Utilities

Utilities — Various helper and utility functions.

Functions

#define MIRAGE_CAST_DATA()
#define MIRAGE_CAST_PTR()
guint8 mirage_helper_ascii2isrc ()
gint mirage_helper_bcd2hex ()
guint16 mirage_helper_calculate_crc16 ()
guint32 mirage_helper_calculate_crc32_fast ()
guint32 mirage_helper_calculate_crc32_standard ()
MirageSectorType mirage_helper_determine_sector_type ()
const gchar * mirage_helper_encoding_from_bom ()
gchar * mirage_helper_find_data_file ()
const gchar * mirage_helper_get_suffix ()
gboolean mirage_helper_has_suffix ()
gint mirage_helper_hex2bcd ()
guint16 * mirage_helper_init_crc16_lut ()
guint32 * mirage_helper_init_crc32_lut ()
guint8 * mirage_helper_init_ecma_130b_scrambler_lut ()
gchar mirage_helper_isrc2ascii ()
void mirage_helper_lba2msf ()
gchar * mirage_helper_lba2msf_str ()
gint mirage_helper_msf2lba ()
gint mirage_helper_msf2lba_str ()
void mirage_helper_sector_edc_ecc_compute_ecc_block ()
void mirage_helper_sector_edc_ecc_compute_edc_block ()
gint mirage_helper_strcasecmp ()
gint mirage_helper_strncasecmp ()
gchar * mirage_helper_format_string ()
gchar * mirage_helper_format_stringd ()
gchar * mirage_helper_format_stringv ()
void mirage_helper_subchannel_deinterleave ()
void mirage_helper_subchannel_interleave ()
guint16 mirage_helper_subchannel_q_calculate_crc ()
void mirage_helper_subchannel_q_decode_isrc ()
void mirage_helper_subchannel_q_decode_mcn ()
void mirage_helper_subchannel_q_encode_isrc ()
void mirage_helper_subchannel_q_encode_mcn ()
gboolean mirage_helper_validate_isrc ()

Types and Values

Includes

#include <mirage-utils.h>

Description

These functions cover various functionality. They are exported because, while primarily designed to be used within libMirage, they could also prove useful to other applications.

Functions

MIRAGE_CAST_DATA()

#define MIRAGE_CAST_DATA(buf,off,type) (*((type *)(buf+off)))

A macro for easy retrieval of data from (unsigned integer) buffer. Mostly to be used in binary image parsers, for example, to retrieve guint32 or guint16 value from buffer.

Parameters

buf

buffer to get data from

 

off

offset in buffer at which to get data

 

type

data type (i.e. 'guint64')

 

MIRAGE_CAST_PTR()

#define MIRAGE_CAST_PTR(buf,off,type) ((type)(buf+off))

A macro for easy placing of pointers within (unsigned integer) buffer. Mostly to be used in binary image parsers, for example, to retrieve a string or a structure from buffer.

Parameters

buf

buffer to place pointer in

 

off

offset in buffer at which to place pointer

 

type

pointer type (i.e. 'gchar *')

 

mirage_helper_ascii2isrc ()

guint8
mirage_helper_ascii2isrc (gchar c);

Converts ASCII character c into ISRC character.

Parameters

c

ASCII character.

[in]

Returns

ISRC character


mirage_helper_bcd2hex ()

gint
mirage_helper_bcd2hex (gint bcd);

Converts bcd-encoded integer into hex-encoded integer.

Parameters

bcd

bcd-encoded integer.

[in]

Returns

hex-encoded integer


mirage_helper_calculate_crc16 ()

guint16
mirage_helper_calculate_crc16 (const guint8 *data,
                               guint length,
                               const guint16 *crctab,
                               gboolean reflected,
                               gboolean invert);

Calculates the CRC-16 checksum of the data stored in data .

Parameters

data

buffer containing data.

[in][array length=length]

length

length of data.

[in]

crctab

pointer to CRC polynomial table.

