int pfm_readpfm_size(FILE *fp,
int *cols, int *rows)
{
char buffer[1024];
pfmGeoRead_=0;
if (pfmCommentRead_) free(pfmCommentRead_);
pfmCommentRead_=0;
pfmGeoSet_=0;
pfmComment_=0;
fp=check_compression(buffer,fp);
#ifdef DEBUG
printf("pfm_readpfm_size: %s\n",buffer);
#endif
if (!((buffer[0]=='F' && buffer[1]>='0' && buffer[1]<='7')
|| (buffer[0]=='P' && buffer[1]>='1' && buffer[1]<='6'))) {
fprintf(stderr,"pfm_readpfm: Wrong fileformat! (F)\n");
fp=stop_decompression(fp);
return 0;
}
read_buffer(buffer,1023,fp);
fgets(buffer,1023,fp);
sscanf(buffer,"%d %d",cols,rows);
fp=stop_decompression(fp);
return 1;
}
/*
* The main procedure is similar to the main found in ARITH1E.C. It has
* to initialize the coder and the model. It then sits in a loop reading
* input symbols and encoding them. One difference is that every 256
* symbols a compression check is performed. If the compression ratio
* falls below 10%, a flush character is encoded. This flushes the encod
* ing model, and will cause the decoder to flush its model when the
* file is being expanded. The second difference is that each symbol is
* repeatedly encoded until a successful encoding occurs. When trying to
* encode a character in a particular order, the model may have to
* transmit an ESCAPE character. If this is the case, the character has
* to be retransmitted using a lower order. This process repeats until a
* successful match is found of the symbol in a particular context.
* Usually this means going down no further than the order -1 model.
* However, the FLUSH and DONE symbols drop back to the order -2 model.
*
*/
void CompressFile(FILE *input,BIT_FILE *output,int argc,char *argv[])
{
SYMBOL s;
int c;
int escaped;
int flush = 0;
long int text_count = 0;
initialize_options( argc, argv );
initialize_model();
initialize_arithmetic_encoder();
for ( ; ; ) {
if ( ( ++text_count & 0x0ff ) == 0 )
flush = check_compression( input, output );
if ( !flush )
c = getc( input );
else
c = FLUSH;
if ( c == EOF )
c = DONE;
do {
escaped = convert_int_to_symbol( c, &s);
encode_symbol( output, &s );
} while ( escaped );
if ( c == DONE )
break;
if ( c == FLUSH ) {
flush_model();
flush = 0;
}
update_model( c );
add_character_to_model( c );
}
flush_arithmetic_encoder( output );
}
static int bmp_checking(const struct bmp_type* img, const unsigned int in_size, const unsigned int max_size)
{
if (!check_version(img))
{
fprintf(stderr,"Wrong BMP version (stegobmp only supports BMPv3\n");
return WRONG_VERSION_ERR;
}
if (in_size > max_size)
{
fprintf(stderr,"The chosen image is too small to contain the message (of size %i bytes whereas maximum file size usable with this image is %i bytes)\n",in_size,max_size);
return TOO_SMALL_ERR;
}
if (!check_compression(img))
{
fprintf(stderr,"stegobmp doesn't support compressed bmp\n");
return COMPRESSED_ERR;
}
return 0;
}
void *pfm_readpfm_type(FILE *fp,
int *cols,
int *rows,
float *minval,
float *maxval,
int storageType,
PFMConvert *convFunc)
{
/* int compressed;*/
void *ret_val;
char buffer[1024];
char *data=0;
