/* pngimage.c
*
* Copyright (c) 2015 John Cunningham Bowler
*
* Last changed in libpng 1.6.20 [December 3, 2015]
*
* This code is released under the libpng license.
* For conditions of distribution and use, see the disclaimer
* and license in png.h
*
* Test the png_read_png and png_write_png interfaces. Given a PNG file load it
* using png_read_png and then write with png_write_png. Test all possible
* transforms.
*/
#include <stdarg.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <stdio.h>
#include <assert.h>
#if defined(HAVE_CONFIG_H) && !defined(PNG_NO_CONFIG_H)
# include <config.h>
#endif
/* Define the following to use this test against your installed libpng, rather
* than the one being built here:
*/
#ifdef PNG_FREESTANDING_TESTS
# include <png.h>
#else
# include "../../png.h"
#endif
#ifndef PNG_SETJMP_SUPPORTED
# include <setjmp.h> /* because png.h did *not* include this */
#endif
#if defined(PNG_INFO_IMAGE_SUPPORTED) && defined(PNG_SEQUENTIAL_READ_SUPPORTED)\
&& (defined(PNG_READ_PNG_SUPPORTED) || PNG_LIBPNG_VER < 10700)
/* If a transform is valid on both read and write this implies that if the
* transform is applied to read it must also be applied on write to produce
* meaningful data. This is because these transforms when performed on read
* produce data with a memory format that does not correspond to a PNG format.
*
* Most of these transforms are invertible; after applying the transform on
* write the result is the original PNG data that would have would have been
* read if no transform were applied.
*
* The exception is _SHIFT, which destroys the low order bits marked as not
* significant in a PNG with the sBIT chunk.
*
* The following table lists, for each transform, the conditions under which it
* is expected to do anything. Conditions are defined as follows:
*
* 1) Color mask bits required - simply a mask to AND with color_type; one of
* these must be present for the transform to fire, except that 0 means
* 'always'.
* 2) Color mask bits which must be absent - another mask - none of these must
* be present.
* 3) Bit depths - a mask of component bit depths for the transform to fire.
* 4) 'read' - the transform works in png_read_png.
* 5) 'write' - the transform works in png_write_png.
* 6) PNG_INFO_chunk; a mask of the chunks that must be present for the
* transform to fire. All must be present - the requirement is that
* png_get_valid() & mask == mask, so if mask is 0 there is no requirement.
*
* The condition refers to the original image state - if multiple transforms are
* used together it is possible to cause a transform that wouldn't fire on the
* original image to fire.
*/
static struct transform_info
{
const char *name;
int transform;
png_uint_32 valid_chunks;
# define CHUNK_NONE 0
# define CHUNK_sBIT PNG_INFO_sBIT
# define CHUNK_tRNS PNG_INFO_tRNS
png_byte color_mask_required;
png_byte color_mask_absent;
# define COLOR_MASK_X 0
# define COLOR_MASK_P PNG_COLOR_MASK_PALETTE
# define COLOR_MASK_C PNG_COLOR_MASK_COLOR
# define COLOR_MASK_A PNG_COLOR_MASK_ALPHA
# define COLOR_MASK_ALL (PALETTE+COLOR+ALPHA) /* absent = gray, no alpha */
png_byte bit_depths;
# define BD_ALL (1 + 2 + 4 + 8 + 16)
# define BD_PAL (1 + 2 + 4 + 8)
# define BD_LOW (1 + 2 + 4)
# define BD_16 16
# define BD_TRUE (8+16) /* i.e. true-color depths */
png_byte when;
# define TRANSFORM_R 1
# define TRANSFORM_W 2
# define TRANSFORM_RW 3
png_byte tested; /* the transform was tested somewhere */
} transform_info[] =
{
/* List ALL the PNG_TRANSFORM_ macros here. Check for support using the READ
* macros; even if the transform is supported on write it cannot be tested
* without the read support.
*/
# define T(name,chunk,cm_required,cm_absent,bd,when)\
{ #name, PNG_TRANSFORM_ ## name, CHUNK_ ## chunk,\
COLOR_MASK_ ## cm_required, COLOR_MASK_ ## cm_absent, BD_ ## bd,\
TRANSFORM_ ## when, 0/*!tested*/ }
#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
T(STRIP_16, NONE, X, X, 16, R),
/* drops the bottom 8 bits when bit depth is 16 */
#endif
#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
T(STRIP_ALPHA, NONE, A, X, ALL, R),
/* removes the alpha channel if present */
#endif
#ifdef PNG_WRITE_PACK_SUPPORTED
# define TRANSFORM_RW_PACK TRANSFORM_RW
#else
# define TRANSFORM_RW_PACK TRANSFORM_R
#endif
#ifdef PNG_READ_PACK_SUPPORTED
T(PACKING, NONE, X, X, LOW, RW_PACK),
/* unpacks low-bit-depth components into 1 byte per component on read,
* reverses this on write.
*/
#endif
#ifdef PNG_WRITE_PACKSWAP_SUPPORTED
# define TRANSFORM_RW_PACKSWAP TRANSFORM_RW
#else
# define TRANSFORM_RW_PACKSWAP TRANSFORM_R
#endif
#ifdef PNG_READ_PACKSWAP_SUPPORTED
T(PACKSWAP, NONE, X, X, LOW, RW_PACKSWAP),
/* reverses the order of low-bit-depth components packed into a byte */
#endif
#ifdef PNG_READ_EXPAND_SUPPORTED
T(EXPAND, NONE, P, X, ALL, R),
/* expands PLTE PNG files to RGB (no tRNS) or RGBA (tRNS) *
* Note that the 'EXPAND' transform does lots of different things: */
T(EXPAND, NONE, X, C, ALL, R),
/* expands grayscale PNG files to RGB, or RGBA */
T(EXPAND, tRNS, X, A, ALL, R),
/* expands the tRNS chunk in files without alpha */
#endif
#ifdef PNG_WRITE_INVERT_SUPPORTED
# define TRANSFORM_RW_INVERT TRANSFORM_RW
#else
# define TRANSFORM_RW_INVERT TRANSFORM_R
#endif
#ifdef PNG_READ_INVERT_SUPPORTED
T(INVERT_MONO, NONE, X, C, ALL, RW_INVERT),
/* converts gray-scale components to 1..0 from 0..1 */
#endif
#ifdef PNG_WRITE_SHIFT_SUPPORTED
# define TRANSFORM_RW_SHIFT TRANSFORM_RW
#else
# define TRANSFORM_RW_SHIFT TRANSFORM_R
#endif
#ifdef PNG_READ_SHIFT_SUPPORTED
T(SHIFT, sBIT, X, X, ALL, RW_SHIFT),
/* reduces component values to the original range based on the sBIT chunk,
* this is only partially reversible - the low bits are lost and cannot be
* recovered on write. In fact write code replicates the bits to generate
* new low-order bits.