[in][array fixed-size=256]

reflected

whether to use the reflected algorithm.

[in]

invert

whether the result should be inverted.

[in]

Returns

CRC-16 checksum of data


mirage_helper_calculate_crc32_fast ()

guint32
mirage_helper_calculate_crc32_fast (const guint8 *data,
                                    guint length,
                                    const guint32 *crctab,
                                    gboolean reflected,
                                    gboolean invert);

Calculates the CRC-32 checksum of the data stored in data . This is fast slice-by-8 implementation that processes 8 bytes at a time, and requires crctab to be allocating using mirage_helper_init_crc32_lut() with slice parameter set to 8.

Parameters

data

buffer containing data.

[in][array length=length]

length

length of data.

[in]

crctab

pointer to CRC polynomial table.

[in][array fixed-size=2048]

reflected

whether to use the reflected algorithm.

[in]

invert

whether the initial value and result should be inverted.

[in]

Returns

CRC-32 checksum of data


mirage_helper_calculate_crc32_standard ()

guint32
mirage_helper_calculate_crc32_standard
                               (const guint8 *data,
                                guint length,
                                const guint32 *crctab,
                                gboolean reflected,
                                gboolean invert);

Calculates the CRC-32 checksum of the data stored in data . This is standard inplementation that processes 1 byte at a time, and requires crctab to be allocated using mirage_helper_init_crc32_lut() with slice parameter set to 1.

Parameters

data

buffer containing data.

[in][array length=length]

length

length of data.

[in]

crctab

pointer to CRC polynomial table.

[in][array fixed-size=256]

reflected

whether to use the reflected algorithm.

[in]

invert

whether the initial value and result should be inverted.

[in]

Returns

CRC-32 checksum of data


mirage_helper_determine_sector_type ()

MirageSectorType
mirage_helper_determine_sector_type (const guint8 *buf);

Determines sector type from its data, based on first 16 bytes, which correspond to sync pattern and header.

This function is intened to be used in image parsers, for determining track mode in cases when full (2352-byte) sector data is available.

Parameters

buf

buffer containing at least first 16 bytes of sector's data.

[in]

Returns

sector type (one of MirageSectorType)


mirage_helper_encoding_from_bom ()

const gchar *
mirage_helper_encoding_from_bom (const guint8 *buffer);

Tries to decode BOM provided in buffer , and based on the result returns the following encodings: UTF-32BE, UTF32-LE, UTF-16LE, UTF-16BE or UTF-8 (if BOM is not valid).

Parameters

buffer

a 4-byte buffer containing BOM.

[in][transfer none][array fixed-size=4]

Returns

the name of encoding, or NULL if UTF-8 is assumed. The string is statically stored and should not be modified.

[transfer none]


mirage_helper_find_data_file ()

gchar *
mirage_helper_find_data_file (const gchar *filename,
                              const gchar *path);

Attempts to find a file with filename filename and path path . filename can be file's basename or an absolute path. path can be either directory path (in this case, it must end with '/') or a filename (i.e. of file descriptor).

If filename is an absolute path, its existence is first checked. If it does not exist, search (see below) is performed in filename 's dirname. If still no match is found and path is not NULL, path 's dirname is combined with filename 's basename, and the combination's existence is checked. If that fails as well, search (see below) is performed in path 's dirname. Searching in the directory is performed as follows. Directory is opened and its content is case-insensitively compared to filename 's basename. All filenames whose beginning match filename are considered, and the shortest one is returned. This way, all possible case variations (i.e. file.iso, FILE.ISO, FiLe.IsO, etc.) are taken into account. This function can return a filename with additional suffices, but only if a file without those extra suffices does not exist. E.g., if search is done for 'data.img', and only 'data.img.gz' exists, it will be returned. However, if both 'data.img' and 'data.img.gz' exist, the former will be returned. The returned string should be freed when no longer needed.

Parameters

filename

declared filename.

[in]

path

path where to look for file (can be a filename), or NULL.

