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inflate: annotate sliding window with sized_by_or_null #1313

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inflate: annotate sliding window with sized_by_or_null #1313

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27 changes: 19 additions & 8 deletions inflate.c
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Original file line number Diff line number Diff line change
Expand Up @@ -127,7 +127,11 @@ int ZEXPORT inflateReset(z_streamp strm) {

if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
state = (struct inflate_state FAR *)strm->state;
state->wsize = 0;
/* Keep wsize when the sliding window allocation is retained so the
window/wsize relationship remains consistent across reset. Clear
wsize only when there is no window. Indices always restart at zero. */
if (state->window == Z_NULL)
state->wsize = 0;
state->whave = 0;
state->wnext = 0;
return inflateResetKeep(strm);
Expand Down Expand Up @@ -162,6 +166,7 @@ int ZEXPORT inflateReset2(z_streamp strm, int windowBits) {
if (state->window != Z_NULL && state->wbits != (unsigned)windowBits) {
ZFREE(strm, state->window);
state->window = Z_NULL;
state->wsize = 0;
}

/* update state and reset the rest of it */
Expand Down Expand Up @@ -255,16 +260,22 @@ local int updatewindow(z_streamp strm, const Bytef *end, unsigned copy) {

state = (struct inflate_state FAR *)strm->state;

/* if it hasn't been done already, allocate space for the window */
/* if it hasn't been done already, allocate space for the window.
Set capacity (wsize) before binding the pointer so the window/wsize
relationship stays consistent for bounds annotations. */
if (state->window == Z_NULL) {
state->wsize = 1U << state->wbits;
state->wnext = 0;
state->whave = 0;
state->window = (unsigned char FAR *)
ZALLOC(strm, 1U << state->wbits,
sizeof(unsigned char));
if (state->window == Z_NULL) return 1;
ZALLOC(strm, state->wsize, sizeof(unsigned char));
if (state->window == Z_NULL) {
state->wsize = 0;
return 1;
}
}

/* if window not in use yet, initialize */
if (state->wsize == 0) {
else if (state->wsize == 0) {
/* Defensive: allocation present but capacity cleared — restore. */
state->wsize = 1U << state->wbits;
state->wnext = 0;
state->whave = 0;
Expand Down
11 changes: 10 additions & 1 deletion inflate.h
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Original file line number Diff line number Diff line change
Expand Up @@ -97,7 +97,16 @@ struct inflate_state {
unsigned wsize; /* window size or zero if not using window */
unsigned whave; /* valid bytes in the window */
unsigned wnext; /* window write index */
unsigned char FAR *window; /* allocated sliding window, if needed */
/* window <-> wsize: NULL iff wsize == 0. Attribute is inert when the
compiler does not support it (default builds unchanged). */
#if defined(__has_attribute) && __has_attribute(__sized_by_or_null__)
unsigned char FAR *window __attribute__((__sized_by_or_null__(wsize)));
#elif defined(__has_attribute) && __has_attribute(__counted_by_or_null__)
unsigned char FAR *window __attribute__((__counted_by_or_null__(wsize)));
#else
unsigned char FAR *window;
#endif
/* allocated sliding window, if needed */
/* bit accumulator */
unsigned long hold; /* input bit accumulator */
unsigned bits; /* number of bits in hold */
Expand Down