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https://github.com/9fans/plan9port.git
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68 lines
1 KiB
C
68 lines
1 KiB
C
#include <u.h>
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#include <libc.h>
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#include <flate.h>
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#include "zlib.h"
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typedef struct Block Block;
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struct Block
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{
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uchar *pos;
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uchar *limit;
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};
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static int
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blgetc(void *vb)
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{
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Block *b;
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b = vb;
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if(b->pos >= b->limit)
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return -1;
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return *b->pos++;
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}
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static int
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blwrite(void *vb, void *buf, int n)
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{
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Block *b;
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b = vb;
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if(n > b->limit - b->pos)
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n = b->limit - b->pos;
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memmove(b->pos, buf, n);
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b->pos += n;
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return n;
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}
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int
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inflatezlibblock(uchar *dst, int dsize, uchar *src, int ssize)
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{
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Block bd, bs;
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int ok;
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if(ssize < 6)
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return FlateInputFail;
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if(((src[0] << 8) | src[1]) % 31)
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return FlateCorrupted;
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if((src[0] & ZlibMeth) != ZlibDeflate
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|| (src[0] & ZlibCInfo) > ZlibWin32k)
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return FlateCorrupted;
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bs.pos = src + 2;
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bs.limit = src + ssize - 6;
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bd.pos = dst;
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bd.limit = dst + dsize;
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ok = inflate(&bd, blwrite, &bs, blgetc);
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if(ok != FlateOk)
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return ok;
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if(adler32(1, dst, bs.pos - dst) != ((bs.pos[0] << 24) | (bs.pos[1] << 16) | (bs.pos[2] << 8) | bs.pos[3]))
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return FlateCorrupted;
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return bd.pos - dst;
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}
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