diff --git a/fxbarcode/oned/BC_OneDimWriter.cpp b/fxbarcode/oned/BC_OneDimWriter.cpp
index 469fb49..2e9093d 100644
--- a/fxbarcode/oned/BC_OneDimWriter.cpp
+++ b/fxbarcode/oned/BC_OneDimWriter.cpp
@@ -20,11 +20,6 @@
  * limitations under the License.
  */
 
-#if defined(UNSAFE_BUFFERS_BUILD)
-// TODO(crbug.com/pdfium/2154): resolve buffer safety issues.
-#pragma allow_unsafe_buffers
-#endif
-
 #include "fxbarcode/oned/BC_OneDimWriter.h"
 
 #include <math.h>
@@ -107,7 +102,7 @@
 }
 
 void CBC_OneDimWriter::CalcTextInfo(const ByteString& text,
-                                    TextCharPos* charPos,
+                                    pdfium::span<TextCharPos> charPos,
                                     CFX_Font* cFont,
                                     float geWidth,
                                     int32_t fontSize,
@@ -156,7 +151,7 @@
                                        const CFX_Matrix& matrix,
                                        const ByteString str,
                                        float geWidth,
-                                       TextCharPos* pCharPos,
+                                       pdfium::span<TextCharPos> pCharPos,
                                        float locX,
                                        float locY,
                                        int32_t barWidth) {
@@ -172,7 +167,7 @@
   CFX_Matrix affine_matrix(1.0, 0.0, 0.0, -1.0, (float)locX,
                            (float)(locY + iFontSize));
   affine_matrix.Concat(matrix);
-  device->DrawNormalText(pdfium::make_span(pCharPos, str.GetLength()), m_pFont,
+  device->DrawNormalText(pCharPos.first(str.GetLength()), m_pFont,
                          static_cast<float>(iFontSize), affine_matrix,
                          m_fontColor, GetTextRenderOptions());
 }
@@ -197,7 +192,7 @@
   }
   int32_t iFontSize = static_cast<int32_t>(fabs(m_fFontSize));
   int32_t iTextHeight = iFontSize + 1;
-  CalcTextInfo(str, charpos.data(), m_pFont, geWidth, iFontSize, charsLen);
+  CalcTextInfo(str, charpos, m_pFont, geWidth, iFontSize, charsLen);
   if (charsLen < 1)
     return true;
 
@@ -226,7 +221,7 @@
       geWidth = (float)barWidth;
       break;
   }
-  ShowDeviceChars(device, matrix, str, geWidth, charpos.data(), (float)locX,
+  ShowDeviceChars(device, matrix, str, geWidth, charpos, (float)locX,
                   (float)locY, barWidth);
   return true;
 }
diff --git a/fxbarcode/oned/BC_OneDimWriter.h b/fxbarcode/oned/BC_OneDimWriter.h
index 085f27a..1251d4e 100644
--- a/fxbarcode/oned/BC_OneDimWriter.h
+++ b/fxbarcode/oned/BC_OneDimWriter.h
@@ -63,12 +63,12 @@
                        const CFX_Matrix& matrix,
                        const ByteString str,
                        float geWidth,
-                       TextCharPos* pCharPos,
+                       pdfium::span<TextCharPos> pCharPos,
                        float locX,
                        float locY,
                        int32_t barWidth);
   void CalcTextInfo(const ByteString& text,
-                    TextCharPos* charPos,
+                    pdfium::span<TextCharPos> charPos,
                     CFX_Font* cFont,
                     float geWidth,
                     int32_t fontSize,
diff --git a/fxbarcode/oned/BC_OnedEAN13Writer.cpp b/fxbarcode/oned/BC_OnedEAN13Writer.cpp
index 9ef53bd..65917f9 100644
--- a/fxbarcode/oned/BC_OnedEAN13Writer.cpp
+++ b/fxbarcode/oned/BC_OnedEAN13Writer.cpp
@@ -156,41 +156,41 @@
   length = tempStr.GetLength();
   int32_t strWidth = static_cast<int32_t>(kWidth * m_outputHScale);
 
