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#include <dirent.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <unistd.h>
#include "river.h"
int river_has_line(river *r)
{
if (r->least >= 0)
return 1;
else
return 0;
}
char *river_least_line(river *r)
{
if (river_has_line(r))
return r->in[r->least]->line;
else
return "(eof)";
}
void river_scroll(river *r)
{
next_line(r->in[r->least]);
}
static int river_find_least(river *r)
{
int i;
r->least = -1;
for ( i = 0; i < r->n; i++ ) {
if ( NULL == r->in[i]->file ) {
continue;
} else if ( r->least == -1 ) {
r->least = i;
} else {
int x = strcmp( r->in[r->least]->line, r->in[i]->line );
if ( x == 0 ) {
next_line(r->in[i]);
} else if ( x > 0 ) {
r->least = i;
}
}
}
return r->least;
}
static int river_close(river* r)
{
int i;
for (i = 0; i < r->n; i++)
{
if (r->out[i])
if (fclose(r->out[i]) != 0)
return 0;
if (r->in[i]->file)
if (fclose(r->in[i]->file) != 0)
return 0;
free(r->in[i]);
}
r->n = 0;
return 1;
}
int rivers_close(river *rivers)
{
unsigned int idx;
for (idx = 0; idx < NUM_RIVERS; idx++)
if (! river_close(&rivers[idx]))
return 0;
return 1;
}
/*
* Compares two rivers, and returns the offset of the smaller one.
*
* Also understands the concept of a "fake prev. river", with index=-1, which
* only compares as smaller than dry rivers (whose inputs is all EOF). This
* makes the pick_smallest_rivers algorithm a bit more straightforward.
*/
int rivers_compare(int prev_idx, int cur_idx, river *rivers)
{
int prev_has_lines;
int cur_has_lines;
/* the "fake river" can only be considered smaller, if the other one is
* at EOF (has no more lines) */
if (prev_idx == -1) {
int smaller = river_has_line(&rivers[cur_idx]) ? cur_idx : prev_idx;
cruft_debug("\t\t\t\tFake prev, smaller= %d\n", smaller);
return smaller;
}
cruft_debug("\t\t\t\tComparing prev_idx=%d and cur_idx=%d\n", prev_idx, cur_idx);
prev_has_lines = river_has_line(&rivers[prev_idx]);
cur_has_lines = river_has_line(&rivers[cur_idx]);
#define A_TIE -2
if (prev_has_lines && cur_has_lines) {
int res = strcmp(river_least_line(&rivers[prev_idx]), river_least_line(&rivers[cur_idx]));
cruft_debug("\t\t\t\tBoth have lines: %s\n", res < 0 ? "prev is smaller" :
res > 0 ? "cur is smaller" : "and are equal");
return res < 0 ? prev_idx : res > 0 ? cur_idx : A_TIE;
} else if (cur_has_lines) {
cruft_debug("\t\t\t\tOnly cur has lines, so wins\n");
return cur_idx;
} else if (prev_has_lines) {
cruft_debug("\t\t\t\tOnly prev has lines, so wins\n");
return prev_idx;
} else {
cruft_debug("\t\t\t\tNone have lines, a tie\n");
return A_TIE;
}
}
/*
* Opens an input file for reading, and an output file (with a changed prefix)
* for writing.
* TODO: because of how the filename is transformed, we are currently limited
* to 4-char prefixes for both input and output filenames.
*/
static int open_streams(char *d_name, river *r)
{
/* XXX buffer overflow */
char filename[1000];
strcpy(filename, d_name);
strncpy(filename, r->output_prefix, strlen(r->output_prefix));
if ((r->out[r->n] = fopen(filename, "w")) == NULL) {
perror(filename);
return 0;
}
if ((r->in[r->n] = init_fn_stream(d_name)) == NULL) {
fclose(r->out[r->n]);
return 0;
}
r->n++;
return 1;
}
int river_output_line(river *r)
{
int ret = fprintf(r->out[r->least], "%s\n", river_least_line(r));
if (ret < 0) {
perror("fprintf");
return 0;
} else
return 1;
}
int rivers_open_files(char *spool_dir_name, river *rivers)
{
DIR* spool_dir;
struct dirent* pde;
spool_dir = opendir( spool_dir_name );
if ( spool_dir == NULL ) {
perror( spool_dir_name );
return 0;
}
if (chdir(spool_dir_name) != 0) {
perror(spool_dir_name);
return 0;
}
while( (pde = readdir( spool_dir )) ) {
unsigned int idx;
for (idx = 0; idx < NUM_RIVERS; idx++) {
river *r = &rivers[idx];
if (strncmp(pde->d_name, r->input_prefix, strlen(r->input_prefix)) == 0)
if (! open_streams(pde->d_name, r))
return 0;
}
}
closedir(spool_dir);
return 1;
}
/* Find the smallest line within each river (among its streams) and return true
* if there is input available in at least one of the rivers */
int rivers_prepare_round(river *rivers)
{
int ret = 0;
unsigned int idx;
for (idx = 0; idx < NUM_RIVERS; idx++)
if (river_find_least(&rivers[idx]) >= 0)
ret = 1;
return ret;
}
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