nuclear@2: /*
nuclear@2: colcycle - color cycling image viewer
nuclear@2: Copyright (C) 2016-2017  John Tsiombikas <nuclear@member.fsf.org>
nuclear@2: 
nuclear@2: This program is free software: you can redistribute it and/or modify
nuclear@2: it under the terms of the GNU General Public License as published by
nuclear@2: the Free Software Foundation, either version 3 of the License, or
nuclear@2: (at your option) any later version.
nuclear@2: 
nuclear@2: This program is distributed in the hope that it will be useful,
nuclear@2: but WITHOUT ANY WARRANTY; without even the implied warranty of
nuclear@2: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
nuclear@2: GNU General Public License for more details.
nuclear@2: 
nuclear@2: You should have received a copy of the GNU General Public License
nuclear@2: along with this program.  If not, see <http://www.gnu.org/licenses/>.
nuclear@2: */
nuclear@2: #include <stdio.h>
nuclear@2: #include <stdlib.h>
nuclear@2: #include <assert.h>
nuclear@2: #include <inttypes.h>
nuclear@2: #include <string.h>
nuclear@2: #if defined(__WATCOMC__) || defined(WIN32)
nuclear@2: #include <malloc.h>
nuclear@2: #else
nuclear@2: #include <alloca.h>
nuclear@2: #endif
nuclear@2: #include "imagelbm.h"
nuclear@2: 
nuclear@2: #ifdef __GNUC__
nuclear@2: #define PACKED	__attribute__((packed))
nuclear@2: #endif
nuclear@2: 
nuclear@2: #ifdef __BYTE_ORDER__
nuclear@2: #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
nuclear@2: #define LENDIAN
nuclear@2: #else
nuclear@2: #define BENDIAN
nuclear@2: #endif
nuclear@2: #endif
nuclear@2: 
nuclear@2: #define MKID(a, b, c, d)	(((a) << 24) | ((b) << 16) | ((c) << 8) | (d))
nuclear@2: 
nuclear@2: #define IS_IFF_CONTAINER(id)	((id) == IFF_FORM || (id) == IFF_CAT || (id) == IFF_LIST)
nuclear@2: 
nuclear@2: enum {
nuclear@2: 	IFF_FORM = MKID('F', 'O', 'R', 'M'),
nuclear@2: 	IFF_CAT = MKID('C', 'A', 'T', ' '),
nuclear@2: 	IFF_LIST = MKID('L', 'I', 'S', 'T'),
nuclear@2: 	IFF_ILBM = MKID('I', 'L', 'B', 'M'),
nuclear@2: 	IFF_PBM = MKID('P', 'B', 'M', ' '),
nuclear@2: 	IFF_BMHD = MKID('B', 'M', 'H', 'D'),
nuclear@2: 	IFF_CMAP = MKID('C', 'M', 'A', 'P'),
nuclear@2: 	IFF_BODY = MKID('B', 'O', 'D', 'Y'),
nuclear@2: 	IFF_CRNG = MKID('C', 'R', 'N', 'G')
nuclear@2: };
nuclear@2: 
nuclear@2: 
nuclear@2: struct chdr {
nuclear@2: 	uint32_t id;
nuclear@2: 	uint32_t size;
nuclear@2: };
nuclear@2: 
nuclear@2: #ifdef __WATCOMC__
nuclear@2: #pragma push(pack, 1)
nuclear@2: #endif
nuclear@2: struct bitmap_header {
nuclear@2: 	uint16_t width, height;
nuclear@2: 	int16_t xoffs, yoffs;
nuclear@2: 	uint8_t nplanes;
nuclear@2: 	uint8_t masking;
nuclear@2: 	uint8_t compression;
nuclear@2: 	uint8_t padding;
nuclear@2: 	uint16_t colorkey;
nuclear@2: 	uint8_t aspect_num, aspect_denom;
nuclear@2: 	int16_t pgwidth, pgheight;
nuclear@2: } PACKED;
nuclear@2: #ifdef __WATCOMC__
nuclear@2: #pragma pop(pack)
nuclear@2: #endif
nuclear@2: 
nuclear@2: enum {
nuclear@2: 	MASK_NONE,
nuclear@2: 	MASK_PLANE,
nuclear@2: 	MASK_COLORKEY,
nuclear@2: 	MASK_LASSO
nuclear@2: };
nuclear@2: 