*/
#endif
#ifdef PNG_WRITE_BGR_SUPPORTED
# define TRANSFORM_RW_BGR TRANSFORM_RW
#else
# define TRANSFORM_RW_BGR TRANSFORM_R
#endif
#ifdef PNG_READ_BGR_SUPPORTED
T(BGR, NONE, C, P, TRUE, RW_BGR),
/* reverses the rgb component values of true-color pixels */
#endif
#ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
# define TRANSFORM_RW_SWAP_ALPHA TRANSFORM_RW
#else
# define TRANSFORM_RW_SWAP_ALPHA TRANSFORM_R
#endif
#ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
T(SWAP_ALPHA, NONE, A, X, TRUE, RW_SWAP_ALPHA),
/* swaps the alpha channel of RGBA or GA pixels to the front - ARGB or
* AG, on write reverses the process.
*/
#endif
#ifdef PNG_WRITE_SWAP_SUPPORTED
# define TRANSFORM_RW_SWAP TRANSFORM_RW
#else
# define TRANSFORM_RW_SWAP TRANSFORM_R
#endif
#ifdef PNG_READ_SWAP_SUPPORTED
T(SWAP_ENDIAN, NONE, X, P, 16, RW_SWAP),
/* byte-swaps 16-bit component values */
#endif
#ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
# define TRANSFORM_RW_INVERT_ALPHA TRANSFORM_RW
#else
# define TRANSFORM_RW_INVERT_ALPHA TRANSFORM_R
#endif
#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
T(INVERT_ALPHA, NONE, A, X, TRUE, RW_INVERT_ALPHA),
/* converts an alpha channel from 0..1 to 1..0 */
#endif
#ifdef PNG_WRITE_FILLER_SUPPORTED
T(STRIP_FILLER_BEFORE, NONE, A, P, TRUE, W), /* 'A' for a filler! */
/* on write skips a leading filler channel; testing requires data with a
* filler channel so this is produced from RGBA or GA images by removing
* the 'alpha' flag from the color type in place.
*/
T(STRIP_FILLER_AFTER, NONE, A, P, TRUE, W),
/* on write strips a trailing filler channel */
#endif
#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
T(GRAY_TO_RGB, NONE, X, C, ALL, R),
/* expands grayscale images to RGB, also causes the palette part of
* 'EXPAND' to happen. Low bit depth grayscale images are expanded to
* 8-bits per component and no attempt is made to convert the image to a
* palette image. While this transform is partially reversible
* png_write_png does not currently support this.
*/
T(GRAY_TO_RGB, NONE, P, X, ALL, R),
/* The 'palette' side effect mentioned above; a bit bogus but this is the
* way the libpng code works.
*/
#endif
#ifdef PNG_READ_EXPAND_16_SUPPORTED
T(EXPAND_16, NONE, X, X, PAL, R),
/* expands images to 16-bits per component, as a side effect expands
* palette images to RGB and expands the tRNS chunk if present, so it can
* modify 16-bit per component images as well:
*/
T(EXPAND_16, tRNS, X, A, 16, R),
/* side effect of EXPAND_16 - expands the tRNS chunk in an RGB or G 16-bit
* image.
*/
#endif
#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
T(SCALE_16, NONE, X, X, 16, R),
/* scales 16-bit components to 8-bits. */
#endif
{ NULL /*name*/, 0, 0, 0, 0, 0, 0, 0/*!tested*/ }
#undef T
};
#define ARRAY_SIZE(a) ((sizeof a)/(sizeof a[0]))
#define TTABLE_SIZE ARRAY_SIZE(transform_info)
/* Some combinations of options that should be reversible are not; these cases
* are bugs.
*/
static int known_bad_combos[][2] =
{
/* problem, antidote */
{ PNG_TRANSFORM_SHIFT | PNG_TRANSFORM_INVERT_ALPHA, 0/*antidote*/ }
};
static int
is_combo(int transforms)
{
return transforms & (transforms-1); /* non-zero if more than one set bit */
}
static int
first_transform(int transforms)
{
return transforms & -transforms; /* lowest set bit */
}
static int
is_bad_combo(int transforms)
{
unsigned int i;
for (i=0; i<ARRAY_SIZE(known_bad_combos); ++i)
{
int combo = known_bad_combos[i][0];
if ((combo & transforms) == combo &&
(transforms & known_bad_combos[i][1]) == 0)
return 1;
}
return 0; /* combo is ok */
}
static const char *
transform_name(int t)
/* The name, if 't' has multiple bits set the name of the lowest set bit is
* returned.
*/
{
unsigned int i;
t &= -t; /* first set bit */
for (i=0; i<TTABLE_SIZE; ++i) if (transform_info[i].name != NULL)
{
if ((transform_info[i].transform & t) != 0)
return transform_info[i].name;
}
return "invalid transform";
}
/* Variables calculated by validate_T below and used to record all the supported
* transforms. Need (unsigned int) here because of the places where these
* values are used (unsigned compares in the 'exhaustive' iterator.)
*/
static unsigned int read_transforms, write_transforms, rw_transforms;
static void
validate_T(void)
/* Validate the above table - this just builds the above values */
{
unsigned int i;
for (i=0; i<TTABLE_SIZE; ++i) if (transform_info[i].name != NULL)
{
if (transform_info[i].when & TRANSFORM_R)
read_transforms |= transform_info[i].transform;
if (transform_info[i].when & TRANSFORM_W)
write_transforms |= transform_info[i].transform;
}
/* Reversible transforms are those which are supported on both read and
* write.
