/* 7zStream.c -- 7z Stream functions

2017-04-03 : Igor Pavlov : Public domain */

#include "Precomp.h"

#include <string.h>

#include "7zTypes.h"

SRes SeqInStream_Read2(const ISeqInStream *stream, void *buf, size_t size, SRes errorType)

{

  while (size != 0)

  {

    size_t processed = size;

    RINOK(ISeqInStream_Read(stream, buf, &processed));

    if (processed == 0)

      return errorType;

    buf = (void *)((Byte *)buf + processed);

    size -= processed;

  }

  return SZ_OK;

}

SRes SeqInStream_Read(const ISeqInStream *stream, void *buf, size_t size)

{

  return SeqInStream_Read2(stream, buf, size, SZ_ERROR_INPUT_EOF);

}

SRes SeqInStream_ReadByte(const ISeqInStream *stream, Byte *buf)

{

  size_t processed = 1;

  RINOK(ISeqInStream_Read(stream, buf, &processed));

  return (processed == 1) ? SZ_OK : SZ_ERROR_INPUT_EOF;

}

SRes LookInStream_SeekTo(const ILookInStream *stream, UInt64 offset)

{

  Int64 t = offset;

  return ILookInStream_Seek(stream, &t, SZ_SEEK_SET);

}

SRes LookInStream_LookRead(const ILookInStream *stream, void *buf, size_t *size)

{

  const void *lookBuf;

  if (*size == 0)

    return SZ_OK;

  RINOK(ILookInStream_Look(stream, &lookBuf, size));

  memcpy(buf, lookBuf, *size);

  return ILookInStream_Skip(stream, *size);

}

SRes LookInStream_Read2(const ILookInStream *stream, void *buf, size_t size, SRes errorType)

{

  while (size != 0)

  {

    size_t processed = size;

    RINOK(ILookInStream_Read(stream, buf, &processed));

    if (processed == 0)

      return errorType;

    buf = (void *)((Byte *)buf + processed);

    size -= processed;

  }

  return SZ_OK;

}

SRes LookInStream_Read(const ILookInStream *stream, void *buf, size_t size)

{

  return LookInStream_Read2(stream, buf, size, SZ_ERROR_INPUT_EOF);

}

#define GET_LookToRead2 CLookToRead2 *p = CONTAINER_FROM_VTBL(pp, CLookToRead2, vt);

static SRes LookToRead2_Look_Lookahead(const ILookInStream *pp, const void **buf, size_t *size)

{

  SRes res = SZ_OK;

  GET_LookToRead2

  size_t size2 = p->size - p->pos;

  if (size2 == 0 && *size != 0)

  {

    p->pos = 0;

    p->size = 0;

    size2 = p->bufSize;

    res = ISeekInStream_Read(p->realStream, p->buf, &size2);

    p->size = size2;

  }

  if (*size > size2)

    *size = size2;

  *buf = p->buf + p->pos;

  return res;

}

static SRes LookToRead2_Look_Exact(const ILookInStream *pp, const void **buf, size_t *size)

{

  SRes res = SZ_OK;

  GET_LookToRead2

  size_t size2 = p->size - p->pos;

  if (size2 == 0 && *size != 0)

  {

    p->pos = 0;

    p->size = 0;

    if (*size > p->bufSize)

      *size = p->bufSize;

    res = ISeekInStream_Read(p->realStream, p->buf, size);

    size2 = p->size = *size;

  }

  if (*size > size2)

    *size = size2;

  *buf = p->buf + p->pos;

  return res;

}

static SRes LookToRead2_Skip(const ILookInStream *pp, size_t offset)

{

  GET_LookToRead2

  p->pos += offset;

  return SZ_OK;

}

static SRes LookToRead2_Read(const ILookInStream *pp, void *buf, size_t *size)

{

  GET_LookToRead2

  size_t rem = p->size - p->pos;

  if (rem == 0)

    return ISeekInStream_Read(p->realStream, buf, size);

  if (rem > *size)

    rem = *size;

  memcpy(buf, p->buf + p->pos, rem);

  p->pos += rem;

  *size = rem;

  return SZ_OK;

}

static SRes LookToRead2_Seek(const ILookInStream *pp, Int64 *pos, ESzSeek origin)

{

  GET_LookToRead2

  p->pos = p->size = 0;

  return ISeekInStream_Seek(p->realStream, pos, origin);

}

void LookToRead2_CreateVTable(CLookToRead2 *p, int lookahead)

{

  p->vt.Look = lookahead ?

      LookToRead2_Look_Lookahead :

      LookToRead2_Look_Exact;

  p->vt.Skip = LookToRead2_Skip;

  p->vt.Read = LookToRead2_Read;

  p->vt.Seek = LookToRead2_Seek;

}

static SRes SecToLook_Read(const ISeqInStream *pp, void *buf, size_t *size)

{

  CSecToLook *p = CONTAINER_FROM_VTBL(pp, CSecToLook, vt);

  return LookInStream_LookRead(p->realStream, buf, size);

}

void SecToLook_CreateVTable(CSecToLook *p)

{

  p->vt.Read = SecToLook_Read;

}

static SRes SecToRead_Read(const ISeqInStream *pp, void *buf, size_t *size)

{

  CSecToRead *p = CONTAINER_FROM_VTBL(pp, CSecToRead, vt);

  return ILookInStream_Read(p->realStream, buf, size);

}

void SecToRead_CreateVTable(CSecToRead *p)

{

  p->vt.Read = SecToRead_Read;

}