Function WriteRecordToFile

tracer-pin/trace.cpp:7–52

#include <string.h>         /* memcpy                                       */

void
WriteRecordToFile(RecordKind kind, uint8_t* data, size_t data_size, FILE* outfile)
{
    uint8_t vlen[4], rlen[5];
    LenLenPair p = calculate_vlen_rlen_sizes(data_size, vlen, rlen);
    size_t vlenlen = p.vlenlen;
    size_t rlenlen = p.rlenlen;

    uint8_t magic = (uint8_t)kind | vlenlen_to_lenlen(vlenlen);

    size_t buf_size = sizeof(magic) + vlenlen + data_size + rlenlen;
    // sizeof(magic) + vlenlen + rlenlen cannot wrap,
    // so we only have to check for wrap on data_size
    if (buf_size < data_size) {
        LOG("data_size exceeds maximum record size");
        return;
    }
    uint8_t* buf = (uint8_t*)alloca(buf_size);
    size_t cursor = 0;

    // cursor
    //    ↓
    // [magic][...]
    buf[cursor] = magic;
    cursor++;

    //        cursor
    //          ↓
    // [magic][vlen][...]
    memcpy(buf + cursor, vlen, vlenlen);
    cursor += vlenlen;

    //              cursor
    //                ↓
    // [magic][vlen][data][...]
    //if (cursor > buf_size - 1 - vlenlen - data_size) return;
    memcpy(buf + cursor, data, data_size);
    cursor += data_size;

    //                    cursor
    //                      ↓
    // [magic][vlen][data][rlen]
    memcpy(buf + cursor, rlen, rlenlen);

    fwrite(buf, buf_size, 1, outfile);
}

size_t
lenlen(uint8_t ty)