courgette/encoded

/* [<][>][^][v][top][bottom][index][help] */
This source file includes following definitions.
WriteVector
ReadVector
WriteU32Delta
ReadU32Delta
WriteVectorU8
ReadVectorU8
DefineRel32Label
DefineAbs32Label
DefineLabelCommon
EndLabels
FinishLabelsCommon
AddOrigin
AddCopy
AddAbs32
AddRel32
AddRel32ARM
AddPeMakeRelocs
AddElfMakeRelocs
AddElfARMMakeRelocs
DebuggingSummary
GetFieldSelect
WriteTo
ReadFrom
VectorAt
EvaluateRel32ARM
AssembleTo
Add
Flush
GeneratePeRelocations
GenerateElfRelocations
WriteEncodedProgram
ReadEncodedProgram
Assemble
DeleteEncodedProgram
// Copyright (c) 2011 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "courgette/encoded_program.h"

#include <algorithm>
#include <map>
#include <string>
#include <vector>

#include "base/environment.h"
#include "base/logging.h"
#include "base/memory/scoped_ptr.h"
#include "base/strings/string_util.h"
#include "base/strings/utf_string_conversions.h"
#include "courgette/courgette.h"
#include "courgette/disassembler_elf_32_arm.h"
#include "courgette/streams.h"
#include "courgette/types_elf.h"

namespace courgette {

// Stream indexes.
const int kStreamMisc    = 0;
const int kStreamOps     = 1;
const int kStreamBytes   = 2;
const int kStreamAbs32Indexes = 3;
const int kStreamRel32Indexes = 4;
const int kStreamAbs32Addresses = 5;
const int kStreamRel32Addresses = 6;
const int kStreamCopyCounts = 7;
const int kStreamOriginAddresses = kStreamMisc;

const int kStreamLimit = 9;

// Constructor is here rather than in the header.  Although the constructor
// appears to do nothing it is fact quite large because of the implicit calls to
// field constructors.  Ditto for the destructor.
EncodedProgram::EncodedProgram() : image_base_(0) {}
EncodedProgram::~EncodedProgram() {}

// Serializes a vector of integral values using Varint32 coding.
template<typename V>
CheckBool WriteVector(const V& items, SinkStream* buffer) {
  size_t count = items.size();
  bool ok = buffer->WriteSizeVarint32(count);
  for (size_t i = 0; ok && i < count;  ++i) {
    COMPILE_ASSERT(sizeof(items[0]) <= sizeof(uint32),  // NOLINT
                   T_must_fit_in_uint32);
    ok = buffer->WriteSizeVarint32(items[i]);
  }
  return ok;
}

template<typename V>
bool ReadVector(V* items, SourceStream* buffer) {
  uint32 count;
  if (!buffer->ReadVarint32(&count))
    return false;

  items->clear();

  bool ok = items->reserve(count);
  for (size_t i = 0;  ok && i < count;  ++i) {
    uint32 item;
    ok = buffer->ReadVarint32(&item);
    if (ok)
      ok = items->push_back(static_cast<typename V::value_type>(item));
  }

  return ok;
}

// Serializes a vector, using delta coding followed by Varint32 coding.
template<typename V>
CheckBool WriteU32Delta(const V& set, SinkStream* buffer) {
  size_t count = set.size();
  bool ok = buffer->WriteSizeVarint32(count);
  uint32 prev = 0;
  for (size_t i = 0;  ok && i < count;  ++i) {
    uint32 current = set[i];
    uint32 delta = current - prev;
    ok = buffer->WriteVarint32(delta);
    prev = current;
  }
  return ok;
}

template <typename V>
static CheckBool ReadU32Delta(V* set, SourceStream* buffer) {
  uint32 count;

  if (!buffer->ReadVarint32(&count))
    return false;

  set->clear();
  bool ok = set->reserve(count);
  uint32 prev = 0;

  for (size_t i = 0; ok && i < count;  ++i) {
    uint32 delta;
    ok = buffer->ReadVarint32(&delta);
    if (ok) {
      uint32 current = prev + delta;
      ok = set->push_back(current);
      prev = current;
    }
  }

