[imager.git] / img16.c

/*
=head1 NAME

img16.c - implements 16-bit images

=head1 SYNOPSIS

  i_img *im = i_img_16_new(int x, int y, int channels);
  # use like a normal image

=head1 DESCRIPTION

Implements 16-bit/sample images.

This basic implementation is required so that we have some larger 
sample image type to work with.

=over

=cut
*/

#include "image.h"
#include "imagei.h"

static int i_ppix_d16(i_img *im, int x, int y, i_color *val);
static int i_gpix_d16(i_img *im, int x, int y, i_color *val);
static int i_glin_d16(i_img *im, int l, int r, int y, i_color *vals);
static int i_plin_d16(i_img *im, int l, int r, int y, i_color *vals);
static int i_ppixf_d16(i_img *im, int x, int y, i_fcolor *val);
static int i_gpixf_d16(i_img *im, int x, int y, i_fcolor *val);
static int i_glinf_d16(i_img *im, int l, int r, int y, i_fcolor *vals);
static int i_plinf_d16(i_img *im, int l, int r, int y, i_fcolor *vals);
static int i_gsamp_d16(i_img *im, int l, int r, int y, i_sample_t *samps, 
                       int *chans, int chan_count);
static int i_gsampf_d16(i_img *im, int l, int r, int y, i_fsample_t *samps, 
                        int *chans, int chan_count);

/*
=item IIM_base_16bit_direct

Base structure used to initialize a 16-bit/sample image.

Internal.

=cut
*/
static i_img IIM_base_16bit_direct =
{
  0, /* channels set */
  0, 0, 0, /* xsize, ysize, bytes */
  ~0, /* ch_mask */
  i_16_bits, /* bits */
  i_direct_type, /* type */
  0, /* virtual */
  NULL, /* idata */
  { 0, 0, NULL }, /* tags */
  NULL, /* ext_data */

  i_ppix_d16, /* i_f_ppix */
  i_ppixf_d16, /* i_f_ppixf */
  i_plin_d16, /* i_f_plin */
  i_plinf_d16, /* i_f_plinf */
  i_gpix_d16, /* i_f_gpix */
  i_gpixf_d16, /* i_f_gpixf */
  i_glin_d16, /* i_f_glin */
  i_glinf_d16, /* i_f_glinf */
  i_gsamp_d16, /* i_f_gsamp */
  i_gsampf_d16, /* i_f_gsampf */

  NULL, /* i_f_gpal */
  NULL, /* i_f_ppal */
  NULL, /* i_f_addcolor */
  NULL, /* i_f_getcolor */
  NULL, /* i_f_colorcount */
  NULL, /* i_f_findcolor */

  NULL, /* i_f_destroy */
};

/* it's possible some platforms won't have a 16-bit integer type,
   so we check for one otherwise we work by bytes directly

   We do assume 8-bit char
*/
#if __STDC_VERSION__ >= 199901L
/* C99 should define something useful */
#include <stdint.h>
#ifdef UINT16_MAX
typedef uint16_t i_sample16_t;
#define GOT16
#endif
#endif

/* check out unsigned short */
#ifndef GOT16
#include <limits.h>
#if USHRT_MAX == 65535
typedef unsigned short i_sample16_t;
#define GOT16
#endif
#endif

#ifdef GOT16

/* we have a real 16-bit unsigned integer */
#define STORE16(bytes, offset, word) \
   (((i_sample16_t *)(bytes))[offset] = (word))
#define STORE8as16(bytes, offset, byte) \
   (((i_sample16_t *)(bytes))[offset] = (byte) * 256)
#define GET16(bytes, offset) \
     (((i_sample16_t *)(bytes))[offset])
#define GET16as8(bytes, offset) \
     (((i_sample16_t *)(bytes))[offset] / 256)

#else

/* we have to do this the hard way */
#define STORE16(bytes, offset, word) \
   ((((unsigned char *)(bytes))[(offset)*2] = (word) >> 8), \
    (((unsigned char *)(bytes))[(offset)*2+1] = (word) & 0xFF))
#define STORE8as16(bytes, offset, byte) \
   ((((unsigned char *)(bytes))[(offset)*2] = (byte)), \
    (((unsigned char *)(bytes))[(offset)*2+1] = 0))
   
