1 files changed, 176 insertions, 0 deletions

diff --git a/C/7zStream.c b/C/7zStream.c
new file mode 100644
index 0000000..28a1460
--- /dev/null
+++ b/C/7zStream.c
@@ -0,0 +1,176 @@
+/* 7zStream.c -- 7z Stream functions
+2021-02-09 : 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 = (Int64)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;
+}