nuclear@2: struct crng {
nuclear@2: 	uint16_t padding;
nuclear@2: 	uint16_t rate;
nuclear@2: 	uint16_t flags;
nuclear@2: 	uint8_t low, high;
nuclear@2: };
nuclear@2: 
nuclear@2: enum {
nuclear@2: 	CRNG_ENABLE = 1,
nuclear@2: 	CRNG_REVERSE = 2
nuclear@2: };
nuclear@2: 
nuclear@2: static int read_header(FILE *fp, struct chdr *hdr);
nuclear@2: static int read_ilbm_pbm(FILE *fp, uint32_t type, uint32_t size, struct image *img);
nuclear@2: static int read_bmhd(FILE *fp, struct bitmap_header *bmhd);
nuclear@2: static int read_crng(FILE *fp, struct crng *crng);
nuclear@2: static int read_body_ilbm(FILE *fp, struct bitmap_header *bmhd, struct image *img);
nuclear@2: static int read_body_pbm(FILE *fp, struct bitmap_header *bmhd, struct image *img);
nuclear@2: static int read_compressed_scanline(FILE *fp, unsigned char *scanline, int width);
nuclear@2: static int read16(FILE *fp, uint16_t *res);
nuclear@2: static int read32(FILE *fp, uint32_t *res);
nuclear@2: static uint16_t swap16(uint16_t x);
nuclear@2: static uint32_t swap32(uint32_t x);
nuclear@2: 
nuclear@2: int file_is_lbm(FILE *fp)
nuclear@2: {
nuclear@2: 	uint32_t type;
nuclear@2: 	struct chdr hdr;
nuclear@2: 
nuclear@2: 	while(read_header(fp, &hdr) != -1) {
nuclear@2: 		if(IS_IFF_CONTAINER(hdr.id)) {
nuclear@2: 			if(read32(fp, &type) == -1) {
nuclear@2: 				break;
nuclear@2: 			}
nuclear@2: 
nuclear@2: 			if(type == IFF_ILBM || type == IFF_PBM ) {
nuclear@2: 				rewind(fp);
nuclear@2: 				return 1;
nuclear@2: 			}
nuclear@2: 			hdr.size -= sizeof type;	/* so we will seek fwd correctly */
nuclear@2: 		}
nuclear@2: 		fseek(fp, hdr.size, SEEK_CUR);
nuclear@2: 	}
nuclear@2: 	fseek(fp, 0, SEEK_SET);
nuclear@2: 	return 0;
nuclear@2: }
nuclear@2: 
nuclear@2: void print_chunkid(uint32_t id)
nuclear@2: {
nuclear@2: 	char str[5] = {0};
nuclear@2: #ifdef LENDIAN
nuclear@2: 	id = swap32(id);
nuclear@2: #endif
nuclear@2: 	memcpy(str, &id, 4);
nuclear@2: 	puts(str);
nuclear@2: }
nuclear@2: 
nuclear@2: int load_image_lbm(struct image *img, FILE *fp)
nuclear@2: {
nuclear@2: 	uint32_t type;
nuclear@2: 	struct chdr hdr;
nuclear@2: 
nuclear@2: 	while(read_header(fp, &hdr) != -1) {
nuclear@2: 		if(IS_IFF_CONTAINER(hdr.id)) {
nuclear@2: 			if(read32(fp, &type) == -1) {
nuclear@2: 				break;
nuclear@2: 			}
nuclear@2: 			hdr.size -= sizeof type;	/* to compensate for having advanced 4 more bytes */
nuclear@2: 
nuclear@2: 			if(type == IFF_ILBM) {
nuclear@2: 				if(read_ilbm_pbm(fp, type, hdr.size, img) == -1) {
nuclear@2: 					return -1;
nuclear@2: 				}
nuclear@2: 				return 0;
nuclear@2: 			}
nuclear@2: 			if(type == IFF_PBM) {
nuclear@2: 				if(read_ilbm_pbm(fp, type, hdr.size, img) == -1) {
nuclear@2: 					return -1;
nuclear@2: 				}
nuclear@2: 				return 0;
nuclear@2: 			}
nuclear@2: 		}
nuclear@2: 		fseek(fp, hdr.size, SEEK_CUR);
nuclear@2: 	}
nuclear@2: 	return 0;
nuclear@2: }
nuclear@2: 
nuclear@2: static int read_header(FILE *fp, struct chdr *hdr)
nuclear@2: {
nuclear@2: 	if(fread(hdr, 1, sizeof *hdr, fp) < sizeof *hdr) {
nuclear@2: 		return -1;
nuclear@2: 	}
nuclear@2: #ifdef LENDIAN
