logmemfile.c

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/*
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * 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.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * Copyright 2006 Joseph Eagar <joeedh@gmail.com>
 */
 
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
 
#include "logImageCore.h"
#include "logmemfile.h"
 
int logimage_fseek(LogImageFile *logFile, intptr_t offset, int origin)
{
  if (logFile->file) {
    fseek(logFile->file, offset, origin);
  }
  else { /* we're seeking in memory */
    if (origin == SEEK_SET) {
      if (offset > logFile->memBufferSize) {
        return 1;
      }
      logFile->memCursor = logFile->memBuffer + offset;
    }
    else if (origin == SEEK_END) {
      if (offset > logFile->memBufferSize) {
        return 1;
      }
      logFile->memCursor = (logFile->memBuffer + logFile->memBufferSize) - offset;
    }
    else if (origin == SEEK_CUR) {
      uintptr_t pos = (uintptr_t)logFile->memCursor - (uintptr_t)logFile->memBuffer;
      if (pos + offset > logFile->memBufferSize) {
        return 1;
      }
 
      logFile->memCursor += offset;
    }
  }
  return 0;
}
 
int logimage_fwrite(void *buffer, size_t size, unsigned int count, LogImageFile *logFile)
{
  if (logFile->file) {
    return fwrite(buffer, size, count, logFile->file);
  }
  /* we're writing to memory */
  /* do nothing as this isn't supported yet */
  return count;
}
 
int logimage_fread(void *buffer, size_t size, unsigned int count, LogImageFile *logFile)
{
  if (logFile->file) {
    return fread(buffer, size, count, logFile->file);
  }
  /* we're reading from memory */
  unsigned char *buf = (unsigned char *)buffer;
  uintptr_t pos = (uintptr_t)logFile->memCursor - (uintptr_t)logFile->memBuffer;
  size_t total_size = size * count;
  if (pos + total_size > logFile->memBufferSize) {
    /* how many elements can we read without overflow ? */
    count = (logFile->memBufferSize - pos) / size;
    /* recompute the size */
    total_size = size * count;
  }
 
  if (total_size != 0) {
    memcpy(buf, logFile->memCursor, total_size);
  }
 
  return count;
}
 
int logimage_read_uchar(unsigned char *x, LogImageFile *logFile)
{
  uintptr_t pos = (uintptr_t)logFile->memCursor - (uintptr_t)logFile->memBuffer;
  if (pos + sizeof(unsigned char) > logFile->memBufferSize) {
    return 1;
  }
 
  *x = *(unsigned char *)logFile->memCursor;
  logFile->memCursor += sizeof(unsigned char);
  return 0;
}
 
int logimage_read_ushort(unsigned short *x, LogImageFile *logFile)
{
  uintptr_t pos = (uintptr_t)logFile->memCursor - (uintptr_t)logFile->memBuffer;
  if (pos + sizeof(unsigned short) > logFile->memBufferSize) {
    return 1;
  }
 
  *x = *(unsigned short *)logFile->memCursor;
  logFile->memCursor += sizeof(unsigned short);
  return 0;
}
 
int logimage_read_uint(unsigned int *x, LogImageFile *logFile)
{
  uintptr_t pos = (uintptr_t)logFile->memCursor - (uintptr_t)logFile->memBuffer;
  if (pos + sizeof(unsigned int) > logFile->memBufferSize) {
    return 1;
  }
 
  *x = *(unsigned int *)logFile->memCursor;
  logFile->memCursor += sizeof(unsigned int);
  return 0;
}