend further than target_search_size, it's cut off.
// Penalty: O(log n), with extremely low constants (it'd require a >256B match to be exactly there).
// Even for big files, the penalty is very likely to remain zero; even hitting double-digit bytes
// would require a file designed exactly for that.
//If multiple matches are equally good, it picks one at random, not the one that's cheaper to encode.
// Penalty: Likely O(n) or O(n log log n), with low constants. I'd guess ~1.4% for my 48MB test file.
//However, due to better heuristics and others' performance optimizations, this one still beats its
// competitors.
//TODO: test multiple same-length matches
// but only for lengths <= 64,
//Possible optimizations:
//divsufsort() takes approximately 1/2 of the total time.
//Each iteration takes four times as long as the previous one.
//If each iteration takes 4 times as long as the previous one, then the last one takes 3/4 of the total time.
//Since divsufsort doesn't depend on anything else, the last iteration can be split off to its own thread.
//This would split it to
//Search, non-final: 1/2 * 1/4 = 1/8
//Search, final: 1/2 * 3/4 = 3/8
//Sort+rev, non-final: 1/2 * 1/4 = 1/8
//Sort+rev, final: 1/2 * 3/4 = 3/8
//All non-final must be done sequentially. Both Sort Final and non-final must be done before Search Final can start.
//This means the final time, if Sort Final is split off, is
//max(1/8+1/8, 3/8) + 3/8 = 6/8 = 3/4
//of the original time.
//Due to
//- the considerable complexity costs (OpenMP doesn't seem able to represent the "insert a wait in
// the middle of this while loop" I would need)
//- the added memory use, approximately 25% higher - it's already high enough
//- libdivsufsort already using threads, which would make the gains lower
// and would increase complexity, as I have to ensure the big one remains threaded -
// and that the small ones are not, as that'd starve the big one
//I deem a possible 25% boost not worthwhile.
//Both sorting algorithms claim O(1) memory use, in addition to the in/outputs. For most hardware,
// this is 5*(source.len+target.len).
//If the output is stored to disk, that's all this algorithm needs as well.
namespace patch { namespace bps {
//TODO: HEAVY cleanups needed here
#include "sais.cpp"
template<typename sais_index_type>
static void sufsort(sais_index_type* SA, const uint8_t* T, sais_index_type n) {
if(n <= 1) { if(n == 1) SA[0] = 0; return; }
sais_main<sais_index_type>(T, SA, 0, n, 256);
}
//According to <https://code.google.com/p/libdivsufsort/wiki/SACA_Benchmarks>, divsufsort achieves
// approximately half the time of SAIS for nearly all files, despite SAIS' promises of linear
// performance (divsufsort claims O(n log n)).
//divsufsort only allocates O(1) for some radix/bucket sorting. SAIS seems constant too.
//I'd prefer to let them allocate from an array I give it, but divsuf doesn't allow that, and there
// are only half a dozen allocations per call anyways.
//This ends up in libdivsufsort if available, otherwise sais.cpp.
#include "divsufsort.h"
static void sufsort(int32_t* SA, uint8_t* T, int32_t n)
{
divsufsort(T, SA, n);
}
#ifdef USE_DIVSUFSORT64
#include "divsufsort64.h"
static void sufsort(int64_t* SA, uint8_t* T, int64_t n)
{
divsufsort(T, SA, n);
}
#endif
template<typename T> static T min(T a, T b) { return a<b ? a : b; }
template<typename T> static T max(T a, T b) { return a<b ? b : a; }
namespace {
//class filecache {
// file& f;
// uint32_t crc32;
// int bytes_used;
// uint8_t bytes[65536];
//
// void append(const uint8_t * data, size_t len)
// {
//
// }
//};
struct bps_creator {
uint8_t* out;
size_t outlen;
size_t outbuflen;
void reserve(size_t len)
{
if (outlen+len > outbuflen)
{
if (!outbuflen) outbuflen = 128;
while (outlen+len > outbuflen) outbuflen *= 2;
out = (uint8_t*)realloc(out, outbuflen);
}
}
void append(const uint8_t * data, size_t len)
{
reserve(len);
memcpy(out+outlen, data, len);
outlen+=len;
}
void appendnum(size_t num)
{
#ifdef TEST_CORRECT
if (num > 1000000000)
printf("ERROR: Attempt to write %.8lX\n",(unsigned long)num),abort();
#endif
reserve(sizeof(size_t)*8/7+1);
while (num >= 128)
{
out[outlen++]=(num&0x7F);
num>>=7;
num--;
}
out[outlen++]=num|0x80;
}
void appendnum32(uint32_t num)
{
reserve(4);
out[outlen++] = num>>0;
out[outlen++] = num>>8;
out[outlen++] = num>>16;
out[outlen++] = num>>24;
}
static size_t maxsize()
{
return SIZE_MAX>>2; // can be reduced to SIZE_MAX>>1 by amending append_cmd, but the mallocs overflow at that point anyways.
