dl.c

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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <inttypes.h>
#include <errno.h>

#include "ev3_io.h"

#include "defs.h"
#include "packets.h"
#include "error.h"
#include "funcs.h"

#define CHUNK_SIZE 1000 // EV3's HID driver doesn't do packets > 1024B

int dl(const char *path, FILE *fp)
{
    int res;
    size_t path_sz = strlen(path) + 1;

    BEGIN_UPLOAD *bu = packet_alloc(BEGIN_UPLOAD, path_sz);
    memcpy(bu->fileName, path, path_sz);
    bu->maxBytes = CHUNK_SIZE;

    //print_bytes(bu, bu->packetLen + PREFIX_SIZE);
    res = ev3_write(handle, (u8 *)bu, bu->packetLen + PREFIX_SIZE);
    if (res < 0)
    {
        errmsg = "Unable to write BEGIN_UPLOAD.";
        return ERR_COMM;
    }
    size_t file_chunksz = sizeof(BEGIN_UPLOAD_REPLY) + bu->maxBytes;
    void *file_chunk = malloc(file_chunksz);

    BEGIN_UPLOAD_REPLY *burep = file_chunk;

    res = ev3_read_timeout(handle, (u8 *)burep, file_chunksz, TIMEOUT);
    if (res <= 0)
    {
        errmsg = "Unable to read BEGIN_UPLOAD";
        return ERR_COMM;
    }

    if (burep->type == VM_ERROR)
    {
        errno = burep->ret;
        fputs("Operation failed.\nlast_reply=", stderr);
        print_bytes(burep, burep->packetLen);


        errmsg = "`BEGIN_UPLOAD` was denied.";
        return ERR_VM;
    }
    unsigned read_so_far = burep->packetLen + 2 - offsetof(BEGIN_UPLOAD_REPLY, bytes);
    fwrite(burep->bytes, read_so_far, 1, fp);

    unsigned total = burep->fileSize;

    CONTINUE_UPLOAD cu = CONTINUE_UPLOAD_INIT;
    cu.fileHandle =burep->fileHandle;
    cu.maxBytes = CHUNK_SIZE + sizeof(BEGIN_UPLOAD_REPLY) - sizeof(CONTINUE_UPLOAD_REPLY);
    //fprintf(stderr, "read %u from total %u bytes.\n", read_so_far, total);
    CONTINUE_UPLOAD_REPLY *curep = file_chunk;
    while(read_so_far < total)
    {
        res = ev3_write(handle, (u8*)&cu, sizeof cu);
        if (res < 0)
        {
            errmsg = "Unable to write CONTINUE_UPLOAD";
            return ERR_COMM;
        }

        res = ev3_read_timeout(handle, (u8 *)curep, file_chunksz, TIMEOUT);
        if (res <= 0)
        {
            errmsg = "Unable to read CONTINUE_UPLOAD_REPLY";
            return ERR_COMM;
        }
        if (curep->type == VM_ERROR)
        {
            errno = curep->ret;
            fputs("Operation failed.\nlast_reply=", stderr);
            print_bytes(curep, curep->packetLen);

            errmsg = "`CONTINUE_UPLOAD` was denied.";
            return ERR_VM;
        }   
        size_t read_this_time = curep->packetLen + 2 - offsetof(CONTINUE_UPLOAD_REPLY, bytes);
        fwrite(curep->bytes, read_this_time, 1, fp);
        cu.fileHandle = curep->fileHandle;
        read_so_far += read_this_time;
        //fprintf(stderr, "read %u from total %u bytes.\n", read_so_far, total);
    }

    errmsg = "`BEGIN_UPLOAD` was successful.";
    return ERR_UNK;

}