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#include <sys/times.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <ctype.h>
#include "mp3_check.h"
#include "support_functions.h"
// Function prototypes go here.
inline int move_to_next_frame(char *possible_mp3_tag, frame_info *mp3_i, gen_info *file_info, command_flags *flags, FILE *);
int get_char_from_file(FILE *, unsigned int *header_value, gen_info *file_info, command_flags *flags, char *possible_mp3_tag);
int scan_file(FILE *, char *filename, meta_options *flag_options, command_flags *flags);
int parse_args(char **argv, meta_options *flag_options, command_flags *flags);
int crc_check_frame(char *data_frame, frame_info *mp3_i);
void init_command_flags_struct(command_flags *flags);
void init_frame_struct(frame_info *FI);
void print_summary(frame_info mp3_i, char *filename);
void print_usage(void);
extern int check_header_value(unsigned int *header, char *filename, frame_info *FI);
extern int check_vbr_and_time(frame_info *mp3_i, vbr_data *vbr_info, gen_info *file_info);
extern int copy_int_array_to_str(char *possible_mp3_tag, char *tag_field, int offset, int length, int max_length);
extern int dump_id3_tag(id3_tag_info *id3_tag);
extern int get_last_char_offset(char *fat_string);
extern int print_frame_info(frame_info *mp3_i, gen_info *file_info);
extern int rotate_char_array(char *byte_list, int *new_byte, gen_info *file_info);
extern int transform_char_array(char *byte_list, gen_info *file_info);
extern int validate_id3_tag(char *possible_mp3_tag, id3_tag_info *id3_tag);
extern void init_id3_tag_struct(id3_tag_info *TAG);
extern void print_sys_usage(void);
extern void translate_time(gen_info *file_info, mp3_time *song_time);
extern void init_vbr_tag_struct(vbr_data *vbr_info);
extern void init_mp3_time_struct(mp3_time *song_time);
extern void init_gen_info_struct(gen_info *file_info);
extern inline int cmp_str(const char *full_str, const char *chk_str, int full_str_offset);
int
scan_file(fp, filename, flag_options, flags)
register FILE *fp;
char *filename;
meta_options *flag_options;
command_flags *flags;
{
int counter = 0;
int END_OF_FILE = FALSE;
int found_first_frame = FALSE;
char possible_mp3_tag[BUFFER_LENGTH];
unsigned int header_value = 0;
// This is set to 'YES' so that I will always get
// the first 4 bytes off the stream no matter what.
char found_valid_header = YES;
char found_weak_header = NO;
// Keep all the structures centralized.
frame_info mp3_i;
vbr_data vbr_info;
mp3_time song_time;
frame_info first_mp3_frame;
id3_tag_info id3_tag;
gen_info file_info;
// Zero these structures out.
init_frame_struct(&first_mp3_frame);
init_vbr_tag_struct(&vbr_info);
init_gen_info_struct(&file_info);
while (!END_OF_FILE) {
if (flags->bflag || flags->aflag) {
// This is the part where if the current byte count
// is greater than the upper limit on the commandline,
// it will break out.
if (flags->bflag && (file_info.byte_count > flag_options->byte_limit))
break;
}
//
// The fist run defaults to 'YES', so the 'else' section
// runs first
//
// The logic below is what travels through the mp3 file,
// and then quickly does a sync checksum to see if it is
// a candidate.
if (!found_valid_header) {
// Just add one character to the end
// and keep the rest. I do not want to grab
// another 4 bytes unless I got a success.
// Putting the below action in a function slows it down quite a bit,
// but, it makes the code more readable.
if (get_char_from_file(fp, &header_value, &file_info, flags, possible_mp3_tag)) {
if (!flags->ssflag && flags->sflag && !flags->fflag) {
(void)fprintf(stdout, "%c", (header_value & 0xff));
}
} else
break;
} else {
// Clear it out of old values.
header_value = 0;
// Grab the complete 4-byte header (if it is one).
for (counter = 0 ; counter < 4 ; counter++) {
if (get_char_from_file(fp, &header_value, &file_info, flags, possible_mp3_tag)) {
if (!flags->ssflag && flags->sflag && !flags->fflag) {
(void)fprintf(stdout, "%c", (header_value & 0xff));
}
} else
break;
}
}
//
// Check if this is a valid frame sync
//
if (((header_value >> 21) & 0x7ff) == 0x7ff) {
found_weak_header = YES;
init_frame_struct(&mp3_i);
if (check_header_value(&header_value, filename, &mp3_i)) {
found_valid_header = YES;
//
// Was the offset of this current frame known
// by the previous frame? It better have...