}
size_t sourcelen;
size_t targetlen;
const uint8_t* targetmem;
enum bpscmd { SourceRead, TargetRead, SourceCopy, TargetCopy };
size_t outpos;
size_t sourcecopypos;
size_t targetcopypos;
size_t numtargetread;
bps_creator(const file& source, const file& target, struct mem metadata)
{
outlen = 0;
outbuflen = 128;
out = (uint8_t*)malloc(outbuflen);
outpos = 0;
sourcecopypos = 0;
targetcopypos = 0;
numtargetread = 0;
append((const uint8_t*)"BPS1", 4);
appendnum(source.size());
appendnum(target.size());
appendnum(metadata.len);
append(metadata.ptr, metadata.len);
}
void move_target(const uint8_t* ptr)
{
targetmem = ptr;
}
size_t encode_delta(size_t prev, size_t next)
{
bool negative = (next<prev);
size_t offset = negative ? prev-next : next-prev;
return (negative?1:0) | (offset<<1);
}
void append_delta(size_t prev, size_t next)
{
appendnum(encode_delta(prev, next));
}
void append_cmd(bpscmd command, size_t count)
{
appendnum((count-1)<<2 | command);
}
void flush_target_read()
{
if (!numtargetread) return;
append_cmd(TargetRead, numtargetread);
append(targetmem+outpos-numtargetread, numtargetread);
numtargetread = 0;
}
size_t emit_source_copy(size_t location, size_t count)
{
if (location == outpos) return emit_source_read(location, count);
flush_target_read();
append_cmd(SourceCopy, count);
append_delta(sourcecopypos, location);
sourcecopypos = location+count;
outpos += count;
return count;
}
size_t emit_source_read(size_t location, size_t count)
{
flush_target_read();
#ifdef TEST_CORRECT
if (location != outpos)
puts("ERROR: SourceRead not from source pointer"),abort();
#endif
append_cmd(SourceRead, count);
outpos+=count;
return count;
}
size_t emit_target_copy(size_t location, size_t count)
{
flush_target_read();
append_cmd(TargetCopy, count);
append_delta(targetcopypos, location);
targetcopypos = location+count;
outpos += count;
return count;
}
size_t emit_target_read()
{
numtargetread++;
outpos++;
return 1;
}
size_t abs_diff(size_t a, size_t b)
{
return (b<a) ? (a-b) : (b-a);
}
size_t num_cost(size_t num)
{
if (num<128) return 1;
if (num<128*128) return 2; // 32KB
if (num<128*128*128) return 3; // 2MB
if (num<128*128*128*128) return 4; // 256MB
// 128^5 is 32GB, let's just assume the sizes don't go any higher...
