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#ifndef TH_GENERIC_FILE
#define TH_GENERIC_FILE "generic/ppm.c"
#else
static int libppm_(Main_load)(lua_State *L)
{
const char *filename = luaL_checkstring(L, 1);
FILE* fp = fopen ( filename, "r" );
if ( !fp ) {
luaL_error(L, "cannot open file <%s> for reading", filename);
}
long W,H,C;
char p,n;
int D, bps, bpc;
// magic number
p = (char)getc(fp);
if ( p != 'P' ) {
W = H = 0;
fclose(fp);
luaL_error(L, "corrupted file");
}
n = (char)getc(fp);
// Dimensions
W = ppm_get_long(fp);
H = ppm_get_long(fp);
// Max color value
D = ppm_get_long(fp);
// Either 8 or 16 bits per pixel
bps = 8;
if (D > 255) {
bps = 16;
}
bpc = bps / 8;
//printf("Loading PPM\nMAGIC: %c%c\nWidth: %ld, Height: %ld\nChannels: %d, Bits-per-pixel: %d\n", p, n, W, H, D, bps);
// load data
int ok = 1;
size_t s;
unsigned char *r = NULL;
if ( n=='6' ) {
C = 3;
s = W*H*C*bpc;
r = malloc(s);
if (fread ( r, 1, s, fp ) < s) ok = 0;
} else if ( n=='5' ) {
C = 1;
s = W*H*C*bpc;
r = malloc(s);
if (fread ( r, 1, s, fp ) < s) ok = 0;
} else if ( n=='3' ) {
int c,i;
C = 3;
s = W*H*C;
r = malloc(s);
for (i=0; i<s; i++) {
if (fscanf ( fp, "%d", &c ) != 1) { ok = 0; break; }
r[i] = 255*c / D;
}
} else if ( n=='2' ) {
int c,i;
C = 1;
s = W*H*C;
r = malloc(s);
for (i=0; i<s; i++) {
if (fscanf ( fp, "%d", &c ) != 1) { ok = 0; break; }
r[i] = 255*c / D;
}
} else {
W=H=C=0;
fclose ( fp );
luaL_error(L, "unsupported magic number: P%c", n);
}
if (!ok) {
fclose ( fp );
luaL_error(L, "corrupted file or read error");
}
// export tensor
THTensor *tensor = THTensor_(newWithSize3d)(C,H,W);
real *data = THTensor_(data)(tensor);
long i,k,j=0;
int val;
for (i=0; i<W*H; i++) {
for (k=0; k<C; k++) {
if (bpc == 1) {
data[k*H*W+i] = (real)r[j++];
} else if (bpc == 2) {
val = r[j] | (r[j+1] << 8);
j += 2;
data[k*H*W+i] = (real)val;
}
}
}
// cleanup
free(r);
fclose(fp);
// return loaded image
luaT_pushudata(L, tensor, torch_Tensor);
return 1;
}
int libppm_(Main_save)(lua_State *L) {
// get args
const char *filename = luaL_checkstring(L, 1);
THTensor *tensor = luaT_checkudata(L, 2, torch_Tensor);
THTensor *tensorc = THTensor_(newContiguous)(tensor);
real *data = THTensor_(data)(tensorc);
// dimensions
long C,H,W,N;
if (tensorc->nDimension == 3) {
C = tensorc->size[0];
H = tensorc->size[1];
W = tensorc->size[2];
} else if (tensorc->nDimension == 2) {
C = 1;
H = tensorc->size[0];
W = tensorc->size[1];
} else {
C=W=H=0;
luaL_error(L, "can only export tensor with geometry: HxW or 1xHxW or 3xHxW");
}
N = C*H*W;
// convert to chars
unsigned char *bytes = (unsigned char*)malloc(N);
long i,k,j=0;
for (i=0; i<W*H; i++) {
for (k=0; k<C; k++) {
bytes[j++] = (unsigned char)data[k*H*W+i];
}
}
// open file
FILE* fp = fopen(filename, "w");
if ( !fp ) {
luaL_error(L, "cannot open file <%s> for writing", filename);
}
// write 3 or 1 channel(s) header
if (C == 3) {
fprintf(fp, "P6\n%ld %ld\n%d\n", W, H, 255);
} else {
fprintf(fp, "P5\n%ld %ld\n%d\n", W, H, 255);
}
// write data
fwrite(bytes, 1, N, fp);
// cleanup
THTensor_(free)(tensorc);
free(bytes);
fclose (fp);
// return result
return 1;
}
static const luaL_Reg libppm_(Main__)[] =
{
{"load", libppm_(Main_load)},
{"save", libppm_(Main_save)},
{NULL, NULL}
};
DLL_EXPORT int libppm_(Main_init)(lua_State *L)
{
luaT_pushmetatable(L, torch_Tensor);
luaT_registeratname(L, libppm_(Main__), "libppm");
return 1;
}
#endif
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