parallel_conv.c

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#include <assert.h>
 
#include "utils/misc.h"
#include "utils/parallel_conv.h"
#include "utils/worker.h"
 
struct parallel_pix_conv_data {
        decoder_t decode;
        int height;
        unsigned char *out_data;
        int out_linesize;
        const unsigned char *in_data;
        int in_linesize;
};
 
static void *parallel_pix_conv_task(void *arg) {
        struct parallel_pix_conv_data *data = arg;
        for (int y = 0; y < data->height; ++y) {
                data->decode(data->out_data, data->in_data, data->out_linesize, DEFAULT_R_SHIFT, DEFAULT_G_SHIFT, DEFAULT_B_SHIFT);
                data->out_data += data->out_linesize;
                data->in_data += data->in_linesize;
        }
        return NULL;
}
 
void parallel_pix_conv(int height, char *out, int out_linesize, const char *in, int in_linesize, decoder_t decode, int threads)
{
        if (threads == 0) {
                threads = get_cpu_core_count();
        }
        assert(threads > 0);
        struct parallel_pix_conv_data data[threads];
 
        for (ptrdiff_t i = 0; i < threads; ++i) {
                data[i].decode = decode;
                data[i].height = height / threads;
                data[i].out_data = (unsigned char *) out + i * data[i].height * out_linesize;
                data[i].out_linesize = out_linesize;
                data[i].in_data = (const unsigned char *) in + i * data[i].height * in_linesize;
                data[i].in_linesize = in_linesize;
                if (i == threads - 1) {
                        data[i].height = height - (threads - 1) * (height / threads);
                }
        }
 
        task_run_parallel(parallel_pix_conv_task, threads, data, sizeof data[0], NULL);
}