// worst case, a bad match is used. except a 32GB match is by definition good.
return 5;
}
bool use_match(bool hastargetread, size_t cost, size_t len)
{
//numbers calculated via trial and error; checking for each cost, optimizing 'len' for each, and checking what happens
//then a pattern was identified and used
//yes, it looks weird
return len >= 1+cost+hastargetread+(len==1);
}
//Return value is how many bytes were used. If you believe the given one sucks, use TargetRead and return 1.
size_t match(bool is_target, size_t pos, size_t len)
{
if (!use_match(
numtargetread,
(!is_target && pos==outpos) ? 1 : // SourceRead
(num_cost(abs_diff(pos, (is_target ? targetcopypos : sourcecopypos)))+1),
len
))
{
return emit_target_read();
}
if (is_target) return emit_target_copy(pos, len);
else return emit_source_copy(pos, len);
}
function<bool(size_t done, size_t total)> progress;
void finish(const uint8_t* source, const uint8_t* target)
{
flush_target_read();
#ifdef TEST_CORRECT
if (outpos != targetlen)
puts("ERROR: patch creates wrong ROM size"),abort();
#endif
appendnum32(crc32(arrayview<byte>(source, sourcelen)));
appendnum32(crc32(arrayview<byte>(target, targetlen)));
appendnum32(crc32(arrayview<byte>(out, outlen)));
}
struct mem getpatch()
{
struct mem ret = { out, outlen };
out = NULL;
return ret;
}
~bps_creator() { free(out); }
};
}
#ifdef TEST_PERF
static int match_len_n=0;
static int match_len_tot=0;
#endif
template<typename off_t>
static off_t match_len(const uint8_t* a, const uint8_t* b, off_t len)
{
off_t i;
for (i=0;i<len && a[i]==b[i];i++) {}
#ifdef TEST_PERF
match_len_n++;
match_len_tot+=i;
#endif
return i;
}
//This one assumes that the longest common prefix of 'a' and 'b' is shared also by 'search'.
//In practice, lexographically, a < search < b, which is a stronger guarantee.
template<typename off_t>
static off_t pick_best_of_two(const uint8_t* search, off_t searchlen,
const uint8_t* data, off_t datalen,
off_t a, off_t b,
off_t* bestlen)
{
off_t commonlen = match_len(data+a, data+b, min(datalen-a, datalen-b));
if (commonlen>=searchlen)
{
*bestlen=searchlen;
return a;
}
if (a+commonlen<datalen && search[commonlen]==data[a+commonlen])
{
// a is better
*bestlen = commonlen + match_len(search+commonlen, data+a+commonlen, min(searchlen, datalen-a)-commonlen);
return a;
}
else
{
// b is better, or they're equal
*bestlen = commonlen + match_len(search+commonlen, data+b+commonlen, min(searchlen, datalen-b)-commonlen);
return b;
}
}
//This one takes a match, which is assumed optimal, and looks for the lexographically closest one
// that either starts before 'maxstart', or starts at or after 'minstart'.
template<typename off_t>
static off_t adjust_match(off_t match, const uint8_t* search, off_t searchlen,
const uint8_t* data,off_t datalen, off_t maxstart,off_t minstart,
const off_t* sorted, off_t sortedlen,
off_t* bestlen)
{
off_t match_up = match;
off_t match_dn = match;
while (match_up>=0 && sorted[match_up]>=maxstart && sorted[match_up]<minstart) match_up--;
while (match_dn<sortedlen && sorted[match_dn]>=maxstart && sorted[match_dn]<minstart) match_dn++;
if (match_up<0 || match_dn>=sortedlen)
{
if (match_up<0 && match_dn>=sortedlen)
{
*bestlen=0;
return 0;
}
off_t pos = sorted[match_up<0 ? match_dn : match_up];
*bestlen = match_len(search, data+pos, min(searchlen, datalen-pos));
return pos;
}
return pick_best_of_two(search,searchlen, data,datalen, sorted[match_up],sorted[match_dn], bestlen);
}
static uint16_t read2_uc(const uint8_t* data)
