diff options
| -rw-r--r-- | pnmtilesplit/pnmtilesplit.c | 77 |
1 files changed, 64 insertions, 13 deletions
diff --git a/pnmtilesplit/pnmtilesplit.c b/pnmtilesplit/pnmtilesplit.c index 8c43807bf..185fa8cb2 100644 --- a/pnmtilesplit/pnmtilesplit.c +++ b/pnmtilesplit/pnmtilesplit.c @@ -7,7 +7,7 @@ * */ -static const char rcsid[] = "$Id: pnmtilesplit.c,v 1.7 2006-09-14 16:52:24 chris Exp $"; +static const char rcsid[] = "$Id: pnmtilesplit.c,v 1.8 2006-09-14 17:21:49 chris Exp $"; #include <sys/types.h> @@ -33,6 +33,16 @@ static const char rcsid[] = "$Id: pnmtilesplit.c,v 1.7 2006-09-14 16:52:24 chris static int verbose; #define debug(...) if (verbose) fprintf(stderr, __VA_ARGS__) +/* xmalloc LEN + * Allocate LEN bytes, returning the allocated buffer on success or dying on + * failure. */ +static void *xmalloc(const size_t s) { + void *v; + if (!(v = malloc(s))) + die("malloc(%u): %s", (unsigned)s, strerror(errno)); + return v; +} + /* open_output_file FORMAT PIPE I J [PID] * Open a new output file, constructing it from FORMAT and the column- and * row-index values I and J. If PIPE is non-NULL, open the file via a pipe @@ -43,7 +53,7 @@ static FILE *open_output_file(const char *fmt, const char *pipe_via, const int i, const int j, pid_t *child_pid) { FILE *fp; char *filename; - filename = malloc(strlen(fmt) + 64); + filename = xmalloc(strlen(fmt) + 64); sprintf(filename, fmt, i, j); /* XXX consider creating directories if they don't already exist? */ if (pipe_via) { @@ -126,6 +136,11 @@ void usage(FILE *fp) { " and TILEROW in the environment of the command are set to\n" " the column and row indices of the tile being generated.\n" "\n" +" -s Use a slow but more correct implementation, which processes\n" +" the image files only through netpbm's own API, rather than\n" +" copying pixel data directly between input and output\n" +" images.\n" +"\n" "Note that you can specify -f /dev/null and use the pipe command to create\n" "the output images, for instance with a command like,\n" " pnmtilesplit -p 'pnmtopng > $TILEROW,$TILECOL.png' -f /dev/null 256 256\n" @@ -147,9 +162,11 @@ int main(int argc, char *argv[]) { pid_t *tile_pid; char *outfile_format = "%d,%d.pnm", *pipe_via = NULL; extern int opterr, optopt, optind; - static const char optstr[] = "hvPf:p:"; - int i, j, c, progress = 0; - tuple *img_row; + static const char optstr[] = "hvPsf:p:"; + int i, j, c, progress = 0, fast_and_ugly = 1; + tuple *img_row = NULL; /* suppress bogus "might be used uninitialised" */ + unsigned char *buf = NULL; + size_t img_rowlen = 0, tile_rowlen = 0; pnm_init(&argc, argv); opterr = 0; @@ -176,6 +193,10 @@ int main(int argc, char *argv[]) { pipe_via = optarg; break; + case 's': + fast_and_ugly = 0; + break; + case '?': default: if (strchr(optstr, optopt)) @@ -233,12 +254,18 @@ int main(int argc, char *argv[]) { debug("input image is %d by %d pixels\n", img_pam.width, img_pam.height); debug(" = %d by %d tiles of %d by %d", cols, rows, tile_w, tile_h); + debug("each pixel contains %d planes, %d bytes per sample", + img_pam.depth, img_pam.bytes_per_sample); - tile_fp = malloc(cols * sizeof *tile_fp); - tile_pam = malloc(cols * sizeof *tile_pam); - tile_pid = malloc(cols * sizeof *tile_pid); + tile_fp = xmalloc(cols * sizeof *tile_fp); + tile_pam = xmalloc(cols * sizeof *tile_pam); + tile_pid = xmalloc(cols * sizeof *tile_pid); - if (!(img_row = pnm_allocpamrow(&img_pam))) + if (fast_and_ugly) { + img_rowlen = img_pam.width * img_pam.depth * img_pam.bytes_per_sample; + buf = xmalloc(img_rowlen); + tile_rowlen = tile_w * img_pam.depth * img_pam.bytes_per_sample; + } else if (!(img_row = pnm_allocpamrow(&img_pam))) die("unable to allocate storage for input row"); for (j = 0; j < rows; ++j) { @@ -258,10 +285,34 @@ int main(int argc, char *argv[]) { /* Copy the image into the various tiles. */ for (y = 0; y < tile_h; ++y) { - pnm_readpamrow(&img_pam, img_row); - for (i = 0; i < cols; ++i) { - pnm_writepamrow(tile_pam + i, img_row + i * tile_w); - fflush(tile_fp[i]); + /* Ugly. libpnm is pretty slow, so for large images it is much + * quicker to copy bytes from input to output streams using + * straight stdio calls. If fast_and_ugly is true (the default) + * then we use such an implementation; but it makes assumptions + * about the format of the input PNM file which might not be + * accurate. So we make this optional. */ + if (fast_and_ugly) { + size_t n; + if (img_rowlen != (n = fread(buf, 1, img_rowlen, img_fp))) { + if (feof(img_fp)) + die("%s: premature EOF", img_name); + else + die("%s: %s", img_name, strerror(errno)); + } + for (i = 0; i < cols; ++i) { + if (tile_rowlen + != (n = fwrite(buf + i * tile_rowlen, + 1, tile_rowlen, tile_fp[i]))) { + die("while writing tile (%d, %d): %s", i, j, + strerror(errno)); + } + } + } else { + pnm_readpamrow(&img_pam, img_row); + for (i = 0; i < cols; ++i) { + pnm_writepamrow(tile_pam + i, img_row + i * tile_w); + fflush(tile_fp[i]); + } } if (progress) fprintf(stderr, "\r%d/%d", j * tile_h + y, img_pam.height); |