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pdftoraster: extract copy_image_rows() helper and add an ASan regression test #206

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Merged
tillkamppeter merged 1 commit into from
Aug 9, 2026
Merged

pdftoraster: extract copy_image_rows() helper and add an ASan regression test #206

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17 changes: 9 additions & 8 deletions Makefile.am
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Original file line number Diff line number Diff line change
Expand Up @@ -92,7 +92,8 @@ lib_LTLIBRARIES = libcupsfilters.la

check_SCRIPTS = \
cupsfilters/testfilters.sh \
cupsfilters/test-pclm-overflow.sh
cupsfilters/test-pclm-overflow.sh \
cupsfilters/test-pdftoraster-copy-height.sh

check_PROGRAMS = \
testcmyk \
Expand All @@ -105,8 +106,7 @@ check_PROGRAMS = \
test-analyze \
test-pdf \
test-ps \
testfilters \
test-pdftoraster-copy-height
testfilters

TESTS = \
testdither \
Expand All @@ -115,9 +115,9 @@ TESTS = \
test-analyze \
test-pdf \
test-ps \
test-pdftoraster-copy-height \
cupsfilters/testfilters.sh \
cupsfilters/test-pclm-overflow.sh
cupsfilters/test-pclm-overflow.sh \
cupsfilters/test-pdftoraster-copy-height.sh

# testcmyk # fails as it opens some image.ppm which is nowerhe to be found.
# testimage # requires also some ppm file as argument
Expand Down Expand Up @@ -323,9 +323,6 @@ test_ps_SOURCES = cupsfilters/fontembed/test-ps.c
test_ps_LDADD = libcupsfilters.la $(CUPS_LIBS)
test_ps_CFLAGS = $(CUPS_CFLAGS)

test_pdftoraster_copy_height_SOURCES = \
cupsfilters/test-pdftoraster-copy-height.c

testfilters_SOURCES = \
cupsfilters/testfilters.c \
$(pkgfiltersinclude_DATA)
Expand All @@ -343,6 +340,10 @@ testfilters_LDFLAGS = \
noinst_PROGRAMS = gen-lorem-text
gen_lorem_text_SOURCES = cupsfilters/gen-lorem-text.c
EXTRA_DIST += cupsfilters/gen-lorem-text.c
# Built by cupsfilters/test-pdftoraster-copy-height.sh under AddressSanitizer
# (not a check_PROGRAM, so it can skip when ASan is absent); named here so it
# ships in "make dist".
EXTRA_DIST += cupsfilters/test-pdftoraster-copy-height.c
# Generated deterministic lorem text for texttopdf tests
BUILT_SOURCES = cupsfilters/test_files/test_text_lorem.txt
CLEANFILES = cupsfilters/test_files/test_text_lorem.txt
Expand Down
172 changes: 99 additions & 73 deletions cupsfilters/pdftoraster.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1710,6 +1710,101 @@ read_ppm_data(FILE *img, // I - Image file
return data;
}

//
// 'copy_image_rows()' - Copy the rendered image rows into the CUPS raster
// page, clamped by copy_height/copy_width so a rendered
// image smaller than the page is padded with background
// rows. Extracted from write_page_image() so the
// copy_height boundary can be exercised directly by the
// unit test against a controlled buffer under ASan.
//

static void
copy_image_rows(cups_raster_t *raster, // I - CUPS raster output
pdftoraster_doc_t *doc, // I - Document attributes
pdf_conversion_function_t *convert, // I - conversion rules
int pageNo, // I - page number (parity)
unsigned char *colordata, // I - rendered image data
unsigned int image_rowsize, // I - bytes per image row
unsigned int copy_height, // I - image rows to copy
unsigned int copy_width, // I - width to copy
unsigned char *lineBuf, // I - scratch line buffer
int bg_color) // I - background fill value
{
unsigned char *dp;
convert_line_func convertLine;

if ((pageNo & 1) == 0)
convertLine = convert->convertLineEven;
else
convertLine = convert->convertLineOdd;

if (doc->header.Duplex && (pageNo & 1) == 0 && doc->swap_image_y)
{
for (unsigned int plane = 0; plane < doc->nplanes; plane ++)
{
unsigned char *bp = colordata + (copy_height - 1) * image_rowsize;