{
return data[0]<<8 | data[1];
}
template<typename off_t>
static uint16_t read2(const uint8_t* data, off_t len)
{
if (len>=2) return read2_uc(data);
else
{
uint16_t out = (EOF_IS_LAST ? 0xFFFF : 0x0000);
if (len==1) out = (data[0]<<8) | (out&0x00FF);
return out;
}
}
template<typename off_t>
static void create_buckets(const uint8_t* data, off_t* index, off_t len, off_t* buckets)
{
off_t low = 0;
off_t high;
for (int n=0;n<65536;n++)
{
//'low' remains from the previous iteration and is a known minimum
high = low+(len/131072)+1; // optimal value: slightly above a third of the distance to the next one
while (true)
{
if (high > len-1) break;
off_t pos = index[high];
uint16_t here = read2(data+pos, len-pos);
if (here >= n) break;
else
{
off_t diff = high-low;
low = high;
high = high+diff*2;
}
}
if (high > len-1) high = len-1;
while (low < high)
{
off_t mid = low + (high-low)/2;
off_t midpos = index[mid];
uint16_t here = read2(data+midpos, len-midpos);
if (here < n) low = mid+1;
else high = mid;
}
buckets[n] = low;
}
buckets[65536] = len;
#ifdef TEST_CORRECT
if (buckets[0]!=0)
{
printf("e: buckets suck, [0]=%i\n", buckets[0]);
abort();
}
for (int n=0;n<65536;n++)
{
off_t low = buckets[n];
off_t high = buckets[n+1];
for (off_t i=low;i<high;i++)
{
if (read2(data+index[i], len-index[i])!=n)
{
printf("e: buckets suck, %i != (%i)[%i]%i [%i-%i]", n, i,index[i],read2(data+index[i],len-index[i]),low,high);
abort();
}
}
//printf("%i:[%i]%i\n",n,low,read2(data+index[low],len-low));
}
#endif
}
template<typename off_t>
static off_t find_index(off_t pos, const uint8_t* data, off_t datalen, const off_t* index, const off_t* buckets)
{
//if (datalen<2) return 0;
uint16_t bucket = read2(data+pos, datalen-pos);
//printf("p=%i b=%i\n",pos,bucket);
//TODO
//off_t low = 0;
//off_t high = datalen-1;
off_t low = buckets[bucket];
off_t high = buckets[bucket+1]-1;
off_t lowmatch = 2;
off_t highmatch = 2;
//printf("b=%i r=%i(%i)-%i(%i)\n",bucket,low,read2(data+index[low],datalen-index[low]),high,read2(data+index[high],datalen-index[high]));
//fflush(stdout);
while (true)
{
off_t mid = low + (high-low)/2;
off_t midpos = index[mid];
if (midpos == pos) return mid;
//printf("r=[%i]%i-%i \n",high-low,low,high,);
//fflush(stdout);
#ifdef TEST_CORRECT
if (low >= high)
{
printf("E: [%i](%i): stuck at %i(%i)-%i(%i)\n", pos, read2_uc(data+pos),
low, read2_uc(data+index[low]), high, read2_uc(data+index[high]));
int n=0;
while (index[n]!=pos) n++;
printf("correct one is %i(%i)\n",n, read2_uc(data+index[n]));
abort();
}
#endif
off_t matchlenstart = min(lowmatch, highmatch);
off_t len = datalen - max(pos, midpos) - matchlenstart;
const uint8_t* search = data+pos+matchlenstart;
const uint8_t* here = data+midpos+matchlenstart;
while (len>0 && *search==*here)
{
search++;
here++;
len--;
}
off_t matchlen = search-data-pos;
bool less;
if (len > 0) less = (*here<*search);
else less = (here > search) ^ EOF_IS_LAST;
if (less)
{
low = mid+1;
lowmatch = matchlen;
}
else
{
high = mid-1;
highmatch = matchlen;
}
if (low+256 > high)
{
off_t i=low;
while (true)
{
if (index[i]==pos) return i;
i++;
}
}
}
}
template<typename off_t>
static void create_reverse_index(off_t* index, off_t* reverse, off_t len)
{
//testcase: linux 3.18.14 -> 4.0.4 .xz
//without: real23.544 user32.930
//with: real22.636 user40.168
//'user' jumps up quite a lot, while 'real' only moves a short bit
//I'm not sure why the tradeoff is so bad (do the cachelines bounce THAT badly?), but I deem it not worth it.