  return ok;
}

// Write a vector as the byte representation of the contents.
//
// (This only really makes sense for a type T that has sizeof(T)==1, otherwise
// serialized representation is not endian-agnostic.  But it is useful to keep
// the possibility of a greater size for experiments comparing Varint32 encoding
// of a vector of larger integrals vs a plain form.)
//
template<typename V>
CheckBool WriteVectorU8(const V& items, SinkStream* buffer) {
  size_t count = items.size();
  bool ok = buffer->WriteSizeVarint32(count);
  if (count != 0 && ok) {
    size_t byte_count = count * sizeof(typename V::value_type);
    ok = buffer->Write(static_cast<const void*>(&items[0]), byte_count);
  }
  return ok;
}

template<typename V>
bool ReadVectorU8(V* items, SourceStream* buffer) {
  uint32 count;
  if (!buffer->ReadVarint32(&count))
    return false;

  items->clear();
  bool ok = items->resize(count, 0);
  if (ok && count != 0) {
    size_t byte_count = count * sizeof(typename V::value_type);
    return buffer->Read(static_cast<void*>(&((*items)[0])), byte_count);
  }
  return ok;
}

////////////////////////////////////////////////////////////////////////////////

CheckBool EncodedProgram::DefineRel32Label(int index, RVA value) {
  return DefineLabelCommon(&rel32_rva_, index, value);
}

CheckBool EncodedProgram::DefineAbs32Label(int index, RVA value) {
  return DefineLabelCommon(&abs32_rva_, index, value);
}

static const RVA kUnassignedRVA = static_cast<RVA>(-1);

CheckBool EncodedProgram::DefineLabelCommon(RvaVector* rvas,
                                            int index,
                                            RVA rva) {
  bool ok = true;
  if (static_cast<int>(rvas->size()) <= index)
    ok = rvas->resize(index + 1, kUnassignedRVA);

  if (ok) {
    DCHECK_EQ((*rvas)[index], kUnassignedRVA)
        << "DefineLabel double assigned " << index;
    (*rvas)[index] = rva;
  }

  return ok;
}

void EncodedProgram::EndLabels() {
  FinishLabelsCommon(&abs32_rva_);
  FinishLabelsCommon(&rel32_rva_);
}

void EncodedProgram::FinishLabelsCommon(RvaVector* rvas) {
  // Replace all unassigned slots with the value at the previous index so they
  // delta-encode to zero.  (There might be better values than zero.  The way to
  // get that is have the higher level assembly program assign the unassigned
  // slots.)
  RVA previous = 0;
  size_t size = rvas->size();
  for (size_t i = 0;  i < size;  ++i) {
    if ((*rvas)[i] == kUnassignedRVA)
      (*rvas)[i] = previous;
    else
      previous = (*rvas)[i];
  }
}

CheckBool EncodedProgram::AddOrigin(RVA origin) {
  return ops_.push_back(ORIGIN) && origins_.push_back(origin);
}

CheckBool EncodedProgram::AddCopy(uint32 count, const void* bytes) {
  const uint8* source = static_cast<const uint8*>(bytes);

  bool ok = true;

  // Fold adjacent COPY instructions into one.  This nearly halves the size of
  // an EncodedProgram with only COPY1 instructions since there are approx plain
  // 16 bytes per reloc.  This has a working-set benefit during decompression.
  // For compression of files with large differences this makes a small (4%)
  // improvement in size.  For files with small differences this degrades the
  // compressed size by 1.3%
  if (!ops_.empty()) {
    if (ops_.back() == COPY1) {
      ops_.back() = COPY;
      ok = copy_counts_.push_back(1);
    }
    if (ok && ops_.back() == COPY) {
      copy_counts_.back() += count;
      for (uint32 i = 0; ok && i < count; ++i) {
        ok = copy_bytes_.push_back(source[i]);
      }
      return ok;
    }
  }

  if (ok) {
    if (count == 1) {
      ok = ops_.push_back(COPY1) && copy_bytes_.push_back(source[0]);
    } else {
      ok = ops_.push_back(COPY) && copy_counts_.push_back(count);
      for (uint32 i = 0; ok && i < count; ++i) {
        ok = copy_bytes_.push_back(source[i]);
      }
    }
  }

  return ok;
}

CheckBool EncodedProgram::AddAbs32(int label_index) {
  return ops_.push_back(ABS32) && abs32_ix_.push_back(label_index);
}

