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Generic bitfield handler functions.

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# Conflicts:
#	lib/dtscmeta.cpp
This commit is contained in:
Thulinma 2015-03-03 11:41:17 +01:00
parent aeb3d683a7
commit 2283cf26e3
3 changed files with 165 additions and 77 deletions
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64
lib/bitfields.cpp Normal file
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@ -0,0 +1,64 @@
#include "bitfields.h"
/// Takes a pointer, offset bitcount and data bitcount, returning the unsigned int read from the givens.
/// offsetBits may be > 7, in which case offsetBits / 8 is added to the pointer automatically.
/// This function assumes Most Significant Bits first.
/// If dataBits > 64, only the last 64 bits are returned.
unsigned long long Bit::getMSB(char * pointer, unsigned int offsetBits, unsigned int dataBits){
//If the offset is a whole byte or more, add the whole bytes to the pointer instead.
pointer += offsetBits >> 3;
//The offset is now guaranteed less than a whole byte.
offsetBits &= 0x07;
unsigned long long retVal = 0;
//Now we parse the remaining bytes
while (dataBits){
//Calculate how many bits we're reading from this byte
//We assume all except for the offset
unsigned int curBits = 8 - offsetBits;
//If that is too much, we use the remainder instead
if (curBits > dataBits){
curBits = dataBits;
}
//First, shift the current return value by the amount of bits we're adding
retVal <<= curBits;
//Next, add those bits from the current pointer position at the correct offset, increasing the pointer by one
retVal |= ((int)(*(pointer++)) << offsetBits) >> (8 - curBits);
//Finally, set the offset to zero and remove curBits from dataBits.
offsetBits = 0;
dataBits -= curBits;
}//Loop until we run out of dataBits, then return the result
return retVal;
}
/// Takes a pointer, offset bitcount and data bitcount, setting to given value.
/// offsetBits may be > 7, in which case offsetBits / 8 is added to the pointer automatically.
/// This function assumes Most Significant Bits first.
/// WARNING: UNFINISHED. DO NOT USE.
/// \todo Finish writing this - untested atm.
void Bit::setMSB(char * pointer, unsigned int offsetBits, unsigned int dataBits, unsigned long long value){
//Set the pointer to the last byte we need to be setting
pointer += (offsetBits + dataBits) >> 3;
//The offset is now guaranteed less than a whole byte.
offsetBits = (offsetBits + dataBits) & 0x07;
unsigned long long retVal = 0;
//Now we set the remaining bytes
while (dataBits){
//Calculate how many bits we're setting in this byte
//We assume all that will fit in the current byte
unsigned int curBits = offsetBits;
//If that is too much, we use the remainder instead
if (curBits > dataBits){
curBits = dataBits;
}
//Set the current pointer position at the correct offset, increasing the pointer by one
retVal |= ((int)(*(pointer++)) << offsetBits) >> (8 - curBits);
*pointer = (((*pointer) << offsetBits) >> offsetBits) | ((value & 0xFF) << (8 - offsetBits));
--pointer;
//Finally, shift the current value by the amount of bits we're adding
value >>= offsetBits;
//... and set the offset to eight and remove curBits from dataBits.
offsetBits = 8;
dataBits -= curBits;
}//Loop until we run out of dataBits, then return the result
}

68
lib/bitfields.h Normal file
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@ -0,0 +1,68 @@
namespace Bit{
//bitfield getters
unsigned long long getMSB(char * pointer, unsigned int offsetBits, unsigned int dataBits);
unsigned long long getByName(char * pointer);
//bitfield setters
void setMSB(char * pointer, unsigned int offsetBits, unsigned int dataBits, unsigned long long value);
void setByName(char * pointer);
//Host to binary/binary to host functions - similar to kernel ntoh/hton functions.