//
// This also defines junk at the beginning as being a bad frame.
//
if ((file_info.good_frame_count > 0) && (file_info.next_expected_frame != file_info.byte_count)) {
file_info.bad_frame_count++;
// I guess if I get to this section,
// I have found an mp3 with some bad
// stuff in it, so I will return a
// fail when the program exits.
(void)fprintf(stderr, "\nAn expected frame was not found. Expected it at offset 0x%x (BYTE %d), now at offset 0x%x (BYTE %d).",
file_info.next_expected_frame, file_info.next_expected_frame, file_info.byte_count, file_info.byte_count);
// Checking to see if a contiguous amount of frames
// were found. This check only occurs when a bad
// frame was found.
if (flags->qflag && (file_info.frame_sequence_count > 0) && (flag_options->min_frame_seq > file_info.frame_sequence_count)) {
(void)fprintf(stderr, "\nMininum contiguous number of frames wasn't reached. Got to %d, needed %d at offset 0x%x (BYTE %d).",
file_info.frame_sequence_count, flag_options->min_frame_seq, file_info.next_expected_frame, file_info.next_expected_frame);
file_info.frame_sequence_count = 0;
}
} else if (file_info.next_expected_frame == file_info.byte_count) {
file_info.good_frame_count++;
file_info.frame_sequence_count++;
} else
printf("\nSomething happened at byte %d. Next expected frame: %d.\n", file_info.byte_count, file_info.next_expected_frame);
//
// The fflag is only good to use when there is *no* valid data,
// and not when there is good data (it should be implied).
// !sflag is set up this way because the data is already being
// shown above.
//
// There are two parts to this header printing.
if (!flags->ssflag && (flags->sflag && flags->fflag))
(void)fprintf(stdout, "%c%c%c%c", ((header_value >> 24) & 0xff),
((header_value >> 16) & 0xff),
((header_value >> 8) & 0xff),
(header_value & 0xff));
// I'm currently in a known good frame,
// so I can safely move forward two characters
// and still be in the frame. I will have to
// compensate when I move to the next frame.
// That is taken care of in move_to_next_frame.
if (mp3_i.PROT_BIT) {
// Now, to grab the 2 bytes for the CRC value.
for (counter = 0 ; counter < 2 ; counter++) {
if (get_char_from_file(fp, &header_value, &file_info, flags, possible_mp3_tag)) {
if (!flags->ssflag && flags->sflag && !flags->fflag) {
(void)fprintf(stdout, "%c", (header_value & 0xff));
}
} else {
break;
}
}
// Now, extract it from the header.
mp3_i.CRC16_VALUE = header_value & 0xffff;
//
// The fflag is only good to use when there is *no* valid data,
// and not when there is good data (it should be implied).
// !sflag is set up this way because the data is already being
// shown above.
//
if (!flags->ssflag && (flags->sflag && flags->fflag))
(void)fprintf(stdout, "%c%c", ((header_value >> 8) & 0xff),
(header_value & 0xff));
}
// If the header is valid, but has bad data,
// it will still store this information. Perhaps
// it would be better to make sure it *really* is
// a good frame before storing any VBR data...
check_vbr_and_time(&mp3_i, &vbr_info, &file_info);
//
// I always want to keep the first frame
// so I can print it out at the end
// consistently.
//
// I am going to disable the 'if' statement
// because for some reason if there's an anomaly
// in the frame, it keeps the data, so I guess
// for now I'll just have this information
// updated at every frame.
//
if (file_info.good_frame_count > 0) {
first_mp3_frame = mp3_i;
found_first_frame = TRUE;
}
// Print out per-frame stats.
if (!flags->sflag && flags->vvflag && (file_info.good_frame_count > 0))
print_frame_info(&mp3_i, &file_info);
//
// This will checkety-check to see if I get the next frame
// when I am supposed to.
