diff --git a/libc/src/stdio/printf_core/CMakeLists.txt b/libc/src/stdio/printf_core/CMakeLists.txt
--- a/libc/src/stdio/printf_core/CMakeLists.txt
+++ b/libc/src/stdio/printf_core/CMakeLists.txt
@@ -3,6 +3,9 @@
   core_structs
   HDRS
     core_structs.h
+  DEPENDS
+    libc.src.__support.CPP.string_view
+    libc.src.__support.FPUtil.fputil
 )
 
 add_object_library(
@@ -17,7 +20,7 @@
     libc.src.__support.ctype_utils
     libc.src.__support.str_to_integer
     libc.src.__support.CPP.bit
-    libc.src.string.memory_utils.memset_implementation
+    libc.src.__support.CPP.string_view
 )
 
 add_object_library(
@@ -27,7 +30,9 @@
   HDRS
     string_writer.h
   DEPENDS
+    libc.src.__support.CPP.string_view
     libc.src.string.memory_utils.memcpy_implementation
+    libc.src.string.memory_utils.memset_implementation
     .core_structs
 )
 
@@ -37,8 +42,6 @@
     writer.cpp
   HDRS
     writer.h
-  DEPENDS
-    libc.src.string.memory_utils.memset_implementation
 )
 
 add_object_library(
@@ -95,6 +98,8 @@
     file_writer.h
   DEPENDS
     libc.src.__support.File.file
+    libc.src.__support.CPP.string_view
+    libc.src.string.memory_utils.memset_implementation
     .core_structs
 )
 
diff --git a/libc/src/stdio/printf_core/char_converter.h b/libc/src/stdio/printf_core/char_converter.h
--- a/libc/src/stdio/printf_core/char_converter.h
+++ b/libc/src/stdio/printf_core/char_converter.h
@@ -9,6 +9,7 @@
 #ifndef LLVM_LIBC_SRC_STDIO_PRINTF_CORE_CHAR_CONVERTER_H
 #define LLVM_LIBC_SRC_STDIO_PRINTF_CORE_CHAR_CONVERTER_H
 
+#include "src/__support/CPP/string_view.h"
 #include "src/stdio/printf_core/converter_utils.h"
 #include "src/stdio/printf_core/core_structs.h"
 #include "src/stdio/printf_core/writer.h"
@@ -19,18 +20,27 @@
 int inline convert_char(Writer *writer, const FormatSection &to_conv) {
   char c = to_conv.conv_val_raw;
 
-  if (to_conv.min_width > 1) {
-    if ((to_conv.flags & FormatFlags::LEFT_JUSTIFIED) ==
-        FormatFlags::LEFT_JUSTIFIED) {
-      RET_IF_RESULT_NEGATIVE(writer->write(&c, 1));
-      RET_IF_RESULT_NEGATIVE(writer->write_chars(' ', to_conv.min_width - 1));
-    } else {
-      RET_IF_RESULT_NEGATIVE(writer->write_chars(' ', to_conv.min_width - 1));
-      RET_IF_RESULT_NEGATIVE(writer->write(&c, 1));
-    }
-  } else {
-    RET_IF_RESULT_NEGATIVE(writer->write(&c, 1));
+  constexpr int string_len = 1;
+
+  size_t padding_spaces =
+      to_conv.min_width > string_len ? to_conv.min_width - string_len : 0;
+
+  // If the padding is on the left side, write the spaces first.
+  if (padding_spaces > 0 &&
+      (to_conv.flags & FormatFlags::LEFT_JUSTIFIED) == 0) {
+    RET_IF_RESULT_NEGATIVE(
+        writer->write_chars(' ', to_conv.min_width - string_len));
+  }
+
+  RET_IF_RESULT_NEGATIVE(writer->write(cpp::string_view(&c, string_len)));
+
+  // If the padding is on the right side, write the spaces last.
+  if (padding_spaces > 0 &&
+      (to_conv.flags & FormatFlags::LEFT_JUSTIFIED) != 0) {
+    RET_IF_RESULT_NEGATIVE(
+        writer->write_chars(' ', to_conv.min_width - string_len));
   }
+
   return WRITE_OK;
 }
 
diff --git a/libc/src/stdio/printf_core/converter.cpp b/libc/src/stdio/printf_core/converter.cpp
--- a/libc/src/stdio/printf_core/converter.cpp
+++ b/libc/src/stdio/printf_core/converter.cpp
@@ -26,11 +26,11 @@
 
 int convert(Writer *writer, const FormatSection &to_conv) {
   if (!to_conv.has_conv)
-    return writer->write(to_conv.raw_string, to_conv.raw_len);
+    return writer->write(to_conv.raw_string);
 