CheckBool EncodedProgram::AddRel32(int label_index) {
  return ops_.push_back(REL32) && rel32_ix_.push_back(label_index);
}

CheckBool EncodedProgram::AddRel32ARM(uint16 op, int label_index) {
  return ops_.push_back(static_cast<OP>(op)) &&
      rel32_ix_.push_back(label_index);
}

CheckBool EncodedProgram::AddPeMakeRelocs(ExecutableType kind) {
  if (kind == EXE_WIN_32_X86)
    return ops_.push_back(MAKE_PE_RELOCATION_TABLE);
  return ops_.push_back(MAKE_PE64_RELOCATION_TABLE);
}

CheckBool EncodedProgram::AddElfMakeRelocs() {
  return ops_.push_back(MAKE_ELF_RELOCATION_TABLE);
}

CheckBool EncodedProgram::AddElfARMMakeRelocs() {
  return ops_.push_back(MAKE_ELF_ARM_RELOCATION_TABLE);
}

void EncodedProgram::DebuggingSummary() {
  VLOG(1) << "EncodedProgram Summary"
          << "\n  image base  " << image_base_
          << "\n  abs32 rvas  " << abs32_rva_.size()
          << "\n  rel32 rvas  " << rel32_rva_.size()
          << "\n  ops         " << ops_.size()
          << "\n  origins     " << origins_.size()
          << "\n  copy_counts " << copy_counts_.size()
          << "\n  copy_bytes  " << copy_bytes_.size()
          << "\n  abs32_ix    " << abs32_ix_.size()
          << "\n  rel32_ix    " << rel32_ix_.size();
}

////////////////////////////////////////////////////////////////////////////////

// For algorithm refinement purposes it is useful to write subsets of the file
// format.  This gives us the ability to estimate the entropy of the
// differential compression of the individual streams, which can provide
// invaluable insights.  The default, of course, is to include all the streams.
//
enum FieldSelect {
  INCLUDE_ABS32_ADDRESSES = 0x0001,
  INCLUDE_REL32_ADDRESSES = 0x0002,
  INCLUDE_ABS32_INDEXES   = 0x0010,
  INCLUDE_REL32_INDEXES   = 0x0020,
  INCLUDE_OPS             = 0x0100,
  INCLUDE_BYTES           = 0x0200,
  INCLUDE_COPY_COUNTS     = 0x0400,
  INCLUDE_MISC            = 0x1000
};

static FieldSelect GetFieldSelect() {
#if 1
  // TODO(sra): Use better configuration.
  scoped_ptr<base::Environment> env(base::Environment::Create());
  std::string s;
  env->GetVar("A_FIELDS", &s);
  if (!s.empty()) {
    return static_cast<FieldSelect>(
        wcstoul(base::ASCIIToWide(s).c_str(), 0, 0));
  }
#endif
  return  static_cast<FieldSelect>(~0);
}

CheckBool EncodedProgram::WriteTo(SinkStreamSet* streams) {
  FieldSelect select = GetFieldSelect();

  // The order of fields must be consistent in WriteTo and ReadFrom, regardless
  // of the streams used.  The code can be configured with all kStreamXXX
  // constants the same.
  //
  // If we change the code to pipeline reading with assembly (to avoid temporary
  // storage vectors by consuming operands directly from the stream) then we
  // need to read the base address and the random access address tables first,
  // the rest can be interleaved.