[in][allow-none]

Returns

a newly allocated string containing the fullpath of file, or NULL.


mirage_helper_get_suffix ()

const gchar *
mirage_helper_get_suffix (const gchar *filename);

Retrieves suffix from filename .

Parameters

filename

filename.

[in]

Returns

pointer to character in filename at which the suffix starts.

[transfer none]


mirage_helper_has_suffix ()

gboolean
mirage_helper_has_suffix (const gchar *filename,
                          const gchar *suffix);

Checks whether file name filename ends with suffix suffix .

Parameters

filename

filename.

[in]

suffix

suffix.

[in]

Returns

TRUE if filename contains suffix suffix , FALSE if not


mirage_helper_hex2bcd ()

gint
mirage_helper_hex2bcd (gint hex);

Converts hex-encoded integer into bcd-encoded integer.

Parameters

hex

hex-encoded integer.

[in]

Returns

bcd-encoded integer


mirage_helper_init_crc16_lut ()

guint16 *
mirage_helper_init_crc16_lut (guint16 genpoly);

Calculates a look-up table for CRC16 based on the generator polynomial.

Parameters

genpoly

generator polynomial.

[in]

Returns

Pointer to the CRC16 look-up table or NULL on failure.


mirage_helper_init_crc32_lut ()

guint32 *
mirage_helper_init_crc32_lut (guint32 genpoly,
                              guint slices);

Calculates a look-up table for CRC32 based on the generator polynomial. The size of the lookup table depends on slices . The standard algorithm processes 1 byte at a time and has a look-up table size of 1KiB, whereas The slice-by-4 and slice-by-8 algorithms use 4 and 8 KiB look-up tables that are derived from the initial look-up table.

Parameters

genpoly

generator polynomial.

[in]

slices

number of bytes to process at once.

[in]

Returns

Pointer to the CRC32 look-up table or NULL on failure.


mirage_helper_init_ecma_130b_scrambler_lut ()

guint8 *
mirage_helper_init_ecma_130b_scrambler_lut
                               (void);

Calculates a look-up table for sector data scrambler from ECMA-130, Annex B. The look-up table consists of 2340 entries, each being a scramble byte for corresponding byte in sector data.

Returns

Pointer to the generated scrambler look-up table or NULL on failure.


mirage_helper_isrc2ascii ()

gchar
mirage_helper_isrc2ascii (guint8 c);

Converts ISRC character c into ASCII character.

Parameters

c

ISRC character.

[in]

Returns

ACSII character


mirage_helper_lba2msf ()

void
mirage_helper_lba2msf (gint lba,
                       gboolean diff,
                       guint8 *m,
                       guint8 *s,
                       guint8 *f);

Converts LBA sector address stored in lba into MSF address, storing each field into m , s and f , respectively.

If diff is TRUE, 150 frames difference is accounted for; this should be used when converting absolute addresses. When converting relative addresses (or lengths), diff should be set to FALSE.

Parameters

lba

LBA address.

[in]

diff

account for the difference.

[in]

m

location to store minutes, or NULL.

[out][allow-none]

s

location to store seconds, or NULL.

[out][allow-none]

f

location to store frames, or NULL.

[out][allow-none]

mirage_helper_lba2msf_str ()

gchar *
mirage_helper_lba2msf_str (gint lba,
                           gboolean diff);

Converts LBA sector address stored in lba into MSF address.

If diff is TRUE, 150 frames difference is accounted for; this should be used when converting absolute addresses. When converting relative addresses (or lengths), diff should be set to FALSE.

Parameters

lba

LBA address.

[in]

diff

account for the difference.

[in]

Returns

a newly-allocated string containing MSF address; it should be freed with g_free() when no longer needed.


mirage_helper_msf2lba ()

gint
mirage_helper_msf2lba (guint8 m,
                       guint8 s,
                       guint8 f,
                       gboolean diff);

Converts MSF sector address stored in m , s and f into LBA address.