float *floatbuffer=0;
double *doublebuffer=0;
int *intbuffer=0;
uint16 *int16buffer=0;
grey *greybuffer=0;
PFM3Byte *ppmbuffer=0;
int byte_order=BYTEORDER;
int r,c;
int type;
int storage_size[]={
sizeof(float),
sizeof(signed int),
sizeof(unsigned int),
sizeof(sint16),
sizeof(uint16),
sizeof(grey),
sizeof(unsigned char),
sizeof(unsigned char),
sizeof(double)
};
ConvertFunc* double2[]={
double2float,
double2sint,
double2sint,
double2uint16,
double2uint16,
0,0,0,
double2double,
0};
ConvertFunc* float2[]={
float2float,
float2sint,
float2sint,
float2uint16,
float2uint16,
0,0,0,
float2double,
0};
ConvertFunc* uint162[]={
uint162float,
uint162sint,
uint162sint,
uint162uint16,
uint162uint16,
0,0,0,
uint162double,
0};
ConvertFunc* sint2[]={
sint2float,
sint2sint,
sint2sint,
sint2uint16,
sint2uint16,
0,0,0,
sint2double,
0};
ConvertFunc* pgm2[]={
pgm2float,
pgm2sint,
pgm2sint,
pgm2uint16,
pgm2uint16,
pgm2pgm,
0,0,
pgm2double,
0};
ConvertFunc* pbm2[]={
0,0,0,0,0,0,0,0,0,0
};
memset(buffer, 0, 1024);
pfmGeoRead_=0;
if (pfmCommentRead_) free(pfmCommentRead_);
pfmCommentRead_=0;
pfmGeoSet_=0;
fp=check_compression(buffer,fp);
#ifdef DEBUG
printf("pfm_readpfm: %s\n",buffer);
#endif
switch (buffer[0]) {
case 'F':
switch (buffer[1]) {
case '0':
type=PFM_FLOAT_ASCII;
break;
case '1':
type=PFM_INT_ASCII;
break;
case '2':
type=PFM_INT16_ASCII;
break;
case '3':
type=PFM_DOUBLE_ASCII;
break;
case '4':
type=PFM_FLOAT_BIN;
break;
case '5':
type=PFM_INT_BIN;
break;
case '6':
type=PFM_INT16_BIN;
break;
case '7':
type=PFM_DOUBLE_BIN;
break;
default:
fprintf(stderr,"pfm_readpfm: Wrong fileformat!\n");
ret_val=0;
goto exit_read_pfm;
}
break;
case 'P':
switch (buffer[1]) {
case '1':
type=PFM_PBM_ASCII;
break;
case '2':
type=PFM_PGM_ASCII;
break;
case '3':
type=PFM_PPM_ASCII;
break;
case '4':
type=PFM_PBM_BIN;
break;
case '5':
type=PFM_PGM_BIN;
break;
case '6':
type=PFM_PPM_BIN;
break;
default:
fprintf(stderr,"pfm_readpfm: Wrong fileformat!\n");
ret_val=0;
goto exit_read_pfm;
}
break;
default:
{
fprintf(stderr,"pfm_readpfm: Wrong fileformat!\n");
ret_val=0;
goto exit_read_pfm;
}
}
if ((type>=PFM_FLOAT_BIN) && (type<=PFM_DOUBLE_BIN))
{
read_buffer(buffer,1023,fp);
#ifdef DEBUG
printf("pfm_readpfm: %s\n",buffer);
#endif
if (buffer[0] == 'L') {
byte_order=PFM_LittleEndian;
}
else {
byte_order=PFM_BigEndian;
}
}
read_buffer(buffer,1023,fp);
#ifdef DEBUG
printf("pfm_readpfm: %s\n",buffer);
#endif
sscanf(buffer,"%d %d",cols,rows);
read_buffer(buffer,1023,fp);
#ifdef DEBUG
printf("pfm_readpfm: %s\n",buffer);
#endif
pfm_mult=0.0;
pfm_offset=0.0;
if (sscanf(buffer,"%f %f %f %f",minval,maxval,&pfm_mult,&pfm_offset)<2) {
*maxval=*minval;
*minval=0.0;
}
if (type==PFM_PGM_BIN && *maxval>255) {
type=PFM_INT16_BIN;
byte_order=PFM_BigEndian;
}
if (type==PFM_PGM_ASCII && *maxval>255 && *maxval<=65535) {
type=PFM_INT16_ASCII;
byte_order=PFM_BigEndian;
}
if (pfm_mult!=0.0) convFunc=StretchConvert;
#ifdef DEBUG
printf("pfm_readpfm: cols=%d rows=%d min=%f max=%f byte_order=%s\n",
*cols,*rows,*minval,*maxval,(byte_order==PFM_BigEndian ? "BE" : "LE"));