  if (select & INCLUDE_MISC) {
    // TODO(sra): write 64 bits.
    if (!streams->stream(kStreamMisc)->WriteVarint32(
            static_cast<uint32>(image_base_))) {
      return false;
    }
  }

  bool success = true;

  if (select & INCLUDE_ABS32_ADDRESSES) {
    success &= WriteU32Delta(abs32_rva_,
                             streams->stream(kStreamAbs32Addresses));
  }

  if (select & INCLUDE_REL32_ADDRESSES) {
    success &= WriteU32Delta(rel32_rva_,
                             streams->stream(kStreamRel32Addresses));
  }

  if (select & INCLUDE_MISC)
    success &= WriteVector(origins_, streams->stream(kStreamOriginAddresses));

  if (select & INCLUDE_OPS) {
    // 5 for length.
    success &= streams->stream(kStreamOps)->Reserve(ops_.size() + 5);
    success &= WriteVector(ops_, streams->stream(kStreamOps));
  }

  if (select & INCLUDE_COPY_COUNTS)
    success &= WriteVector(copy_counts_, streams->stream(kStreamCopyCounts));

  if (select & INCLUDE_BYTES)
    success &= WriteVectorU8(copy_bytes_, streams->stream(kStreamBytes));

  if (select & INCLUDE_ABS32_INDEXES)
    success &= WriteVector(abs32_ix_, streams->stream(kStreamAbs32Indexes));

  if (select & INCLUDE_REL32_INDEXES)
    success &= WriteVector(rel32_ix_, streams->stream(kStreamRel32Indexes));

  return success;
}

bool EncodedProgram::ReadFrom(SourceStreamSet* streams) {
  // TODO(sra): read 64 bits.
  uint32 temp;
  if (!streams->stream(kStreamMisc)->ReadVarint32(&temp))
    return false;
  image_base_ = temp;

  if (!ReadU32Delta(&abs32_rva_, streams->stream(kStreamAbs32Addresses)))
    return false;
  if (!ReadU32Delta(&rel32_rva_, streams->stream(kStreamRel32Addresses)))
    return false;
  if (!ReadVector(&origins_, streams->stream(kStreamOriginAddresses)))
    return false;
  if (!ReadVector(&ops_, streams->stream(kStreamOps)))
    return false;
  if (!ReadVector(&copy_counts_, streams->stream(kStreamCopyCounts)))
    return false;
  if (!ReadVectorU8(&copy_bytes_, streams->stream(kStreamBytes)))
    return false;
  if (!ReadVector(&abs32_ix_, streams->stream(kStreamAbs32Indexes)))
    return false;
  if (!ReadVector(&rel32_ix_, streams->stream(kStreamRel32Indexes)))
    return false;

  // Check that streams have been completely consumed.
  for (int i = 0;  i < kStreamLimit;  ++i) {
    if (streams->stream(i)->Remaining() > 0)
      return false;
  }

  return true;
}

// Safe, non-throwing version of std::vector::at().  Returns 'true' for success,
// 'false' for out-of-bounds index error.
template<typename V, typename T>
bool VectorAt(const V& v, size_t index, T* output) {
  if (index >= v.size())
    return false;
  *output = v[index];
  return true;
}