//#pragma omp parallel for
for (off_t i=0;i<len;i++) reverse[index[i]]=i;
}
template<typename off_t>
static off_t nextsize(off_t outpos, off_t sortedsize, off_t targetlen)
{
while (outpos >= sortedsize-256 && sortedsize < targetlen)
sortedsize = min(sortedsize*4+3, targetlen);
return sortedsize;
}
template<typename off_t>
off_t lerp(off_t x, off_t y, float frac)
{
return x + (y-x)*frac;
}
template<typename off_t>
static result create_suf_core(const file& source, const file& target, struct bps_creator * out)
{
#define error(which) do { err = which; goto error; } while(0)
result err;
size_t realsourcelen = source.size();
size_t realtargetlen = target.size();
size_t overflowtest = realsourcelen + realtargetlen;
//source+target length is bigger than size_t
if (overflowtest < realsourcelen) return e_too_big;
//source+target doesn't fit in unsigned off_t
if ((size_t)(off_t)overflowtest != overflowtest) return e_too_big;
//source+target doesn't fit in signed off_t
if ((off_t)overflowtest < 0) return e_too_big;
//the mallocs would overflow
if (realsourcelen+realtargetlen >= SIZE_MAX/sizeof(off_t)) return e_too_big;
if (realsourcelen+realtargetlen >= out->maxsize()) return e_too_big;
off_t sourcelen = realsourcelen;
off_t targetlen = realtargetlen;
uint8_t* mem_joined = (uint8_t*)malloc(sizeof(uint8_t)*(realsourcelen+realtargetlen));
off_t* sorted = (off_t*)malloc(sizeof(off_t)*(realsourcelen+realtargetlen));
off_t* buckets = (off_t*)malloc(sizeof(off_t)*65537);
if (!sorted || !mem_joined || !buckets)
{
free(mem_joined);
free(sorted);
free(buckets);
return e_out_of_mem;
}
//sortedsize is how much of the target file is sorted
off_t sortedsize = targetlen;
//divide by 4 for each iteration, to avoid sorting 50% of the file (the sorter is slow)
while (sortedsize/4 > sourcelen && sortedsize > 1024) sortedsize >>= 2;
off_t prevsortedsize = 0;
off_t outpos = 0;
goto reindex; // jump into the middle so I won't need a special case to enter it
while (outpos < targetlen)
{
if (outpos >= sortedsize-256 && sortedsize < targetlen)
{
sortedsize = nextsize(outpos, sortedsize, targetlen);
reindex:
//this isn't an exact science
const float percSort = 0.50;
const float percBuck = 0.10;
//const float percFind = 0.40; // unused
const size_t progPreSort = lerp(prevsortedsize, sortedsize, 0);
const size_t progPreBuck = lerp(prevsortedsize, sortedsize, percSort);
const size_t progPreFind = lerp(prevsortedsize, sortedsize, percSort+percBuck);
prevsortedsize = sortedsize;
if (out->progress(progPreSort, targetlen)) error(e_canceled);
if (target.read(arrayvieww<byte>(mem_joined, sortedsize), 0) < (size_t)sortedsize) error(e_io);
if (source.read(arrayvieww<byte>(mem_joined+sortedsize, sourcelen), 0) < (size_t)sourcelen) error(e_io);
out->move_target(mem_joined);
sufsort(sorted, mem_joined, sortedsize+sourcelen);
if (out->progress(progPreBuck, targetlen)) error(e_canceled);
create_buckets(mem_joined, sorted, sortedsize+sourcelen, buckets);
if (out->progress(progPreFind, targetlen)) error(e_canceled);
}
off_t matchlen = 0;
off_t matchpos = adjust_match(find_index(outpos, mem_joined, sortedsize+sourcelen, sorted, buckets),
mem_joined+outpos, sortedsize-outpos,
mem_joined,sortedsize+sourcelen, outpos,sortedsize,
sorted, sortedsize+sourcelen,
&matchlen);
#ifdef TEST_CORRECT
if (matchlen && matchpos >= outpos && matchpos < sortedsize) puts("ERROR: found match in invalid location"),abort();