//
if (mp3_i.PROT_BIT)
file_info.next_expected_frame = file_info.byte_count + mp3_i.FRAME_LENGTH - 2;
else
file_info.next_expected_frame = file_info.byte_count + mp3_i.FRAME_LENGTH;
// Keep on searching the whole mp3? Ok, lemme skip though the data
// to get to the next header.
if (flags->aflag || (flags->bflag && (flag_options->byte_limit > 0))) {
if (!move_to_next_frame(possible_mp3_tag, &mp3_i, &file_info, flags, fp))
break;
} else
// I found my first valid header, so I can quit now.
break;
} else {
// I guess if I get to this section,
// I have found an mp3 with some bad
// stuff in it, so I will return a
// fail when the program exits.
file_info.bad_frame_count++;
if (flags->vflag)
(void)fprintf(stderr, "\nA possible header 0x%x passed the weak sieve, but failed the strong one at offset 0x%x (BYTE %d).",
header_value, file_info.byte_count, file_info.byte_count);
if (flags->qflag && (file_info.frame_sequence_count > 0) && (flag_options->min_frame_seq > file_info.frame_sequence_count)) {
(void)fprintf(stderr, "\nMininum contiguous number of frames wasn't reached. Got to %d, needed %d at offset 0x%x (BYTE %d).",
file_info.frame_sequence_count, flag_options->min_frame_seq, file_info.next_expected_frame, file_info.next_expected_frame);
file_info.frame_sequence_count = 0;
}
}
} else if (file_info.file_pos == 4 && (header_value & 0xffffff00) == 0x49443300){
// Getting to this section means we may have an ID3V2.x.x header
(void)fprintf(stderr, "Possible ID3v2 frame found, skipping\n");
// Since this section is going to be under serious development,
// the flag 'eflag' will allow mp3_check to record a bad frame
// when an id3v2 tag is found. This will allow the user to weed
// out troublesome id3v2 mp3s.
mp3_i.ID3V2 = TRUE;
if (flags->eflag) {
if (flags->qflag && (file_info.frame_sequence_count > 0) && (flag_options->min_frame_seq > file_info.frame_sequence_count)) {
(void)fprintf(stderr, "\nMininum contiguous number of frames wasn't reached. Got to %d, needed %d at offset 0x%x (BYTE %d).",
file_info.frame_sequence_count, flag_options->min_frame_seq, file_info.next_expected_frame, file_info.next_expected_frame);
file_info.frame_sequence_count = 0;
}
file_info.bad_frame_count++;
}
// TODO: Full ID3V2 checking & processing instead of skipping
// Throw away the next two bytes - the first one should always be > 0xff
// The next 4 bytes represent the len encoded to avoid 0x80 bits set
for (counter = 0 ; counter < 6 ; counter++) {
if (get_char_from_file(fp, &header_value, &file_info, flags, possible_mp3_tag)) {
if (!flags->ssflag && flags->sflag && !flags->fflag) {
(void)fprintf(stdout, "%c", (header_value & 0xff));
}
} else {
break;
}
}
// calculate the proper length
counter = ((header_value>>3)&0xfe00000)
| ((header_value>>2)&0x1fc000)
| ((header_value>>1)&0x3f80)
| (header_value&0x7f);
// TODO: account for Unsynchronization!
// we may won't skip all of it if Unsynchroized is set (0x80 in byte 5 of file)
// account for the 10 byte header and the next header
// this is to avoide excess messages during sync
file_info.next_expected_frame = counter + 14;
// skip the ID3V2 frame
while (counter-- > 0){
if (get_char_from_file(fp, &header_value, &file_info, flags, possible_mp3_tag)) {
if (!flags->ssflag && flags->sflag && !flags->fflag) {
(void)fprintf(stdout, "%c", (header_value & 0xff));
}
} else {
break;
}
}
// and mark as not currently synchronized - force it
found_valid_header = YES;
found_weak_header = NO;
} else {
// Getting to this section does not mean we got
// an invalid mp3 file...
found_valid_header = NO;
found_weak_header = NO;
}
} // WHILE
if (!flags->sflag) {
if (flags->pflag) {
printf("%s %s\t%s %d\t%s %d\t%s %d", "FILE_NAME", filename, "GOOD_FRAMES", file_info.good_frame_count, "BAD_FRAMES", file_info.bad_frame_count, "LAST_BYTE_CHECKED", file_info.byte_count);
} else {
printf("\n");
printf("%-20s%s\n", "FILE_NAME", filename);
printf("%-20s%d\n", "GOOD_FRAMES", file_info.good_frame_count);
printf("%-20s%d\n", "BAD_FRAMES", file_info.bad_frame_count);
printf("%-20s%d", "LAST_BYTE_CHECKED", file_info.byte_count);
}
if ((vbr_info.high_rate != vbr_info.low_rate) && (file_info.good_frame_count > 0)) {
// I do not want floating values in ave_rate. Seems silly
// to have a decimal point for that.
