nel/3rdparty/seven_zip/7zStream.c

   1 /* 7zStream.c -- 7z Stream functions
   2 2017-04-03 : Igor Pavlov : Public domain */
   3
   4 #include "Precomp.h"
   5
   6 #include <string.h>
   7
   8 #include "7zTypes.h"
   9
  10 SRes SeqInStream_Read2(const ISeqInStream *stream, void *buf, size_t size, SRes errorType)
  11 {
  12   while (size != 0)
  13   {
  14     size_t processed = size;
  15     RINOK(ISeqInStream_Read(stream, buf, &processed));
  16     if (processed == 0)
  17       return errorType;
  18     buf = (void *)((Byte *)buf + processed);
  19     size -= processed;
  20   }
  21   return SZ_OK;
  22 }
  23
  24 SRes SeqInStream_Read(const ISeqInStream *stream, void *buf, size_t size)
  25 {
  26   return SeqInStream_Read2(stream, buf, size, SZ_ERROR_INPUT_EOF);
  27 }
  28
  29 SRes SeqInStream_ReadByte(const ISeqInStream *stream, Byte *buf)
  30 {
  31   size_t processed = 1;
  32   RINOK(ISeqInStream_Read(stream, buf, &processed));
  33   return (processed == 1) ? SZ_OK : SZ_ERROR_INPUT_EOF;
  34 }
  35
  36
  37
  38 SRes LookInStream_SeekTo(const ILookInStream *stream, UInt64 offset)
  39 {
  40   Int64 t = offset;
  41   return ILookInStream_Seek(stream, &t, SZ_SEEK_SET);
  42 }
  43
  44 SRes LookInStream_LookRead(const ILookInStream *stream, void *buf, size_t *size)
  45 {
  46   const void *lookBuf;
  47   if (*size == 0)
  48     return SZ_OK;
  49   RINOK(ILookInStream_Look(stream, &lookBuf, size));
  50   memcpy(buf, lookBuf, *size);
  51   return ILookInStream_Skip(stream, *size);
  52 }
  53
  54 SRes LookInStream_Read2(const ILookInStream *stream, void *buf, size_t size, SRes errorType)
  55 {
  56   while (size != 0)
  57   {
  58     size_t processed = size;
  59     RINOK(ILookInStream_Read(stream, buf, &processed));
  60     if (processed == 0)
  61       return errorType;
  62     buf = (void *)((Byte *)buf + processed);
  63     size -= processed;
  64   }
  65   return SZ_OK;
  66 }
  67
  68 SRes LookInStream_Read(const ILookInStream *stream, void *buf, size_t size)
  69 {
  70   return LookInStream_Read2(stream, buf, size, SZ_ERROR_INPUT_EOF);
  71 }
  72
  73
  74
  75 #define GET_LookToRead2 CLookToRead2 *p = CONTAINER_FROM_VTBL(pp, CLookToRead2, vt);
  76
  77 static SRes LookToRead2_Look_Lookahead(const ILookInStream *pp, const void **buf, size_t *size)
  78 {
  79   SRes res = SZ_OK;
  80   GET_LookToRead2
  81   size_t size2 = p->size - p->pos;
  82   if (size2 == 0 && *size != 0)
  83   {
  84     p->pos = 0;
  85     p->size = 0;
  86     size2 = p->bufSize;
  87     res = ISeekInStream_Read(p->realStream, p->buf, &size2);
  88     p->size = size2;
  89   }
  90   if (*size > size2)
  91     *size = size2;
  92   *buf = p->buf + p->pos;
  93   return res;
  94 }
  95
  96 static SRes LookToRead2_Look_Exact(const ILookInStream *pp, const void **buf, size_t *size)
  97 {
  98   SRes res = SZ_OK;
  99   GET_LookToRead2
 100   size_t size2 = p->size - p->pos;
 101   if (size2 == 0 && *size != 0)
 102   {
 103     p->pos = 0;
 104     p->size = 0;
 105     if (*size > p->bufSize)
 106       *size = p->bufSize;
 107     res = ISeekInStream_Read(p->realStream, p->buf, size);
 108     size2 = p->size = *size;
 109   }
 110   if (*size > size2)
 111     *size = size2;
 112   *buf = p->buf + p->pos;
 113   return res;
 114 }
 115
 116 static SRes LookToRead2_Skip(const ILookInStream *pp, size_t offset)
 117 {
 118   GET_LookToRead2
 119   p->pos += offset;
 120   return SZ_OK;
 121 }
 122
 123 static SRes LookToRead2_Read(const ILookInStream *pp, void *buf, size_t *size)
 124 {
 125   GET_LookToRead2
 126   size_t rem = p->size - p->pos;
 127   if (rem == 0)
 128     return ISeekInStream_Read(p->realStream, buf, size);
 129   if (rem > *size)
 130     rem = *size;
 131   memcpy(buf, p->buf + p->pos, rem);
 132   p->pos += rem;
 133   *size = rem;
 134   return SZ_OK;
 135 }
 136
 137 static SRes LookToRead2_Seek(const ILookInStream *pp, Int64 *pos, ESzSeek origin)
 138 {
 139   GET_LookToRead2
 140   p->pos = p->size = 0;
 141   return ISeekInStream_Seek(p->realStream, pos, origin);
 142 }
 143
 144 void LookToRead2_CreateVTable(CLookToRead2 *p, int lookahead)
 145 {
 146   p->vt.Look = lookahead ?
 147       LookToRead2_Look_Lookahead :
 148       LookToRead2_Look_Exact;
 149   p->vt.Skip = LookToRead2_Skip;
 150   p->vt.Read = LookToRead2_Read;
 151   p->vt.Seek = LookToRead2_Seek;
 152 }
 153
 154
 155
 156 static SRes SecToLook_Read(const ISeqInStream *pp, void *buf, size_t *size)
 157 {
 158   CSecToLook *p = CONTAINER_FROM_VTBL(pp, CSecToLook, vt);
 159   return LookInStream_LookRead(p->realStream, buf, size);
 160 }
 161
 162 void SecToLook_CreateVTable(CSecToLook *p)
 163 {
 164   p->vt.Read = SecToLook_Read;
 165 }
 166
 167 static SRes SecToRead_Read(const ISeqInStream *pp, void *buf, size_t *size)
 168 {
 169   CSecToRead *p = CONTAINER_FROM_VTBL(pp, CSecToRead, vt);
 170   return ILookInStream_Read(p->realStream, buf, size);
 171 }
 172
 173 void SecToRead_CreateVTable(CSecToRead *p)
 174 {
 175   p->vt.Read = SecToRead_Read;
 176 }