nuclear@2: 	hdr->id = swap32(hdr->id);
nuclear@2: 	hdr->size = swap32(hdr->size);
nuclear@2: #endif
nuclear@2: 	return 0;
nuclear@2: }
nuclear@2: 
nuclear@2: static int read_ilbm_pbm(FILE *fp, uint32_t type, uint32_t size, struct image *img)
nuclear@2: {
nuclear@2: 	int i, res = -1;
nuclear@2: 	struct chdr hdr;
nuclear@2: 	struct bitmap_header bmhd;
nuclear@2: 	struct crng crng;
nuclear@2: 	struct colrange *crnode;
nuclear@2: 	unsigned char pal[3 * 256];
nuclear@2: 	unsigned char *pptr;
nuclear@2: 	long start = ftell(fp);
nuclear@2: 
nuclear@2: 	memset(img, 0, sizeof *img);
nuclear@2: 
nuclear@2: 	while(read_header(fp, &hdr) != -1 && ftell(fp) - start < size) {
nuclear@2: 		switch(hdr.id) {
nuclear@2: 		case IFF_BMHD:
nuclear@2: 			assert(hdr.size == 20);
nuclear@2: 			if(read_bmhd(fp, &bmhd) == -1) {
nuclear@2: 				return -1;
nuclear@2: 			}
nuclear@2: 			img->width = bmhd.width;
nuclear@2: 			img->height = bmhd.height;
nuclear@2: 			img->bpp = bmhd.nplanes;
nuclear@2: 			if(bmhd.nplanes > 8) {
nuclear@2: 				fprintf(stderr, "%d planes found, only paletized LBM files supported\n", bmhd.nplanes);
nuclear@2: 				return -1;
nuclear@2: 			}
nuclear@2: 			if(!(img->pixels = malloc(img->width * img->height))) {
nuclear@2: 				fprintf(stderr, "failed to allocate %dx%d image\n", img->width, img->height);
nuclear@2: 				return -1;
nuclear@2: 			}
nuclear@2: 			break;
nuclear@2: 
nuclear@2: 		case IFF_CMAP:
nuclear@2: 			assert(hdr.size / 3 <= 256);
nuclear@2: 
nuclear@2: 			if(fread(pal, 1, hdr.size, fp) < hdr.size) {
nuclear@2: 				fprintf(stderr, "failed to read colormap\n");
nuclear@2: 				return -1;
nuclear@2: 			}
nuclear@2: 			pptr = pal;
nuclear@2: 			for(i=0; i<256; i++) {
nuclear@2: 				img->palette[i].r = *pptr++;
nuclear@2: 				img->palette[i].g = *pptr++;
nuclear@2: 				img->palette[i].b = *pptr++;
nuclear@2: 			}
nuclear@2: 			break;
nuclear@2: 
nuclear@2: 		case IFF_CRNG:
nuclear@2: 			assert(hdr.size == sizeof crng);
nuclear@2: 
nuclear@2: 			if(read_crng(fp, &crng) == -1) {
nuclear@2: 				fprintf(stderr, "failed to read color cycling range chunk\n");
nuclear@2: 				return -1;
nuclear@2: 			}
nuclear@2: 			if(crng.low != crng.high && crng.rate > 0) {
nuclear@2: 				if(!(crnode = malloc(sizeof *crnode))) {
nuclear@2: 					fprintf(stderr, "failed to allocate color range node\n");
nuclear@2: 					return -1;
nuclear@2: 				}
nuclear@2: 				crnode->low = crng.low;
nuclear@2: 				crnode->high = crng.high;
nuclear@2: 				crnode->cmode = (crng.flags & CRNG_REVERSE) ? CYCLE_REVERSE : CYCLE_NORMAL;
nuclear@2: 				crnode->rate = crng.rate;
nuclear@2: 				crnode->next = img->range;
nuclear@2: 				img->range = crnode;
nuclear@2: 				++img->num_ranges;
nuclear@2: 			}
nuclear@2: 			break;
nuclear@2: 
nuclear@2: 		case IFF_BODY:
nuclear@2: 			if(!img->pixels) {
nuclear@2: 				fprintf(stderr, "malformed ILBM image: encountered BODY chunk before BMHD\n");
nuclear@2: 				return -1;
nuclear@2: 			}
nuclear@2: 			if(type == IFF_ILBM) {
nuclear@2: 				if(read_body_ilbm(fp, &bmhd, img) == -1) {