vbr_info.ave_rate = vbr_info.sum_rate / file_info.good_frame_count;
if (flags->pflag) {
// I don't want any newlines for the below line because
// the pflag option is to print it out all one one line
printf("\t%s %d\t%s %d\t%s %d", "VBR_HIGH", vbr_info.high_rate, "VBR_LOW", vbr_info.low_rate, "VBR_AVERAGE", vbr_info.ave_rate);
} else {
printf("\n");
printf("%-20s%d\n", "VBR_HIGH", vbr_info.high_rate);
printf("%-20s%d\n", "VBR_LOW", vbr_info.low_rate);
printf("%-20s%d", "VBR_AVERAGE", vbr_info.ave_rate);
}
}
if (found_first_frame) {
if (flags->vflag && !flags->pflag) {
print_summary(first_mp3_frame, filename);
}
translate_time(&file_info, &song_time);
if (flags->pflag)
printf("\t%-20s%02u:%02u.%02u\n", "SONG_LENGTH", song_time.minutes, song_time.seconds, song_time.frac_second);
else
printf("\n%-20s%02u:%02u.%02u\n", "SONG_LENGTH", song_time.minutes, song_time.seconds, song_time.frac_second);
} else {
// This line below closes the strings above.
// notice that at the end of the last string, there is no newline...
printf("\n");
}
}
init_id3_tag_struct(&id3_tag);
transform_char_array(possible_mp3_tag, &file_info);
if (flags->iflag && validate_id3_tag(possible_mp3_tag, &id3_tag)) {
if (flags->iflag && flags->fflag && flags->sflag)
dump_id3_tag(&id3_tag);
if (!flags->sflag && flags->vflag) {
printf("\n%-20s%d\n", "MP3_TAG", 1);
printf("%-20s%s\n", "TITLE", id3_tag.TITLE);
printf("%-20s%s\n", "ARTIST", id3_tag.ARTIST);
printf("%-20s%s\n", "ALBUM", id3_tag.ALBUM);
printf("%-20s%s\n", "YEAR", id3_tag.YEAR);
printf("%-20s%s\n", "COMMENT", id3_tag.COMMENT);
printf("%-20s%d\n", "GENRE", id3_tag.GENRE);
printf("%-20s%d\n", "TRACK", id3_tag.TRACK_NUMBER);
printf("%-20s%d\n", "ID3.11", id3_tag.ID3_311_VERSION);
}
} else if (!flags->sflag && flags->iflag) {
printf("\n%-20s%d\n", "MP3_TAG", 0);
}
if (ferror(fp)) {
fprintf(stderr, "mp3_check: %s %s\n", filename, strerror(errno));
clearerr(fp);
}
if (ferror(stdout)) {
fprintf(stderr, "mp3_check: stdout %s\n", strerror(errno));
exit (1);
}
//
// The 'file_info.bad_frame_count' seems
// the best way to find errors,
// so I will use it.
//
if (file_info.bad_frame_count > 0)
return(FAIL);
else
return(PASS);
}
void
init_command_flags_struct(flags)
command_flags *flags;
{
flags->aflag = FALSE;
flags->bflag = FALSE;
flags->eflag = FALSE;
flags->fflag = FALSE;
flags->iflag = FALSE;
flags->pflag = FALSE;
flags->qflag = FALSE;
flags->sflag = FALSE;
flags->ssflag = FALSE;
flags->vflag = FALSE;
flags->vvflag = FALSE;
}
void
print_summary(mp3_i, filename)
frame_info mp3_i;
char *filename;
{
printf("\n");
printf("%-20s%d\n", "TRUE", 1);
printf("%-20s%d\n", "FALSE", 0);
printf("%-20s%d\n", "MPV_1", mp3_i.MPV_1);
printf("%-20s%d\n", "MPV_2", mp3_i.MPV_2);
printf("%-20s%d\n", "MPV_25", mp3_i.MPV_25);
printf("%-20s%d\n", "MPV_RESERVED", mp3_i.MPV_RESERVED);
printf("%-20s%d\n", "L1", mp3_i.L1);
printf("%-20s%d\n", "L2", mp3_i.L2);
printf("%-20s%d\n", "L3", mp3_i.L3);
printf("%-20s%d\n", "L_RESERVED", mp3_i.L_RESERVED);
printf("%-20s%d\n", "PROT_BIT", mp3_i.PROT_BIT);
printf("%-20s%d\n", "BIT_RATE", mp3_i.BIT_RATE);
printf("%-20s%d\n", "SAMPLE_FREQ", mp3_i.SAMPLE_FREQ);
printf("%-20s%d\n", "SAMPLES_PER_FRAME", mp3_i.SAMPLES_PER_FRAME);
printf("%-20s%d\n", "PAD_BIT", mp3_i.PAD_BIT);
