homework-jianmu/source/libs/index/src/index_fst_counting_writer.c

/*
 * Copyright (c) 2019 TAOS Data, Inc. <jhtao@taosdata.com>
 *
 * This program is free software: you can use, redistribute, and/or modify
 * it under the terms of the GNU Affero General Public License, version 3
 * or later ("AGPL"), as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */
#include "tutil.h"
#include "indexInt.h"
#include "index_fst_util.h"
#include "index_fst_counting_writer.h"

static int writeCtxDoWrite(WriterCtx *ctx, uint8_t *buf, int len) {
  if (ctx->offset + len > ctx->limit) {
    return -1;
  }

  if (ctx->type == TFile) {
    assert(len == tfWrite(ctx->fd, buf, len));
  } else {
    memcpy(ctx->mem + ctx->offset, buf, len);
  } 
  ctx->offset += len;
  return len;
}
static int writeCtxDoRead(WriterCtx *ctx, uint8_t *buf, int len) {
  int nRead = 0; 
  if (ctx->type == TFile) {
    nRead = tfRead(ctx->fd, buf, len);
  } else {
    memcpy(buf, ctx->mem + ctx->offset, len);
  }
  ctx->offset += nRead;

  return nRead;
} 
static int writeCtxDoFlush(WriterCtx *ctx) {
  if (ctx->type == TFile) {
    //tfFsync(ctx->fd);
    //tfFlush(ctx->fd);
  } else {
    // do nothing
  }
  return 1;
}

WriterCtx* writerCtxCreate(WriterType type, bool readOnly) {     
  WriterCtx *ctx = calloc(1, sizeof(WriterCtx));
  if (ctx == NULL) { return NULL; }

  ctx->type = type;
  if (ctx->type == TFile) {
    tfInit();
    // ugly code, refactor later
    if (readOnly == false) {
      ctx->fd = tfOpenCreateWriteAppend(tmpFile);  
    } else {
      ctx->fd = tfOpenReadWrite(tmpFile);
    } 
    if (ctx->fd < 0) {
      indexError("open file error %d", errno);       
    }
  } else if (ctx->type == TMemory) {
    ctx->mem = calloc(1, DefaultMem * sizeof(uint8_t));
  } 
  ctx->write = writeCtxDoWrite;
  ctx->read  = writeCtxDoRead;
  ctx->flush = writeCtxDoFlush;

  ctx->offset = 0;
  ctx->limit  = DefaultMem;

  return ctx;
}
void writerCtxDestroy(WriterCtx *ctx) {
  if (ctx->type == TMemory) {
    free(ctx->mem);
  } else {
    tfClose(ctx->fd);    
    tfCleanup();
  }
  free(ctx);
}


FstCountingWriter *fstCountingWriterCreate(void *wrt, bool readOnly) {
  FstCountingWriter *cw = calloc(1, sizeof(FstCountingWriter)); 
  if (cw == NULL) { return NULL; }
  
  cw->wrt = (void *)(writerCtxCreate(TFile, readOnly)); 
  return cw; 
}
void fstCountingWriterDestroy(FstCountingWriter *cw) {
  // free wrt object: close fd or free mem 
  fstCountingWriterFlush(cw);
  writerCtxDestroy((WriterCtx *)(cw->wrt));
  free(cw);
}

int fstCountingWriterWrite(FstCountingWriter *write, uint8_t *buf, uint32_t len) {
  if (write == NULL) { return 0; } 
  // update checksum 
  // write data to file/socket or mem
  WriterCtx *ctx = write->wrt;

  int nWrite = ctx->write(ctx, buf, len); 
  assert(nWrite == len);
  write->count += len;
  return len; 
} 
int fstCountingWriterRead(FstCountingWriter *write, uint8_t *buf, uint32_t len) {
  if (write == NULL) { return 0; }
  WriterCtx *ctx = write->wrt;
  int nRead = ctx->read(ctx, buf, len);
  //assert(nRead == len);
  return nRead; 
} 

uint32_t fstCountingWriterMaskedCheckSum(FstCountingWriter *write) {
  return 0;
}
int fstCountingWriterFlush(FstCountingWriter *write) {
  WriterCtx *ctx = write->wrt;
  ctx->flush(ctx);
  //write->wtr->flush
  return 1;
}

void fstCountingWriterPackUintIn(FstCountingWriter *writer, uint64_t n,  uint8_t nBytes) {
  assert(1 <= nBytes && nBytes <= 8);
  uint8_t *buf = calloc(8, sizeof(uint8_t));  
  for (uint8_t i = 0; i < nBytes; i++) {
    buf[i] = (uint8_t)n; 
    n = n >> 8;
  }
  fstCountingWriterWrite(writer, buf, nBytes);
  free(buf);
  return;
}

uint8_t fstCountingWriterPackUint(FstCountingWriter *writer, uint64_t n) {
  uint8_t nBytes = packSize(n);
  fstCountingWriterPackUintIn(writer, n, nBytes);
  return nBytes; 
}