diff options
| author | Robert Ancell <robert.ancell@canonical.com> | 2018-12-05 11:56:34 +1300 |
|---|---|---|
| committer | Robert Ancell <robert.ancell@canonical.com> | 2019-01-16 15:47:09 +1300 |
| commit | a314f59344cb3fb2ca63264b44fa2f6cad8c86db (patch) | |
| tree | 8a1517817974643b0dd270f6554c758962196138 | |
| parent | 0b9d00413d9f31231af348e7761b98bb5501980d (diff) | |
| download | gdk-pixbuf-a314f59344cb3fb2ca63264b44fa2f6cad8c86db.tar.gz | |
gif: Simplify LZW clear code handling
The existing code had a special state for handling codes after a clear code was
received. This is more simply handled by using the 'lzw_oldcode' variable. This
makes code that is less likely to introduce errors.
| -rw-r--r-- | gdk-pixbuf/io-gif.c | 21 |
1 files changed, 3 insertions, 18 deletions
diff --git a/gdk-pixbuf/io-gif.c b/gdk-pixbuf/io-gif.c index f2207360e..be5bfc235 100644 --- a/gdk-pixbuf/io-gif.c +++ b/gdk-pixbuf/io-gif.c @@ -163,7 +163,6 @@ struct _GifContext int code_last_byte; /* lzw context */ - gint lzw_fresh; gint lzw_code_size; guchar lzw_set_code_size; gint lzw_max_code; @@ -567,23 +566,9 @@ static int lzw_read_byte (GifContext *context) { int code, incode; - gint retval; gint my_retval; register int i; - if (context->lzw_fresh) { - do { - retval = get_code (context, context->lzw_code_size); - if (retval < 0) { - return retval; - } - - context->lzw_firstcode = context->lzw_oldcode = retval; - } while (context->lzw_firstcode == context->lzw_clear_code); - context->lzw_fresh = FALSE; - return context->lzw_firstcode; - } - if (context->lzw_sp > context->lzw_stack) { my_retval = *--(context->lzw_sp); return my_retval; @@ -601,7 +586,7 @@ lzw_read_byte (GifContext *context) context->lzw_max_code_size = 2 * context->lzw_clear_code; context->lzw_max_code = context->lzw_clear_code + 2; context->lzw_sp = context->lzw_stack; - context->lzw_fresh = TRUE; + context->lzw_oldcode = code; return -3; } else if (code == context->lzw_end_code) { int count; @@ -659,7 +644,7 @@ lzw_read_byte (GifContext *context) CHECK_LZW_SP (); *(context->lzw_sp)++ = context->lzw_firstcode = context->lzw_table[1][code]; - if ((code = context->lzw_max_code) < (1 << MAX_LZW_BITS)) { + if (context->lzw_oldcode != context->lzw_clear_code && (code = context->lzw_max_code) < (1 << MAX_LZW_BITS)) { context->lzw_table[0][code] = context->lzw_oldcode; context->lzw_table[1][code] = context->lzw_firstcode; ++context->lzw_max_code; @@ -1128,7 +1113,7 @@ gif_prepare_lzw (GifContext *context) context->lzw_end_code = context->lzw_clear_code + 1; context->lzw_max_code_size = 2 * context->lzw_clear_code; context->lzw_max_code = context->lzw_clear_code + 2; - context->lzw_fresh = TRUE; + context->lzw_oldcode = context->lzw_clear_code; context->code_curbit = 0; context->code_lastbit = 0; /* During initialistion (in gif_lzw_fill_buffer) we substract 2 from |