printf("%-20s%d\n", "PRIV_BIT", mp3_i.PRIV_BIT);
printf("%-20s%d\n", "STEREO", mp3_i.STEREO);
printf("%-20s%d\n", "JOINT_STEREO", mp3_i.JOINT_STEREO);
printf("%-20s%d\n", "DUAL_STEREO", mp3_i.DUAL_STEREO);
printf("%-20s%d\n", "SINGLE_CHANNEL", mp3_i.SINGLE_CHANNEL);
printf("%-20s%d\n", "MODE_EXTENSION", mp3_i.MODE_EXTENSION);
printf("%-20s%d\n", "ID3V2", mp3_i.ID3V2);
printf("%-20s%d\n", "FRAME_LENGTH", mp3_i.FRAME_LENGTH);
printf("%-20s%d\n", "COPYRIGHT", mp3_i.COPYRIGHT);
printf("%-20s%d\n", "ORIGINAL", mp3_i.ORIGINAL);
printf("%-20s%d\n", "EMPH_NONE", mp3_i.EMPH_NONE);
printf("%-20s%d\n", "EMPH_5015", mp3_i.EMPH_5015);
printf("%-20s%d\n", "EMPH_RESERV", mp3_i.EMPH_RESERV);
printf("%-20s%d\n", "EMPH_CCIT", mp3_i.EMPH_CCIT);
printf("%-20s%d\n", "CHECK_STATE", mp3_i.check_state);
printf("%-20s%s\n", "BIN_STRING", mp3_i.BIN_STRING);
}
void
init_frame_struct(FI)
frame_info *FI;
{
static frame_info empty_frame;
static int inited = 0;
if (!inited)
{
int i = 0;
inited = 1;
empty_frame.FRAME_LENGTH = 0;
empty_frame.FRAME_DATA_LENGTH = 0;
empty_frame.CRC16_VALUE = 0;
empty_frame.CORRECT_CRC16_VALUE = 0;
empty_frame.BIT_RATE = 0;
empty_frame.SAMPLE_FREQ = 0;
empty_frame.SAMPLES_PER_FRAME = 0;
empty_frame.MPV_1 = 0;
empty_frame.MPV_2 = 0;
empty_frame.MPV_25 = 0;
empty_frame.MPV_RESERVED = 0;
empty_frame.L1 = 0;
empty_frame.L2 = 0;
empty_frame.L3 = 0;
empty_frame.L_RESERVED = 0;
empty_frame.PROT_BIT = 0;
empty_frame.PAD_BIT = 0;
empty_frame.PRIV_BIT = 0;
empty_frame.STEREO = 0;
empty_frame.JOINT_STEREO = 0;
empty_frame.DUAL_STEREO = 0;
empty_frame.SINGLE_CHANNEL = 0;
empty_frame.MODE_EXTENSION = 0;
empty_frame.ID3V2 = 0;
empty_frame.COPYRIGHT = 0;
empty_frame.ORIGINAL = 0;
empty_frame.EMPH_NONE = 0;
empty_frame.EMPH_5015 = 0;
empty_frame.EMPH_RESERV = 0;
empty_frame.EMPH_CCIT = 0;
for (i=0 ; i < 32 ; i++)
empty_frame.BIN_STRING[i] = '0';
empty_frame.BIN_STRING[32] = '\0';
empty_frame.INT_HEADER = 0;
empty_frame.check_state = 0;
}
/* bitwise copy */
*FI = empty_frame;
}
void
print_usage(void)
{
(void)fprintf(stderr, "\nusage: mp3_check [-e] [-p] [-v[v]] [-a] [-b[<byte_count>]] [-i] [-s[s]] [-h] [-] [file ...]\n");
(void)fprintf(stderr, " -q<number> Determines the mininum <number> of contiguous frames\n");
(void)fprintf(stderr, " that must be present for an error NOT to occur.\n");
(void)fprintf(stderr, " Analyzing random data will find spurious MP3 headers,\n");
(void)fprintf(stderr, " but finding <number> sequential headers are even\n");
(void)fprintf(stderr, " harder to find.\n\n");
(void)fprintf(stderr, " -e While id3v2 support is under development, this flag will\n");
(void)fprintf(stderr, " allow you to have mp3_check record a frame error when\n");
(void)fprintf(stderr, " a id3v2 tag is found.\n\n");
(void)fprintf(stderr, " -p Shows just the essentials (what you get without the\n");
(void)fprintf(stderr, " -v option) on a single line for easy parsing. The\n");
(void)fprintf(stderr, " fields are separated by tabs, and the name/value pairs\n");
(void)fprintf(stderr, " are separated by spaces.\n\n");
(void)fprintf(stderr, " -v[v] Lists details about the mp3 in name -> value order.\n");
(void)fprintf(stderr, " Adding an extra 'v' at the end gives details about\n");