*/
rw_transforms = read_transforms & write_transforms;
}
/* FILE DATA HANDLING
* The original file is cached in memory. During write the output file is
* written to memory.
*
* In both cases the file data is held in a linked list of buffers - not all
* of these are in use at any time.
*/
#define NEW(type) ((type *)malloc(sizeof (type)))
#define DELETE(ptr) (free(ptr))
struct buffer_list
{
struct buffer_list *next; /* next buffer in list */
png_byte buffer[1024]; /* the actual buffer */
};
struct buffer
{
struct buffer_list *last; /* last buffer in use */
size_t end_count; /* bytes in the last buffer */
struct buffer_list *current; /* current buffer being read */
size_t read_count; /* count of bytes read from current */
struct buffer_list first; /* the very first buffer */
};
static void
buffer_init(struct buffer *buffer)
/* Call this only once for a given buffer */
{
buffer->first.next = NULL;
buffer->last = NULL;
buffer->current = NULL;
}
static void
buffer_destroy_list(struct buffer_list *list)
{
if (list != NULL)
{
struct buffer_list *next = list->next;
DELETE(list);
buffer_destroy_list(next);
}
}
static void
buffer_destroy(struct buffer *buffer)
{
struct buffer_list *list = buffer->first.next;
buffer_init(buffer);
buffer_destroy_list(list);
}
#ifdef PNG_WRITE_SUPPORTED
static void
buffer_start_write(struct buffer *buffer)
{
buffer->last = &buffer->first;
buffer->end_count = 0;
buffer->current = NULL;
}
#endif
static void
buffer_start_read(struct buffer *buffer)
{
buffer->current = &buffer->first;
buffer->read_count = 0;
}
#ifdef ENOMEM /* required by POSIX 1003.1 */
# define MEMORY ENOMEM
#else
# define MEMORY ERANGE /* required by ANSI-C */
#endif
static struct buffer *
get_buffer(png_structp pp)
/* Used from libpng callbacks to get the current buffer */
{
return (struct buffer*)png_get_io_ptr(pp);
}
static struct buffer_list *
buffer_extend(struct buffer_list *current)
{
struct buffer_list *add;
assert(current->next == NULL);
add = NEW(struct buffer_list);
if (add == NULL)
return NULL;
add->next = NULL;
current->next = add;
return add;
}
/* Load a buffer from a file; does the equivalent of buffer_start_write. On a
* read error returns an errno value, else returns 0.
*/
static int
buffer_from_file(struct buffer *buffer, FILE *fp)
{
struct buffer_list *last = &buffer->first;
size_t count = 0;
for (;;)
{
size_t r = fread(last->buffer+count, 1/*size*/,
(sizeof last->buffer)-count, fp);
if (r > 0)
{
count += r;
if (count >= sizeof last->buffer)
{
assert(count == sizeof last->buffer);
count = 0;
if (last->next == NULL)
{
last = buffer_extend(last);
if (last == NULL)
return MEMORY;
}
else
last = last->next;
}
}
else /* fread failed - probably end of file */
{
if (feof(fp))
{
buffer->last = last;
buffer->end_count = count;
return 0; /* no error */
}
/* Some kind of funky error; errno should be non-zero */
return errno == 0 ? ERANGE : errno;
}
}
}
/* This structure is used to control the test of a single file. */
typedef enum
{
VERBOSE, /* switches on all messages */
INFORMATION,
WARNINGS, /* switches on warnings */
LIBPNG_WARNING,
APP_WARNING,
ERRORS, /* just errors */
APP_FAIL, /* continuable error - no need to longjmp */
LIBPNG_ERROR, /* this and higher cause a longjmp */
LIBPNG_BUG, /* erroneous behavior in libpng */
APP_ERROR, /* such as out-of-memory in a callback */
QUIET, /* no normal messages */
USER_ERROR, /* such as file-not-found */
INTERNAL_ERROR
} error_level;
#define LEVEL_MASK 0xf /* where the level is in 'options' */
#define EXHAUSTIVE 0x010 /* Test all combinations of active options */
#define STRICT 0x020 /* Fail on warnings as well as errors */
#define LOG 0x040 /* Log pass/fail to stdout */
#define CONTINUE 0x080 /* Continue on APP_FAIL errors */
#define SKIP_BUGS 0x100 /* Skip over known bugs */
#define LOG_SKIPPED 0x200 /* Log skipped bugs */
#define FIND_BAD_COMBOS 0x400 /* Attempt to deduce bad combos */
#define LIST_COMBOS 0x800 /* List combos by name */
/* Result masks apply to the result bits in the 'results' field below; these
* bits are simple 1U<<error_level. A pass requires either nothing worse than
* warnings (--relaxes) or nothing worse than information (--strict)
*/
#define RESULT_STRICT(r) (((r) & ~((1U<<WARNINGS)-1)) == 0)
#define RESULT_RELAXED(r) (((r) & ~((1U<<ERRORS)-1)) == 0)
struct display
{
jmp_buf error_return; /* Where to go to on error */
const char *filename; /* The name of the original file */
const char *operation; /* Operation being performed */
int transforms; /* Transform used in operation */
png_uint_32 options; /* See display_log below */
png_uint_32 results; /* A mask of errors seen */
png_structp original_pp; /* used on the original read */
png_infop original_ip; /* set by the original read */
png_size_t original_rowbytes; /* of the original rows: */
png_bytepp original_rows; /* from the original read */
/* Original chunks valid */
png_uint_32 chunks;
/* Original IHDR information */
png_uint_32 width;
png_uint_32 height;
int bit_depth;
int color_type;
int interlace_method;
int compression_method;
int filter_method;
/* Derived information for the original image. */
int active_transforms; /* transforms that do something on read */
int ignored_transforms; /* transforms that should do nothing */
/* Used on a read, both the original read and when validating a written
* image.
*/
png_structp read_pp;
png_infop read_ip;
# ifdef PNG_WRITE_SUPPORTED
/* Used to write a new image (the original info_ptr is used) */
png_structp write_pp;
struct buffer written_file; /* where the file gets written */
# endif
struct buffer original_file; /* Data read from the original file */
};
static void
display_init(struct display *dp)
/* Call this only once right at the start to initialize the control
* structure, the (struct buffer) lists are maintained across calls - the
* memory is not freed.