-  CalcTextInfo(tempStr, &charpos[1], m_pFont, (float)strWidth, iFontSize,
-               blank);
+  pdfium::span<TextCharPos> charpos_span = pdfium::make_span(charpos);
+  CalcTextInfo(tempStr, charpos_span.subspan(1), m_pFont, (float)strWidth,
+               iFontSize, blank);
   {
     CFX_Matrix affine_matrix1(1.0, 0.0, 0.0, -1.0,
                               kLeftPosition * m_outputHScale,
                               (float)(m_Height - iTextHeight) + iFontSize);
     affine_matrix1.Concat(matrix);
-    device->DrawNormalText(pdfium::make_span(charpos).subspan(1, length),
-                           m_pFont, static_cast<float>(iFontSize),
-                           affine_matrix1, m_fontColor, GetTextRenderOptions());
+    device->DrawNormalText(charpos_span.subspan(1, length), m_pFont,
+                           static_cast<float>(iFontSize), affine_matrix1,
+                           m_fontColor, GetTextRenderOptions());
   }
   tempStr = str.Substr(7, 6);
   length = tempStr.GetLength();
-  CalcTextInfo(tempStr, &charpos[7], m_pFont, (float)strWidth, iFontSize,
-               blank);
+  CalcTextInfo(tempStr, charpos_span.subspan(7), m_pFont, (float)strWidth,
+               iFontSize, blank);
   {
     CFX_Matrix affine_matrix1(1.0, 0.0, 0.0, -1.0,
                               (kLeftPosition + 47) * m_outputHScale,
                               (float)(m_Height - iTextHeight + iFontSize));
     affine_matrix1.Concat(matrix);
-    device->DrawNormalText(pdfium::make_span(charpos).subspan(7, length),
-                           m_pFont, static_cast<float>(iFontSize),
-                           affine_matrix1, m_fontColor, GetTextRenderOptions());
+    device->DrawNormalText(charpos_span.subspan(7, length), m_pFont,
+                           static_cast<float>(iFontSize), affine_matrix1,
+                           m_fontColor, GetTextRenderOptions());
   }
   tempStr = str.First(1);
   length = tempStr.GetLength();
   strWidth = 7 * static_cast<int32_t>(strWidth * m_outputHScale);
 
-  CalcTextInfo(tempStr, charpos.data(), m_pFont, (float)strWidth, iFontSize,
-               blank);
+  CalcTextInfo(tempStr, charpos, m_pFont, (float)strWidth, iFontSize, blank);
   {
     CFX_Matrix affine_matrix1(1.0, 0.0, 0.0, -1.0, 0.0,
                               (float)(m_Height - iTextHeight + iFontSize));
     affine_matrix1.Concat(matrix);
-    device->DrawNormalText(pdfium::make_span(charpos).first(length), m_pFont,
+    device->DrawNormalText(charpos_span.first(length), m_pFont,
                            static_cast<float>(iFontSize), affine_matrix1,
                            m_fontColor, GetTextRenderOptions());
   }
diff --git a/fxbarcode/oned/BC_OnedEAN8Writer.cpp b/fxbarcode/oned/BC_OnedEAN8Writer.cpp
index d2dd393..2cf46a6 100644
--- a/fxbarcode/oned/BC_OnedEAN8Writer.cpp
+++ b/fxbarcode/oned/BC_OnedEAN8Writer.cpp
@@ -147,27 +147,27 @@
   device->FillRect(re, kBackgroundColor);
   int32_t strWidth = static_cast<int32_t>(kWidth * m_outputHScale);
 
-  CalcTextInfo(tempStr, charpos.data(), m_pFont, (float)strWidth, iFontSize,
-               blank);
+  pdfium::span<TextCharPos> charpos_span = pdfium::make_span(charpos);
+  CalcTextInfo(tempStr, charpos, m_pFont, (float)strWidth, iFontSize, blank);
   {
     CFX_Matrix affine_matrix1(1.0, 0.0, 0.0, -1.0,
                               kLeftPosition * m_outputHScale,
                               (float)(m_Height - iTextHeight + iFontSize));
     affine_matrix1.Concat(matrix);
-    device->DrawNormalText(pdfium::make_span(charpos).first(iLen), m_pFont,
+    device->DrawNormalText(charpos_span.first(iLen), m_pFont,
                            static_cast<float>(iFontSize), affine_matrix1,
                            m_fontColor, GetTextRenderOptions());
   }
   tempStr = str.Substr(4, 4);
   iLen = tempStr.GetLength();
-  CalcTextInfo(tempStr, &charpos[4], m_pFont, (float)strWidth, iFontSize,
-               blank);
+  CalcTextInfo(tempStr, charpos_span.subspan(4), m_pFont, (float)strWidth,
+               iFontSize, blank);
   {
     CFX_Matrix affine_matrix1(1.0, 0.0, 0.0, -1.0,
                               (kLeftPosition + 33) * m_outputHScale,
                               (float)(m_Height - iTextHeight + iFontSize));
     affine_matrix1.Concat(matrix);
-    device->DrawNormalText(pdfium::make_span(charpos).subspan(4, iLen), m_pFont,
+    device->DrawNormalText(charpos_span.subspan(4, iLen), m_pFont,
                            static_cast<float>(iFontSize), affine_matrix1,
                            m_fontColor, GetTextRenderOptions());
   }
diff --git a/fxbarcode/oned/BC_OnedUPCAWriter.cpp b/fxbarcode/oned/BC_OnedUPCAWriter.cpp
index 55a6a02..140f200 100644
--- a/fxbarcode/oned/BC_OnedUPCAWriter.cpp
+++ b/fxbarcode/oned/BC_OnedUPCAWriter.cpp
@@ -136,52 +136,56 @@
   device->FillRect(re, kBackgroundColor);
   float strWidth = kWidth * m_outputHScale;
 
