VeraCrypt
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path: root/src/Boot/Windows/Decompressor.c
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Diffstat (limited to 'src/Boot/Windows/Decompressor.c')
-rw-r--r--src/Boot/Windows/Decompressor.c66
1 files changed, 16 insertions, 50 deletions
diff --git a/src/Boot/Windows/Decompressor.c b/src/Boot/Windows/Decompressor.c
index c3883352..efdbed91 100644
--- a/src/Boot/Windows/Decompressor.c
+++ b/src/Boot/Windows/Decompressor.c
@@ -47,7 +47,6 @@ struct state {
/* input state */
unsigned char *in; /* input buffer */
- unsigned int inlen; /* available input at in */
unsigned int incnt; /* bytes read so far */
int bitbuf; /* bit buffer */
int bitcnt; /* number of bits in bit buffer */
@@ -81,9 +80,6 @@ local int stored(struct state *s)
/* discard leftover bits from current byte (assumes s->bitcnt < 8) */
s->bitbuf = 0;
s->bitcnt = 0;
-
- if (s->incnt + 4 > s->inlen)
- return 2; /* not enough input */
/* get length and check against its one's complement */
len = s->in[s->incnt++];
@@ -91,9 +87,6 @@ local int stored(struct state *s)
if (s->in[s->incnt++] != (~len & 0xff) ||
s->in[s->incnt++] != ((~len >> 8) & 0xff))
return -2; /* didn't match complement! */
-
- if (s->incnt + len > s->inlen)
- return 2; /* not enough input */
/* copy len bytes from in to out */
if (s->out != NIL) {
@@ -117,8 +110,6 @@ struct huffman {
short *symbol; /* canonically ordered symbols */
};
-/* use slow version of decode to save code space */
-#define SLOW
#ifdef SLOW
local int decode(struct state *s, struct huffman *h)
@@ -372,39 +363,28 @@ local int dynamic(struct state *s)
int len; /* last length to repeat */
symbol = decode(s, &lencode);
- if (symbol < 0) return symbol;
if (symbol < 16) /* length in 0..15 */
lengths[index++] = symbol;
else { /* repeat instruction */
len = 0; /* assume repeating zeros */
- switch(symbol)
- {
- case 16: { /* repeat last length 3..6 times */
- if (index == 0) return -5; /* no last length! */
- len = lengths[index - 1]; /* last length */
- symbol = 3 + bits(s, 2);
- break;
- }
- case 17: /* repeat zero 3..10 times */
- symbol = 3 + bits(s, 3);
- break;
- default: /* == 18, repeat zero 11..138 times */
- symbol = 11 + bits(s, 7);
- break;
- }
- if ((index + symbol > nlen + ndist))
+ if (symbol == 16) { /* repeat last length 3..6 times */
+ if (index == 0) return -5; /* no last length! */
+ len = lengths[index - 1]; /* last length */
+ symbol = 3 + bits(s, 2);
+ }
+ else if (symbol == 17) /* repeat zero 3..10 times */
+ symbol = 3 + bits(s, 3);
+ else /* == 18, repeat zero 11..138 times */
+ symbol = 11 + bits(s, 7);
+ if (index + symbol > nlen + ndist)
return -6; /* too many lengths! */
while (symbol--) /* repeat last or zero symbol times */
lengths[index++] = len;
}
}
- /* check for end-of-block code -- there better be one! */
- if (lengths[256] == 0)
- return -9;
-
/* build huffman table for literal/length codes */
- err = construct(&lencode, lengths, nlen);
+ err = construct(&lencode, lengths, nlen);
if (err < 0 || (err > 0 && nlen - lencode.count[0] != 1))
return -7; /* only allow incomplete codes if just one code */
@@ -424,8 +404,7 @@ void _acrtused () { }
int far main (
unsigned char *dest, /* pointer to destination pointer */
unsigned int destlen, /* amount of output space */
- unsigned char *source, /* pointer to source data pointer */
- unsigned int sourcelen)
+ unsigned char *source) /* pointer to source data pointer */
{
struct state s; /* input/output state */
int last, type; /* block information */
@@ -438,7 +417,6 @@ int far main (
/* initialize input state */
s.in = source;
- s.inlen = sourcelen;
s.incnt = 0;
s.bitbuf = 0;
s.bitcnt = 0;
@@ -447,22 +425,10 @@ int far main (
do {
last = bits(&s, 1); /* one if last block */
type = bits(&s, 2); /* block type 0..3 */
- switch(type)
- {
- case 0:
- err = stored(&s);
- break;
- case 1:
- err = fixed(&s);
- break;
- case 2:
- err = dynamic(&s);
- break;
- default:
- err = -1; /* type == 3, invalid */
- break;
- }
-
+ err = type == 0 ? stored(&s) :
+ (type == 1 ? fixed(&s) :
+ (type == 2 ? dynamic(&s) :
+ -1)); /* type == 3, invalid */
if (err != 0) break; /* return with error */
} while (!last);