ref: 94916808dd9a53ac297ab537851791894b919828
dir: /sys/src/cmd/jpg/readppm.c/
#include <u.h> #include <libc.h> #include <bio.h> #include <draw.h> #include <ctype.h> #include "imagefile.h" Rawimage *readppm(Biobuf*, Rawimage*); /* * fetch a non-comment character. */ static int Bgetch(Biobufhdr *b) { int c; for(;;) { c = Bgetc(b); if(c == '#') { while((c = Bgetc(b)) != Beof && c != '\n') ; } return c; } } /* * fetch a nonnegative decimal integer. */ static int Bgetint(Biobufhdr *b) { int c; int i; while((c = Bgetch(b)) != Beof && !isdigit(c)) ; if(c == Beof) return -1; i = 0; do { i = i*10 + (c-'0'); } while((c = Bgetch(b)) != Beof && isdigit(c)); return i; } static int Bgetdecimalbit(Biobufhdr *b) { int c; while((c = Bgetch(b)) != Beof && c != '0' && c != '1') ; if(c == Beof) return -1; return c == '1'; } static int bitc, nbit; static int Bgetbit(Biobufhdr *b) { if(nbit == 0) { nbit = 8; bitc = Bgetc(b); if(bitc == -1) return -1; } nbit--; return (bitc >> nbit) & 0x1; } static void Bflushbit(Biobufhdr*) { nbit = 0; } Rawimage** readpixmap(int fd, int colorspace) { Rawimage **array, *a; Biobuf b; char buf[ERRMAX]; int i; char *e; USED(colorspace); if(Binit(&b, fd, OREAD) < 0) return nil; werrstr(""); e = "out of memory"; if((array = malloc(sizeof *array)) == nil) goto Error; if((array[0] = malloc(sizeof *array[0])) == nil) goto Error; memset(array[0], 0, sizeof *array[0]); for(i=0; i<3; i++) array[0]->chans[i] = nil; e = "bad file format"; switch(Bgetc(&b)) { case 'P': Bungetc(&b); a = readppm(&b, array[0]); break; default: a = nil; break; } if(a == nil) goto Error; array[0] = a; return array; Error: if(array) free(array[0]); free(array); errstr(buf, sizeof buf); if(buf[0] == 0) strcpy(buf, e); errstr(buf, sizeof buf); return nil; } typedef struct Pix Pix; struct Pix { char magic; int maxcol; int (*fetch)(Biobufhdr*); int nchan; int chandesc; int invert; void (*flush)(Biobufhdr*); }; static Pix pix[] = { { '1', 1, Bgetdecimalbit, 1, CY, 1, nil }, /* portable bitmap */ { '4', 1, Bgetbit, 1, CY, 1, Bflushbit }, /* raw portable bitmap */ { '2', 0, Bgetint, 1, CY, 0, nil }, /* portable greymap */ { '5', 0, Bgetc, 1, CY, 0, nil }, /* raw portable greymap */ { '3', 0, Bgetint, 3, CRGB, 0, nil }, /* portable pixmap */ { '6', 0, Bgetc, 3, CRGB, 0, nil }, /* raw portable pixmap */ { 0 }, }; Rawimage* readppm(Biobuf *b, Rawimage *a) { int i, ch, wid, ht, r, c; int maxcol, nchan, invert; int (*fetch)(Biobufhdr*); uchar *rgb[3]; char buf[ERRMAX]; char *e; Pix *p; e = "bad file format"; if(Bgetc(b) != 'P') goto Error; c = Bgetc(b); for(p=pix; p->magic; p++) if(p->magic == c) break; if(p->magic == 0) goto Error; wid = Bgetint(b); ht = Bgetint(b); if(wid <= 0 || ht <= 0) goto Error; a->r = Rect(0,0,wid,ht); maxcol = p->maxcol; if(maxcol == 0) { maxcol = Bgetint(b); if(maxcol <= 0) goto Error; } e = "out of memory"; for(i=0; i<p->nchan; i++) if((rgb[i] = a->chans[i] = malloc(wid*ht)) == nil) goto Error; a->nchans = p->nchan; a->chanlen = wid*ht; a->chandesc = p->chandesc; e = "error reading file"; fetch = p->fetch; nchan = p->nchan; invert = p->invert; for(r=0; r<ht; r++) { for(c=0; c<wid; c++) { for(i=0; i<nchan; i++) { if((ch = (*fetch)(b)) < 0) goto Error; if(invert) ch = maxcol - ch; *rgb[i]++ = (ch * 255)/maxcol; } } if(p->flush) (*p->flush)(b); } return a; Error: errstr(buf, sizeof buf); if(buf[0] == 0) strcpy(buf, e); errstr(buf, sizeof buf); for(i=0; i<3; i++) free(a->chans[i]); free(a->cmap); return nil; }