diff options
Diffstat (limited to 'utils/sqz/zqs.c')
| -rw-r--r-- | utils/sqz/zqs.c | 243 |
1 files changed, 243 insertions, 0 deletions
diff --git a/utils/sqz/zqs.c b/utils/sqz/zqs.c new file mode 100644 index 00000000..b9b2a163 --- /dev/null +++ b/utils/sqz/zqs.c @@ -0,0 +1,243 @@ +#include <lib9.h> +#include <a.out.h> +#include "squeeze.h" + +/* + * forsyth@vitanuova.com + */ + +/* + * for details of `unsqueeze' see: + * + * %A Mark Taunton + * %T Compressed Executables: An Exercise in Thinking Small + * %P 385-404 + * %I USENIX + * %B USENIX Conference Proceedings + * %D Summer 1991 + * %C Nashville, TN + * + * several of the unimplemented improvements described in the paper + * have been implemented here + * + * there is a further transformation on the powerpc (QFLAG!=0) to shuffle bits + * in certain instructions so as to push the fixed bits to the top of the word. + */ + +typedef struct Squeeze Squeeze; +struct Squeeze { + int n; + ulong tab[7*256]; +}; + +enum { + CHECK = 1 /* check precise bounds in Squeeze array */ +}; + +#define GET4(p) (((((((p)[0]<<8)|(p)[1])<<8)|(p)[2])<<8)|(p)[3]) + +static uchar out[3*1024*1024]; +static uchar bigb[1024*1024]; +static ulong top; +static int qflag = 1; +static int islittle = 0; +static ulong chksum, oldsum; +static int rdtab(int, Squeeze*, int); +static long unsqueezefd(int, void*); +static uchar* unsqueeze(uchar*, uchar*, uchar*, Squeeze*, Squeeze*, ulong); +static uchar* unsqzseg(int, uchar*, long, ulong); + +void +main(int argc, char **argv) +{ + int fd; + long n; + + if(argc < 2) + exits("args"); + fd = open(argv[1], OREAD); + if(fd < 0) + exits("open"); + n = unsqueezefd(fd, out); + if(n < 0){ + fprint(2, "zqs: can't unsqueeze\n"); + exits("err"); + } + if(write(1, out, n) != n){ + fprint(2, "zqs: write error: %r\n"); + exits("err"); + } + fprint(2, "%ld bytes, %8.8lux csum\n", n, chksum); + exits(0); +} + +static long +unsqueezefd(int fd, void *v) +{ + uchar *wp, *out; + ulong toptxt, topdat; + long asis, nst, nsd; + Sqhdr sqh; + Exec ex; + + out = (uchar*)v; + if(read(fd, &sqh, SQHDRLEN) != SQHDRLEN) + return -1; + if(GET4(sqh.magic) != SQMAGIC) + return -1; + if(read(fd, &ex, sizeof(Exec)) != sizeof(Exec)) + return -1; + toptxt = GET4(sqh.toptxt); + topdat = GET4(sqh.topdat); + oldsum = GET4(sqh.sum); + asis = GET4(sqh.asis); + if(asis < 0) + asis = 0; + nst = GET4(sqh.text); + nsd = GET4(sqh.data); + switch(GET4((uchar*)&ex.magic)){ + case Q_MAGIC: + if(qflag) + fprint(2, "PowerPC mode\n"); + islittle = 0; + break; + case E_MAGIC: + case 0xA0E1: /* arm AIF */ + islittle = 1; + qflag = 0; + break; + default: + fprint(2, "Unknown magic: %8.8ux\n", GET4((uchar*)&ex.magic)); + qflag = 0; + break; + } + memmove(out, &ex, sizeof(ex)); + wp = unsqzseg(fd, out + sizeof(ex), nst, toptxt); + if(wp == nil) + return -1; + wp = unsqzseg(fd, wp, nsd, topdat); + if(wp == nil) + return -1; + if(asis){ + if(read(fd, wp, asis) != asis) + return -1; + wp += asis; + } + return wp-out; +} + +static uchar* +unsqzseg(int fd, uchar *wp, long ns, ulong top) +{ + Squeeze sq3, sq4; + + if(ns == 0) + return wp; + if(rdtab(fd, &sq3, 0) < 0) + return nil; + if(rdtab(fd, &sq4, 8) < 0) + return nil; + fprint(2, "tables: %d %d\n", sq3.n, sq4.n); + if(read(fd, bigb, ns) != ns) + return nil; + return unsqueeze(wp, bigb, bigb+ns, &sq3, &sq4, top); +} + +static uchar* +unsqueeze(uchar *wp, uchar *rp, uchar *ep, Squeeze *sq3, Squeeze *sq4, ulong top) +{ + ulong nx; + int code, n; + + if(qflag){ + QREMAP(top); /* adjust top just once, outside the loop */ + } + while(rp < ep){ + code = *rp++; + n = 0; + nx = code>>4; + do{ + if(nx == 0){ + nx = top; + }else{ + if(nx==1){ + if(rp+3 >= ep) + return nil; + nx = (((((rp[3]<<8)|rp[2])<<8)|rp[1])<<8)|rp[0]; + rp += 4; + }else if(nx <= 8){ /* 2 to 8 */ + if(rp+1 >= ep) + return nil; + nx = ((nx-2)<<8) | rp[0]; + if(CHECK && nx >= sq4->n) + return nil; /* corrupted file */ + nx = sq4->tab[nx] | rp[1]; + rp += 2; + }else{ /* 9 to 15 */ + if(rp >= ep) + return nil; /* corrupted file */ + nx = ((nx-9)<<8) | rp[0]; + if(CHECK && nx >= sq3->n) + return nil; /* corrupted file */ + nx = sq3->tab[nx]; + rp++; + } + if(rp > ep) + return nil; /* corrupted file */ + if(qflag){ + QREMAP(nx); + } + } + if(islittle){ + wp[0] = nx; + wp[1] = nx>>8; + wp[2] = nx>>16; + wp[3] = nx>>24; + }else{ + wp[0] = nx>>24; + wp[1] = nx>>16; + wp[2] = nx>>8; + wp[3] = nx; + } + wp += 4; + chksum += nx; + nx = code & 0xF; + }while(++n == 1); + } + return wp; +} + +static int +rdtab(int fd, Squeeze *sq, int shift) +{ + uchar b[7*256*5], *p, *ep; + ulong v, w; + int i; + + if(read(fd, b, 2) != 2) + return -1; + i = (b[0]<<8) | b[1]; + if(1) + fprint(2, "table: %d\n", i); + if((i -= 2) > 0){ + if(read(fd, b, i) != i) + return -1; + } + sq->n = 0; + p = b; + ep = b+i; + v = 0; + while(p < ep){ + w = 0; + do{ + if(p >= ep) + return -1; + w = (w<<7) | (*p & 0x7F); + }while(*p++ & 0x80); + v += w; + if(0) + fprint(2, "%d %8.8lux %8.8lux\n", sq->n, v, w); + sq->tab[sq->n++] = v << shift; + } + return 0; +} |