CheckBool EncodedProgram::EvaluateRel32ARM(OP op,
                                           size_t& ix_rel32_ix,
                                           RVA& current_rva,
                                           SinkStream* output) {
  switch (op & 0x0000F000) {
    case REL32ARM8: {
      uint32 index;
      if (!VectorAt(rel32_ix_, ix_rel32_ix, &index))
        return false;
      ++ix_rel32_ix;
      RVA rva;
      if (!VectorAt(rel32_rva_, index, &rva))
        return false;
      uint32 decompressed_op;
      if (!DisassemblerElf32ARM::Decompress(ARM_OFF8,
                                            static_cast<uint16>(op),
                                            static_cast<uint32>(rva -
                                                                current_rva),
                                            &decompressed_op)) {
        return false;
      }
      uint16 op16 = decompressed_op;
      if (!output->Write(&op16, 2))
        return false;
      current_rva += 2;
      break;
    }
    case REL32ARM11: {
      uint32 index;
      if (!VectorAt(rel32_ix_, ix_rel32_ix, &index))
        return false;
      ++ix_rel32_ix;
      RVA rva;
      if (!VectorAt(rel32_rva_, index, &rva))
        return false;
      uint32 decompressed_op;
      if (!DisassemblerElf32ARM::Decompress(ARM_OFF11, (uint16) op,
                                            (uint32) (rva - current_rva),
                                            &decompressed_op)) {
        return false;
      }
      uint16 op16 = decompressed_op;
      if (!output->Write(&op16, 2))
        return false;
      current_rva += 2;
      break;
    }
    case REL32ARM24: {
      uint32 index;
      if (!VectorAt(rel32_ix_, ix_rel32_ix, &index))
        return false;
      ++ix_rel32_ix;
      RVA rva;
      if (!VectorAt(rel32_rva_, index, &rva))
        return false;
      uint32 decompressed_op;
      if (!DisassemblerElf32ARM::Decompress(ARM_OFF24, (uint16) op,
                                            (uint32) (rva - current_rva),
                                            &decompressed_op)) {
        return false;
      }
      if (!output->Write(&decompressed_op, 4))
        return false;
      current_rva += 4;
      break;
    }
    case REL32ARM25: {
      uint32 index;
      if (!VectorAt(rel32_ix_, ix_rel32_ix, &index))
        return false;
      ++ix_rel32_ix;
      RVA rva;
      if (!VectorAt(rel32_rva_, index, &rva))
        return false;
      uint32 decompressed_op;
      if (!DisassemblerElf32ARM::Decompress(ARM_OFF25, (uint16) op,
                                            (uint32) (rva - current_rva),
                                            &decompressed_op)) {
        return false;
      }
      uint32 words = (decompressed_op << 16) | (decompressed_op >> 16);
      if (!output->Write(&words, 4))
        return false;
      current_rva += 4;
      break;
    }
    case REL32ARM21: {
      uint32 index;
      if (!VectorAt(rel32_ix_, ix_rel32_ix, &index))
        return false;
      ++ix_rel32_ix;
      RVA rva;
      if (!VectorAt(rel32_rva_, index, &rva))
        return false;
      uint32 decompressed_op;
      if (!DisassemblerElf32ARM::Decompress(ARM_OFF21, (uint16) op,
                                            (uint32) (rva - current_rva),
                                            &decompressed_op)) {
        return false;
      }
      uint32 words = (decompressed_op << 16) | (decompressed_op >> 16);
      if (!output->Write(&words, 4))
        return false;
      current_rva += 4;
      break;
    }
    default:
      return false;
  }

  return true;
}

CheckBool EncodedProgram::AssembleTo(SinkStream* final_buffer) {
  // For the most part, the assembly process walks the various tables.
  // ix_mumble is the index into the mumble table.
  size_t ix_origins = 0;
  size_t ix_copy_counts = 0;
  size_t ix_copy_bytes = 0;
  size_t ix_abs32_ix = 0;
  size_t ix_rel32_ix = 0;

  RVA current_rva = 0;

  bool pending_pe_relocation_table = false;
  uint8 pending_pe_relocation_table_type = 0x03;  // IMAGE_REL_BASED_HIGHLOW
  Elf32_Word pending_elf_relocation_table_type = 0;
  SinkStream bytes_following_relocation_table;