*/
{
memset(dp, 0, sizeof *dp);
dp->options = WARNINGS; /* default to !verbose, !quiet */
dp->filename = NULL;
dp->operation = NULL;
dp->original_pp = NULL;
dp->original_ip = NULL;
dp->original_rows = NULL;
dp->read_pp = NULL;
dp->read_ip = NULL;
buffer_init(&dp->original_file);
# ifdef PNG_WRITE_SUPPORTED
dp->write_pp = NULL;
buffer_init(&dp->written_file);
# endif
}
static void
display_clean_read(struct display *dp)
{
if (dp->read_pp != NULL)
png_destroy_read_struct(&dp->read_pp, &dp->read_ip, NULL);
}
#ifdef PNG_WRITE_SUPPORTED
static void
display_clean_write(struct display *dp)
{
if (dp->write_pp != NULL)
png_destroy_write_struct(&dp->write_pp, NULL);
}
#endif
static void
display_clean(struct display *dp)
{
# ifdef PNG_WRITE_SUPPORTED
display_clean_write(dp);
# endif
display_clean_read(dp);
dp->original_rowbytes = 0;
dp->original_rows = NULL;
dp->chunks = 0;
png_destroy_read_struct(&dp->original_pp, &dp->original_ip, NULL);
/* leave the filename for error detection */
dp->results = 0; /* reset for next time */
}
static void
display_destroy(struct display *dp)
{
/* Release any memory held in the display. */
# ifdef PNG_WRITE_SUPPORTED
buffer_destroy(&dp->written_file);
# endif
buffer_destroy(&dp->original_file);
}
static struct display *
get_dp(png_structp pp)
/* The display pointer is always stored in the png_struct error pointer */
{
struct display *dp = (struct display*)png_get_error_ptr(pp);
if (dp == NULL)
{
fprintf(stderr, "pngimage: internal error (no display)\n");
exit(99); /* prevents a crash */
}
return dp;
}
/* error handling */
#ifdef __GNUC__
# define VGATTR __attribute__((__format__ (__printf__,3,4)))
/* Required to quiet GNUC warnings when the compiler sees a stdarg function
* that calls one of the stdio v APIs.
*/
#else
# define VGATTR
#endif
static void VGATTR
display_log(struct display *dp, error_level level, const char *fmt, ...)
/* 'level' is as above, fmt is a stdio style format string. This routine
* does not return if level is above LIBPNG_WARNING
*/
{
dp->results |= 1U << level;
if (level > (error_level)(dp->options & LEVEL_MASK))
{
const char *lp;
va_list ap;
switch (level)
{
case INFORMATION: lp = "information"; break;
case LIBPNG_WARNING: lp = "warning(libpng)"; break;
case APP_WARNING: lp = "warning(pngimage)"; break;
case APP_FAIL: lp = "error(continuable)"; break;
case LIBPNG_ERROR: lp = "error(libpng)"; break;
case LIBPNG_BUG: lp = "bug(libpng)"; break;
case APP_ERROR: lp = "error(pngimage)"; break;
case USER_ERROR: lp = "error(user)"; break;
case INTERNAL_ERROR: /* anything unexpected is an internal error: */
case VERBOSE: case WARNINGS: case ERRORS: case QUIET:
default: lp = "bug(pngimage)"; break;
}
fprintf(stderr, "%s: %s: %s",
dp->filename != NULL ? dp->filename : "<stdin>", lp, dp->operation);
if (dp->transforms != 0)
{
int tr = dp->transforms;
if (is_combo(tr))
{
if (dp->options & LIST_COMBOS)
{
int trx = tr;
fprintf(stderr, "(");
if (trx)
{
int start = 0;
while (trx)
{
int trz = trx & -trx;
if (start) fprintf(stderr, "+");
fprintf(stderr, "%s", transform_name(trz));
start = 1;
trx &= ~trz;
}
}
else
fprintf(stderr, "-");
fprintf(stderr, ")");
}
else
fprintf(stderr, "(0x%x)", tr);
}
else
fprintf(stderr, "(%s)", transform_name(tr));
}
fprintf(stderr, ": ");
va_start(ap, fmt);
vfprintf(stderr, fmt, ap);
va_end(ap);
fputc('\n', stderr);
}
/* else do not output any message */
/* Errors cause this routine to exit to the fail code */
if (level > APP_FAIL || (level > ERRORS && !(dp->options & CONTINUE)))
longjmp(dp->error_return, level);
}
/* error handler callbacks for libpng */
static void PNGCBAPI
display_warning(png_structp pp, png_const_charp warning)
{
display_log(get_dp(pp), LIBPNG_WARNING, "%s", warning);
}
static void PNGCBAPI
display_error(png_structp pp, png_const_charp error)
{
struct display *dp = get_dp(pp);
display_log(dp, LIBPNG_ERROR, "%s", error);
}
static void
display_cache_file(struct display *dp, const char *filename)
/* Does the initial cache of the file. */
{
FILE *fp;
int ret;
dp->filename = filename;
if (filename != NULL)
{
fp = fopen(filename, "rb");
if (fp == NULL)
display_log(dp, USER_ERROR, "open failed: %s", strerror(errno));
}
else
fp = stdin;
ret = buffer_from_file(&dp->original_file, fp);
fclose(fp);
if (ret != 0)
display_log(dp, APP_ERROR, "read failed: %s", strerror(ret));
}
static void
buffer_read(struct display *dp, struct buffer *bp, png_bytep data,
png_size_t size)
{
struct buffer_list *last = bp->current;
size_t read_count = bp->read_count;
while (size > 0)
{
size_t avail;
if (last == NULL ||
(last == bp->last && read_count >= bp->end_count))
{
display_log(dp, USER_ERROR, "file truncated (%lu bytes)",
(unsigned long)size);
/*NOTREACHED*/
break;
}
else if (read_count >= sizeof last->buffer)
{
/* Move to the next buffer: */
last = last->next;
read_count = 0;
bp->current = last; /* Avoid update outside the loop */
/* And do a sanity check (the EOF case is caught above) */
if (last == NULL)
{
display_log(dp, INTERNAL_ERROR, "damaged buffer list");
/*NOTREACHED*/
break;
}
}
avail = (sizeof last->buffer) - read_count;
if (avail > size)
avail = size;
memcpy(data, last->buffer + read_count, avail);
read_count += avail;
size -= avail;
data += avail;
}
bp->read_count = read_count;
}
static void PNGCBAPI
read_function(png_structp pp, png_bytep data, png_size_t size)
{
buffer_read(get_dp(pp), get_buffer(pp), data, size);
}
static void
read_png(struct display *dp, struct buffer *bp, const char *operation,
int transforms)
{
png_structp pp;
png_infop ip;
/* This cleans out any previous read and sets operation and transforms to
* empty.