If diff is TRUE, 150 frames difference is accounted for; this should be used when converting absolute addresses. When converting relative addresses (or lengths), diff should be set to FALSE.

Parameters

m

minutes.

[in]

s

seconds.

[in]

f

frames.

[in]

diff

difference.

[in]

Returns

integer representing LBA address


mirage_helper_msf2lba_str ()

gint
mirage_helper_msf2lba_str (const gchar *msf,
                           gboolean diff);

Converts MSF sector address stored in msf string into LBA address.

If diff is TRUE, 150 frames difference is accounted for; this should be used when converting absolute addresses. When converting relative addresses (or lengths), diff should be set to FALSE.

Parameters

msf

MSF string.

[in]

diff

difference.

[in]

Returns

integer representing LBA address or -1 on failure.


mirage_helper_sector_edc_ecc_compute_ecc_block ()

void
mirage_helper_sector_edc_ecc_compute_ecc_block
                               (const guint8 *src,
                                guint32 major_count,
                                guint32 minor_count,
                                guint32 major_mult,
                                guint32 minor_inc,
                                guint8 *dest);

Calculates ECC (error correction code) for data in src and writes the result into dest . The code assumes 2352 byte sectors. It can calculate both P and Q layer of ECC data, depending on major_count , minor_count , major_mult and minor_inc.

To calculate ECC (first P, then Q layer) for different types of sectors and store it into sector data, use:

  • Mode 1 sector:
    mirage_helper_sector_edc_ecc_compute_ecc_block(sector_buffer+0xC, 86, 24, 2, 86, sector_buffer+0x81C);
    mirage_helper_sector_edc_ecc_compute_ecc_block(sector_buffer+0xC, 52, 43, 86, 88, sector_buffer+0x8C8);
    
  • Mode 2 Form 1 sector:
    mirage_helper_sector_edc_ecc_compute_ecc_block(sector_buffer+0xC, 86, 24, 2, 86, sector_buffer+0x81C); \n
    mirage_helper_sector_edc_ecc_compute_ecc_block(sector_buffer+0xC, 52, 43, 86, 88, sector_buffer+0x8C8);
    

(This is assuming all other sector data, including EDC, is already stored in sector_buffer and that sector_buffer is 2532 bytes long)

Parameters

src

data to calculate ECC data for.

[in]

major_count

major count.

[in]

minor_count

minor count.

[in]

major_mult

major multiplicator.

[in]

minor_inc

minor increment.

[in]

dest

buffer to write calculated ECC data into.

[out caller-allocates]

mirage_helper_sector_edc_ecc_compute_edc_block ()

void
mirage_helper_sector_edc_ecc_compute_edc_block
                               (const guint8 *src,
                                guint16 size,
                                guint8 *dest);

Calculates EDC (error detection code) for data in src of length size and writes the result into dest .

To calculate EDC for different types of sectors and store it into sector data, use:

  • Mode 1 sector:
    mirage_helper_sector_edc_ecc_compute_edc_block(sector_buffer+0x00, 0x810, sector_buffer+0x810);
    
  • Mode 2 Form 1 sector:
    mirage_helper_sector_edc_ecc_compute_edc_block(sector_buffer+0x10, 0x808, sector_buffer+0x818);
    
  • Mode 2 Form 2 sector:
    mirage_helper_sector_edc_ecc_compute_edc_block(sector_buffer+0x10, 0x91C, sector_buffer+0x92C);
    

(This is assuming all other sector data is already stored in sector_buffer and that sector_buffer is 2532 bytes long)

Parameters

src

data to calculate EDC data for.

[in][array length=size]

size

size of data in src .

[in]

dest

buffer to write calculated EDC data into (4 bytes).

[out caller-allocates][array fixed-size=4]

mirage_helper_strcasecmp ()

gint
mirage_helper_strcasecmp (const gchar *str1,
                          const gchar *str2);

Replacement function for g_strcasecmp/strcasecmp, which can properly handle UTF-8. Glib docs state this is only an approximation, albeit it should be a fairly good one.

