Remove compute_offset_length()
We either want to calculate only offset (compute_offset()), or offset and remaining length (compute_offset_and_remaining()) Move old generic code to check_offset_length_no_exception()) svn path=/trunk/; revision=50551
This commit is contained in:
Jakub Zawadzki
parent
614e45a25a
commit
d5450ff925
101
epan/tvbuff.c
101
epan/tvbuff.c
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@ -227,30 +227,11 @@ tvb_new_child_real_data(tvbuff_t *parent, const guint8* data, const guint length
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return tvb;
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}
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/* Computes the absolute offset and length based on a possibly-negative offset
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* and a length that is possible -1 (which means "to the end of the data").
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* Returns integer indicating whether the offset is in bounds (0) or
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* not (exception number). The integer ptrs are modified with the new offset and length.
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* No exception is thrown.
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*
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* XXX - we return success (0), if the offset is positive and right
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* after the end of the tvbuff (i.e., equal to the length). We do this
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* so that a dissector constructing a subset tvbuff for the next protocol
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* will get a zero-length tvbuff, not an exception, if there's no data
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* left for the next protocol - we want the next protocol to be the one
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* that gets an exception, so the error is reported as an error in that
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* protocol rather than the containing protocol. */
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static int
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compute_offset_length(const tvbuff_t *tvb,
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const gint offset, const gint length_val,
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guint *offset_ptr, guint *length_ptr)
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compute_offset(const tvbuff_t *tvb, const gint offset, guint *offset_ptr)
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{
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int exception;
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DISSECTOR_ASSERT(offset_ptr);
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DISSECTOR_ASSERT(length_ptr);
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/* Compute the offset */
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if (offset >= 0) {
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/* Positive offset - relative to the beginning of the packet. */
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if ((guint) offset > tvb->reported_length) {
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@ -286,21 +267,34 @@ compute_offset_length(const tvbuff_t *tvb,
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}
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}
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/* Compute the length */
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if (length_val < -1) {
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/* XXX - ReportedBoundsError? */
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return BoundsError;
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}
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else if (length_val == -1) {
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*length_ptr = tvb->length - *offset_ptr;
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}
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else {
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*length_ptr = length_val;
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}
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return 0;
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}
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static int
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compute_offset_and_remaining(const tvbuff_t *tvb, const gint offset, guint *offset_ptr, guint *rem_len)
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{
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int exception;
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exception = compute_offset(tvb, offset, offset_ptr);
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if (!exception)
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*rem_len = tvb->length - *offset_ptr;
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return exception;
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}
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/* Computes the absolute offset and length based on a possibly-negative offset
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* and a length that is possible -1 (which means "to the end of the data").
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* Returns integer indicating whether the offset is in bounds (0) or
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* not (exception number). The integer ptrs are modified with the new offset and length.
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* No exception is thrown.
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*
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* XXX - we return success (0), if the offset is positive and right
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* after the end of the tvbuff (i.e., equal to the length). We do this
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* so that a dissector constructing a subset tvbuff for the next protocol
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* will get a zero-length tvbuff, not an exception, if there's no data
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* left for the next protocol - we want the next protocol to be the one
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* that gets an exception, so the error is reported as an error in that
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* protocol rather than the containing protocol. */
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static int
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check_offset_length_no_exception(const tvbuff_t *tvb,
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const gint offset, gint const length_val,
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@ -308,11 +302,26 @@ check_offset_length_no_exception(const tvbuff_t *tvb,
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{
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guint end_offset;
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int exception;
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exception = compute_offset_length(tvb, offset, length_val, offset_ptr, length_ptr);
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DISSECTOR_ASSERT(offset_ptr);
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DISSECTOR_ASSERT(length_ptr);
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/* Compute the offset */
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exception = compute_offset(tvb, offset, offset_ptr);
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if (exception)
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return exception;
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if (length_val < -1) {
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/* XXX - ReportedBoundsError? */
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return BoundsError;
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}
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/* Compute the length */
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if (length_val == -1)
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*length_ptr = tvb->length - *offset_ptr;
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else
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*length_ptr = length_val;
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/*
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* Compute the offset of the first byte past the length.
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*/
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@ -652,31 +661,31 @@ tvb_length(const tvbuff_t *tvb)
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gint
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tvb_length_remaining(const tvbuff_t *tvb, const gint offset)
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{
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guint abs_offset, abs_length;
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guint abs_offset, rem_length;
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int exception;
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DISSECTOR_ASSERT(tvb && tvb->initialized);
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exception = compute_offset_length(tvb, offset, -1, &abs_offset, &abs_length);
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exception = compute_offset_and_remaining(tvb, offset, &abs_offset, &rem_length);
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if (exception)
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return -1;
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return abs_length;
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return rem_length;
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}
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guint
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tvb_ensure_length_remaining(const tvbuff_t *tvb, const gint offset)
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{
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guint abs_offset, abs_length;
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guint abs_offset, rem_length;
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int exception;
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DISSECTOR_ASSERT(tvb && tvb->initialized);
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exception = compute_offset_length(tvb, offset, -1, &abs_offset, &abs_length);
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exception = compute_offset_and_remaining(tvb, offset, &abs_offset, &rem_length);
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if (exception)
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THROW(exception);
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if (abs_length == 0) {
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if (rem_length == 0) {
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/*
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* This routine ensures there's at least one byte available.
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* There aren't any bytes available, so throw the appropriate
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@ -691,7 +700,7 @@ tvb_ensure_length_remaining(const tvbuff_t *tvb, const gint offset)
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} else
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THROW(BoundsError);
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}
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return abs_length;
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return rem_length;
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}
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@ -742,12 +751,12 @@ tvb_ensure_bytes_exist(const tvbuff_t *tvb, const gint offset, const gint length
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gboolean
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tvb_offset_exists(const tvbuff_t *tvb, const gint offset)
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{
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guint abs_offset, abs_length;
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guint abs_offset;
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int exception;
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DISSECTOR_ASSERT(tvb && tvb->initialized);
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exception = compute_offset_length(tvb, offset, -1, &abs_offset, &abs_length);
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exception = compute_offset(tvb, offset, &abs_offset);
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if (exception)
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return FALSE;
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@ -770,12 +779,12 @@ tvb_reported_length(const tvbuff_t *tvb)
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gint
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tvb_reported_length_remaining(const tvbuff_t *tvb, const gint offset)
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{
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guint abs_offset, abs_length;
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guint abs_offset;
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int exception;
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DISSECTOR_ASSERT(tvb && tvb->initialized);
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exception = compute_offset_length(tvb, offset, -1, &abs_offset, &abs_length);
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exception = compute_offset(tvb, offset, &abs_offset);
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if (exception)
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return -1;
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@ -1064,7 +1073,7 @@ composite_memcpy(tvbuff_t *tvb, void* _target, guint abs_offset, size_t abs_leng
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* then iterate across the other member tvb's, copying their portions
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* until we have copied all data.
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*/
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exception = compute_offset_length(member_tvb, abs_offset - composite->start_offsets[i], -1,
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exception = compute_offset_and_remaining(member_tvb, abs_offset - composite->start_offsets[i],
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&member_offset, &member_length);
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DISSECTOR_ASSERT(!exception);
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