*/
display_clean_read(dp);
if (operation != NULL) /* else this is a verify and do not overwrite info */
{
dp->operation = operation;
dp->transforms = transforms;
}
dp->read_pp = pp = png_create_read_struct(PNG_LIBPNG_VER_STRING, dp,
display_error, display_warning);
if (pp == NULL)
display_log(dp, LIBPNG_ERROR, "failed to create read struct");
/* The png_read_png API requires us to make the info struct, but it does the
* call to png_read_info.
*/
dp->read_ip = ip = png_create_info_struct(pp);
if (ip == NULL)
display_log(dp, LIBPNG_ERROR, "failed to create info struct");
# ifdef PNG_SET_USER_LIMITS_SUPPORTED
/* Remove the user limits, if any */
png_set_user_limits(pp, 0x7fffffff, 0x7fffffff);
# endif
/* Set the IO handling */
buffer_start_read(bp);
png_set_read_fn(pp, bp, read_function);
png_read_png(pp, ip, transforms, NULL/*params*/);
#if 0 /* crazy debugging */
{
png_bytep pr = png_get_rows(pp, ip)[0];
size_t rb = png_get_rowbytes(pp, ip);
size_t cb;
char c = ' ';
fprintf(stderr, "%.4x %2d (%3lu bytes):", transforms, png_get_bit_depth(pp,ip), (unsigned long)rb);
for (cb=0; cb<rb; ++cb)
fputc(c, stderr), fprintf(stderr, "%.2x", pr[cb]), c='.';
fputc('\n', stderr);
}
#endif
}
static void
update_display(struct display *dp)
/* called once after the first read to update all the info, original_pp and
* original_ip must have been filled in.
*/
{
png_structp pp;
png_infop ip;
/* Now perform the initial read with a 0 tranform. */
read_png(dp, &dp->original_file, "original read", 0/*no transform*/);
/* Move the result to the 'original' fields */
dp->original_pp = pp = dp->read_pp, dp->read_pp = NULL;
dp->original_ip = ip = dp->read_ip, dp->read_ip = NULL;
dp->original_rowbytes = png_get_rowbytes(pp, ip);
if (dp->original_rowbytes == 0)
display_log(dp, LIBPNG_BUG, "png_get_rowbytes returned 0");
dp->chunks = png_get_valid(pp, ip, 0xffffffff);
if ((dp->chunks & PNG_INFO_IDAT) == 0) /* set by png_read_png */
display_log(dp, LIBPNG_BUG, "png_read_png did not set IDAT flag");
dp->original_rows = png_get_rows(pp, ip);
if (dp->original_rows == NULL)
display_log(dp, LIBPNG_BUG, "png_read_png did not create row buffers");
if (!png_get_IHDR(pp, ip,
&dp->width, &dp->height, &dp->bit_depth, &dp->color_type,
&dp->interlace_method, &dp->compression_method, &dp->filter_method))
display_log(dp, LIBPNG_BUG, "png_get_IHDR failed");
/* 'active' transforms are discovered based on the original image format;
* running one active transform can activate others. At present the code
* does not attempt to determine the closure.
*/
{
png_uint_32 chunks = dp->chunks;
int active = 0, inactive = 0;
int ct = dp->color_type;
int bd = dp->bit_depth;
unsigned int i;
for (i=0; i<TTABLE_SIZE; ++i) if (transform_info[i].name != NULL)
{
int transform = transform_info[i].transform;
if ((transform_info[i].valid_chunks == 0 ||
(transform_info[i].valid_chunks & chunks) != 0) &&
(transform_info[i].color_mask_required & ct) ==
transform_info[i].color_mask_required &&
(transform_info[i].color_mask_absent & ct) == 0 &&
(transform_info[i].bit_depths & bd) != 0 &&
(transform_info[i].when & TRANSFORM_R) != 0)
active |= transform;
else if ((transform_info[i].when & TRANSFORM_R) != 0)
inactive |= transform;
}
/* Some transforms appear multiple times in the table; the 'active' status
* is the logical OR of these and the inactive status must be adjusted to
* take this into account.
*/
inactive &= ~active;
dp->active_transforms = active;
dp->ignored_transforms = inactive; /* excluding write-only transforms */
}
}
static int
compare_read(struct display *dp, int applied_transforms)
{
/* Compare the png_info from read_ip with original_info */
size_t rowbytes;
png_uint_32 width, height;
int bit_depth, color_type;
int interlace_method, compression_method, filter_method;
const char *e = NULL;
png_get_IHDR(dp->read_pp, dp->read_ip, &width, &height, &bit_depth,
&color_type, &interlace_method, &compression_method, &filter_method);
# define C(item) if (item != dp->item) \
display_log(dp, APP_WARNING, "IHDR " #item "(%lu) changed to %lu",\
(unsigned long)dp->item, (unsigned long)item), e = #item
/* The IHDR should be identical: */
C(width);
C(height);
C(bit_depth);
C(color_type);
C(interlace_method);
C(compression_method);
C(filter_method);
/* 'e' remains set to the name of the last thing changed: */
if (e)
display_log(dp, APP_ERROR, "IHDR changed (%s)", e);
/* All the chunks from the original PNG should be preserved in the output PNG
* because the PNG format has not been changed.
*/
{
unsigned long chunks =
png_get_valid(dp->read_pp, dp->read_ip, 0xffffffff);
if (chunks != dp->chunks)
display_log(dp, APP_FAIL, "PNG chunks changed from 0x%lx to 0x%lx",
(unsigned long)dp->chunks, chunks);
}
/* rowbytes should be the same */
rowbytes = png_get_rowbytes(dp->read_pp, dp->read_ip);
/* NOTE: on 64-bit systems this may trash the top bits of rowbytes,
* which could lead to weird error messages.