-  CalcTextInfo(tempStr, &charpos[1], m_pFont, strWidth, iFontSize, blank);
+  pdfium::span<TextCharPos> charpos_span = pdfium::make_span(charpos);
+  CalcTextInfo(tempStr, charpos_span.subspan(1), m_pFont, strWidth, iFontSize,
+               blank);
   {
     CFX_Matrix affine_matrix1(1.0, 0.0, 0.0, -1.0,
                               kLeftPosition * m_outputHScale,
                               (float)(m_Height - iTextHeight + iFontSize));
     affine_matrix1.Concat(matrix);
-    device->DrawNormalText(pdfium::make_span(charpos).subspan(1, length),
-                           m_pFont, static_cast<float>(iFontSize),
-                           affine_matrix1, m_fontColor, GetTextRenderOptions());
+    device->DrawNormalText(charpos_span.subspan(1, length), m_pFont,
+                           static_cast<float>(iFontSize), affine_matrix1,
+                           m_fontColor, GetTextRenderOptions());
   }
   tempStr = str.Substr(6, 5);
   length = tempStr.GetLength();
-  CalcTextInfo(tempStr, &charpos[6], m_pFont, strWidth, iFontSize, blank);
+  CalcTextInfo(tempStr, charpos_span.subspan(6), m_pFont, strWidth, iFontSize,
+               blank);
   {
     CFX_Matrix affine_matrix1(1.0, 0.0, 0.0, -1.0,
                               (kLeftPosition + 40) * m_outputHScale,
                               (float)(m_Height - iTextHeight + iFontSize));
     affine_matrix1.Concat(matrix);
-    device->DrawNormalText(pdfium::make_span(charpos).subspan(6, length),
-                           m_pFont, static_cast<float>(iFontSize),
-                           affine_matrix1, m_fontColor, GetTextRenderOptions());
+    device->DrawNormalText(charpos_span.subspan(6, length), m_pFont,
+                           static_cast<float>(iFontSize), affine_matrix1,
+                           m_fontColor, GetTextRenderOptions());
   }
   tempStr = str.First(1);
   length = tempStr.GetLength();
   strWidth = 7 * m_outputHScale;
 
-  CalcTextInfo(tempStr, charpos.data(), m_pFont, strWidth, iFontSize, blank);
+  CalcTextInfo(tempStr, charpos, m_pFont, strWidth, iFontSize, blank);
   {
     CFX_Matrix affine_matrix1(1.0, 0.0, 0.0, -1.0, 0,
                               (float)(m_Height - iTextHeight + iFontSize));
     affine_matrix1.Concat(matrix);
-    device->DrawNormalText(pdfium::make_span(charpos).first(length), m_pFont,
+    device->DrawNormalText(charpos_span.first(length), m_pFont,
                            static_cast<float>(iFontSize), affine_matrix1,
                            m_fontColor, GetTextRenderOptions());
   }
   tempStr = str.Substr(11, 1);
   length = tempStr.GetLength();
-  CalcTextInfo(tempStr, &charpos[11], m_pFont, strWidth, iFontSize, blank);
+  CalcTextInfo(tempStr, charpos_span.subspan(11), m_pFont, strWidth, iFontSize,
+               blank);
   {
     CFX_Matrix affine_matrix1(1.0, 0.0, 0.0, -1.0,
                               (kLeftPosition + 85) * m_outputHScale,
                               (float)(m_Height - iTextHeight + iFontSize));
     affine_matrix1.Concat(matrix);
-    device->DrawNormalText(pdfium::make_span(charpos).subspan(11, length),
-                           m_pFont, static_cast<float>(iFontSize),
-                           affine_matrix1, m_fontColor, GetTextRenderOptions());
+    device->DrawNormalText(charpos_span.subspan(11, length), m_pFont,
+                           static_cast<float>(iFontSize), affine_matrix1,
+                           m_fontColor, GetTextRenderOptions());
   }
   return true;
 }