/// Retrieves a short in network order from the pointer p.
inline unsigned short btohs(char * p) {
return ((unsigned short)p[0] << 8) | p[1];
}
/// Stores a short value of val in network order to the pointer p.
inline void htobs(char * p, unsigned short val) {
p[0] = (val >> 8) & 0xFF;
p[1] = val & 0xFF;
}
/// Retrieves a long in network order from the pointer p.
inline unsigned long btohl(char * p) {
return ((unsigned long)p[0] << 24) | ((unsigned long)p[1] << 16) | ((unsigned long)p[2] << 8) | p[3];
}
/// Stores a long value of val in network order to the pointer p.
inline void htobl(char * p, unsigned long val) {
p[0] = (val >> 24) & 0xFF;
p[1] = (val >> 16) & 0xFF;
p[2] = (val >> 8) & 0xFF;
p[3] = val & 0xFF;
}
/// Retrieves a long in network order from the pointer p.
inline unsigned long btoh24(char * p) {
return ((unsigned long)p[0] << 16) | ((unsigned long)p[1] << 8) | p[2];
}
/// Stores a long value of val in network order to the pointer p.
inline void htob24(char * p, unsigned long val) {
p[0] = (val >> 16) & 0xFF;
p[1] = (val >> 8) & 0xFF;
p[2] = val & 0xFF;
}
/// Retrieves a long long in network order from the pointer p.
inline unsigned long long btohll(char * p) {
return ((unsigned long long)p[0] << 56) | ((unsigned long long)p[1] << 48) | ((unsigned long long)p[2] << 40) | ((unsigned long long)p[3] << 32) | ((unsigned long)p[4] << 24) | ((unsigned long)p[5] << 16) | ((unsigned long)p[6] << 8) | p[7];
}
/// Stores a long value of val in network order to the pointer p.
inline void htobll(char * p, unsigned long long val) {
p[0] = (val >> 56) & 0xFF;
p[1] = (val >> 48) & 0xFF;
p[2] = (val >> 40) & 0xFF;
p[3] = (val >> 32) & 0xFF;
p[4] = (val >> 24) & 0xFF;
p[5] = (val >> 16) & 0xFF;
p[6] = (val >> 8) & 0xFF;
p[7] = val & 0xFF;
}
}

110
lib/dtscmeta.cpp
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@ -1,52 +1,12 @@
#include "dtsc.h"
#include "defines.h"
#include "bitfields.h"
#include <cstdlib>
#include <cstring>
#include <iomanip>
#define AUDIO_KEY_INTERVAL 5000 ///< This define controls the keyframe interval for non-video tracks, such as audio and metadata tracks.
/// Retrieves a short in network order from the pointer p.
static unsigned short btohs(char * p) {
return ((unsigned short)p[0] << 8) | p[1];
}
/// Stores a short value of val in network order to the pointer p.
static void htobs(char * p, unsigned short val) {
p[0] = (val >> 8) & 0xFF;
p[1] = val & 0xFF;
}
/// Retrieves a long in network order from the pointer p.
static unsigned long btohl(char * p) {
return ((unsigned long)p[0] << 24) | ((unsigned long)p[1] << 16) | ((unsigned long)p[2] << 8) | p[3];
}
/// Stores a long value of val in network order to the pointer p.
static void htobl(char * p, unsigned long val) {
p[0] = (val >> 24) & 0xFF;
p[1] = (val >> 16) & 0xFF;
p[2] = (val >> 8) & 0xFF;
p[3] = val & 0xFF;
}
/// Retrieves a long long in network order from the pointer p.
static unsigned long long btohll(char * p) {
return ((unsigned long long)p[0] << 56) | ((unsigned long long)p[1] << 48) | ((unsigned long long)p[2] << 40) | ((unsigned long long)p[3] << 32) | ((unsigned long)p[4] << 24) | ((unsigned long)p[5] << 16) | ((unsigned long)p[6] << 8) | p[7];
}
/// Stores a long value of val in network order to the pointer p.
static void htobll(char * p, unsigned long long val) {
p[0] = (val >> 56) & 0xFF;
p[1] = (val >> 48) & 0xFF;
p[2] = (val >> 40) & 0xFF;
p[3] = (val >> 32) & 0xFF;
p[4] = (val >> 24) & 0xFF;
p[5] = (val >> 16) & 0xFF;
p[6] = (val >> 8) & 0xFF;
p[7] = val & 0xFF;
}
namespace DTSC {
/// Default constructor for packets - sets a null pointer and invalid packet.
