#if?0?/*?in?case?someone?actually?tries?to?compile?this?*/

/*?example.c?-?an?example?of?using?libpng
?*?Last?changed?in?libpng?1.5.19?[August?21?2014]
?*?Maintained?1998-2014?Glenn?Randers-Pehrson
?*?Maintained?1996?1997?Andreas?Dilger
?*?Written?1995?1996?Guy?Eric?Schalnat?Group?42?Inc.
?*/

/*?This?is?an?example?of?how?to?use?libpng?to?read?and?write?PNG?files.
?*?The?file?libpng-manual.txt?is?much?more?verbose?then?this.??If?you?have?not
?*?read?it?do?so?first.??This?was?designed?to?be?a?starting?point?of?an
?*?implementation.??This?is?not?officially?part?of?libpng?is?hereby?placed
?*?in?the?public?domain?and?therefore?does?not?require?a?copyright?notice.
?*?To?the?extent?possible?under?law?the?authors?have?waived?all?copyright?and
?*?related?or?neighboring?rights?to?this?file.
?*
?*?This?file?does?not?currently?compile?because?it?is?missing?certain
?*?parts?like?allocating?memory?to?hold?an?image.??You?will?have?to
?*?supply?these?parts?to?get?it?to?compile.??For?an?example?of?a?minimal
?*?working?PNG?reader/writer?see?pngtest.c?included?in?this?distribution;
?*?see?also?the?programs?in?the?contrib?directory.
?*/

#define?_POSIX_SOURCE?1??/*?libpng?and?zlib?are?POSIX-compliant.??You?may
??????????????????????????*?change?this?if?your?application?uses?non-POSIX
??????????????????????????*?extensions.?*/

#include?“png.h“

?/*?The?png_jmpbuf（）?macro?used?in?error?handling?became?available?in
??*?libpng?version?1.0.6.??If?you?want?to?be?able?to?run?your?code?with?older
??*?versions?of?libpng?you?must?define?the?macro?yourself?（but?only?if?it
??*?is?not?already?defined?by?libpng!）.
??*/

#ifndef?png_jmpbuf
#??define?png_jmpbuf（png_ptr）?（（png_ptr）->png_jmpbuf）
#endif

/*?Check?to?see?if?a?file?is?a?PNG?file?using?png_sig_cmp（）.??png_sig_cmp（）
?*?returns?zero?if?the?image?is?a?PNG?and?nonzero?if?it?isn‘t?a?PNG.
?*
?*?The?function?check_if_png（）?shown?here?but?not?used?returns?nonzero?（true）
?*?if?the?file?can?be?opened?and?is?a?PNG?0?（false）?otherwise.
?*
?*?If?this?call?is?successful?and?you?are?going?to?keep?the?file?open
?*?you?should?call?png_set_sig_bytes（png_ptr?PNG_BYTES_TO_CHECK）;?once
?*?you?have?created?the?png_ptr?so?that?libpng?knows?your?application
?*?has?read?that?many?bytes?from?the?start?of?the?file.??Make?sure?you
?*?don‘t?call?png_set_sig_bytes（）?with?more?than?8?bytes?read?or?give?it
?*?an?incorrect?number?of?bytes?read?or?you?will?either?have?read?too
?*?many?bytes?（your?fault）?or?you?are?telling?libpng?to?read?the?wrong
?*?number?of?magic?bytes?（also?your?fault）.
?*
?*?Many?applications?already?read?the?first?2?or?4?bytes?from?the?start
?*?of?the?image?to?determine?the?file?type?so?it?would?be?easiest?just
?*?to?pass?the?bytes?to?png_sig_cmp（）?or?even?skip?that?if?you?know
?*?you?have?a?PNG?file?and?call?png_set_sig_bytes（）.
?*/
#define?PNG_BYTES_TO_CHECK?4
int?check_if_png（char?*file_name?FILE?**fp）
{
???char?buf[PNG_BYTES_TO_CHECK];

???/*?Open?the?prospective?PNG?file.?*/
???if?（（*fp?=?fopen（fi

?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----
?????目錄???????????0??2017-01-04?15:28??libpng-1.5.28\
?????文件????????2474??2016-12-29?08:35??libpng-1.5.28\ANNOUNCE
?????文件??????221470??2016-12-29?08:35??libpng-1.5.28\CHANGES
?????文件???????24394??2016-12-29?08:35??libpng-1.5.28\CMakeLists.txt
?????文件???????17103??2016-12-29?08:35??libpng-1.5.28\INSTALL
?????文件????????4637??2016-12-29?08:35??libpng-1.5.28\LICENSE
?????文件????????9433??2015-03-16?06:13??libpng-1.5.28\Makefile.am
?????文件???????80206??2016-12-29?08:35??libpng-1.5.28\Makefile.in
?????文件???????11172??2016-12-29?08:35??libpng-1.5.28\README
?????文件????????1068??2016-10-30?22:24??libpng-1.5.28\TODO
?????文件??????374800??2016-12-29?08:35??libpng-1.5.28\aclocal.m4
?????目錄???????????0??2017-01-04?15:25??libpng-1.5.28\arm\
?????文件????????6994??2016-12-29?08:35??libpng-1.5.28\arm\arm_init.c
?????文件????????7638??2016-12-29?08:35??libpng-1.5.28\arm\filter_neon.S
?????文件?????????877??2010-09-15?04:22??libpng-1.5.28\autogen.sh
?????文件????????7333??2015-02-22?02:40??libpng-1.5.28\compile
?????文件???????42938??2015-02-22?02:40??libpng-1.5.28\config.guess
?????文件????????3160??2016-12-29?08:35??libpng-1.5.28\config.h.in
?????文件???????35987??2015-02-22?02:40??libpng-1.5.28\config.sub
?????文件??????476053??2016-12-29?08:35??libpng-1.5.28\configure
?????文件????????9090??2016-12-29?08:35??libpng-1.5.28\configure.ac
?????目錄???????????0??2017-01-04?15:25??libpng-1.5.28\contrib\
?????文件?????????210??2011-11-17?02:52??libpng-1.5.28\contrib\README.txt
?????目錄???????????0??2017-01-04?15:25??libpng-1.5.28\contrib\gregbook\
?????文件???????18097??2016-12-29?08:35??libpng-1.5.28\contrib\gregbook\COPYING
?????文件????????2373??2016-12-29?08:35??libpng-1.5.28\contrib\gregbook\LICENSE
?????文件????????3940??2016-12-29?08:35??libpng-1.5.28\contrib\gregbook\Makefile.mingw32
?????文件????????2990??2016-12-29?08:35??libpng-1.5.28\contrib\gregbook\Makefile.sgi
?????文件????????4093??2016-12-29?08:35??libpng-1.5.28\contrib\gregbook\Makefile.unx
?????文件????????3357??2016-12-29?08:35??libpng-1.5.28\contrib\gregbook\Makefile.w32
?????文件????????7850??2016-12-29?08:35??libpng-1.5.28\contrib\gregbook\README
............此處省略623個文件信息