nuclear@2: 					fprintf(stderr, "failed to read interleaved pixel data\n");
nuclear@2: 					return -1;
nuclear@2: 				}
nuclear@2: 			} else {
nuclear@2: 				assert(type == IFF_PBM);
nuclear@2: 				if(read_body_pbm(fp, &bmhd, img) == -1) {
nuclear@2: 					fprintf(stderr, "failed to read linear pixel data\n");
nuclear@2: 					return -1;
nuclear@2: 				}
nuclear@2: 			}
nuclear@2: 			res = 0;	/* sucessfully read image */
nuclear@2: 			break;
nuclear@2: 
nuclear@2: 		default:
nuclear@2: 			/* skip unknown chunks */
nuclear@2: 			fseek(fp, hdr.size, SEEK_CUR);
nuclear@2: 			if(ftell(fp) & 1) {
nuclear@2: 				/* chunks must start at even offsets */
nuclear@2: 				fseek(fp, 1, SEEK_CUR);
nuclear@2: 			}
nuclear@2: 		}
nuclear@2: 	}
nuclear@2: 
nuclear@2: 	return res;
nuclear@2: }
nuclear@2: 
nuclear@2: 
nuclear@2: static int read_bmhd(FILE *fp, struct bitmap_header *bmhd)
nuclear@2: {
nuclear@2: 	if(fread(bmhd, sizeof *bmhd, 1, fp) < 1) {
nuclear@2: 		return -1;
nuclear@2: 	}
nuclear@2: #ifdef LENDIAN
nuclear@2: 	bmhd->width = swap16(bmhd->width);
nuclear@2: 	bmhd->height = swap16(bmhd->height);
nuclear@2: 	bmhd->xoffs = swap16(bmhd->xoffs);
nuclear@2: 	bmhd->yoffs = swap16(bmhd->yoffs);
nuclear@2: 	bmhd->colorkey = swap16(bmhd->colorkey);
nuclear@2: 	bmhd->pgwidth = swap16(bmhd->pgwidth);
nuclear@2: 	bmhd->pgheight = swap16(bmhd->pgheight);
nuclear@2: #endif
nuclear@2: 	return 0;
nuclear@2: }
nuclear@2: 
nuclear@2: static int read_crng(FILE *fp, struct crng *crng)
nuclear@2: {
nuclear@2: 	if(fread(crng, sizeof *crng, 1, fp) < 1) {
nuclear@2: 		return -1;
nuclear@2: 	}
nuclear@2: #ifdef LENDIAN
nuclear@2: 	crng->rate = swap16(crng->rate);
nuclear@2: 	crng->flags = swap16(crng->flags);
nuclear@2: #endif
nuclear@2: 	return 0;
nuclear@2: }
nuclear@2: 
nuclear@2: /* scanline: [bp0 row][bp1 row]...[bpN-1 row][opt mask row]
nuclear@2:  * each uncompressed row is width / 8 bytes
nuclear@2:  */
nuclear@2: static int read_body_ilbm(FILE *fp, struct bitmap_header *bmhd, struct image *img)
nuclear@2: {
nuclear@2: 	int i, j, k, bitidx;
nuclear@2: 	int rowsz = img->width / 8;
nuclear@2: 	unsigned char *src, *dest = img->pixels;
nuclear@2: 	unsigned char *rowbuf = alloca(rowsz);
nuclear@2: 
nuclear@2: 	assert(bmhd->width == img->width);
nuclear@2: 	assert(bmhd->height == img->height);
nuclear@2: 	assert(img->pixels);
nuclear@2: 
nuclear@2: 	for(i=0; i<img->height; i++) {
nuclear@2: 
nuclear@2: 		memset(dest, 0, img->width);	/* clear the whole scanline to OR bits into place */
nuclear@2: 
nuclear@2: 		for(j=0; j<bmhd->nplanes; j++) {
nuclear@2: 			// read a row corresponding to bitplane j
nuclear@2: 			if(bmhd->compression) {
nuclear@2: 				if(read_compressed_scanline(fp, rowbuf, rowsz) == -1) {
nuclear@2: 					return -1;
nuclear@2: 				}
nuclear@2: 			} else {
nuclear@2: 				if(fread(rowbuf, 1, rowsz, fp) < rowsz) {
nuclear@2: 					return -1;
nuclear@2: 				}
nuclear@2: 			}
nuclear@2: 
nuclear@2: 			// distribute all bits across the linear output scanline
nuclear@2: 			src = rowbuf;
nuclear@2: 			bitidx = 0;
nuclear@2: 