Packet::Packet() {
@ -275,7 +235,7 @@ namespace DTSC {
if (p + 4 >= max) {
return 0;//out of packet!
}
return p + 5 + p[1] * 256 * 256 * 256 + p[2] * 256 * 256 + p[3] * 256 + p[4];
return p + 5 + Bit::btohl(p+1);
}
if (p[0] == DTSC_OBJ || p[0] == DTSC_CON) {
p++;
@ -284,7 +244,7 @@ namespace DTSC {
if (p + 2 >= max) {
return 0;//out of packet!
}
p += 2 + (p[0] * 256 + p[1]);//skip size
p += 2 + Bit::btohs(p);//skip size
//otherwise, search through the contents, if needed, and continue
p = skipDTSC(p, max);
if (!p) {
@ -373,7 +333,7 @@ namespace DTSC {
}
return getInt("time");
}
return ((long long int)ntohl(((int *)(data + 12))[0]) << 32) | ntohl(((int *)(data + 12))[1]);
return Bit::btohll(data + 12);
}
///\brief Returns the track id of the packet.
@ -382,7 +342,7 @@ namespace DTSC {
if (version != DTSC_V2) {
return getInt("trackid");
}
return ntohl(((int *)data)[2]);
return Bit::btohl(data+8);
}
///\brief Returns a pointer to the payload of this packet.
@ -466,7 +426,7 @@ namespace DTSC {
if (i + 2 >= p + len) {
return Scan();//out of packet!
}
unsigned int strlen = i[0] * 256 + i[1];
unsigned int strlen = Bit::btohs(i);
i += 2;
if (ind_len == strlen && strncmp(indice, i, strlen) == 0) {
return Scan(i + strlen, len - (i - p));
@ -522,7 +482,7 @@ namespace DTSC {
if (i + 2 >= p + len) {
return Scan();//out of packet!
}
unsigned int strlen = i[0] * 256 + i[1];
unsigned int strlen = Bit::btohs(i);
i += 2;
arr_indice++;
i = skipDTSC(i + strlen, p + len);
@ -564,7 +524,7 @@ namespace DTSC {
if (i + 2 >= p + len) {
return Scan();//out of packet!
}
unsigned int strlen = i[0] * 256 + i[1];
unsigned int strlen = Bit::btohs(i);
i += 2;
if (arr_indice == num) {
return Scan(i + strlen, len - (i - p));
@ -591,7 +551,7 @@ namespace DTSC {
if (i + 2 >= p + len) {
return "";//out of packet!
}
unsigned int strlen = i[0] * 256 + i[1];
unsigned int strlen = Bit::btohs(i);
i += 2;
if (arr_indice == num) {
return std::string(i, strlen);
@ -641,7 +601,7 @@ namespace DTSC {
long long Scan::asInt() {
switch (getType()) {
case DTSC_INT:
return ((long long int)p[1] << 56) | ((long long int)p[2] << 48) | ((long long int)p[3] << 40) | ((long long int)p[4] << 32) | ((long long int)p[5] << 24) | ((long long int)p[6] << 16) | ((long long int)p[7] << 8) | p[8];
return Bit::btohll(p+1);
case DTSC_STR:
char * str;
unsigned int strlen;
@ -685,7 +645,7 @@ namespace DTSC {
switch (getType()) {
case DTSC_STR:
result = p + 5;
strlen = p[1] * 256 * 256 * 256 + p[2] * 256 * 256 + p[3] * 256 + p[4];
strlen = Bit::btohl(p+1);
return;
default:
result = 0;
@ -759,7 +719,7 @@ namespace DTSC {
std::string Scan::toPrettyString(unsigned int indent) {
switch (getType()) {
case DTSC_STR: {
unsigned int strlen = p[1] * 256 * 256 * 256 + p[2] * 256 * 256 + p[3] * 256 + p[4];
unsigned int strlen = Bit::btohl(p+1);
if (strlen > 250) {
std::stringstream ret;
ret << "\"" << strlen << " bytes of data\"";
@ -790,7 +750,7 @@ namespace DTSC {
ret << "," << std::endl;
}
first = false;
unsigned int strlen = i[0] * 256 + i[1];
unsigned int strlen = Bit::btohs(i);
i += 2;
ret << std::string((size_t)indent, ' ') << "\"" << std::string(i, strlen) << "\": " << Scan(i + strlen, len - (i - p)).toPrettyString(indent);
i = skipDTSC(i + strlen, p + len);
@ -834,34 +794,32 @@ namespace DTSC {
