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-rw-r--r--source/fitz/compressed-buffer.c19
-rw-r--r--source/pdf/pdf-stream.c197
2 files changed, 126 insertions, 90 deletions
diff --git a/source/fitz/compressed-buffer.c b/source/fitz/compressed-buffer.c
index 85890c72..d1c73351 100644
--- a/source/fitz/compressed-buffer.c
+++ b/source/fitz/compressed-buffer.c
@@ -27,7 +27,8 @@ fz_open_image_decomp_stream(fz_context *ctx, fz_stream *chain, fz_compression_pa
switch (params->type)
{
case FZ_IMAGE_FAX:
- *l2factor = 0;
+ if (l2factor)
+ *l2factor = 0;
return fz_open_faxd(ctx, chain,
params->u.fax.k,
params->u.fax.end_of_line,
@@ -37,26 +38,30 @@ fz_open_image_decomp_stream(fz_context *ctx, fz_stream *chain, fz_compression_pa
params->u.fax.end_of_block,
params->u.fax.black_is_1);
case FZ_IMAGE_JPEG:
- if (*l2factor > 3)
+ if (l2factor && *l2factor > 3)
*l2factor = 3;
- return fz_open_dctd(ctx, chain, params->u.jpeg.color_transform, *l2factor, NULL);
+ return fz_open_dctd(ctx, chain, params->u.jpeg.color_transform, l2factor ? *l2factor : 0, NULL);
case FZ_IMAGE_RLD:
- *l2factor = 0;
+ if (l2factor)
+ *l2factor = 0;
return fz_open_rld(ctx, chain);
case FZ_IMAGE_FLATE:
- *l2factor = 0;
+ if (l2factor)
+ *l2factor = 0;
chain = fz_open_flated(ctx, chain, 15);
if (params->u.flate.predictor > 1)
chain = fz_open_predict(ctx, chain, params->u.flate.predictor, params->u.flate.columns, params->u.flate.colors, params->u.flate.bpc);
return chain;
case FZ_IMAGE_LZW:
- *l2factor = 0;
+ if (l2factor)
+ *l2factor = 0;
chain = fz_open_lzwd(ctx, chain, params->u.lzw.early_change);
if (params->u.lzw.predictor > 1)
chain = fz_open_predict(ctx, chain, params->u.lzw.predictor, params->u.lzw.columns, params->u.lzw.colors, params->u.lzw.bpc);
return chain;
default:
- *l2factor = 0;
+ if (l2factor)
+ *l2factor = 0;
break;
}
diff --git a/source/pdf/pdf-stream.c b/source/pdf/pdf-stream.c
index ad1e5e2c..b7b85cc3 100644
--- a/source/pdf/pdf-stream.c
+++ b/source/pdf/pdf-stream.c
@@ -76,11 +76,8 @@ pdf_load_jbig2_globals(fz_context *ctx, pdf_document *doc, pdf_obj *dict)
return globals;
}
-/*
- * Create a filter given a name and param dictionary.
- */
-static fz_stream *
-build_filter(fz_context *ctx, fz_stream *chain, pdf_document *doc, pdf_obj *f, pdf_obj *p, int num, int gen, fz_compression_params *params)
+static void
+build_compression_params(fz_context *ctx, pdf_obj *f, pdf_obj *p, fz_compression_params *params)
{
int predictor = pdf_to_int(ctx, pdf_dict_get(ctx, p, PDF_NAME_Predictor));
pdf_obj *columns_obj = pdf_dict_get(ctx, p, PDF_NAME_Columns);
@@ -88,16 +85,9 @@ build_filter(fz_context *ctx, fz_stream *chain, pdf_document *doc, pdf_obj *f, p
int colors = pdf_to_int(ctx, pdf_dict_get(ctx, p, PDF_NAME_Colors));
int bpc = pdf_to_int(ctx, pdf_dict_get(ctx, p, PDF_NAME_BitsPerComponent));
- if (params)
- params->type = FZ_IMAGE_RAW;
-
- if (pdf_name_eq(ctx, f, PDF_NAME_ASCIIHexDecode) || pdf_name_eq(ctx, f, PDF_NAME_AHx))
- return fz_open_ahxd(ctx, chain);
-
- else if (pdf_name_eq(ctx, f, PDF_NAME_ASCII85Decode) || pdf_name_eq(ctx, f, PDF_NAME_A85))
- return fz_open_a85d(ctx, chain);
+ params->type = FZ_IMAGE_RAW;
- else if (pdf_name_eq(ctx, f, PDF_NAME_CCITTFaxDecode) || pdf_name_eq(ctx, f, PDF_NAME_CCF))
+ if (pdf_name_eq(ctx, f, PDF_NAME_CCITTFaxDecode) || pdf_name_eq(ctx, f, PDF_NAME_CCF))
{
pdf_obj *k = pdf_dict_get(ctx, p, PDF_NAME_K);
pdf_obj *eol = pdf_dict_get(ctx, p, PDF_NAME_EndOfLine);
@@ -105,89 +95,75 @@ build_filter(fz_context *ctx, fz_stream *chain, pdf_document *doc, pdf_obj *f, p
pdf_obj *rows = pdf_dict_get(ctx, p, PDF_NAME_Rows);
pdf_obj *eob = pdf_dict_get(ctx, p, PDF_NAME_EndOfBlock);
