diff options
Diffstat (limited to 'zlib/inffast.c')
| -rw-r--r-- | zlib/inffast.c | 47 |
1 files changed, 30 insertions, 17 deletions
diff --git a/zlib/inffast.c b/zlib/inffast.c index 61a78ee933f..aa7f1d4d2ad 100644 --- a/zlib/inffast.c +++ b/zlib/inffast.c @@ -1,5 +1,5 @@ /* inffast.c -- process literals and length/distance pairs fast - * Copyright (C) 1995-1998 Mark Adler + * Copyright (C) 1995-2002 Mark Adler * For conditions of distribution and use, see copyright notice in zlib.h */ @@ -93,28 +93,41 @@ z_streamp z; /* do the copy */ m -= c; - if ((uInt)(q - s->window) >= d) /* offset before dest */ - { /* just copy */ - r = q - d; - *q++ = *r++; c--; /* minimum count is three, */ - *q++ = *r++; c--; /* so unroll loop a little */ - } - else /* else offset after destination */ + r = q - d; + if (r < s->window) /* wrap if needed */ { - e = d - (uInt)(q - s->window); /* bytes from offset to end */ - r = s->end - e; /* pointer to offset */ - if (c > e) /* if source crosses, */ + do { + r += s->end - s->window; /* force pointer in window */ + } while (r < s->window); /* covers invalid distances */ + e = s->end - r; + if (c > e) { - c -= e; /* copy to end of window */ + c -= e; /* wrapped copy */ do { - *q++ = *r++; + *q++ = *r++; } while (--e); - r = s->window; /* copy rest from start of window */ + r = s->window; + do { + *q++ = *r++; + } while (--c); } + else /* normal copy */ + { + *q++ = *r++; c--; + *q++ = *r++; c--; + do { + *q++ = *r++; + } while (--c); + } + } + else /* normal copy */ + { + *q++ = *r++; c--; + *q++ = *r++; c--; + do { + *q++ = *r++; + } while (--c); } - do { /* copy all or what's left */ - *q++ = *r++; - } while (--c); break; } else if ((e & 64) == 0) |