1 #include <u.h>
2 #include <libc.h>
3 #include <bio.h>
4 #include <draw.h>
5 #include <ctype.h>
6 #include "imagefile.h"
7 
8 Rawimage *readppm(Biobuf*, Rawimage*);
9 
10 /*
11  * fetch a non-comment character.
12  */
13 static
14 int
15 Bgetch(Biobuf *b)
16 {
17 	int c;
18 
19 	for(;;) {
20 		c = Bgetc(b);
21 		if(c == '#') {
22 			while((c = Bgetc(b)) != Beof && c != '\n')
23 				;
24 		}
25 		return c;
26 	}		
27 }
28 
29 /*
30  * fetch a nonnegative decimal integer.
31  */
32 static
33 int
34 Bgetint(Biobuf *b)
35 {
36 	int c;
37 	int i;
38 
39 	while((c = Bgetch(b)) != Beof && !isdigit(c))
40 		;
41 	if(c == Beof)
42 		return -1;
43 
44 	i = 0;
45 	do { 
46 		i = i*10 + (c-'0');
47 	} while((c = Bgetch(b)) != Beof && isdigit(c));
48 
49 	return i;
50 }
51 
52 static
53 int
54 Bgetdecimalbit(Biobuf *b)
55 {
56 	int c;
57 	while((c = Bgetch(b)) != Beof && c != '0' && c != '1')
58 		;
59 	if(c == Beof)
60 		return -1;
61 	return c == '1';
62 }
63 
64 static int bitc, nbit;
65 
66 static
67 int
68 Bgetbit(Biobuf *b)
69 {
70 	if(nbit == 0) {
71 		nbit = 8;
72 		bitc = Bgetc(b);
73 		if(bitc == -1)
74 			return -1;
75 	}
76 	nbit--;
77 	return (bitc >> (nbit-1)) & 0x1;
78 }
79 
80 static
81 void
82 Bflushbit(Biobuf *b)
83 {
84 	USED(b);
85 	nbit = 0;
86 }
87 
88 
89 Rawimage**
90 readpixmap(int fd, int colorspace)
91 {
92 	Rawimage **array, *a;
93 	Biobuf b;
94 	char buf[ERRMAX];
95 	int i;
96 	char *e;
97 
98 	USED(colorspace);
99 	if(Binit(&b, fd, OREAD) < 0)
100 		return nil;
101 
102 	werrstr("");
103 	e = "out of memory";
104 	if((array = malloc(sizeof *array)) == nil)
105 		goto Error;
106 	if((array[0] = malloc(sizeof *array[0])) == nil)
107 		goto Error;
108 	memset(array[0], 0, sizeof *array[0]);
109 
110 	for(i=0; i<3; i++)
111 		array[0]->chans[i] = nil;
112 
113 	e = "bad file format";
114 	switch(Bgetc(&b)) {
115 	case 'P':
116 		Bungetc(&b);
117 		a = readppm(&b, array[0]);
118 		break;
119 	default:
120 		a = nil;
121 		break;
122 	}
123 	if(a == nil)
124 		goto Error;
125 	array[0] = a;
126 
127 	return array;
128 
129 Error:
130 	if(array)
131 		free(array[0]);
132 	free(array);
133 
134 	errstr(buf, sizeof buf);
135 	if(buf[0] == 0)
136 		strcpy(buf, e);
137 	errstr(buf, sizeof buf);
138 
139 	return nil;
140 }
141 
142 typedef struct Pix	Pix;
143 struct Pix {
144 	char magic;
145 	int	maxcol;
146 	int	(*fetch)(Biobuf*);
147 	int	nchan;
148 	int	chandesc;
149 	int	invert;
150 	void	(*flush)(Biobuf*);
151 };
152 
153 static Pix pix[] = {
154 	{ '1', 1, Bgetdecimalbit, 1, CY, 1, 0 },	/* portable bitmap */
155 	{ '4', 1, Bgetbit, 1, CY, 1, Bflushbit },	/* raw portable bitmap */
156 	{ '2', 0, Bgetint, 1, CY, 0, 0 },	/* portable greymap */
157 	{ '5', 0, Bgetc, 1, CY, 0, 0 },	/* raw portable greymap */
158 	{ '3', 0, Bgetint, 3, CRGB, 0, 0 },	/* portable pixmap */
159 	{ '6', 0, Bgetc, 3, CRGB, 0, 0 },	/* raw portable pixmap */
160 	{ 0 },
161 };
162 
163 Rawimage*
164 readppm(Biobuf *b, Rawimage *a)
165 {
166 	int i, ch, wid, ht, r, c;
167 	int maxcol, nchan, invert;
168 	int (*fetch)(Biobuf*);
169 	uchar *rgb[3];
170 	char buf[ERRMAX];
171 	char *e;
172 	Pix *p;
173 
174 	e = "bad file format";
175 	if(Bgetc(b) != 'P')
176 		goto Error;
177 
178 	c = Bgetc(b);
179 	for(p=pix; p->magic; p++)
180 		if(p->magic == c)
181 			break;
182 	if(p->magic == 0)
183 		goto Error;
184 
185 
186 	wid = Bgetint(b);
187 	ht = Bgetint(b);
188 	if(wid <= 0 || ht <= 0)
189 		goto Error;
190 	a->r = Rect(0,0,wid,ht);
191 
192 	maxcol = p->maxcol;
193 	if(maxcol == 0) {
194 		maxcol = Bgetint(b);
195 		if(maxcol <= 0)
196 			goto Error;
197 	}
198 
199 	e = "out of memory";
200 	for(i=0; i<p->nchan; i++)
201 		if((rgb[i] = a->chans[i] = malloc(wid*ht)) == nil)
202 			goto Error;
203 	a->nchans = p->nchan;
204 	a->chanlen = wid*ht;
205 	a->chandesc = p->chandesc;
206 
207 	e = "error reading file";
208 
209 	fetch = p->fetch;
210 	nchan = p->nchan;
211 	invert = p->invert;
212 	for(r=0; r<ht; r++) {
213 		for(c=0; c<wid; c++) {
214 			for(i=0; i<nchan; i++) {
215 				if((ch = (*fetch)(b)) < 0)
216 					goto Error;
217 				if(invert)
218 					ch = maxcol - ch;
219 				*rgb[i]++ = (ch * 255)/maxcol;
220 			}
221 		}
222 		if(p->flush)
223 			(*p->flush)(b);
224 	}
225 
226 	return a;
227 
228 Error:
229 	errstr(buf, sizeof buf);
230 	if(buf[0] == 0)
231 		strcpy(buf, e);
232 	errstr(buf, sizeof buf);
233 
234 	for(i=0; i<3; i++)
235 		free(a->chans[i]);
236 	free(a->cmap);
237 	return nil;
238 }