(void)fprintf(stderr, " each frame. Extremly verbose!\n\n");
(void)fprintf(stderr, " -a Checks the mp3 from stem to stern (default).\n");
(void)fprintf(stderr, " If any other flags are present, it will not be\n");
(void)fprintf(stderr, " enabled, and will instead behave as though the\n");
(void)fprintf(stderr, " '-b' switch is present.\n\n");
(void)fprintf(stderr, " -b[<byte_count>] If a frame is not found by <byte_count> bytes,\n");
(void)fprintf(stderr, " quit, and return an error. If byte_count\n");
(void)fprintf(stderr, " is not specified, it will search until the\n");
(void)fprintf(stderr, " first valid frame and quit.\n\n");
(void)fprintf(stderr, " -i Check to see if there is a ID3 tag, and if so,\n");
(void)fprintf(stderr, " display the info.\n\n");
(void)fprintf(stderr, " -s[s|f] Sends the mp3 to stdout (for CGI applications).\n");
(void)fprintf(stderr, " If an additional 's' is there, then no output is\n");
(void)fprintf(stderr, " made, just errors are reported (super silent).\n");
(void)fprintf(stderr, " With the 'f' used, only valid frames are sent\n");
(void)fprintf(stderr, " to stdout ('f'ixing the mp3 is attempted). Also,\n");
(void)fprintf(stderr, " it is important to note that the id3 tag will not\n");
(void)fprintf(stderr, " be included in the 'f'ixed mp3. If you want it\n");
(void)fprintf(stderr, " included, you have to include the '-i' option.\n\n");
(void)fprintf(stderr, " -h Print this text including the version.\n\n");
(void)fprintf(stderr, "* VERSION: %s \n", CURRENT_VERSION);
(void)fprintf(stderr, "* HOMEPAGE: %s \n", HOMEPAGE);
(void)fprintf(stderr, "* AUTHOR : %s \n", AUTHOR);
exit(1);
}
int
parse_args(argv, flag_options, flags)
char **argv;
meta_options *flag_options;
command_flags *flags;
{
register FILE *fp;
char *filename;
int error_count = 0;
int found_file = FALSE;
do {
if (*argv) {
if (strcmp(*argv, "-") == 0) {
found_file = TRUE;
filename = "stdin";
fp = stdin;
++argv;
} else if ((fp = fopen(*argv, "rb")) != NULL) {
found_file = TRUE;
filename = *argv++;
} else {
fprintf (stderr, "mp3_check: %s %s\n", *argv, strerror(errno));
++argv;
continue;
}
}
if (found_file) {
if (!scan_file(fp, filename, flag_options, flags))
error_count++;
if (fp != stdin)
(void)fclose(fp);
found_file = FALSE;
}
} while (*argv);
if (error_count > 0)
return(FAIL);
else
return(PASS);
}
inline int
move_to_next_frame(possible_mp3_tag, mp3_i, file_info, flags, fp)
char *possible_mp3_tag;
frame_info *mp3_i;
gen_info *file_info;
command_flags *flags;
FILE *fp;
{
int counter = 0;
int unk_char = 0;
int actual_bytes_read = 0;
register char *data_frame;
const int print_to_stdout = !flags->ssflag && (flags->sflag || flags->fflag);
int bytes_to_read = 0;
// Here, mp3_check adjusts for the CRC checksum
if (mp3_i->PROT_BIT)
bytes_to_read = mp3_i->FRAME_LENGTH - 6; // 6 is for the offset after the header plus the two CRC bytes.
else
bytes_to_read = mp3_i->FRAME_LENGTH - 4; // 4 is for the offset after the header
// The data_frame variable stores the contents
// of the mp3 frame without the header. I can then
// use this information to run crc16 analysis on it.
data_frame = (char *) malloc (bytes_to_read);
// This for loop cycles though the frame data. All I want to know
// is if the frame header is valid or not...