*/
if (rowbytes != dp->original_rowbytes)
display_log(dp, APP_ERROR, "PNG rowbytes changed from %lu to %lu",
(unsigned long)dp->original_rowbytes, (unsigned long)rowbytes);
/* The rows should be the same too, unless the applied transforms includes
* the shift transform, in which case low bits may have been lost.
*/
{
png_bytepp rows = png_get_rows(dp->read_pp, dp->read_ip);
unsigned int mask; /* mask (if not zero) for the final byte */
if (bit_depth < 8)
{
/* Need the stray bits at the end, this depends only on the low bits
* of the image width; overflow does not matter. If the width is an
* exact multiple of 8 bits this gives a mask of 0, not 0xff.
*/
mask = 0xff & (0xff00 >> ((bit_depth * width) & 7));
}
else
mask = 0;
if (rows == NULL)
display_log(dp, LIBPNG_BUG, "png_get_rows returned NULL");
if ((applied_transforms & PNG_TRANSFORM_SHIFT) == 0 ||
(dp->active_transforms & PNG_TRANSFORM_SHIFT) == 0 ||
color_type == PNG_COLOR_TYPE_PALETTE)
{
unsigned long y;
for (y=0; y<height; ++y)
{
png_bytep row = rows[y];
png_bytep orig = dp->original_rows[y];
if (memcmp(row, orig, rowbytes-(mask != 0)) != 0 || (mask != 0 &&
((row[rowbytes-1] & mask) != (orig[rowbytes-1] & mask))))
{
size_t x;
/* Find the first error */
for (x=0; x<rowbytes-1; ++x) if (row[x] != orig[x])
break;
display_log(dp, APP_FAIL,
"byte(%lu,%lu) changed 0x%.2x -> 0x%.2x",
(unsigned long)x, (unsigned long)y, orig[x], row[x]);
return 0; /* don't keep reporting failed rows on 'continue' */
}
}
}
else
{
unsigned long y;
int bpp; /* bits-per-pixel then bytes-per-pixel */
/* components are up to 8 bytes in size */
png_byte sig_bits[8];
png_color_8p sBIT;
if (png_get_sBIT(dp->read_pp, dp->read_ip, &sBIT) != PNG_INFO_sBIT)
display_log(dp, INTERNAL_ERROR,
"active shift transform but no sBIT in file");
switch (color_type)
{
case PNG_COLOR_TYPE_GRAY:
sig_bits[0] = sBIT->gray;
bpp = bit_depth;
break;
case PNG_COLOR_TYPE_GA:
sig_bits[0] = sBIT->gray;
sig_bits[1] = sBIT->alpha;
bpp = 2 * bit_depth;
break;
case PNG_COLOR_TYPE_RGB:
sig_bits[0] = sBIT->red;
sig_bits[1] = sBIT->green;
sig_bits[2] = sBIT->blue;
bpp = 3 * bit_depth;
break;
case PNG_COLOR_TYPE_RGBA:
sig_bits[0] = sBIT->red;
sig_bits[1] = sBIT->green;
sig_bits[2] = sBIT->blue;
sig_bits[3] = sBIT->alpha;
bpp = 4 * bit_depth;
break;
default:
display_log(dp, LIBPNG_ERROR, "invalid colour type %d",
color_type);
/*NOTREACHED*/
bpp = 0;
break;
}
{
int b;
for (b=0; 8*b<bpp; ++b)
{
/* libpng should catch this; if not there is a security issue
* because an app (like this one) may overflow an array. In fact
* libpng doesn't catch this at present.
*/
if (sig_bits[b] == 0 || sig_bits[b] > bit_depth/*!palette*/)
display_log(dp, LIBPNG_BUG,
"invalid sBIT[%u] value %d returned for PNG bit depth %d",
b, sig_bits[b], bit_depth);
}
}
if (bpp < 8 && bpp != bit_depth)
{
/* sanity check; this is a grayscale PNG; something is wrong in the
* code above.
*/
display_log(dp, INTERNAL_ERROR, "invalid bpp %u for bit_depth %u",
bpp, bit_depth);
}
switch (bit_depth)
{
int b;
case 16: /* Two bytes per component, big-endian */
for (b = (bpp >> 4); b > 0; --b)
{
unsigned int sig = (unsigned int)(0xffff0000 >> sig_bits[b]);
sig_bits[2*b+1] = (png_byte)sig;
sig_bits[2*b+0] = (png_byte)(sig >> 8); /* big-endian */
}
break;
case 8: /* One byte per component */
for (b=0; b*8 < bpp; ++b)
sig_bits[b] = (png_byte)(0xff00 >> sig_bits[b]);
break;
case 1: /* allowed, but dumb */
/* Value is 1 */
sig_bits[0] = 0xff;
break;
case 2: /* Replicate 4 times */
/* Value is 1 or 2 */
b = 0x3 & ((0x3<<2) >> sig_bits[0]);
b |= b << 2;
b |= b << 4;
sig_bits[0] = (png_byte)b;
break;
case 4: /* Relicate twice */
/* Value is 1, 2, 3 or 4 */
b = 0xf & ((0xf << 4) >> sig_bits[0]);
b |= b << 4;
sig_bits[0] = (png_byte)b;
break;
default:
display_log(dp, LIBPNG_BUG, "invalid bit depth %d", bit_depth);
break;
}
/* Convert bpp to bytes; this gives '1' for low-bit depth grayscale,
* where there are multiple pixels per byte.