It compares the two strings str1 and str2 , ignoring the case of the characters. It returns an integer less than, equal to, or greater than zero if str1 is found, respectively, to be less than, to match, or be greater than str2 .

Parameters

str1

first string.

[in]

str2

second string.

[in]

Returns

an integer less than, equal to, or greater than zero if str1 is found, respectively, to be less than, to match, or be greater than str2 .


mirage_helper_strncasecmp ()

gint
mirage_helper_strncasecmp (const gchar *str1,
                           const gchar *str2,
                           gint len);

Replacement function for g_strncasecmp/strncasecmp, which can properly handle UTF-8. Glib docs state this is only an approximation, albeit it should be a fairly good one.

It compares first len characters of string str1 and str2 , ignoring the case of the characters. It returns an integer less than, equal to, or greater than zero if first len characters of str1 is found, respectively, to be less than, to match, or be greater than first len characters of str2 .

Parameters

str1

first string.

[in]

str2

second string.

[in]

len

length of string to compare.

[in]

Returns

an integer less than, equal to, or greater than zero if first len characters of str1 is found, respectively, to be less than, to match, or be greater than first len characters of str2 .


mirage_helper_format_string ()

gchar *
mirage_helper_format_string (const gchar *format,
                             ...);

General-purpose string formatter with token replacement. Similarly to sprintf, the tokens begin with percent character, but instead of denoting format type, the tokens denote placeholders for user-defined replacements. Sprintf-like field width and precision modifiers are supported for formatting the replacements. If replacement is not specified for a replacement token found in format, then the token is removed in the output string.

If replacement does not exist and the token to be replaced is preceded by other word-caracters (see GRegex documentation for details), in addition to the replacement token, all those word characters are removed together with the leading non-word character.

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// Example: formatting a filename
output = mirage_helper_format_string("%b-%02s-track%t.%e",
    "b", g_variant_new_string("some_image"),
    "s", g_variant_new_int16(1),
    "t", g_variant_new_int16(3),
    "e", g_variant_new_string("iso"), NULL);
// output = "some_image-01-track3.iso"

// Example: removal of preceding characters when replacement does not exist
output = mirage_helper_format_string("%b-%02s-track%t.%e",
    "b", g_variant_new_string("some_image"),
    "s", g_variant_new_int16(1),
    "e", g_variant_new_string("iso"), NULL);
// output = "some_image-01.iso"

Varargs is a NULL-terminated list of replacement token/value pairs, where a replacement token/value pair is a pair of string and a GVariant.

Parameters

format

format string.

[in]

...

NULL-terminated list of replacement token/value pairs.

[in]

Returns

string with all replacement tokens either replaced or removed. The string should be freed using g_free() when no longer needed.

[transfer full]


mirage_helper_format_stringd ()

gchar *
mirage_helper_format_stringd (const gchar *format,
                              GHashTable *dictionary);

Dictionary-version of mirage_helper_format_string().

dictionary is a GHashTable where keys are replacement token strings and each value is a GVariant containing corresponding token replacement value.

Parameters

format

format string.

[in]

dictionary

a GHashTable containing replacement token/value pairs.

[in]

Returns

string with all replacement tokens either replaced or removed. The string should be freed using g_free() when no longer needed.

[transfer full]


mirage_helper_format_stringv ()

gchar *
mirage_helper_format_stringv (const gchar *format,
                              va_list args);

Variable-argument-list-version of mirage_helper_format_string().

args is a NULL-terminated list of replacement token/value pairs, where a replacement token/value pair is a pair of string and a GVariant.

Parameters

format

format string.

[in]

args

NULL-terminated list of replacement token/value pairs.

[in]

Returns

string with all replacement tokens either replaced or removed. The string should be freed using g_free() when no longer needed.