if (memcmp(mem_joined+matchpos, mem_joined+outpos, matchlen)) puts("ERROR: found match doesn't match"),abort();
#endif
off_t taken;
if (matchpos >= sortedsize) taken = out->match(false, matchpos-sortedsize, matchlen);
else taken = out->match(true, matchpos, matchlen);
#ifdef TEST_CORRECT
if (taken < 0) puts("ERROR: match() returned negative"),abort();
if (matchlen >= 7 && taken < matchlen) printf("ERROR: match() took %i bytes, offered %i\n", taken, matchlen),abort();
#endif
outpos += taken;
}
out->finish(mem_joined+sortedsize, mem_joined);
err = e_ok;
error:
free(buckets);
free(sorted);
free(mem_joined);
return err;
}
template<typename T> static result create_suf_pick(const file& source, const file& target, struct bps_creator * bps);
template<> result create_suf_pick<uint32_t>(const file& source, const file& target, struct bps_creator * bps)
{
return create_suf_core<int32_t>(source, target, bps);
}
template<> result create_suf_pick<uint64_t>(const file& source, const file& target, struct bps_creator * bps)
{
result err = create_suf_core<int32_t>(source, target, bps);
if (err==e_too_big) err = create_suf_core<int64_t>(source, target, bps);
return err;
}
//This one picks a function based on 32-bit integers if that fits. This halves memory use for common inputs.
//It also handles some stuff related to the BPS headers and footers.
result create(const file& source, const file& target, const file& metadata, file& patch,
function<bool(size_t done, size_t total)> progress)
{
mem metamem = metadata.mmap();
bps_creator bps(source, target, metamem);
metadata.unmap(metamem.v());
bps.progress = progress;
size_t maindata = bps.outlen;
//off_t must be signed
result err = create_suf_pick<size_t>(source, target, &bps);
if (err!=e_ok) return err;
mem patchmem = bps.getpatch();
patch.write(patchmem.v());
free(patchmem.ptr);
while ((patchmem.ptr[maindata]&0x80) == 0x00) maindata++;
if (maindata==patchmem.len-12-1) return e_identical;
return e_ok;
}
#ifdef BPS_STANDALONE
#include <stdio.h>
static struct mem ReadWholeFile(const char * filename)
{
struct mem null = {NULL, 0};
FILE * file=fopen(filename, "rb");
if (!file) return null;
fseek(file, 0, SEEK_END);
size_t len=ftell(file);
fseek(file, 0, SEEK_SET);
unsigned char * data=(unsigned char*)malloc(len);
size_t truelen=fread(data, 1,len, file);
fclose(file);
if (len!=truelen)
{
free(data);
return null;
}
struct mem ret = { (unsigned char*)data, len };
return ret;
}
static bool WriteWholeFile(const char * filename, struct mem data)
{
FILE * file=fopen(filename, "wb");
if (!file) return false;
unsigned int truelen=fwrite(data.ptr, 1,data.len, file);
fclose(file);
return (truelen==data.len);
}
int main(int argc, char * argv[])
{
//struct mem out = ReadWholeFile(argv[2]);
//printf("check=%.8X\n",crc32(out.ptr, out.len));
struct mem in = ReadWholeFile(argv[1]);
struct mem out = ReadWholeFile(argv[2]);
struct mem null = {NULL, 0};
struct mem p={NULL,0};
//int n=50;
//for(int i=0;i<n;i++)
//printf("%i/%i\n",i,n),
bps_create_delta(in,out,null,&p, NULL,NULL);
printf("len=%lu \n",p.len);
printf("check=%.8X\n",*(uint32_t*)(p.ptr+p.len-4));
WriteWholeFile(argv[3], p);
free(in.ptr);
free(out.ptr);
free(p.ptr);
#ifdef TEST_PERF
printf("%i/%i=%f\n",match_len_tot,match_len_n,(float)match_len_tot/match_len_n);
#endif
}
#endif
}}