*/
bpp = (bpp+7) >> 3;
/* The mask can be combined with sig_bits[0] */
if (mask != 0)
{
mask &= sig_bits[0];
if (bpp != 1 || mask == 0)
display_log(dp, INTERNAL_ERROR, "mask calculation error %u, %u",
bpp, mask);
}
for (y=0; y<height; ++y)
{
png_bytep row = rows[y];
png_bytep orig = dp->original_rows[y];
unsigned long x;
for (x=0; x<(width-(mask!=0)); ++x)
{
int b;
for (b=0; b<bpp; ++b)
{
if ((*row++ & sig_bits[b]) != (*orig++ & sig_bits[b]))
{
display_log(dp, APP_FAIL,
"significant bits at (%lu[%u],%lu) changed %.2x->%.2x",
x, b, y, orig[-1], row[-1]);
return 0;
}
}
}
if (mask != 0 && (*row & mask) != (*orig & mask))
{
display_log(dp, APP_FAIL,
"significant bits at (%lu[end],%lu) changed", x, y);
return 0;
}
} /* for y */
}
}
return 1; /* compare succeeded */
}
#ifdef PNG_WRITE_SUPPORTED
static void
buffer_write(struct display *dp, struct buffer *buffer, png_bytep data,
png_size_t size)
/* Generic write function used both from the write callback provided to
* libpng and from the generic read code.
*/
{
/* Write the data into the buffer, adding buffers as required */
struct buffer_list *last = buffer->last;
size_t end_count = buffer->end_count;
while (size > 0)
{
size_t avail;
if (end_count >= sizeof last->buffer)
{
if (last->next == NULL)
{
last = buffer_extend(last);
if (last == NULL)
display_log(dp, APP_ERROR, "out of memory saving file");
}
else
last = last->next;
buffer->last = last; /* avoid the need to rewrite every time */
end_count = 0;
}
avail = (sizeof last->buffer) - end_count;
if (avail > size)
avail = size;
memcpy(last->buffer + end_count, data, avail);
end_count += avail;
size -= avail;
data += avail;
}
buffer->end_count = end_count;
}
static void PNGCBAPI
write_function(png_structp pp, png_bytep data, png_size_t size)
{
buffer_write(get_dp(pp), get_buffer(pp), data, size);
}
static void
write_png(struct display *dp, png_infop ip, int transforms)
{
display_clean_write(dp); /* safety */
buffer_start_write(&dp->written_file);
dp->operation = "write";
dp->transforms = transforms;
dp->write_pp = png_create_write_struct(PNG_LIBPNG_VER_STRING, dp,
display_error, display_warning);
if (dp->write_pp == NULL)
display_log(dp, APP_ERROR, "failed to create write png_struct");
png_set_write_fn(dp->write_pp, &dp->written_file, write_function,
NULL/*flush*/);
# ifdef PNG_SET_USER_LIMITS_SUPPORTED
/* Remove the user limits, if any */
png_set_user_limits(dp->write_pp, 0x7fffffff, 0x7fffffff);
# endif
/* Certain transforms require the png_info to be zapped to allow the
* transform to work correctly.
*/
if (transforms & (PNG_TRANSFORM_PACKING|
PNG_TRANSFORM_STRIP_FILLER|
PNG_TRANSFORM_STRIP_FILLER_BEFORE))
{
int ct = dp->color_type;
if (transforms & (PNG_TRANSFORM_STRIP_FILLER|
PNG_TRANSFORM_STRIP_FILLER_BEFORE))
ct &= ~PNG_COLOR_MASK_ALPHA;
png_set_IHDR(dp->write_pp, ip, dp->width, dp->height, dp->bit_depth, ct,
dp->interlace_method, dp->compression_method, dp->filter_method);
}
png_write_png(dp->write_pp, ip, transforms, NULL/*params*/);
/* Clean it on the way out - if control returns to the caller then the
* written_file contains the required data.
*/
display_clean_write(dp);
}
#endif /* WRITE_SUPPORTED */
static int
skip_transform(struct display *dp, int tr)
/* Helper to test for a bad combo and log it if it is skipped */
{
if ((dp->options & SKIP_BUGS) != 0 && is_bad_combo(tr))
{
/* Log this to stdout if logging is on, otherwise just do an information
* display_log.
*/
if ((dp->options & LOG_SKIPPED) != 0)
{
printf("SKIP: %s transforms ", dp->filename);
while (tr != 0)
{
int next = first_transform(tr);
tr &= ~next;
printf("%s", transform_name(next));
if (tr != 0)
putchar('+');
}
putchar('\n');
}
else
display_log(dp, INFORMATION, "%s: skipped known bad combo 0x%x",
dp->filename, tr);
return 1; /* skip */
}
return 0; /* don't skip */
}
static void
test_one_file(struct display *dp, const char *filename)
{
/* First cache the file and update the display original file
* information for the new file.
*/
dp->operation = "cache file";
dp->transforms = 0;
display_cache_file(dp, filename);
update_display(dp);
/* First test: if there are options that should be ignored for this file
* verify that they really are ignored.
*/
if (dp->ignored_transforms != 0)
{
read_png(dp, &dp->original_file, "ignored transforms",
dp->ignored_transforms);
/* The result should be identical to the original_rows */
if (!compare_read(dp, 0/*transforms applied*/))
return; /* no point testing more */
}
#ifdef PNG_WRITE_SUPPORTED
/* Second test: write the original PNG data out to a new file (to test the
* write side) then read the result back in and make sure that it hasn't
* changed.
*/
dp->operation = "write";
write_png(dp, dp->original_ip, 0/*transforms*/);
read_png(dp, &dp->written_file, NULL, 0/*transforms*/);
if (!compare_read(dp, 0/*transforms applied*/))
return;
#endif
/* Third test: the active options. Test each in turn, or, with the
* EXHAUSTIVE option, test all possible combinations.
*/
{
/* Use unsigned int here because the code below to increment through all
* the possibilities exhaustively has to use a compare and that must be
* unsigned, because some transforms are negative on a 16-bit system.
*/
unsigned int active = dp->active_transforms;
const int exhaustive = (dp->options & EXHAUSTIVE) != 0;
unsigned int current = first_transform(active);
unsigned int bad_transforms = 0;
unsigned int bad_combo = ~0U; /* bitwise AND of failing transforms */
unsigned int bad_combo_list = 0; /* bitwise OR of failures */
for (;;)
{
read_png(dp, &dp->original_file, "active transforms", current);
/* If this involved any irreversible transformations then if we write
* it out with just the reversible transformations and read it in again
* with the same transforms we should get the same thing. At present
* this isn't done - it just seems like a waste of time and it would
* require two sets of read png_struct/png_info.
*
* If there were no irreversible transformations then if we write it
* out and read it back in again (without the reversible transforms)
* we should get back to the place where we started.