#define GET16(bytes, offset) \
   (((unsigned char *)(bytes))[(offset)*2] * 256 \
    + ((unsigned char *)(bytes))[(offset)*2+1])
#define GET16as8(bytes, offset) \
   (((unsigned char *)(bytes))[(offset)*2] << 8)

#endif

/*
=item i_img_16_new(int x, int y, int ch)

Creates a new 16-bit per sample image.
*/
i_img *i_img_16_new_low(i_img *im, int x, int y, int ch) {
  mm_log((1,"i_img_16_new(x %d, y %d, ch %d)\n", x, y, ch));
  
  *im = IIM_base_16bit_direct;
  i_tags_new(&im->tags);
  im->xsize = x;
  im->ysize = y;
  im->channels = ch;
  im->bytes = x * y * ch * 2;
  im->ext_data = NULL;
  im->idata = mymalloc(im->bytes);
  if (im->idata) {
    memset(im->idata, 0, im->bytes);
  }
  else {
    i_tags_destroy(&im->tags);
    im = NULL;
  }
  
  return im;
}

i_img *i_img_16_new(int x, int y, int ch) {
  i_img *im;

  im = mymalloc(sizeof(i_img));
  if (im) {
    if (!i_img_16_new_low(im, x, y, ch)) {
      myfree(im);
      im = NULL;
    }
  }
  
  mm_log((1, "(%p) <- i_img_16_new\n", im));
  
  return im;
}

static int i_ppix_d16(i_img *im, int x, int y, i_color *val) {
  int off, ch;

  if (x < 0 || x >= im->xsize || y < 0 || y > im->ysize) 
    return -1;

  off = (x + y * im->xsize) * im->channels;
  for (ch = 0; ch < im->channels; ++ch)
    STORE8as16(im->idata, off+ch, val->channel[ch]);

  return 0;
}

static int i_gpix_d16(i_img *im, int x, int y, i_color *val) {
  int off, ch;

  if (x < 0 || x >= im->xsize || y < 0 || y > im->ysize) 
    return -1;

  off = (x + y * im->xsize) * im->channels;
  for (ch = 0; ch < im->channels; ++ch)
    val->channel[ch] = GET16as8(im->idata, off+ch);

  return 0;
}

static int i_ppixf_d16(i_img *im, int x, int y, i_fcolor *val) {
  int off, ch;

  if (x < 0 || x >= im->xsize || y < 0 || y > im->ysize) 
    return -1;

  off = (x + y * im->xsize) * im->channels;
  for (ch = 0; ch < im->channels; ++ch)
    STORE16(im->idata, off+ch, SampleFTo16(val->channel[ch]));

  return 0;
}

static int i_gpixf_d16(i_img *im, int x, int y, i_fcolor *val) {
  int off, ch;

  if (x < 0 || x >= im->xsize || y < 0 || y > im->ysize) 
    return -1;

  off = (x + y * im->xsize) * im->channels;
  for (ch = 0; ch < im->channels; ++ch)
    val->channel[ch] = Sample16ToF(GET16(im->idata, off+ch));

  return 0;
}

static int i_glin_d16(i_img *im, int l, int r, int y, i_color *vals) {
  int ch, count, i;
  int off;
  if (y >=0 && y < im->ysize && l < im->xsize && l >= 0) {
    if (r > im->xsize)
      r = im->xsize;
    off = (l+y*im->xsize) * im->channels;
    count = r - l;
    for (i = 0; i < count; ++i) {
      for (ch = 0; ch < im->channels; ++ch) {
	vals[i].channel[ch] = GET16as8(im->idata, off);
        ++off;
      }
    }
    return count;
  }
  else {
    return 0;
  }
}

static int i_plin_d16(i_img *im, int l, int r, int y, i_color *vals) {
  int ch, count, i;
  int off;
  if (y >=0 && y < im->ysize && l < im->xsize && l >= 0) {
    if (r > im->xsize)
      r = im->xsize;
    off = (l+y*im->xsize) * im->channels;
    count = r - l;
    for (i = 0; i < count; ++i) {
      for (ch = 0; ch < im->channels; ++ch) {
        STORE8as16(im->idata, off, vals[i].channel[ch]);
        ++off;
      }
    }
    return count;
  }
  else {
    return 0;
  }
}