  SinkStream* output = final_buffer;

  for (size_t ix_ops = 0;  ix_ops < ops_.size();  ++ix_ops) {
    OP op = ops_[ix_ops];

    switch (op) {
      default:
        if (!EvaluateRel32ARM(op, ix_rel32_ix, current_rva, output))
          return false;
        break;

      case ORIGIN: {
        RVA section_rva;
        if (!VectorAt(origins_, ix_origins, &section_rva))
          return false;
        ++ix_origins;
        current_rva = section_rva;
        break;
      }

      case COPY: {
        uint32 count;
        if (!VectorAt(copy_counts_, ix_copy_counts, &count))
          return false;
        ++ix_copy_counts;
        for (uint32 i = 0;  i < count;  ++i) {
          uint8 b;
          if (!VectorAt(copy_bytes_, ix_copy_bytes, &b))
            return false;
          ++ix_copy_bytes;
          if (!output->Write(&b, 1))
            return false;
        }
        current_rva += count;
        break;
      }

      case COPY1: {
        uint8 b;
        if (!VectorAt(copy_bytes_, ix_copy_bytes, &b))
          return false;
        ++ix_copy_bytes;
        if (!output->Write(&b, 1))
          return false;
        current_rva += 1;
        break;
      }

      case REL32: {
        uint32 index;
        if (!VectorAt(rel32_ix_, ix_rel32_ix, &index))
          return false;
        ++ix_rel32_ix;
        RVA rva;
        if (!VectorAt(rel32_rva_, index, &rva))
          return false;
        uint32 offset = (rva - (current_rva + 4));
        if (!output->Write(&offset, 4))
          return false;
        current_rva += 4;
        break;
      }

      case ABS32: {
        uint32 index;
        if (!VectorAt(abs32_ix_, ix_abs32_ix, &index))
          return false;
        ++ix_abs32_ix;
        RVA rva;
        if (!VectorAt(abs32_rva_, index, &rva))
          return false;
        uint32 abs32 = static_cast<uint32>(rva + image_base_);
        if (!abs32_relocs_.push_back(current_rva) || !output->Write(&abs32, 4))
          return false;
        current_rva += 4;
        break;
      }

      case MAKE_PE_RELOCATION_TABLE: {
        // We can see the base relocation anywhere, but we only have the
        // information to generate it at the very end.  So we divert the bytes
        // we are generating to a temporary stream.
        if (pending_pe_relocation_table)
          return false;  // Can't have two base relocation tables.

        pending_pe_relocation_table = true;
        output = &bytes_following_relocation_table;
        break;
        // There is a potential problem *if* the instruction stream contains
        // some REL32 relocations following the base relocation and in the same
        // section.  We don't know the size of the table, so 'current_rva' will
        // be wrong, causing REL32 offsets to be miscalculated.  This never
        // happens; the base relocation table is usually in a section of its
        // own, a data-only section, and following everything else in the
        // executable except some padding zero bytes.  We could fix this by
        // emitting an ORIGIN after the MAKE_BASE_RELOCATION_TABLE.
      }

      case MAKE_PE64_RELOCATION_TABLE: {
        if (pending_pe_relocation_table)
          return false;  // Can't have two base relocation tables.

        pending_pe_relocation_table = true;
        pending_pe_relocation_table_type = 0x0A;  // IMAGE_REL_BASED_DIR64
        output = &bytes_following_relocation_table;
        break;
      }

      case MAKE_ELF_ARM_RELOCATION_TABLE: {
        // We can see the base relocation anywhere, but we only have the
        // information to generate it at the very end.  So we divert the bytes
        // we are generating to a temporary stream.
        if (pending_elf_relocation_table_type)
          return false;  // Can't have two base relocation tables.

        pending_elf_relocation_table_type = R_ARM_RELATIVE;
        output = &bytes_following_relocation_table;
        break;
      }

      case MAKE_ELF_RELOCATION_TABLE: {
        // We can see the base relocation anywhere, but we only have the
        // information to generate it at the very end.  So we divert the bytes
        // we are generating to a temporary stream.
        if (pending_elf_relocation_table_type)
          return false;  // Can't have two base relocation tables.

        pending_elf_relocation_table_type = R_386_RELATIVE;
        output = &bytes_following_relocation_table;
        break;
      }
    }
  }

  if (pending_pe_relocation_table) {
    if (!GeneratePeRelocations(final_buffer,
                               pending_pe_relocation_table_type) ||
        !final_buffer->Append(&bytes_following_relocation_table))
      return false;
  }

  if (pending_elf_relocation_table_type) {
    if (!GenerateElfRelocations(pending_elf_relocation_table_type,
                                final_buffer) ||
        !final_buffer->Append(&bytes_following_relocation_table))
      return false;
  }

