diff options
| -rw-r--r-- | src/coding.c | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/src/coding.c b/src/coding.c index 59589caee61..e90d57144f6 100644 --- a/src/coding.c +++ b/src/coding.c @@ -7324,9 +7324,13 @@ produce_annotation (struct coding_system *coding, ptrdiff_t pos) In this case, if CODING->src_pos is positive, it is a position of the source text in the buffer, otherwise, the source text is in the gap area of the buffer, and CODING->src_pos specifies the offset of - the text from GPT (which must be the same as PT). If this is the - same buffer as CODING->dst_object, CODING->src_pos must be - negative. + the text from the end of the gap (and GPT must be equal to PT). + + When the text is taken from the gap, it can't be at the beginning + of the gap because the new decoded text is progressively acumulated + at the beginning of the gap before it gets inserted at PT (this way, + as the output grows, the input shrinks, so we only need to allocate + enough space for `max(IN, OUT)` instead of `IN + OUT`). If CODING->src_object is a string, CODING->src_pos is an index to that string. |