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