#endif
if (type==PFM_PPM_BIN) {
ppmbuffer=(PFM3Byte*)malloc(sizeof(PFM3Byte));
ppmbuffer->r=(unsigned char*)calloc(*cols*(*rows),storage_size[storageType]);
ppmbuffer->g=(unsigned char*)calloc(*cols*(*rows),storage_size[storageType]);
ppmbuffer->b=(unsigned char*)calloc(*cols*(*rows),storage_size[storageType]);
if (ppmbuffer && ppmbuffer->r && ppmbuffer->g && ppmbuffer->b)
data=(void*)ppmbuffer;
}
else data =(void*)calloc(*cols*(*rows),storage_size[storageType]);
if (!data)
{
fprintf(stderr,"pfm_readpfm: Out of memory while allocating input buffer!\n");
ret_val=0;
goto exit_read_pfm;
}
switch (type)
{
case PFM_FLOAT_ASCII:
if (!float2[storageType]) {
fprintf(stderr,"pfm_readpfm: conversion from float to type %d not implemented\n",storageType);
ret_val=0;
goto exit_read_pfm;
}
floatbuffer=(float*)calloc(*cols,sizeof(float));
if (!floatbuffer) {
fprintf(stderr,"pfm_readpfm: Out of memory (temporary float buffer)!\n");
ret_val=0;
goto exit_read_pfm;
}
for (r=0; r<*rows; r++) {
for (c=0; c<*cols; c++) {
fscanf(fp,"%f",&(floatbuffer[c]));
}
float2[storageType](&data[r*(*cols)*storage_size[storageType]],
floatbuffer,
*cols,
convFunc,
*minval,
*maxval);
}
free(floatbuffer);
break;
case PFM_FLOAT_BIN:
if (!float2[storageType]) {
fprintf(stderr,"pfm_readpfm: conversion from float to type %d not implemented\n",storageType);
ret_val=0;
goto exit_read_pfm;
}
floatbuffer=(float*)calloc(*cols,sizeof(float));
if (!floatbuffer) {
fprintf(stderr,"pfm_readpfm: Out of memory (temporary float buffer)!\n");
ret_val=0;
goto exit_read_pfm;
}
for (r=0; r<*rows; r++) {
fread(floatbuffer,sizeof(float),*cols,fp);
swapfloat(floatbuffer,*cols,byte_order);
float2[storageType](&data[r*(*cols)*storage_size[storageType]],
floatbuffer,
*cols,
convFunc,
*minval,
*maxval);
}
free(floatbuffer);
break;
case PFM_DOUBLE_ASCII:
if (!double2[storageType]) {
fprintf(stderr,"pfm_readpfm: conversion from double to type %d not implemented\n",storageType);
ret_val=0;
goto exit_read_pfm;
}
doublebuffer=(double*)calloc(*cols,sizeof(double));
if (!doublebuffer) {
fprintf(stderr,"pfm_readpfm: Out of memory (temporary double buffer)!\n");
ret_val=0;
goto exit_read_pfm;
}
for (r=0; r<*rows; r++) {
for (c=0; c<*cols; c++) {
fscanf(fp,"%lf",&(doublebuffer[c]));
}
double2[storageType](&data[r*(*cols)*storage_size[storageType]],
doublebuffer,
*cols,
convFunc,
*minval,
*maxval);
}
free(doublebuffer);
break;
case PFM_DOUBLE_BIN:
if (!double2[storageType]) {
fprintf(stderr,"pfm_readpfm: conversion from double to type %d not implemented\n",storageType);
ret_val=0;
goto exit_read_pfm;
}
doublebuffer=(double*)calloc(*cols,sizeof(double));
if (!doublebuffer) {
fprintf(stderr,"pfm_readpfm: Out of memory (temporary double buffer)!\n");
ret_val=0;
goto exit_read_pfm;
}
for (r=0; r<*rows; r++) {
fread(doublebuffer,sizeof(double),*cols,fp);
swapdouble(doublebuffer,*cols,byte_order);
double2[storageType](&data[r*(*cols)*storage_size[storageType]],
doublebuffer,
*cols,
convFunc,
*minval,
*maxval);
}
free(doublebuffer);
break;
case PFM_INT_ASCII:
if (!sint2[storageType]) {
fprintf(stderr,"pfm_readpfm: conversion from int to type %d not implemented\n",storageType);
ret_val=0;
goto exit_read_pfm;
}
intbuffer =(int*)calloc(*cols,sizeof(int));
if (!intbuffer) {
fprintf(stderr,"pfm_readpfm: Out of memory (temporary int buffer)!\n");
ret_val=0;
goto exit_read_pfm;
}
for (r=0; r<*rows; r++) {
for (c=0; c<*cols; c++) {
fscanf(fp,"%d",&(intbuffer[c]));
}
sint2[storageType](&data[r*(*cols)*storage_size[storageType]],
intbuffer,
*cols,
convFunc,
*minval,
*maxval);
}
free(intbuffer);
break;
case PFM_INT_BIN:
if (!sint2[storageType]) {
fprintf(stderr,"pfm_readpfm: conversion from int to type %d not implemented\n",storageType);
ret_val=0;
goto exit_read_pfm;
}
intbuffer =(int*)calloc(*cols,sizeof(int));
if (!intbuffer) {
fprintf(stderr,"pfm_readpfm: Out of memory (temporary int buffer)!\n");
ret_val=0;
goto exit_read_pfm;
}
for (r=0; r<*rows; r++) {
fread(intbuffer,sizeof(int),*cols,fp);
swapint(intbuffer,*cols,byte_order);
sint2[storageType](&data[r*(*cols)*storage_size[storageType]],
intbuffer,
*cols,
convFunc,
*minval,
*maxval);
}
free(intbuffer);
break;
case PFM_INT16_ASCII:
if (!uint162[storageType]) {
fprintf(stderr,"pfm_readpfm: conversion from int16 to type %d not implemented\n",storageType);
ret_val=0;
goto exit_read_pfm;
}
int16buffer =(uint16*)calloc(*cols,sizeof(uint16));
if (!int16buffer) {
fprintf(stderr,"pfm_readpfm: Out of memory (temporary int16 buffer)!\n");
ret_val=0;
goto exit_read_pfm;
}
for (r=0; r<*rows; r++) {
for (c=0; c<*cols; c++) {
fscanf(fp,"%hd",&(int16buffer[c])); /* "%d" -> "%hd" (T. Wiebesiek, 31.3.2005) */
}
uint162[storageType](&data[r*(*cols)*storage_size[storageType]],
int16buffer,
*cols,
convFunc,
*minval,
*maxval);
}
free(int16buffer);
break;
case PFM_INT16_BIN:
if (!uint162[storageType]) {
fprintf(stderr,"pfm_readpfm: conversion from int16 to type %d not implemented\n",storageType);
ret_val=0;
goto exit_read_pfm;
}
int16buffer =(uint16*)calloc(*cols,sizeof(uint16));
if (!int16buffer) {
fprintf(stderr,"pfm_readpfm: Out of memory (temporary int16 buffer)!\n");
ret_val=0;
goto exit_read_pfm;
}
for (r=0; r<*rows; r++) {
fread(int16buffer,sizeof(uint16),*cols,fp);
swapint16(int16buffer,*cols,byte_order);
uint162[storageType](&data[r*(*cols)*storage_size[storageType]],
int16buffer,
*cols,
convFunc,
*minval,
*maxval);
}
free(int16buffer);
break;
case PFM_PGM_ASCII:
fprintf(stderr,"pfm_readpfm: PGM ASCII not implemented!\n");
ret_val=0;
goto exit_read_pfm;
break;
case PFM_PGM_BIN:
if (!pgm2[storageType]) {
fprintf(stderr,"pfm_readpfm: conversion from pgm to type %d not implemented\n",storageType);
ret_val=0;
goto exit_read_pfm;
}
greybuffer =(grey*)calloc(*cols,sizeof(grey));
if (!greybuffer) {
fprintf(stderr,"pfm_readpfm: Out of memory (temporary pgm buffer)!\n");
ret_val=0;
goto exit_read_pfm;
}
for (r=0; r<*rows; r++) {
fread(greybuffer,sizeof(grey),*cols,fp);
pgm2[storageType](&data[r*(*cols)*storage_size[storageType]],
greybuffer,
*cols,
convFunc,
*minval,
*maxval);
}
free(greybuffer);
break;
case PFM_PBM_ASCII:
fprintf(stderr,"pfm_readpfm: PBM ASCII not implented!\n");
ret_val=0;
goto exit_read_pfm;
break;
case PFM_PBM_BIN:
fprintf(stderr,"pfm_readpfm: PBM BIN not implented!\n");
ret_val=0;
goto exit_read_pfm;
if (!pbm2[storageType]) {
fprintf(stderr,"pfm_readpfm: conversion from pgm to type %d not implemented\n",storageType);
ret_val=0;
goto exit_read_pfm;
}
greybuffer =(grey*)calloc(*cols,sizeof(grey));
if (!greybuffer) {
fprintf(stderr,"pfm_readpfm: Out of memory (temporary pgm buffer)!\n");
ret_val=0;
goto exit_read_pfm;
}
for (r=0; r<*rows; r++) {
fread(greybuffer,sizeof(grey),*cols,fp);
pgm2[storageType](&data[r*(*cols)*storage_size[storageType]],
greybuffer,
*cols,
convFunc,
*minval,
*maxval);
}
free(greybuffer);
break;
case PFM_PPM_BIN:
pfm_read_ppm(fp,*cols,*rows,ppmbuffer);
#if 0
if (!pgm2[storageType]) {
fprintf(stderr,"pfm_readpfm: conversion from pgm to type %d not implemented\n",storageType);
ret_val=0;
goto exit_read_pfm;
}
#endif
break;
}
exit_read_pfm:
if (compressed_) fp=stop_decompression(fp);
return data;
}
int pfm_readpfm_header(FILE *fp,
int *cols, int *rows,
float *minval, float *maxval,
int *storageType)
{
long filepos;
char buffer[1024];
int cols_, rows_;
float minval_, maxval_;
int type;
int byte_order;
pfmGeoRead_=0;
if (pfmCommentRead_) free(pfmCommentRead_);
pfmCommentRead_=0;
pfmGeoSet_=0;
pfmComment_=0;
filepos=ftell(fp);
fp=check_compression(buffer,fp);
#ifdef DEBUG
printf("pfm_readpfm_header: %s\n",buffer);
#endif
switch (buffer[0]) {
case 'F':
switch (buffer[1]) {
case '0':
type=PFM_FLOAT_ASCII;
break;
case '1':
type=PFM_INT_ASCII;
break;
case '2':
type=PFM_INT16_ASCII;
break;
case '3':
type=PFM_DOUBLE_ASCII;
break;
case '4':
type=PFM_FLOAT_BIN;
break;
case '5':
type=PFM_INT_BIN;
break;
case '6':
type=PFM_INT16_BIN;
break;
case '7':
type=PFM_DOUBLE_BIN;
break;
default:
fprintf(stderr,"pfm_readpfm: Wrong fileformat!\n");
fp=stop_decompression(fp);
fseek(fp,filepos,SEEK_SET);
return 0;
}
break;
case 'P':
switch (buffer[1]) {
case '1':
type=PFM_PBM_ASCII;
break;
case '2':
type=PFM_PGM_ASCII;
break;
case '3':
type=PFM_PPM_ASCII;
break;
case '4':
type=PFM_PBM_BIN;
#if 0
fprintf(stderr,"pfm_readpfm: PBM not supported by libpfm, use libpbm!\n");
#endif
fp=stop_decompression(fp);
fseek(fp,filepos,SEEK_SET);
return 0;
break;
case '5':
type=PFM_PGM_BIN;
break;
case '6':
type=PFM_PPM_BIN;
#if 0
fprintf(stderr,"pfm_readpfm: PPM not supported by libpfm, use libppm!\n");
fp=stop_decompression(fp);
fseek(fp,filepos,SEEK_SET);
return 0;
#endif
break;
default:
fprintf(stderr,"pfm_readpfm: Wrong fileformat!\n");
fp=stop_decompression(fp);
fseek(fp,filepos,SEEK_SET);
return 0;
}
break;
default:
fprintf(stderr,"pfm_readpfm: Wrong fileformat!\n");
fp=stop_decompression(fp);
fseek(fp,filepos,SEEK_SET);
return 0;
}
if ((type>PFM_SINT16_ASCII) && (type<PFM_PGM_ASCII)) {
read_buffer(buffer,1023,fp);
if (buffer[0] == 'L') {
byte_order=PFM_LittleEndian;
}
else {
byte_order=PFM_BigEndian;
}
}
read_buffer(buffer,1023,fp);
sscanf(buffer,"%d %d",&cols_,&rows_);
read_buffer(buffer,1023,fp);
