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| author | Robin Watts <robin.watts@artifex.com> | 2016-06-11 16:01:53 +0100 |
|---|---|---|
| committer | Robin Watts <robin.watts@artifex.com> | 2016-06-14 12:53:03 +0100 |
| commit | c0759acc6e5bd8167ab4983fc51eb1212da6a216 (patch) | |
| tree | b46f6a783f5e6dd8e09fc7c0ca318ac34b88fb81 /source/fitz/filter-lzw.c | |
| parent | 60edbbde3a384401cbefe338e55e7a5f52cad5f4 (diff) | |
| download | mupdf-c0759acc6e5bd8167ab4983fc51eb1212da6a216.tar.xz | |
Update TIFF LZW decode.
TIFF 5.0 uses a slightly laxer set of rules for TIFF decode.
Specifically, when we hit the maximum code, we are not required
to send a clear code immediately, but it can overrrun.
We don't bother storing codes > 12 bits, because they can never
be used. This avoids the need to extend the table.
Diffstat (limited to 'source/fitz/filter-lzw.c')
| -rw-r--r-- | source/fitz/filter-lzw.c | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/source/fitz/filter-lzw.c b/source/fitz/filter-lzw.c index ff655c9e..cb977772 100644 --- a/source/fitz/filter-lzw.c +++ b/source/fitz/filter-lzw.c @@ -33,6 +33,7 @@ struct fz_lzwd_s int early_change; int reverse_bits; + int old_tiff; int min_bits; /* minimum num bits/code */ int code_bits; /* num bits/code */ int code; /* current code */ @@ -92,7 +93,9 @@ next_lzwd(fz_context *ctx, fz_stream *stm, int len) break; } - if (next_code > NUM_CODES && code != LZW_CLEAR(lzw)) + /* Old Tiffs are allowed to NOT send the clear code, and to + * overrun at the end. */ + if (!lzw->old_tiff && next_code > NUM_CODES && code != LZW_CLEAR(lzw)) { fz_warn(ctx, "missing clear code in lzw decode"); code = LZW_CLEAR(lzw); @@ -111,17 +114,17 @@ next_lzwd(fz_context *ctx, fz_stream *stm, int len) { old_code = code; } - else if (next_code == NUM_CODES) + else if (!lzw->old_tiff && next_code == NUM_CODES) { /* TODO: Ghostscript checks for a following clear code before tolerating */ fz_warn(ctx, "tolerating a single out of range code in lzw decode"); next_code++; } - else if (code > next_code || next_code >= NUM_CODES) + else if (code > next_code || (!lzw->old_tiff && next_code >= NUM_CODES)) { fz_warn(ctx, "out of range code encountered in lzw decode"); } - else + else if (next_code < NUM_CODES) { /* add new entry to the code table */ table[next_code].prev = old_code; @@ -200,7 +203,7 @@ close_lzwd(fz_context *ctx, void *state_) /* Default: early_change = 1 */ fz_stream * -fz_open_lzwd(fz_context *ctx, fz_stream *chain, int early_change, int min_bits, int reverse_bits) +fz_open_lzwd(fz_context *ctx, fz_stream *chain, int early_change, int min_bits, int reverse_bits, int old_tiff) { fz_lzwd *lzw = NULL; int i; @@ -220,6 +223,7 @@ fz_open_lzwd(fz_context *ctx, fz_stream *chain, int early_change, int min_bits, lzw->eod = 0; lzw->early_change = early_change; lzw->reverse_bits = reverse_bits; + lzw->old_tiff = old_tiff; lzw->min_bits = min_bits; lzw->code_bits = lzw->min_bits; lzw->code = -1; |