  // Final verification check: did we consume all lists?
  if (ix_copy_counts != copy_counts_.size())
    return false;
  if (ix_copy_bytes != copy_bytes_.size())
    return false;
  if (ix_abs32_ix != abs32_ix_.size())
    return false;
  if (ix_rel32_ix != rel32_ix_.size())
    return false;

  return true;
}

// RelocBlock has the layout of a block of relocations in the base relocation
// table file format.
//
struct RelocBlockPOD {
  uint32 page_rva;
  uint32 block_size;
  uint16 relocs[4096];  // Allow up to one relocation per byte of a 4k page.
};

COMPILE_ASSERT(offsetof(RelocBlockPOD, relocs) == 8, reloc_block_header_size);

class RelocBlock {
 public:
  RelocBlock() {
    pod.page_rva = ~0;
    pod.block_size = 8;
  }

  void Add(uint16 item) {
    pod.relocs[(pod.block_size-8)/2] = item;
    pod.block_size += 2;
  }

  CheckBool Flush(SinkStream* buffer) WARN_UNUSED_RESULT {
    bool ok = true;
    if (pod.block_size != 8) {
      if (pod.block_size % 4 != 0) {  // Pad to make size multiple of 4 bytes.
        Add(0);
      }
      ok = buffer->Write(&pod, pod.block_size);
      pod.block_size = 8;
    }
    return ok;
  }
  RelocBlockPOD pod;
};

CheckBool EncodedProgram::GeneratePeRelocations(SinkStream* buffer,
                                                uint8 type) {
  std::sort(abs32_relocs_.begin(), abs32_relocs_.end());

  RelocBlock block;

  bool ok = true;
  for (size_t i = 0;  ok && i < abs32_relocs_.size();  ++i) {
    uint32 rva = abs32_relocs_[i];
    uint32 page_rva = rva & ~0xFFF;
    if (page_rva != block.pod.page_rva) {
      ok &= block.Flush(buffer);
      block.pod.page_rva = page_rva;
    }
    if (ok)
      block.Add(((static_cast<uint16>(type)) << 12 ) | (rva & 0xFFF));
  }
  ok &= block.Flush(buffer);
  return ok;
}

CheckBool EncodedProgram::GenerateElfRelocations(Elf32_Word r_info,
                                                 SinkStream* buffer) {
  std::sort(abs32_relocs_.begin(), abs32_relocs_.end());

  Elf32_Rel relocation_block;

  relocation_block.r_info = r_info;

  bool ok = true;
  for (size_t i = 0;  ok && i < abs32_relocs_.size();  ++i) {
    relocation_block.r_offset = abs32_relocs_[i];
    ok = buffer->Write(&relocation_block, sizeof(Elf32_Rel));
  }

  return ok;
}
////////////////////////////////////////////////////////////////////////////////

Status WriteEncodedProgram(EncodedProgram* encoded, SinkStreamSet* sink) {
  if (!encoded->WriteTo(sink))
    return C_STREAM_ERROR;
  return C_OK;
}

Status ReadEncodedProgram(SourceStreamSet* streams, EncodedProgram** output) {
  EncodedProgram* encoded = new EncodedProgram();
  if (encoded->ReadFrom(streams)) {
    *output = encoded;
    return C_OK;
  }
  delete encoded;
  return C_DESERIALIZATION_FAILED;
}

Status Assemble(EncodedProgram* encoded, SinkStream* buffer) {
  bool assembled = encoded->AssembleTo(buffer);
  if (assembled)
    return C_OK;
  return C_ASSEMBLY_FAILED;
}

void DeleteEncodedProgram(EncodedProgram* encoded) {
  delete encoded;
}

}  // end namespace
/* [<][>][^][v][top][bottom][index][help] */
root/courgette/encoded_program.cc

DEFINITIONS