   switch (to_conv.conv_name) {
   case '%':
-    return writer->write("%", 1);
+    return writer->write("%");
   case 'c':
     return convert_char(writer, to_conv);
   case 's':
@@ -63,7 +63,7 @@
   case 'p':
     return convert_pointer(writer, to_conv);
   default:
-    return writer->write(to_conv.raw_string, to_conv.raw_len);
+    return writer->write(to_conv.raw_string);
   }
   return -1;
 }
diff --git a/libc/src/stdio/printf_core/core_structs.h b/libc/src/stdio/printf_core/core_structs.h
--- a/libc/src/stdio/printf_core/core_structs.h
+++ b/libc/src/stdio/printf_core/core_structs.h
@@ -37,8 +37,7 @@
 struct FormatSection {
   bool has_conv;
 
-  const char *__restrict raw_string;
-  size_t raw_len;
+  cpp::string_view raw_string;
 
   // Format Specifier Values
   FormatFlags flags = FormatFlags(0);
@@ -58,8 +57,7 @@
     if (has_conv != other.has_conv)
       return false;
 
-    if (cpp::string_view(raw_string, raw_len) !=
-        cpp::string_view(other.raw_string, other.raw_len))
+    if (raw_string != other.raw_string)
       return false;
 
     if (has_conv) {
diff --git a/libc/src/stdio/printf_core/file_writer.h b/libc/src/stdio/printf_core/file_writer.h
--- a/libc/src/stdio/printf_core/file_writer.h
+++ b/libc/src/stdio/printf_core/file_writer.h
@@ -9,6 +9,7 @@
 #ifndef LLVM_LIBC_SRC_STDIO_PRINTF_CORE_FILE_WRITER_H
 #define LLVM_LIBC_SRC_STDIO_PRINTF_CORE_FILE_WRITER_H
 
+#include "src/__support/CPP/string_view.h"
 #include "src/__support/File/file.h"
 
 #include <stddef.h>
@@ -33,8 +34,9 @@
 
 // write_to_file treats raw_pointer as a File and calls its write
 // function.
-int write_to_file(void *raw_pointer, const char *__restrict to_write,
-                  size_t len);
+int write_str_to_file(void *raw_pointer, cpp::string_view new_string);
+
+int write_chars_to_file(void *raw_pointer, char new_char, size_t len);
 
 } // namespace printf_core
 } // namespace __llvm_libc
diff --git a/libc/src/stdio/printf_core/file_writer.cpp b/libc/src/stdio/printf_core/file_writer.cpp
--- a/libc/src/stdio/printf_core/file_writer.cpp
+++ b/libc/src/stdio/printf_core/file_writer.cpp
@@ -7,6 +7,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "src/stdio/printf_core/file_writer.h"
+#include "src/__support/CPP/string_view.h"
 #include "src/__support/File/file.h"
 #include "src/stdio/printf_core/core_structs.h"
 #include <stddef.h>
@@ -23,10 +24,23 @@
   return written;
 }
 
-int write_to_file(void *raw_pointer, const char *__restrict to_write,
-                  size_t len) {
+int write_str_to_file(void *raw_pointer, cpp::string_view new_string) {
   FileWriter *file_writer = reinterpret_cast<FileWriter *>(raw_pointer);
-  return file_writer->write(to_write, len);
+  return file_writer->write(new_string.data(), new_string.size());
+}
+
+int write_chars_to_file(void *raw_pointer, char new_char, size_t len) {
+  FileWriter *file_writer = reinterpret_cast<FileWriter *>(raw_pointer);
+  constexpr size_t BUFF_SIZE = 8;
+  char buff[BUFF_SIZE] = {new_char};
+  int result;
+  while (len > BUFF_SIZE) {
+    result = file_writer->write(buff, BUFF_SIZE);
+    if (result < 0)
+      return result;
+    len -= BUFF_SIZE;
+  }
+  return file_writer->write(buff, len);
 }
 
 } // namespace printf_core
diff --git a/libc/src/stdio/printf_core/float_hex_converter.h b/libc/src/stdio/printf_core/float_hex_converter.h
--- a/libc/src/stdio/printf_core/float_hex_converter.h
+++ b/libc/src/stdio/printf_core/float_hex_converter.h
@@ -9,6 +9,7 @@
 #ifndef LLVM_LIBC_SRC_STDIO_PRINTF_CORE_FLOAT_HEX_CONVERTER_H
 #define LLVM_LIBC_SRC_STDIO_PRINTF_CORE_FLOAT_HEX_CONVERTER_H
 