static int i_glinf_d16(i_img *im, int l, int r, int y, i_fcolor *vals) {
  int ch, count, i;
  int off;
  if (y >=0 && y < im->ysize && l < im->xsize && l >= 0) {
    if (r > im->xsize)
      r = im->xsize;
    off = (l+y*im->xsize) * im->channels;
    count = r - l;
    for (i = 0; i < count; ++i) {
      for (ch = 0; ch < im->channels; ++ch) {
	vals[i].channel[ch] = Sample16ToF(GET16(im->idata, off));
        ++off;
      }
    }
    return count;
  }
  else {
    return 0;
  }
}

static int i_plinf_d16(i_img *im, int l, int r, int y, i_fcolor *vals) {
  int ch, count, i;
  int off;
  if (y >=0 && y < im->ysize && l < im->xsize && l >= 0) {
    if (r > im->xsize)
      r = im->xsize;
    off = (l+y*im->xsize) * im->channels;
    count = r - l;
    for (i = 0; i < count; ++i) {
      for (ch = 0; ch < im->channels; ++ch) {
        STORE16(im->idata, off, SampleFTo16(vals[i].channel[ch]));
        ++off;
      }
    }
    return count;
  }
  else {
    return 0;
  }
}

static int i_gsamp_d16(i_img *im, int l, int r, int y, i_sample_t *samps, 
                       int *chans, int chan_count) {
  int ch, count, i, w;
  int off;

  if (y >=0 && y < im->ysize && l < im->xsize && l >= 0) {
    if (r > im->xsize)
      r = im->xsize;
    off = (l+y*im->xsize) * im->channels;
    w = r - l;
    count = 0;

    if (chans) {
      /* make sure we have good channel numbers */
      for (ch = 0; ch < chan_count; ++ch) {
        if (chans[ch] < 0 || chans[ch] >= im->channels) {
          i_push_errorf(0, "No channel %d in this image", chans[ch]);
          return 0;
        }
      }
      for (i = 0; i < w; ++i) {
        for (ch = 0; ch < chan_count; ++ch) {
          *samps++ = GET16as8(im->idata, off+chans[ch]);
          ++count;
        }
        off += im->channels;
      }
    }
    else {
      for (i = 0; i < w; ++i) {
        for (ch = 0; ch < chan_count; ++ch) {
          *samps++ = GET16as8(im->idata, off+ch);
          ++count;
        }
        off += im->channels;
      }
    }

    return count;
  }
  else {
    return 0;
  }
}

static int i_gsampf_d16(i_img *im, int l, int r, int y, i_fsample_t *samps, 
                        int *chans, int chan_count) {
  int ch, count, i, w;
  int off;

  if (y >=0 && y < im->ysize && l < im->xsize && l >= 0) {
    if (r > im->xsize)
      r = im->xsize;
    off = (l+y*im->xsize) * im->channels;
    w = r - l;
    count = 0;

    if (chans) {
      /* make sure we have good channel numbers */
      for (ch = 0; ch < chan_count; ++ch) {
        if (chans[ch] < 0 || chans[ch] >= im->channels) {
          i_push_errorf(0, "No channel %d in this image", chans[ch]);
          return 0;
        }
      }
      for (i = 0; i < w; ++i) {
        for (ch = 0; ch < chan_count; ++ch) {
          *samps++ = Sample16ToF(GET16(im->idata, off+chans[ch]));
          ++count;
        }
        off += im->channels;
      }
    }
    else {
      for (i = 0; i < w; ++i) {
        for (ch = 0; ch < chan_count; ++ch) {
          *samps++ = Sample16ToF(GET16(im->idata, off+ch));
          ++count;
        }
        off += im->channels;
      }
    }