for (unsigned int h = doc->header.cupsHeight; h > 0; h--)
{
if (h <= copy_height) // inside valid page/image area
{
if (doc->allocLineBuf)
memset(lineBuf, bg_color, doc->bytesPerLine);
for (unsigned int band = 0; band < doc->nbands; band ++)
{
dp = convertLine(bp, lineBuf, h - 1, plane + band,
copy_width,
doc->bytesPerLine, doc, convert->convertCSpace);
cupsRasterWritePixels(raster, dp, doc->bytesPerLine);
}
bp -= image_rowsize;
}
else // Image shorter than page, thus whitespace
{
if (doc->allocLineBuf)
{
memset(lineBuf, bg_color, doc->bytesPerLine);
cupsRasterWritePixels(raster, lineBuf, doc->bytesPerLine);
}
}
}
}
}
else
{
for (unsigned int plane = 0; plane < doc->nplanes; plane++)
{
unsigned char *bp = colordata;
for (unsigned int h = 0; h < doc->header.cupsHeight; h++)
{
if (h < copy_height) // inside valid page/image area
{
if (doc->allocLineBuf)
memset(lineBuf, bg_color, doc->bytesPerLine);

for (unsigned int band = 0; band < doc->nbands; band++)
{
dp = convertLine(bp, lineBuf, h, plane + band, copy_width,
doc->bytesPerLine, doc, convert->convertCSpace);
cupsRasterWritePixels(raster, dp, doc->bytesPerLine);
}
bp += image_rowsize;
}
else // Image shorter than page, thus whitespace
{
if (doc->allocLineBuf)
{
memset(lineBuf, bg_color, doc->bytesPerLine);
cupsRasterWritePixels(raster, lineBuf, doc->bytesPerLine);
}
}
}
}
}
}


//
// 'write_page_image()' - bridge between PDF rendering tool and CUPS raster Output
//
Expand All @@ -1724,9 +1819,7 @@ write_page_image(cups_raster_t *raster, // I - Cups raster output data struct
void *icd)
{
int i;
convert_line_func convertLine;
unsigned char *lineBuf = NULL;
unsigned char *dp;
unsigned int image_rowsize = 0;
int fakeres[2];
int bg_color = 255;
Expand Down Expand Up @@ -1958,82 +2051,15 @@ write_page_image(cups_raster_t *raster, // I - Cups raster output data struct
}
}

if ((pageNo & 1) == 0)
convertLine = convert->convertLineEven;
else
convertLine = convert->convertLineOdd;

// This will be the safe copy limit;
// In some cases, the PDFtoppm might output where image sizes are
// This will be the safe copy limit;
// In some cases, the PDFtoppm might output where image sizes are
// smaller than expected page size.
// copy_height and copy_width act as safe copy limit in this.
unsigned int copy_height = (height < doc->header.cupsHeight) ? height : doc->header.cupsHeight;
unsigned int copy_width = (width < doc->header.cupsWidth) ? width : doc->header.cupsWidth;

if (doc->header.Duplex && (pageNo & 1) == 0 && doc->swap_image_y)
{
for (unsigned int plane = 0; plane < doc->nplanes; plane ++)
{
unsigned char *bp = colordata + (copy_height - 1) * image_rowsize;

for (unsigned int h = doc->header.cupsHeight; h > 0; h--)
{
if (h <= copy_height) // inside valid page/image area
{
if (doc->allocLineBuf)
memset(lineBuf, bg_color, doc->bytesPerLine);
for (unsigned int band = 0; band < doc->nbands; band ++)
{
dp = convertLine(bp, lineBuf, h - 1, plane + band,
copy_width,
doc->bytesPerLine, doc, convert->convertCSpace);
cupsRasterWritePixels(raster, dp, doc->bytesPerLine);
}
bp -= image_rowsize;
}
else // Image shorter than page, thus whitespace
{
if (doc->allocLineBuf)
{
memset(lineBuf, bg_color, doc->bytesPerLine);
cupsRasterWritePixels(raster, lineBuf, doc->bytesPerLine);
}
}
}
}
}
else
{
for (unsigned int plane = 0; plane < doc->nplanes; plane++)
{
unsigned char *bp = colordata;
for (unsigned int h = 0; h < doc->header.cupsHeight; h++)
{
if (h < copy_height) // inside valid page/image area
{
if (doc->allocLineBuf)
memset(lineBuf, bg_color, doc->bytesPerLine);

for (unsigned int band = 0; band < doc->nbands; band++)
{
dp = convertLine(bp, lineBuf, h, plane + band, copy_width,
doc->bytesPerLine, doc, convert->convertCSpace);
cupsRasterWritePixels(raster, dp, doc->bytesPerLine);
}
bp += image_rowsize;
}
else // Image shorter than page, thus whitespace
{
if (doc->allocLineBuf)
{
memset(lineBuf, bg_color, doc->bytesPerLine);
cupsRasterWritePixels(raster, lineBuf, doc->bytesPerLine);
}
}
}
}
}

copy_image_rows(raster, doc, convert, pageNo, colordata, image_rowsize,
copy_height, copy_width, lineBuf, bg_color);
free(colordata);
if (lineBuf)
free(lineBuf);
Expand Down
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