pdf_obj *bi1 = pdf_dict_get(ctx, p, PDF_NAME_BlackIs1);
- if (params)
- {
- /* We will shortstop here */
- params->type = FZ_IMAGE_FAX;
- params->u.fax.k = (k ? pdf_to_int(ctx, k) : 0);
- params->u.fax.end_of_line = (eol ? pdf_to_bool(ctx, eol) : 0);
- params->u.fax.encoded_byte_align = (eba ? pdf_to_bool(ctx, eba) : 0);
- params->u.fax.columns = (columns_obj ? columns : 1728);
- params->u.fax.rows = (rows ? pdf_to_int(ctx, rows) : 0);
- params->u.fax.end_of_block = (eob ? pdf_to_bool(ctx, eob) : 1);
- params->u.fax.black_is_1 = (bi1 ? pdf_to_bool(ctx, bi1) : 0);
- return chain;
- }
- return fz_open_faxd(ctx, chain,
- k ? pdf_to_int(ctx, k) : 0,
- eol ? pdf_to_bool(ctx, eol) : 0,
- eba ? pdf_to_bool(ctx, eba) : 0,
- columns_obj ? columns : 1728,
- rows ? pdf_to_int(ctx, rows) : 0,
- eob ? pdf_to_bool(ctx, eob) : 1,
- bi1 ? pdf_to_bool(ctx, bi1) : 0);
- }
+ params->type = FZ_IMAGE_FAX;
+ params->u.fax.k = (k ? pdf_to_int(ctx, k) : 0);
+ params->u.fax.end_of_line = (eol ? pdf_to_bool(ctx, eol) : 0);
+ params->u.fax.encoded_byte_align = (eba ? pdf_to_bool(ctx, eba) : 0);
+ params->u.fax.columns = (columns_obj ? columns : 1728);
+ params->u.fax.rows = (rows ? pdf_to_int(ctx, rows) : 0);
+ params->u.fax.end_of_block = (eob ? pdf_to_bool(ctx, eob) : 1);
+ params->u.fax.black_is_1 = (bi1 ? pdf_to_bool(ctx, bi1) : 0);
+ }
else if (pdf_name_eq(ctx, f, PDF_NAME_DCTDecode) || pdf_name_eq(ctx, f, PDF_NAME_DCT))
{
pdf_obj *ct = pdf_dict_get(ctx, p, PDF_NAME_ColorTransform);
- if (params)
- {
- /* We will shortstop here */
- params->type = FZ_IMAGE_JPEG;
- params->u.jpeg.color_transform = (ct ? pdf_to_int(ctx, ct) : -1);
- return chain;
- }
- return fz_open_dctd(ctx, chain, ct ? pdf_to_int(ctx, ct) : -1, 0, NULL);
- }
+ params->type = FZ_IMAGE_JPEG;
+ params->u.jpeg.color_transform = (ct ? pdf_to_int(ctx, ct) : -1);
+ }
else if (pdf_name_eq(ctx, f, PDF_NAME_RunLengthDecode) || pdf_name_eq(ctx, f, PDF_NAME_RL))
{
- if (params)
- {
- /* We will shortstop here */
- params->type = FZ_IMAGE_RLD;
- return chain;
- }
- return fz_open_rld(ctx, chain);
+ params->type = FZ_IMAGE_RLD;
}
else if (pdf_name_eq(ctx, f, PDF_NAME_FlateDecode) || pdf_name_eq(ctx, f, PDF_NAME_Fl))
{
- if (params)
- {
- /* We will shortstop here */
- params->type = FZ_IMAGE_FLATE;
- params->u.flate.predictor = predictor;
- params->u.flate.columns = columns;
- params->u.flate.colors = colors;
- params->u.flate.bpc = bpc;
- return chain;
- }
- chain = fz_open_flated(ctx, chain, 15);
- if (predictor > 1)
- chain = fz_open_predict(ctx, chain, predictor, columns, colors, bpc);
- return chain;
+ params->type = FZ_IMAGE_FLATE;
+ params->u.flate.predictor = predictor;
+ params->u.flate.columns = columns;
+ params->u.flate.colors = colors;
+ params->u.flate.bpc = bpc;
}
-
else if (pdf_name_eq(ctx, f, PDF_NAME_LZWDecode) || pdf_name_eq(ctx, f, PDF_NAME_LZW))
{
pdf_obj *ec = pdf_dict_get(ctx, p, PDF_NAME_EarlyChange);
- if (params)
- {
- /* We will shortstop here */
- params->type = FZ_IMAGE_LZW;
- params->u.lzw.predictor = predictor;
- params->u.lzw.columns = columns;
- params->u.lzw.colors = colors;
- params->u.lzw.bpc = bpc;
- params->u.lzw.early_change = (ec ? pdf_to_int(ctx, ec) : 1);
- return chain;
- }
- chain = fz_open_lzwd(ctx, chain, ec ? pdf_to_int(ctx, ec) : 1);
- if (predictor > 1)
- chain = fz_open_predict(ctx, chain, predictor, columns, colors, bpc);
- return chain;
+
+ params->type = FZ_IMAGE_LZW;
+ params->u.lzw.predictor = predictor;
+ params->u.lzw.columns = columns;
+ params->u.lzw.colors = colors;
+ params->u.lzw.bpc = bpc;
+ params->u.lzw.early_change = (ec ? pdf_to_int(ctx, ec) : 1);
}
+}
+
+/*
+ * Create a filter given a name and param dictionary.