[transfer full]


mirage_helper_subchannel_deinterleave ()

void
mirage_helper_subchannel_deinterleave (gint subchan,
                                       const guint8 *channel96,
                                       guint8 *channel12);

Deinterleaves subchannel data of type subchan from subchannel data stored in channel96 and writes the resulting subhcannel data into subchannel12 .

Parameters

subchan

subchannel type.

[in]

channel96

buffer containing subchannel data to deinterleave (96 bytes).

[in][array fixed-size=96]

channel12

buffer to deinterleave subchannel data into (12 bytes).

[out caller-allocates][array fixed-size=12]

mirage_helper_subchannel_interleave ()

void
mirage_helper_subchannel_interleave (gint subchan,
                                     const guint8 *channel12,
                                     guint8 *channel96);

Interleaves subchannel data of type subchan stored in channel12 into subchannel data stored in subchannel96 .

Parameters

subchan

subchannel type.

[in]

channel12

buffer containing subchannel data to interleave (12 bytes).

[in][array fixed-size=12]

channel96

buffer to interleave subchannel data into (96 bytes).

[out caller-allocates][array fixed-size=96]

mirage_helper_subchannel_q_calculate_crc ()

guint16
mirage_helper_subchannel_q_calculate_crc
                               (const guint8 *data);

Calculates the CRC-16 checksum of the Q subchannel data stored in data .

Parameters

data

buffer containing Q subchannel data (10 bytes).

[in][array fixed-size=10]

Returns

CRC-16 checksum of Q subchannel data


mirage_helper_subchannel_q_decode_isrc ()

void
mirage_helper_subchannel_q_decode_isrc
                               (const guint8 *buf,
                                gchar *isrc);

Decodes ISRC stored in buf into string isrc .

Parameters

buf

buffer containing encoded ISRC (8 bytes).

[in][array fixed-size=8]

isrc

string to decode ISRC into (12 bytes).

[out caller-allocates][array fixed-size=12]

mirage_helper_subchannel_q_decode_mcn ()

void
mirage_helper_subchannel_q_decode_mcn (const guint8 *buf,
                                       gchar *mcn);

Decodes MCN stored in buf into string mcn .

Parameters

buf

buffer containing encoded MCN (7 bytes).

[in][array fixed-size=7]

mcn

string to decode MCN into (13 bytes).

[out caller-allocates][array fixed-size=13]

mirage_helper_subchannel_q_encode_isrc ()

void
mirage_helper_subchannel_q_encode_isrc
                               (guint8 *buf,
                                const gchar *isrc);

Encodes ISRC string isrc into buffer buf .

Parameters

buf

buffer to encode ISRC into (8 bytes).

[out caller-allocates][array fixed-size=8]

isrc

ISRC string (12 bytes).

[in][array fixed-size=12]

mirage_helper_subchannel_q_encode_mcn ()

void
mirage_helper_subchannel_q_encode_mcn (guint8 *buf,
                                       const gchar *mcn);

Encodes MCN string mcn into buffer buf .

Parameters

buf

buffer to encode MCN into (7 bytes).

[out caller-allocates][array fixed-size=7]

mcn

MCN string (13 bytes).

[in][array fixed-size=13]

mirage_helper_validate_isrc ()

gboolean
mirage_helper_validate_isrc (const gchar *isrc);

Performs a limited validation of an ISRC string.

Parameters

isrc

An ASCII encoded ISRC string.

[in][array fixed-size=12]

Returns

TRUE or FALSE

Types and Values

enum MirageSubChannel

Subchannel type for interleaving/deinterleaving.

Members

SUBCHANNEL_W

W subchannel data

 

SUBCHANNEL_V

V subchannel data

 

SUBCHANNEL_U

U subchannel data

 

SUBCHANNEL_T

T subchannel data

 

SUBCHANNEL_S

S subchannel data

 

SUBCHANNEL_R

R subchannel data

 

SUBCHANNEL_Q

Q subchannel data

 

SUBCHANNEL_P

P subchannel data