// basically, I know I got a good frame, I just want to hurry
// to the next one.
// I am not sure if the '!print_to_stdout' is still useful here.
// I should check on this later...
if (fp!=stdin && !print_to_stdout && !flags->iflag) {
if (mp3_i->PROT_BIT) {
actual_bytes_read = fread (data_frame, sizeof(char), bytes_to_read, fp);
if (actual_bytes_read == bytes_to_read) {
file_info->file_pos += bytes_to_read;
file_info->byte_count += bytes_to_read;
// May be useful later for working on the CRC stuff.
//(void)fprintf(stdout,"Got in. Read %d bytes.\n", bytes_to_read);
//(void)fprintf(stdout,"Data size is %d bytes.\n", actual_bytes_read);
mp3_i->FRAME_DATA_LENGTH = actual_bytes_read;
if (crc_check_frame(data_frame, mp3_i)) {
(void)fprintf(stdout, "crc16 check passed.\n");
return(PASS);
} else {
// I am not sure why I have to do the '& 0xffff' at the end for only
// one crc16 value. Weird.
//(void)fprintf(stderr, "BROKEN_CODE: The crc16 checksum failed. Expected 0x%x, got 0x%x.\n", mp3_i->CRC16_VALUE, mp3_i->CORRECT_CRC16_VALUE & 0xffff);
// Since it doesn't work right yet, I'll leave this disabled.
//return(FAIL);
}
} else {
(void)fprintf(stderr,"File error while trying to read frame into memory.\n");
return(FAIL);
}
} else {
if (!fseek (fp, bytes_to_read, SEEK_CUR)) {
file_info->file_pos += bytes_to_read;
file_info->byte_count += bytes_to_read;
return(PASS);
}
}
} else {
// Walk though the contents by hand if we've got to print the
// contents, or if we're reading from stdin, or if something
// went wrong with fseek().
for (counter = 0 ; counter < bytes_to_read ; counter++) {
if ((unk_char = getc(fp)) != EOF) {
++file_info->file_pos;
++file_info->byte_count;
data_frame[counter] = unk_char;
// This is to keep track of the id3
// tag that is at the end of mp3s.
if (flags->iflag)
rotate_char_array(possible_mp3_tag, &unk_char, file_info);
// Since I know I am in a good frame, print out the data.
// When I am in this function, it doesnt matter if the fflag
// is set.
if (print_to_stdout)
(void) fprintf (stdout, "%c", unk_char );
} else {
return(FAIL);
break;
}
}
}
return(PASS);
}
int
crc_check_frame(data_frame, mp3_i)
char *data_frame;
frame_info *mp3_i;
{
///////////////////////////////////////
// NOTE: This function works correctly
///////////////////////////////////////
// CRC-16 table. Nice and fast.