    return count;
  }
  else {
    return 0;
  }
}
Commit	Line	Data
faa9b3e7 TC	1	/*
	2	=head1 NAME
	3
	4	img16.c - implements 16-bit images
	5
	6	=head1 SYNOPSIS
	7
	8	i_img *im = i_img_16_new(int x, int y, int channels);
	9	# use like a normal image
	10
	11	=head1 DESCRIPTION
	12
	13	Implements 16-bit/sample images.
	14
	15	This basic implementation is required so that we have some larger
	16	sample image type to work with.
	17
	18	=over
	19
	20	=cut
	21	*/
	22
	23	#include "image.h"
	24	#include "imagei.h"
	25
	26	static int i_ppix_d16(i_img im, int x, int y, i_color val);
	27	static int i_gpix_d16(i_img im, int x, int y, i_color val);
	28	static int i_glin_d16(i_img im, int l, int r, int y, i_color vals);
	29	static int i_plin_d16(i_img im, int l, int r, int y, i_color vals);
	30	static int i_ppixf_d16(i_img im, int x, int y, i_fcolor val);
	31	static int i_gpixf_d16(i_img im, int x, int y, i_fcolor val);
	32	static int i_glinf_d16(i_img im, int l, int r, int y, i_fcolor vals);
	33	static int i_plinf_d16(i_img im, int l, int r, int y, i_fcolor vals);
	34	static int i_gsamp_d16(i_img im, int l, int r, int y, i_sample_t samps,
	35	int *chans, int chan_count);
	36	static int i_gsampf_d16(i_img im, int l, int r, int y, i_fsample_t samps,
	37	int *chans, int chan_count);
	38
	39	/*
	40	=item IIM_base_16bit_direct
	41
	42	Base structure used to initialize a 16-bit/sample image.
	43
	44	Internal.
	45
	46	=cut
	47	*/
	48	static i_img IIM_base_16bit_direct =
	49	{
	50	0, /* channels set */
	51	0, 0, 0, /* xsize, ysize, bytes */
	52	~0, /* ch_mask */
	53	i_16_bits, /* bits */
	54	i_direct_type, /* type */
	55	0, /* virtual */
	56	NULL, /* idata */
	57	{ 0, 0, NULL }, /* tags */
	58	NULL, /* ext_data */
	59
	60	i_ppix_d16, /* i_f_ppix */
	61	i_ppixf_d16, /* i_f_ppixf */
	62	i_plin_d16, /* i_f_plin */
	63	i_plinf_d16, /* i_f_plinf */
	64	i_gpix_d16, /* i_f_gpix */
65	i_gpixf_d16, /* i_f_gpixf */
66	i_glin_d16, /* i_f_glin */
67	i_glinf_d16, /* i_f_glinf */
68	i_gsamp_d16, /* i_f_gsamp */
69	i_gsampf_d16, /* i_f_gsampf */
70
71	NULL, /* i_f_gpal */
72	NULL, /* i_f_ppal */
73	NULL, /* i_f_addcolor */
74	NULL, /* i_f_getcolor */
75	NULL, /* i_f_colorcount */
76	NULL, /* i_f_findcolor */
77
78	NULL, /* i_f_destroy */
79	};
80
81	/* it's possible some platforms won't have a 16-bit integer type,
82	so we check for one otherwise we work by bytes directly
83
84	We do assume 8-bit char
85	*/
86	#if __STDC_VERSION__ >= 199901L
87	/* C99 should define something useful */
88	#include <stdint.h>
89	#ifdef UINT16_MAX
90	typedef uint16_t i_sample16_t;
91	#define GOT16
92	#endif
93	#endif
94
95	/* check out unsigned short */
96	#ifndef GOT16
97	#include <limits.h>
98	#if USHRT_MAX == 65535
99	typedef unsigned short i_sample16_t;
100	#define GOT16
101	#endif
102	#endif
103
104	#ifdef GOT16
105
106	/* we have a real 16-bit unsigned integer */
107	#define STORE16(bytes, offset, word) \
108	(((i_sample16_t *)(bytes))[offset] = (word))
109	#define STORE8as16(bytes, offset, byte) \
110	(((i_sample16_t )(bytes))[offset] = (byte) 256)
111	#define GET16(bytes, offset) \
112	(((i_sample16_t *)(bytes))[offset])
113	#define GET16as8(bytes, offset) \
114	(((i_sample16_t *)(bytes))[offset] / 256)
115
116	#else
117
118	/* we have to do this the hard way */
119	#define STORE16(bytes, offset, word) \
120	((((unsigned char )(bytes))[(offset)2] = (word) >> 8), \