pfm_mult=1.0;
pfm_offset=0.0;
if (sscanf(buffer,"%f %f %f %f",&minval_,&maxval_,&pfm_mult,&pfm_offset)<2) {
maxval_=minval_;
minval_=0;
}
if (type==PFM_PGM_BIN && maxval_>255) type=PFM_INT16_BIN;
if (type==PFM_PGM_ASCII && maxval_>255 && maxval_<=65535) type=PFM_INT16_ASCII;
if (storageType) {
switch (type) {
case PFM_FLOAT_ASCII:
case PFM_FLOAT_BIN:
*storageType=PFM_FLOAT;
break;
case PFM_DOUBLE_ASCII:
case PFM_DOUBLE_BIN:
*storageType=PFM_DOUBLE;
break;
case PFM_INT_ASCII:
case PFM_INT_BIN:
*storageType=PFM_SINT;
break;
case PFM_INT16_ASCII:
case PFM_INT16_BIN:
*storageType=PFM_UINT16;
break;
case PFM_SINT16_ASCII:
case PFM_SINT16_BIN:
*storageType=PFM_SINT16;
break;
case PFM_PGM_ASCII:
case PFM_PGM_BIN:
*storageType=PFM_BYTE;
break;
case PFM_PBM_ASCII:
case PFM_PBM_BIN:
*storageType=PFM_BIT;
break;
case PFM_PPM_ASCII:
case PFM_PPM_BIN:
*storageType=PFM_3BYTE;
break;
}
#ifdef DEBUG
printf("storageType=%d\n",*storageType);
#endif
}
if (minval) *minval=minval_;
if (maxval) *maxval=maxval_;
if (cols) *cols=cols_;
if (rows) *rows=rows_;
#ifdef DEBUG
printf("cols=%d, rows=%d, minval=%f, maxval=%f\n",cols_,rows_,minval_,maxval_);
#endif
fp=stop_decompression(fp);
fseek(fp,filepos,SEEK_SET);
return 1;
}
static int lsbX_crypt_extract(FILE* image, FILE** msg_f, const char* name, const char *passwd,
const enum encrypt_type algo, const enum encrypt_block_type blk_algo,
byte_reader *reader)
{
uint8_t* encrypted_content;
uint8_t* decrypted_content;
struct bmp_type img;
unsigned int offset = 0;
uint32_t encrypted_size, msg_size, extension_size, decrypted_size;
char* filename;
/* header loading */
load_img_header(image, &img);
if (!check_version(&img) || !check_compression(&img)) {
fprintf(stderr, "Format not supported (either the file is not a BMPv3 or it uses compression. Exiting.\n");
return -1;
}
/* content loading */
img.matrix = malloc(sizeof(uint8_t)*img.usable_size);
load_img_matrix(image, &img);
/*reading size*/
if ((*reader)(&encrypted_size, sizeof(uint32_t), &img, &offset) != 0) {
fprintf(stderr, "EOF was reached prematurely while attempting to read the embedded crypted file's size\n");
free(img.matrix);
return -1;
}
encrypted_size = ntohl(encrypted_size);
if (encrypted_size > img.usable_size) {
fprintf(stderr, "Fetched encrypted message size is bigger than carrier (%i <-> %i bytes)! Exiting.\n",encrypted_size,img.usable_size);
free(img.matrix);
return -1;
}
/*reading encrypted content*/
encrypted_content = malloc(sizeof(uint8_t)*encrypted_size);
decrypted_content = malloc(sizeof(uint8_t)*encrypted_size);
if ((*reader)(encrypted_content, encrypted_size, &img, &offset) != 0) {
fprintf(stderr, "EOF was reached prematurely while attempting to read the embedded crypted file's content\n");
free(img.matrix);
free(encrypted_content);
free(decrypted_content);
return -1;
}
/* freeing the matrix we won't need anymore */
free(img.matrix);
/* decrypting */
if (decrypt(encrypted_content, encrypted_size, (unsigned char*) passwd, algo, blk_algo, decrypted_content, &decrypted_size) != 0)
return -1;