+ */
+static fz_stream *
+build_filter(fz_context *ctx, fz_stream *chain, pdf_document *doc, pdf_obj *f, pdf_obj *p, int num, int gen, fz_compression_params *params)
+{
+ fz_compression_params local_params;
+
+ if (params == NULL)
+ params = &local_params;
+
+ build_compression_params(ctx, f, p, params);
+
+ /* If we were using params we were passed in, and we successfully
+ * recognised the image type, we can use the existing filter and
+ * shortstop here. */
+ if (params != &local_params && params->type != FZ_IMAGE_RAW)
+ return chain;
+
+ if (params->type != FZ_IMAGE_RAW)
+ return fz_open_image_decomp_stream(ctx, chain, params, NULL);
+
+ if (pdf_name_eq(ctx, f, PDF_NAME_ASCIIHexDecode) || pdf_name_eq(ctx, f, PDF_NAME_AHx))
+ return fz_open_ahxd(ctx, chain);
+
+ else if (pdf_name_eq(ctx, f, PDF_NAME_ASCII85Decode) || pdf_name_eq(ctx, f, PDF_NAME_A85))
+ return fz_open_a85d(ctx, chain);
else if (pdf_name_eq(ctx, f, PDF_NAME_JBIG2Decode))
{
@@ -496,6 +472,59 @@ pdf_guess_filter_length(int len, char *filter)
return len;
}
+/* Check if an entry has a cached stream and return whether it is directly
+ * reusable. A buffer is directly reusable only if the stream is
+ * uncompressed, or if it is compressed purely a compression method we can
+ * return details of in fz_compression_params.
+ *
+ * If the stream is reusable return 1, and set params as required, otherwise
+ * return 0. */
+static int
+can_reuse_buffer(fz_context *ctx, pdf_xref_entry *entry, fz_compression_params *params)
+{
+ pdf_obj *f;
+ pdf_obj *p;
+
+ if (!entry || !entry->obj || !entry->stm_buf)
+ return 0;
+
+ if (params)
+ params->type = FZ_IMAGE_RAW;
+
+ f = pdf_dict_geta(ctx, entry->obj, PDF_NAME_Filter, PDF_NAME_F);
+ /* If there are no filters, it's uncompressed, and we can use it */
+ if (!f)
+ return 1;
+
+ p = pdf_dict_geta(ctx, entry->obj, PDF_NAME_DecodeParms, PDF_NAME_DP);
+ if (pdf_is_array(ctx, f))
+ {
+ int len = pdf_array_len(ctx, f);
+
+ /* Empty array of filters. It's uncompressed. We can cope. */
+ if (len == 0)
+ return 1;
+ /* 1 filter is the most we can hope to cope with - if more,*/
+ if (len != 1)
+ return 0;
+ p = pdf_array_get(ctx, p, 0);
+ }
+ if (pdf_is_null(ctx, f))
+ return 1; /* Null filter is uncompressed */
+ if (!pdf_is_name(ctx, f))
+ return 0;
+
+ /* There are filters, so unless we have the option of shortstopping,
+ * we can't use the existing buffer. */
+ if (!params)
+ return 0;
+
+ build_compression_params(ctx, f, p, params);
+
+ return (params->type == FZ_IMAGE_RAW) ? 0 : 1;
+
+}
+
static fz_buffer *
pdf_load_image_stream(fz_context *ctx, pdf_document *doc, int num, int gen, int orig_num, int orig_gen, fz_compression_params *params, int *truncated)
{
@@ -509,7 +538,9 @@ pdf_load_image_stream(fz_context *ctx, pdf_document *doc, int num, int gen, int
if (num > 0 && num < pdf_xref_len(ctx, doc))
{
pdf_xref_entry *entry = pdf_get_xref_entry(ctx, doc, num);
- if (entry->stm_buf)
+ /* Return ref to existing buffer, but only if uncompressed,
+ * or shortstoppable */
+ if (can_reuse_buffer(ctx, entry, params))
return fz_keep_buffer(ctx, entry->stm_buf);
}
generated by cgit v1.2.3 (git 2.25.1) at 2024-06-16 07:23:31 +0000