121	(((unsigned char )(bytes))[(offset)2+1] = (word) & 0xFF))
122	#define STORE8as16(bytes, offset, byte) \
123	((((unsigned char )(bytes))[(offset)2] = (byte)), \
124	(((unsigned char )(bytes))[(offset)2+1] = 0))
125
126	#define GET16(bytes, offset) \
127	(((unsigned char )(bytes))[(offset)2] * 256 \
128	+ ((unsigned char )(bytes))[(offset)2+1])
129	#define GET16as8(bytes, offset) \
130	(((unsigned char )(bytes))[(offset)2] << 8)
131
132	#endif
133
134	/*
135	=item i_img_16_new(int x, int y, int ch)
136
137	Creates a new 16-bit per sample image.
138	*/
139	i_img i_img_16_new_low(i_img im, int x, int y, int ch) {
140	mm_log((1,"i_img_16_new(x %d, y %d, ch %d)\n", x, y, ch));
141
142	*im = IIM_base_16bit_direct;
143	i_tags_new(&im->tags);
144	im->xsize = x;
145	im->ysize = y;
146	im->channels = ch;
147	im->bytes = x * y * ch * 2;
148	im->ext_data = NULL;
149	im->idata = mymalloc(im->bytes);
150	if (im->idata) {
151	memset(im->idata, 0, im->bytes);
152	}
153	else {
154	i_tags_destroy(&im->tags);
155	im = NULL;
156	}
157
158	return im;
159	}
160
161	i_img *i_img_16_new(int x, int y, int ch) {
162	i_img *im;
163
164	im = mymalloc(sizeof(i_img));
165	if (im) {
166	if (!i_img_16_new_low(im, x, y, ch)) {
167	myfree(im);
168	im = NULL;
169	}
170	}
171
172	mm_log((1, "(%p) <- i_img_16_new\n", im));
173
174	return im;
175	}
176
177	static int i_ppix_d16(i_img im, int x, int y, i_color val) {
178	int off, ch;
179
180	if (x < 0 \|\| x >= im->xsize \|\| y < 0 \|\| y > im->ysize)
181	return -1;
182
183	off = (x + y * im->xsize) * im->channels;
184	for (ch = 0; ch < im->channels; ++ch)
185	STORE8as16(im->idata, off+ch, val->channel[ch]);
186
187	return 0;
188	}
189
190	static int i_gpix_d16(i_img im, int x, int y, i_color val) {
191	int off, ch;
192
193	if (x < 0 \|\| x >= im->xsize \|\| y < 0 \|\| y > im->ysize)
194	return -1;
195
196	off = (x + y * im->xsize) * im->channels;
197	for (ch = 0; ch < im->channels; ++ch)
198	val->channel[ch] = GET16as8(im->idata, off+ch);
199
200	return 0;
201	}
202
203	static int i_ppixf_d16(i_img im, int x, int y, i_fcolor val) {
204	int off, ch;
205
206	if (x < 0 \|\| x >= im->xsize \|\| y < 0 \|\| y > im->ysize)
207	return -1;
208
209	off = (x + y * im->xsize) * im->channels;
210	for (ch = 0; ch < im->channels; ++ch)
211	STORE16(im->idata, off+ch, SampleFTo16(val->channel[ch]));
212
213	return 0;
214	}
215
216	static int i_gpixf_d16(i_img im, int x, int y, i_fcolor val) {
217	int off, ch;
218
219	if (x < 0 \|\| x >= im->xsize \|\| y < 0 \|\| y > im->ysize)
220	return -1;
221
222	off = (x + y * im->xsize) * im->channels;
223	for (ch = 0; ch < im->channels; ++ch)
224	val->channel[ch] = Sample16ToF(GET16(im->idata, off+ch));
225
226	return 0;
227	}
228
229	static int i_glin_d16(i_img im, int l, int r, int y, i_color vals) {
230	int ch, count, i;
231	int off;
232	if (y >=0 && y < im->ysize && l < im->xsize && l >= 0) {
233	if (r > im->xsize)
234	r = im->xsize;
235	off = (l+yim->xsize) im->channels;
236	count = r - l;
237	for (i = 0; i < count; ++i) {
238	for (ch = 0; ch < im->channels; ++ch) {
239	vals[i].channel[ch] = GET16as8(im->idata, off);
240	++off;
241	}
242	}
243	return count;
244	}
245	else {
246	return 0;
247	}
248	}
249
250	static int i_plin_d16(i_img im, int l, int r, int y, i_color vals) {
251	int ch, count, i;
252	int off;
253	if (y >=0 && y < im->ysize && l < im->xsize && l >= 0) {