/* reading the actual data size */
memcpy(&msg_size, decrypted_content, sizeof(uint32_t));
msg_size = ntohl(msg_size);
if (msg_size > decrypted_size - sizeof(uint32_t) - 1) { /* -1 because the extension must be at least a '\0' at the end */
fprintf(stderr, "Message to be read bigger than decrypted chunk (%i <-> %i)! Exiting.\n", msg_size, decrypted_size);
free(encrypted_content);
free(decrypted_content);
return -1;
}
/* reading extension */
extension_size = decrypted_size - msg_size - sizeof(uint32_t);
/* building the filename */
filename = malloc(sizeof(uint8_t)*(strlen(name)+extension_size));
strncpy(filename, name, strlen(name)+1);
strncat(filename, (char*) &(decrypted_content[sizeof(uint32_t)+msg_size]), extension_size);
/* writing to file */
*msg_f = fopen(filename, "wb");
fwrite((char*) &(decrypted_content[sizeof(uint32_t)]), sizeof(uint8_t), msg_size, *msg_f);
free(encrypted_content);
free(decrypted_content);
free(filename);
return 0;
}
static int lsbX_extract(FILE* image, FILE** msg_f, const char* name, byte_reader* reader, byte_counter* counter)
{
char *msg, *extension;
struct bmp_type img;
uint32_t offset = 0;
uint32_t msg_size;
int extension_size;
char* filename;
/* header loading */
load_img_header(image, &img);
if (!check_version(&img) || !check_compression(&img)) {
fprintf(stderr, "Format not supported (either the file is not a BMPv3 or it uses compression. Exiting.\n");
return -1;
}
/* content loading */
img.matrix = malloc(sizeof(uint8_t)*img.usable_size);
load_img_matrix(image, &img);
/*reading size*/
if ((*reader)(&msg_size, sizeof(uint32_t), &img, &offset) != 0) {
fprintf(stderr, "EOF was reached prematurely while attempting to read the embedded file's size\n");
free(img.matrix);
return -1;
}
msg_size = ntohl(msg_size);
if (msg_size > img.usable_size) {
fprintf(stderr, "Fetched message size is bigger than carrier (%i <-> %i bytes)! Exiting.\n",msg_size,img.usable_size);
free(img.matrix);
return -1;
}
/*reading content*/
msg = calloc(msg_size, sizeof(uint8_t));
if ((*reader)(msg, msg_size, &img, &offset) != 0) {
fprintf(stderr, "EOF was reached prematurely while attempting to read the embedded file's content\n");
free(img.matrix);
free(msg);
return -1;
}
/*reading extension*/
if ((extension_size = (*counter)(&img, offset)) == -1) {
fprintf(stderr, "EOF was reached prematurely while attempting to read the embedded file's extension.\n"
"Continuing anyway but the result is likely to be unusable.\n");
extension_size = 1;
extension = malloc(sizeof(char));
*extension = '\0';
} else {
extension = malloc(sizeof(char)*extension_size);
(*reader)(extension, extension_size, &img, &offset); /* safe as we already checked the existence of the extension */
}
/* extension_size includes '\0' */
filename = malloc(sizeof(char)*(extension_size+strlen(name)));
strncpy(filename, name, strlen(name)+1);
strncat(filename, extension, extension_size);
*msg_f = fopen(filename, "wb");
fwrite(msg, sizeof(uint8_t), msg_size, *msg_f);
free(msg);
free(filename);
free(img.matrix);
free(extension);
return 0;
}
