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#include <u.h>
#include <libc.h>
#include <flate.h>
#include "zlib.h"
typedef struct Block Block;
struct Block
{
uchar *pos;
uchar *limit;
};
static int
blgetc(void *vb)
{
Block *b;
b = vb;
if(b->pos >= b->limit)
return -1;
return *b->pos++;
}
static int
blwrite(void *vb, void *buf, int n)
{
Block *b;
b = vb;
if(n > b->limit - b->pos)
n = b->limit - b->pos;
memmove(b->pos, buf, n);
b->pos += n;
return n;
}
int
inflatezlibblock(uchar *dst, int dsize, uchar *src, int ssize)
{
Block bd, bs;
int ok;
if(ssize < 6)
return FlateInputFail;
if(((src[0] << 8) | src[1]) % 31)
return FlateCorrupted;
if((src[0] & ZlibMeth) != ZlibDeflate
|| (src[0] & ZlibCInfo) > ZlibWin32k)
return FlateCorrupted;
bs.pos = src + 2;
bs.limit = src + ssize - 6;
bd.pos = dst;
bd.limit = dst + dsize;
ok = inflate(&bd, blwrite, &bs, blgetc);
if(ok != FlateOk)
return ok;
if(adler32(1, dst, bs.pos - dst) != ((bs.pos[0] << 24) | (bs.pos[1] << 16) | (bs.pos[2] << 8) | bs.pos[3]))
return FlateCorrupted;
return bd.pos - dst;
}
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