On 26 July 2013 21:02, Richard Hughes <hughsi...@gmail.com> wrote: > If it fails for other people I'll work on a small > reproducer that illustrates the problem.
Okay, reproducer attached. Simply save the profile and the C file in the same place and do: gcc -o test test.c `pkg-config --cflags --libs lcms2` && ./test This is now called my "Schrödinger" bug. Basically, if you do these exact things you can write a profile with a corrupt metadata tag: * cmsOpenProfileFromFile() or cmsOpenProfileFromMem() * unused = cmsReadTag(p, cmsSigMetaTag) * cmsSaveProfileToMem() * Save memory blob to a file If you do cmsOpenProfileFromFile() on the new file and then cmsReadTag(p, cmsSigMetaTag) you get: ERROR: Bad dictionary Name/Value ERROR: Corrupted tag 'meta' It seems by "observing" the dictionary using cmsReadTag() somehow corrupts it, so when it is saved it's then unreadable. If you don't do the initial cmsReadTag(p, cmsSigMetaTag) or use cmsSaveProfileToFile() then the bug does not manifest itself. I'm very confused, so any help welcome, thanks! Richard.
ibm-t61.icc
Description: Binary data
//gcc -o test test.c `pkg-config --cflags --libs lcms2` && ./test
#include <lcms2.h>
#include <assert.h>
#include <stdlib.h>
static void
error_cb(cmsContext context_id, cmsUInt32Number code, const char *message)
{
printf("ERROR: %s\n", message);
}
int
main(int argc, char *argv[])
{
char *data;
cmsHANDLE dict;
cmsHPROFILE p;
cmsUInt32Number clen;
const cmsDICTentry *entry;
FILE *fp;
int rc;
/* setup log handler */
cmsSetLogErrorHandler(error_cb);
/* open file */
p = cmsOpenProfileFromFile("./ibm-t61.icc", "r");
assert(p);
/* read dictionary, but don't do anything with the value */
//COMMENT OUT THE NEXT TWO LINES AND IT WORKS FINE!!!
dict = cmsReadTag(p, cmsSigMetaTag);
assert(dict);
/* serialize profile to memory */
rc = cmsSaveProfileToMem(p, NULL, &clen);
assert(rc);
data = malloc(clen);
rc = cmsSaveProfileToMem(p, data, &clen);
assert(rc);
/* write the memory blob to a file */
//NOTE: The crash does not happen if cmsSaveProfileToFile() is used */
fp = fopen("./new.icc", "w");
fwrite(data, 1, clen, fp);
fclose(fp);
free(data);
cmsCloseProfile(p);
/* open newly created file and read metadata */
p = cmsOpenProfileFromFile("./new.icc", "r");
//ERROR: Bad dictionary Name/Value
//ERROR: Corrupted tag 'meta'
//test: test.c:59: main: Assertion `dict' failed.
dict = cmsReadTag(p, cmsSigMetaTag);
assert(dict);
return 0;
}
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