static short crc_table[] = {
0x0000, 0xC0C1, 0xC181, 0x0140, 0xC301, 0x03C0, 0x0280, 0xC241,
0xC601, 0x06C0, 0x0780, 0xC741, 0x0500, 0xC5C1, 0xC481, 0x0440,
0xCC01, 0x0CC0, 0x0D80, 0xCD41, 0x0F00, 0xCFC1, 0xCE81, 0x0E40,
0x0A00, 0xCAC1, 0xCB81, 0x0B40, 0xC901, 0x09C0, 0x0880, 0xC841,
0xD801, 0x18C0, 0x1980, 0xD941, 0x1B00, 0xDBC1, 0xDA81, 0x1A40,
0x1E00, 0xDEC1, 0xDF81, 0x1F40, 0xDD01, 0x1DC0, 0x1C80, 0xDC41,
0x1400, 0xD4C1, 0xD581, 0x1540, 0xD701, 0x17C0, 0x1680, 0xD641,
0xD201, 0x12C0, 0x1380, 0xD341, 0x1100, 0xD1C1, 0xD081, 0x1040,
0xF001, 0x30C0, 0x3180, 0xF141, 0x3300, 0xF3C1, 0xF281, 0x3240,
0x3600, 0xF6C1, 0xF781, 0x3740, 0xF501, 0x35C0, 0x3480, 0xF441,
0x3C00, 0xFCC1, 0xFD81, 0x3D40, 0xFF01, 0x3FC0, 0x3E80, 0xFE41,
0xFA01, 0x3AC0, 0x3B80, 0xFB41, 0x3900, 0xF9C1, 0xF881, 0x3840,
0x2800, 0xE8C1, 0xE981, 0x2940, 0xEB01, 0x2BC0, 0x2A80, 0xEA41,
0xEE01, 0x2EC0, 0x2F80, 0xEF41, 0x2D00, 0xEDC1, 0xEC81, 0x2C40,
0xE401, 0x24C0, 0x2580, 0xE541, 0x2700, 0xE7C1, 0xE681, 0x2640,
0x2200, 0xE2C1, 0xE381, 0x2340, 0xE101, 0x21C0, 0x2080, 0xE041,
0xA001, 0x60C0, 0x6180, 0xA141, 0x6300, 0xA3C1, 0xA281, 0x6240,
0x6600, 0xA6C1, 0xA781, 0x6740, 0xA501, 0x65C0, 0x6480, 0xA441,
0x6C00, 0xACC1, 0xAD81, 0x6D40, 0xAF01, 0x6FC0, 0x6E80, 0xAE41,
0xAA01, 0x6AC0, 0x6B80, 0xAB41, 0x6900, 0xA9C1, 0xA881, 0x6840,
0x7800, 0xB8C1, 0xB981, 0x7940, 0xBB01, 0x7BC0, 0x7A80, 0xBA41,
0xBE01, 0x7EC0, 0x7F80, 0xBF41, 0x7D00, 0xBDC1, 0xBC81, 0x7C40,
0xB401, 0x74C0, 0x7580, 0xB541, 0x7700, 0xB7C1, 0xB681, 0x7640,
0x7200, 0xB2C1, 0xB381, 0x7340, 0xB101, 0x71C0, 0x7080, 0xB041,
0x5000, 0x90C1, 0x9181, 0x5140, 0x9301, 0x53C0, 0x5280, 0x9241,
0x9601, 0x56C0, 0x5780, 0x9741, 0x5500, 0x95C1, 0x9481, 0x5440,
0x9C01, 0x5CC0, 0x5D80, 0x9D41, 0x5F00, 0x9FC1, 0x9E81, 0x5E40,
0x5A00, 0x9AC1, 0x9B81, 0x5B40, 0x9901, 0x59C0, 0x5880, 0x9841,
0x8801, 0x48C0, 0x4980, 0x8941, 0x4B00, 0x8BC1, 0x8A81, 0x4A40,
0x4E00, 0x8EC1, 0x8F81, 0x4F40, 0x8D01, 0x4DC0, 0x4C80, 0x8C41,
0x4400, 0x84C1, 0x8581, 0x4540, 0x8701, 0x47C0, 0x4680, 0x8641,
0x8201, 0x42C0, 0x4380, 0x8341, 0x4100, 0x81C1, 0x8081, 0x4040
};
register int i = 0;
register short crc = 0;
int size_of_data = mp3_i->FRAME_DATA_LENGTH;
// For testing value of 0x4c44 is returned (correct).
//strcpy(data_frame, "This is a string");
for (i=0 ; i < size_of_data; i++)
crc = ((crc >> 8) & 0xff) ^ crc_table[(crc ^ *data_frame++) & 0xff];
mp3_i->CORRECT_CRC16_VALUE = crc & 0xffff;
if (mp3_i->CRC16_VALUE == mp3_i->CORRECT_CRC16_VALUE)
return(PASS);
else
return(FAIL);
}
int
get_char_from_file(fp, header_value, file_info, flags, possible_mp3_tag)
register FILE *fp;
unsigned int *header_value;
command_flags *flags;
gen_info *file_info;
char *possible_mp3_tag;
{
int step_char = 0;
if ((step_char = getc(fp)) != EOF) {
// This keeps the 32 bit header, and rotates out
// the oldest, and adds a new one.
*header_value = (*header_value << 8) + step_char;
++file_info->file_pos;
++file_info->byte_count;
// This section keeps track of the last 128 Bytes of the stream
// to later check for mp3 tags.
if (flags->iflag)
rotate_char_array(possible_mp3_tag, &step_char, file_info);
return(PASS);
} else
return(FAIL);
}
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