Fix to buffer issue where stb_strscpy would use + 1 for buffer length when stb_p_strcpy_s is called, causing a stack variable corrupted issue.
Fix to readdir_raw to no longer account for stb_strscpy having + 1 in buffer length.
This fixes two issues with an assert failing. I tested that the
first part fixes#909 and the second fixes#897.
1. Loading 16/24/32-bit BMP from memory caused an assert to fail
(excluding 16-bit BMP with hsz 12).
img_buffer offset was always compared with the buffer for
stbi_load_from_file() but stbi_load_from_memory() uses an external
buffer.
Resolution: Change s->buffer_start to s->img_buffer_original.
2. Loading BMP with large header from file caused assert to fail.
img_buffer points to stbi_uc buffer_start[128] but the largest BMP
supported has a 138 byte header (hsz 124) causing img_buffer to wrap
around to an offset of 10. The assert fails because 138 (header size)
!= 10 (offset in temp read buffer).
Resolution: Add the previously read bytes to the offset in temp read
buffer to get the absolute offset.
The issues were introduced by the commit c440a53d06
("stb_image: fix reading BMP with explicit masks").
I propose to remove this line because f->valid_bits will never be less than zero since, in the while loop, you're adding 8 to it. Therefore, it will always evaluate to false. This is to help remove redundant code.
The documentation of that operation already said:
> Returns a pointer to the first uninitialized item added.
This also makes a lot of sense, allowing easy initialization. But the
implementation returned the index of the first uninitialized element
instead.