*/
#ifdef PNG_WRITE_SUPPORTED
if ((current & write_transforms) == current)
{
/* All transforms reversible: write the PNG with the transformations
* reversed, then read it back in with no transformations. The
* result should be the same as the original apart from the loss of
* low order bits because of the SHIFT/sBIT transform.
*/
dp->operation = "reversible transforms";
write_png(dp, dp->read_ip, current);
/* And if this is read back in, because all the transformations were
* reversible, the result should be the same.
*/
read_png(dp, &dp->written_file, NULL, 0);
if (!compare_read(dp, current/*for the SHIFT/sBIT transform*/))
{
/* This set of transforms failed. If a single bit is set - if
* there is just one transform - don't include this in further
* 'exhaustive' tests. Notice that each transform is tested on
* its own before testing combos in the exhaustive case.
*/
if (is_combo(current))
{
bad_combo &= current;
bad_combo_list |= current;
}
else
bad_transforms |= current;
}
}
#endif
/* Now move to the next transform */
if (exhaustive) /* all combinations */
{
unsigned int next = current;
do
{
if (next == read_transforms) /* Everything tested */
goto combo;
++next;
} /* skip known bad combos if the relevant option is set; skip
* combos involving known bad single transforms in all cases.
*/
while ( (next & read_transforms) <= current
|| (next & active) == 0 /* skip cases that do nothing */
|| (next & bad_transforms) != 0
|| skip_transform(dp, next));
assert((next & read_transforms) == next);
current = next;
}
else /* one at a time */
{
active &= ~current;
if (active == 0)
goto combo;
current = first_transform(active);
}
}
combo:
if (dp->options & FIND_BAD_COMBOS)
{
/* bad_combos identifies the combos that occur in all failing cases;
* bad_combo_list identifies transforms that do not prevent the
* failure.
*/
if (bad_combo != ~0U)
printf("%s[0x%x]: PROBLEM: 0x%x[0x%x] ANTIDOTE: 0x%x\n",
dp->filename, active, bad_combo, bad_combo_list,
rw_transforms & ~bad_combo_list);
else
printf("%s: no %sbad combos found\n", dp->filename,
(dp->options & SKIP_BUGS) ? "additional " : "");
}
}
}
static int
do_test(struct display *dp, const char *file)
/* Exists solely to isolate the setjmp clobbers */
{
int ret = setjmp(dp->error_return);
if (ret == 0)
{
test_one_file(dp, file);
return 0;
}
else if (ret < ERRORS) /* shouldn't longjmp on warnings */
display_log(dp, INTERNAL_ERROR, "unexpected return code %d", ret);
return ret;
}
int
main(const int argc, const char * const * const argv)
{
/* For each file on the command line test it with a range of transforms */
int option_end, ilog = 0;
struct display d;
validate_T();
display_init(&d);
for (option_end=1; option_end<argc; ++option_end)
{
const char *name = argv[option_end];
if (strcmp(name, "--verbose") == 0)
d.options = (d.options & ~LEVEL_MASK) | VERBOSE;
else if (strcmp(name, "--warnings") == 0)
d.options = (d.options & ~LEVEL_MASK) | WARNINGS;
else if (strcmp(name, "--errors") == 0)
d.options = (d.options & ~LEVEL_MASK) | ERRORS;
else if (strcmp(name, "--quiet") == 0)
d.options = (d.options & ~LEVEL_MASK) | QUIET;
else if (strcmp(name, "--exhaustive") == 0)
d.options |= EXHAUSTIVE;
else if (strcmp(name, "--fast") == 0)
d.options &= ~EXHAUSTIVE;
else if (strcmp(name, "--strict") == 0)
d.options |= STRICT;
else if (strcmp(name, "--relaxed") == 0)
d.options &= ~STRICT;
else if (strcmp(name, "--log") == 0)
{
ilog = option_end; /* prevent display */
d.options |= LOG;
}
else if (strcmp(name, "--nolog") == 0)
d.options &= ~LOG;
else if (strcmp(name, "--continue") == 0)
d.options |= CONTINUE;
else if (strcmp(name, "--stop") == 0)
d.options &= ~CONTINUE;
else if (strcmp(name, "--skip-bugs") == 0)
d.options |= SKIP_BUGS;
else if (strcmp(name, "--test-all") == 0)
d.options &= ~SKIP_BUGS;
else if (strcmp(name, "--log-skipped") == 0)
d.options |= LOG_SKIPPED;
else if (strcmp(name, "--nolog-skipped") == 0)
d.options &= ~LOG_SKIPPED;
else if (strcmp(name, "--find-bad-combos") == 0)
d.options |= FIND_BAD_COMBOS;
else if (strcmp(name, "--nofind-bad-combos") == 0)
d.options &= ~FIND_BAD_COMBOS;
else if (strcmp(name, "--list-combos") == 0)
d.options |= LIST_COMBOS;
else if (strcmp(name, "--nolist-combos") == 0)
d.options &= ~LIST_COMBOS;
else if (name[0] == '-' && name[1] == '-')
{
fprintf(stderr, "pngimage: %s: unknown option\n", name);
return 99;
}
else
break; /* Not an option */
}
{
int i;
int errors = 0;
for (i=option_end; i<argc; ++i)
{
{
int ret = do_test(&d, argv[i]);
if (ret > QUIET) /* abort on user or internal error */
return 99;
}
/* Here on any return, including failures, except user/internal issues
*/
{
const int pass = (d.options & STRICT) ?
RESULT_STRICT(d.results) : RESULT_RELAXED(d.results);
if (!pass)
++errors;
if (d.options & LOG)
{
int j;
printf("%s: pngimage ", pass ? "PASS" : "FAIL");
for (j=1; j<option_end; ++j) if (j != ilog)
printf("%s ", argv[j]);
printf("%s\n", d.filename);
}
}
display_clean(&d);
}
/* Release allocated memory */
display_destroy(&d);
return errors != 0;
}
}
#else /* !INFO_IMAGE || !SEQUENTIAL_READ || !READ_PNG*/
int
main(void)
{
fprintf(stderr, "pngimage: no support for png_read/write_image\n");
return 77;
}
#endif