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