254	if (r > im->xsize)
255	r = im->xsize;
256	off = (l+yim->xsize) im->channels;
257	count = r - l;
258	for (i = 0; i < count; ++i) {
259	for (ch = 0; ch < im->channels; ++ch) {
260	STORE8as16(im->idata, off, vals[i].channel[ch]);
261	++off;
262	}
263	}
264	return count;
265	}
266	else {
267	return 0;
268	}
269	}
270
271	static int i_glinf_d16(i_img im, int l, int r, int y, i_fcolor vals) {
272	int ch, count, i;
273	int off;
274	if (y >=0 && y < im->ysize && l < im->xsize && l >= 0) {
275	if (r > im->xsize)
276	r = im->xsize;
277	off = (l+yim->xsize) im->channels;
278	count = r - l;
279	for (i = 0; i < count; ++i) {
280	for (ch = 0; ch < im->channels; ++ch) {
281	vals[i].channel[ch] = Sample16ToF(GET16(im->idata, off));
282	++off;
283	}
284	}
285	return count;
286	}
287	else {
288	return 0;
289	}
290	}
291
292	static int i_plinf_d16(i_img im, int l, int r, int y, i_fcolor vals) {
293	int ch, count, i;
294	int off;
295	if (y >=0 && y < im->ysize && l < im->xsize && l >= 0) {
296	if (r > im->xsize)
297	r = im->xsize;
298	off = (l+yim->xsize) im->channels;
299	count = r - l;
300	for (i = 0; i < count; ++i) {
301	for (ch = 0; ch < im->channels; ++ch) {
302	STORE16(im->idata, off, SampleFTo16(vals[i].channel[ch]));
303	++off;
304	}
305	}
306	return count;
307	}
308	else {
309	return 0;
310	}
311	}
312
313	static int i_gsamp_d16(i_img im, int l, int r, int y, i_sample_t samps,
314	int *chans, int chan_count) {
315	int ch, count, i, w;
316	int off;
317
318	if (y >=0 && y < im->ysize && l < im->xsize && l >= 0) {
319	if (r > im->xsize)
320	r = im->xsize;
321	off = (l+yim->xsize) im->channels;
322	w = r - l;
323	count = 0;
324
325	if (chans) {
326	/* make sure we have good channel numbers */
327	for (ch = 0; ch < chan_count; ++ch) {
328	if (chans[ch] < 0 \|\| chans[ch] >= im->channels) {
329	i_push_errorf(0, "No channel %d in this image", chans[ch]);
330	return 0;
331	}
332	}
333	for (i = 0; i < w; ++i) {
334	for (ch = 0; ch < chan_count; ++ch) {
335	*samps++ = GET16as8(im->idata, off+chans[ch]);
336	++count;
337	}
338	off += im->channels;
339	}
340	}
341	else {
342	for (i = 0; i < w; ++i) {
343	for (ch = 0; ch < chan_count; ++ch) {
344	*samps++ = GET16as8(im->idata, off+ch);
345	++count;
346	}
347	off += im->channels;
348	}
349	}
350
351	return count;
352	}
353	else {
354	return 0;
355	}
356	}
357
358	static int i_gsampf_d16(i_img im, int l, int r, int y, i_fsample_t samps,
359	int *chans, int chan_count) {
360	int ch, count, i, w;
361	int off;
362
363	if (y >=0 && y < im->ysize && l < im->xsize && l >= 0) {
364	if (r > im->xsize)
365	r = im->xsize;
366	off = (l+yim->xsize) im->channels;
367	w = r - l;
368	count = 0;
369
370	if (chans) {
371	/* make sure we have good channel numbers */
372	for (ch = 0; ch < chan_count; ++ch) {
373	if (chans[ch] < 0 \|\| chans[ch] >= im->channels) {
374	i_push_errorf(0, "No channel %d in this image", chans[ch]);
375	return 0;
376	}
377	}
378	for (i = 0; i < w; ++i) {
379	for (ch = 0; ch < chan_count; ++ch) {
380	*samps++ = Sample16ToF(GET16(im->idata, off+chans[ch]));
381	++count;
382	}
383	off += im->channels;
384	}
385	}
386	else {
387	for (i = 0; i < w; ++i) {
388	for (ch = 0; ch < chan_count; ++ch) {
389	*samps++ = Sample16ToF(GET16(im->idata, off+ch));
390	++count;
391	}
392	off += im->channels;
393	}
394	}
395
396	return count;
397	}
398	else {
399	return 0;
400	}
401	}
402