///\brief Returns the payloadsize of a part
long Part::getSize() {
return ((long)data[0] << 16) | ((long)data[1] << 8) | data[2];
return Bit::btoh24(data);
}
///\brief Sets the payloadsize of a part
void Part::setSize(long newSize) {
data[0] = (newSize & 0xFF0000) >> 16;
data[1] = (newSize & 0x00FF00) >> 8;
data[2] = (newSize & 0x0000FF);
Bit::htob24(data, newSize);
}
///\brief Retruns the duration of a part
short Part::getDuration() {
return btohs(data + 3);
return Bit::btohs(data + 3);
}
///\brief Sets the duration of a part
void Part::setDuration(short newDuration) {
htobs(data + 3, newDuration);
Bit::htobs(data + 3, newDuration);
}
///\brief returns the offset of a part
long Part::getOffset() {
return btohl(data + 5);
return Bit::btohl(data + 5);
}
///\brief Sets the offset of a part
void Part::setOffset(long newOffset) {
htobl(data + 5, newOffset);
Bit::htobl(data + 5, newOffset);
}
///\brief Returns the data of a part
@ -890,43 +848,41 @@ namespace DTSC {
}
unsigned long Key::getLength() {
return ((data[5] << 16) | (data[6] << 8) | data[7]);
return Bit::btoh24(data+5);
}
void Key::setLength(unsigned long newLength) {
data[7] = newLength & 0xFF;
data[6] = (newLength >> 8) & 0xFF;
data[5] = (newLength >> 16) & 0xFF;
Bit::htob24(data+5, newLength);
}
///\brief Returns the number of a keyframe
unsigned long Key::getNumber() {
return btohs(data + 8);
return Bit::btohs(data + 8);
}
///\brief Sets the number of a keyframe
void Key::setNumber(unsigned long newNumber) {
htobs(data + 8, newNumber);
Bit::htobs(data + 8, newNumber);
}
///\brief Returns the number of parts of a keyframe
unsigned short Key::getParts() {
return btohs(data + 10);
return Bit::btohs(data + 10);
}
///\brief Sets the number of parts of a keyframe
void Key::setParts(unsigned short newParts) {
htobs(data + 10, newParts);
Bit::htobs(data + 10, newParts);
}
///\brief Returns the timestamp of a keyframe
unsigned long long Key::getTime() {
return btohl(data + 12);
return Bit::btohl(data + 12);
}
///\brief Sets the timestamp of a keyframe
void Key::setTime(unsigned long long newTime) {
htobl(data + 12, newTime);
Bit::htobl(data + 12, newTime);
}
///\brief Returns the data of this keyframe struct
@ -943,12 +899,12 @@ namespace DTSC {
///\brief Returns the duration of this fragment
unsigned long Fragment::getDuration() {
return btohl(data);
return Bit::btohl(data);
}
///\brief Sets the duration of this fragment
void Fragment::setDuration(unsigned long newDuration) {
htobl(data, newDuration);
Bit::htobl(data, newDuration);
}
///\brief Returns the length of this fragment
@ -963,22 +919,22 @@ namespace DTSC {
///\brief Returns the number of the first keyframe in this fragment
unsigned long Fragment::getNumber() {
return btohs(data + 5);
return Bit::btohs(data + 5);
}
///\brief Sets the number of the first keyframe in this fragment
void Fragment::setNumber(unsigned long newNumber) {
htobs(data + 5, newNumber);
Bit::htobs(data + 5, newNumber);
}
///\brief Returns the size of a fragment
unsigned long Fragment::getSize() {
return btohl(data + 7);
return Bit::btohl(data + 7);
}
///\brief Sets the size of a fragement
void Fragment::setSize(unsigned long newSize) {
htobl(data + 7, newSize);
Bit::htobl(data + 7, newSize);
}
///\brief Returns thte data of this fragment structure