Revert "Return pdfium::span<char> from ByteString::GetBuffer()."

This reverts commit 80a6cbe0a427e155de8555bc867af745d10f9777.
Reason for revert: too many abrts in beta branch.

TBR: dsinclair@chromium.org
Bug: 832557, 832978, 832992, 833062, 833097
Change-Id: I7d511dbb224ddc644be96ea2f3770ad6f73debf5
Reviewed-on: https://pdfium-review.googlesource.com/30792
Commit-Queue: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Reviewed-by: dsinclair <dsinclair@chromium.org>

3 files changed, 49 insertions, 63 deletions

diff --git a/core/fpdfapi/page/cpdf_image.cpp b/core/fpdfapi/page/cpdf_image.cpp
index b10134611c..ec826dc5ed 100644
--- a/core/fpdfapi/page/cpdf_image.cpp
+++ b/core/fpdfapi/page/cpdf_image.cpp
@@ -200,16 +200,13 @@ void CPDF_Image::SetImage(const RetainPtr<CFX_DIBitmap>& pBitmap) {
       pCS->AddNew<CPDF_Name>("DeviceRGB");
       pCS->AddNew<CPDF_Number>(1);
       ByteString ct;
-      {
-        // Span's lifetime must end before ReleaseBuffer() below.
-        pdfium::span<char> pBuf = ct.GetBuffer(6);
-        pBuf[0] = (char)reset_r;
-        pBuf[1] = (char)reset_g;
-        pBuf[2] = (char)reset_b;
-        pBuf[3] = (char)set_r;
-        pBuf[4] = (char)set_g;
-        pBuf[5] = (char)set_b;
-      }
+      char* pBuf = ct.GetBuffer(6);
+      pBuf[0] = (char)reset_r;
+      pBuf[1] = (char)reset_g;
+      pBuf[2] = (char)reset_b;
+      pBuf[3] = (char)set_r;
+      pBuf[4] = (char)set_g;
+      pBuf[5] = (char)set_b;
       ct.ReleaseBuffer(6);
       pCS->AddNew<CPDF_String>(ct, true);
     }
diff --git a/core/fpdfapi/parser/fpdf_parser_decode.cpp b/core/fpdfapi/parser/fpdf_parser_decode.cpp
index 2fdc4daa49..90dca2edcb 100644
--- a/core/fpdfapi/parser/fpdf_parser_decode.cpp
+++ b/core/fpdfapi/parser/fpdf_parser_decode.cpp
@@ -469,22 +469,20 @@ ByteString PDF_EncodeText(const wchar_t* pString, int len) {
   if (len == -1)
     len = wcslen(pString);
 
-  int i;
   ByteString result;
-  {
-    pdfium::span<char> dest_buf = result.GetBuffer(len);
-    for (i = 0; i < len; ++i) {
-      int code;
-      for (code = 0; code < 256; ++code) {
-        if (PDFDocEncoding[code] == pString[i])
-          break;
-      }
-
-      if (code == 256)
+  char* dest_buf1 = result.GetBuffer(len);
+  int i;
+  for (i = 0; i < len; ++i) {
+    int code;
+    for (code = 0; code < 256; ++code) {
+      if (PDFDocEncoding[code] == pString[i])
         break;
-
-      dest_buf[i] = code;
     }
+
+    if (code == 256)
+      break;
+
+    dest_buf1[i] = code;
   }
   result.ReleaseBuffer(i);
   if (i == len)
@@ -495,18 +493,15 @@ ByteString PDF_EncodeText(const wchar_t* pString, int len) {
     return result;
   }
 
