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#include <cstdio>
#include <cstdlib>
////////////////////////////////////////////////////////////////////////////////
static inline
int getc_and_check(FILE *f, const char* filename)
{
int c;
c = getc(f);
if (feof(f)) {
fprintf(stderr, "Error while reading a comment from %s\n", filename);
exit(-1);
}
return c;
}
////////////////////////////////////////////////////////////////////////////////
static inline
void eat_comments(FILE *f, const char* filename, int& c) noexcept
{
int length = 0;
length = getc_and_check(f, filename) << 8;
length |= getc_and_check(f, filename);
length -= 2;
for (int i = 0; i < length; ++i)
c = getc_and_check(f, filename);
}
////////////////////////////////////////////////////////////////////////////////
int main(int argc, char* argv[])
{
if (argc < 3)
{
fprintf(stderr,
"compare_files expects two arguments <filename1, filename2>\n");
exit(-1);
}
FILE *f1 = fopen(argv[1], "rb");
if (f1 == NULL)
{
fprintf(stderr, "Unable to open file %s.\n", argv[1]);
return -1;
}
FILE *f2 = fopen(argv[2], "rb");
if (f2 == NULL)
{
fprintf(stderr, "Unable to open file %s.\n", argv[2]);
return -1;
}
bool tile_started = false;
int old_c1 = ' ';
while (1) // both files must end at the same time
{
int c1 = getc(f1);
int c2 = getc(f2);
bool eof1 = (feof(f1) != 0), eof2 = (feof(f2) != 0);
if (eof1 && eof2) // both reached end of file
{
fprintf(stdout, "Matching files.\n");
return 0;
}
else if (!eof1 && !eof2)
{
if (c1 != c2)
return -1;
if (!tile_started && old_c1 == 0xFF && c1 == 0x64) {
eat_comments(f1, argv[1], c1);
eat_comments(f2, argv[2], c2);
}
if (!tile_started && old_c1 == 0xFF && c1 == 0x90) {
// stop checking comments when a tile starts; we ignoring
// the case where tile can also have comments
tile_started = true;
}
old_c1 = c1;
}
else // only one of them reached end of file
{
fprintf(stderr, "One file finished before the other one.\n");
return -1;
}
}
fclose(f1);
fclose(f2);
return 0;
}
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