nuclear@2: 			for(k=0; k<img->width; k++) {
nuclear@2: 				dest[k] |= ((*src >> (7 - bitidx)) & 1) << j;
nuclear@2: 
nuclear@2: 				if(++bitidx >= 8) {
nuclear@2: 					bitidx = 0;
nuclear@2: 					++src;
nuclear@2: 				}
nuclear@2: 			}
nuclear@2: 		}
nuclear@2: 
nuclear@2: 		if(bmhd->masking & MASK_PLANE) {
nuclear@2: 			/* skip the mask (1bpp) */
nuclear@2: 			fseek(fp, rowsz, SEEK_CUR);
nuclear@2: 		}
nuclear@2: 
nuclear@2: 		dest += img->width;
nuclear@2: 	}
nuclear@2: 	return 0;
nuclear@2: }
nuclear@2: 
nuclear@2: static int read_body_pbm(FILE *fp, struct bitmap_header *bmhd, struct image *img)
nuclear@2: {
nuclear@2: 	int i;
nuclear@2: 	int npixels = img->width * img->height;
nuclear@2: 	unsigned char *dptr = img->pixels;
nuclear@2: 
nuclear@2: 	assert(bmhd->width == img->width);
nuclear@2: 	assert(bmhd->height == img->height);
nuclear@2: 	assert(img->pixels);
nuclear@2: 
nuclear@2: 	if(bmhd->compression) {
nuclear@2: 		for(i=0; i<img->height; i++) {
nuclear@2: 			if(read_compressed_scanline(fp, dptr, img->width) == -1) {
nuclear@2: 				return -1;
nuclear@2: 			}
nuclear@2: 			dptr += img->width;
nuclear@2: 		}
nuclear@2: 
nuclear@2: 	} else {
nuclear@2: 		/* uncompressed */
nuclear@2: 		if(fread(img->pixels, 1, npixels, fp) < npixels) {
nuclear@2: 			return -1;
nuclear@2: 		}
nuclear@2: 	}
nuclear@2: 	return 0;
nuclear@2: }
nuclear@2: 
nuclear@2: static int read_compressed_scanline(FILE *fp, unsigned char *scanline, int width)
nuclear@2: {
nuclear@2: 	int i, count, x = 0;
nuclear@2: 	signed char ctl;
nuclear@2: 
nuclear@2: 	while(x < width) {
nuclear@2: 		if(fread(&ctl, 1, 1, fp) < 1) return -1;
nuclear@2: 
nuclear@2: 		if(ctl == -128) continue;
nuclear@2: 
nuclear@2: 		if(ctl >= 0) {
nuclear@2: 			count = ctl + 1;
nuclear@2: 			if(fread(scanline, 1, count, fp) < count) return -1;
nuclear@2: 			scanline += count;
nuclear@2: 
nuclear@2: 		} else {
nuclear@2: 			unsigned char pixel;
nuclear@2: 			count = 1 - ctl;
nuclear@2: 			if(fread(&pixel, 1, 1, fp) < 1) return -1;
nuclear@2: 
nuclear@2: 			for(i=0; i<count; i++) {
nuclear@2: 				*scanline++ = pixel;
nuclear@2: 			}
nuclear@2: 		}
nuclear@2: 
nuclear@2: 		x += count;
nuclear@2: 	}
nuclear@2: 
nuclear@2: 	return 0;
nuclear@2: }
nuclear@2: 
nuclear@2: static int read16(FILE *fp, uint16_t *res)
nuclear@2: {
nuclear@2: 	if(fread(res, sizeof *res, 1, fp) < 1) {
nuclear@2: 		return -1;
nuclear@2: 	}
nuclear@2: #ifdef LENDIAN
nuclear@2: 	*res = swap16(*res);
nuclear@2: #endif
nuclear@2: 	return 0;
nuclear@2: }
nuclear@2: 
nuclear@2: static int read32(FILE *fp, uint32_t *res)
nuclear@2: {
nuclear@2: 	if(fread(res, sizeof *res, 1, fp) < 1) {
nuclear@2: 		return -1;
nuclear@2: 	}
nuclear@2: #ifdef LENDIAN
nuclear@2: 	*res = swap32(*res);
nuclear@2: #endif
nuclear@2: 	return 0;
nuclear@2: }
nuclear@2: 
nuclear@2: static uint16_t swap16(uint16_t x)
nuclear@2: {
nuclear@2: 	return (x << 8) | (x >> 8);
nuclear@2: }
nuclear@2: 
nuclear@2: static uint32_t swap32(uint32_t x)
nuclear@2: {
nuclear@2: 	return (x << 24) | ((x & 0xff00) << 8) | ((x & 0xff0000) >> 8) | (x >> 24);
nuclear@2: }