-  size_t dest_index = 0;
-  size_t encLen = len * 2 + 2;
-  {
-    pdfium::span<char> cspan = result.GetBuffer(encLen);
-    auto dest_buf = pdfium::make_span(reinterpret_cast<uint8_t*>(cspan.data()),
-                                      cspan.size());
-    dest_buf[dest_index++] = 0xfe;
-    dest_buf[dest_index++] = 0xff;
-    for (int j = 0; j < len; ++j) {
-      dest_buf[dest_index++] = pString[j] >> 8;
-      dest_buf[dest_index++] = static_cast<uint8_t>(pString[j]);
-    }
+  int encLen = len * 2 + 2;
+
+  uint8_t* dest_buf2 = reinterpret_cast<uint8_t*>(result.GetBuffer(encLen));
+  dest_buf2[0] = 0xfe;
+  dest_buf2[1] = 0xff;
+  dest_buf2 += 2;
+  for (int j = 0; j < len; ++j) {
+    *dest_buf2++ = pString[j] >> 8;
+    *dest_buf2++ = static_cast<uint8_t>(pString[j]);
   }
   result.ReleaseBuffer(encLen);
   return result;
diff --git a/core/fpdfapi/parser/fpdf_parser_utility.cpp b/core/fpdfapi/parser/fpdf_parser_utility.cpp
index b6b94aa84e..c486a76706 100644
--- a/core/fpdfapi/parser/fpdf_parser_utility.cpp
+++ b/core/fpdfapi/parser/fpdf_parser_utility.cpp
@@ -93,23 +93,20 @@ ByteString PDF_NameDecode(const ByteStringView& bstr) {
   if (!bstr.Contains('#'))
     return ByteString(bstr);
 
-  size_t src_size = bstr.GetLength();
-  size_t out_index = 0;
+  int size = bstr.GetLength();
   ByteString result;
-  {
-    // Span's lifetime must end before ReleaseBuffer() below.
-    pdfium::span<char> pDest = result.GetBuffer(src_size);
-    for (size_t i = 0; i < src_size; i++) {
-      if (bstr[i] == '#' && i < src_size - 2) {
-        pDest[out_index++] = FXSYS_HexCharToInt(bstr[i + 1]) * 16 +
-                             FXSYS_HexCharToInt(bstr[i + 2]);
-        i += 2;
-      } else {
-        pDest[out_index++] = bstr[i];
-      }
+  char* pDestStart = result.GetBuffer(size);
+  char* pDest = pDestStart;
+  for (int i = 0; i < size; i++) {
+    if (bstr[i] == '#' && i < size - 2) {
+      *pDest++ = FXSYS_HexCharToInt(bstr[i + 1]) * 16 +
+                 FXSYS_HexCharToInt(bstr[i + 2]);
+      i += 2;
+    } else {
+      *pDest++ = bstr[i];
     }
   }
-  result.ReleaseBuffer(out_index);
+  result.ReleaseBuffer(static_cast<size_t>(pDest - pDestStart));
   return result;
 }
 
@@ -131,23 +128,20 @@ ByteString PDF_NameEncode(const ByteString& orig) {
     return orig;
 
   ByteString res;
-  {
-    // Span's lifetime must end before ReleaseBuffer() below.
-    pdfium::span<char> dest_buf = res.GetBuffer(dest_len);
-    dest_len = 0;
-    for (i = 0; i < src_len; i++) {
-      uint8_t ch = src_buf[i];
-      if (ch >= 0x80 || PDFCharIsWhitespace(ch) || ch == '#' ||
-          PDFCharIsDelimiter(ch)) {
-        dest_buf[dest_len++] = '#';
-        FXSYS_IntToTwoHexChars(ch, &dest_buf[dest_len]);
-        dest_len += 2;
-        continue;
-      }
+  char* dest_buf = res.GetBuffer(dest_len);
+  dest_len = 0;
+  for (i = 0; i < src_len; i++) {
+    uint8_t ch = src_buf[i];
+    if (ch >= 0x80 || PDFCharIsWhitespace(ch) || ch == '#' ||
+        PDFCharIsDelimiter(ch)) {
+      dest_buf[dest_len++] = '#';
+      FXSYS_IntToTwoHexChars(ch, dest_buf + dest_len);
+      dest_len += 2;
+    } else {
       dest_buf[dest_len++] = ch;
     }
-    dest_buf[dest_len] = 0;
   }
+  dest_buf[dest_len] = 0;
   res.ReleaseBuffer(res.GetStringLength());
   return res;
 }