+#include "src/__support/CPP/string_view.h"
 #include "src/__support/FPUtil/FEnvImpl.h"
 #include "src/__support/FPUtil/FPBits.h"
 #include "src/stdio/printf_core/converter_utils.h"
@@ -193,6 +194,7 @@
   char prefix[PREFIX_LEN];
   prefix[0] = '0';
   prefix[1] = a + ('x' - 'a');
+  const cpp::string_view prefix_str(prefix, PREFIX_LEN);
 
   // If the precision is greater than the actual result, pad with 0s
   if (to_conv.precision > static_cast<int>(mant_digits - 1))
@@ -201,11 +203,12 @@
   bool has_hexadecimal_point =
       (mant_digits > 1) || ((to_conv.flags & FormatFlags::ALTERNATE_FORM) ==
                             FormatFlags::ALTERNATE_FORM);
-  constexpr char HEXADECIMAL_POINT = '.';
+  constexpr cpp::string_view HEXADECIMAL_POINT(".");
 
   // This is for the letter 'p' before the exponent.
   const char exp_seperator = a + ('p' - 'a');
   constexpr int EXP_SEPERATOR_LEN = 1;
+  const cpp::string_view exp_seperator_str(&exp_seperator, EXP_SEPERATOR_LEN);
 
   padding = to_conv.min_width - (sign_char > 0 ? 1 : 0) - PREFIX_LEN -
             mant_digits - (has_hexadecimal_point ? 1 : 0) - EXP_SEPERATOR_LEN -
@@ -218,18 +221,19 @@
     // The pattern is (sign), 0x, digit, (.), (other digits), (zeroes), p,
     // exponent, (spaces)
     if (sign_char > 0)
-      RET_IF_RESULT_NEGATIVE(writer->write(&sign_char, 1));
-    RET_IF_RESULT_NEGATIVE(writer->write(prefix, PREFIX_LEN));
-    RET_IF_RESULT_NEGATIVE(writer->write(mant_buffer, 1));
+      RET_IF_RESULT_NEGATIVE(writer->write(cpp::string_view(&sign_char, 1)));
+    RET_IF_RESULT_NEGATIVE(writer->write(prefix_str));
+    RET_IF_RESULT_NEGATIVE(writer->write(cpp::string_view(mant_buffer, 1)));
     if (has_hexadecimal_point)
-      RET_IF_RESULT_NEGATIVE(writer->write(&HEXADECIMAL_POINT, 1));
+      RET_IF_RESULT_NEGATIVE(writer->write(HEXADECIMAL_POINT));
     if (mant_digits > 1)
-      RET_IF_RESULT_NEGATIVE(writer->write(mant_buffer + 1, mant_digits - 1));
+      RET_IF_RESULT_NEGATIVE(
+          writer->write(cpp::string_view(mant_buffer + 1, mant_digits - 1)));
     if (trailing_zeroes > 0)
       RET_IF_RESULT_NEGATIVE(writer->write_chars('0', trailing_zeroes));
-    RET_IF_RESULT_NEGATIVE(writer->write(&exp_seperator, EXP_SEPERATOR_LEN));
-    RET_IF_RESULT_NEGATIVE(
-        writer->write(exp_buffer + exp_cur, EXP_LEN - exp_cur));
+    RET_IF_RESULT_NEGATIVE(writer->write(exp_seperator_str));
+    RET_IF_RESULT_NEGATIVE(writer->write(
+        cpp::string_view(exp_buffer + exp_cur, EXP_LEN - exp_cur)));
     if (padding > 0)
       RET_IF_RESULT_NEGATIVE(writer->write_chars(' ', padding));
   } else {
@@ -239,21 +243,22 @@
                           FormatFlags::LEADING_ZEROES))
       RET_IF_RESULT_NEGATIVE(writer->write_chars(' ', padding));
     if (sign_char > 0)
-      RET_IF_RESULT_NEGATIVE(writer->write(&sign_char, 1));
-    RET_IF_RESULT_NEGATIVE(writer->write(prefix, PREFIX_LEN));
+      RET_IF_RESULT_NEGATIVE(writer->write(cpp::string_view(&sign_char, 1)));
+    RET_IF_RESULT_NEGATIVE(writer->write(prefix_str));
     if ((padding > 0) && ((to_conv.flags & FormatFlags::LEADING_ZEROES) ==
                           FormatFlags::LEADING_ZEROES))
       RET_IF_RESULT_NEGATIVE(writer->write_chars('0', padding));
-    RET_IF_RESULT_NEGATIVE(writer->write(mant_buffer, 1));
+    RET_IF_RESULT_NEGATIVE(writer->write(cpp::string_view(mant_buffer, 1)));
     if (has_hexadecimal_point)
-      RET_IF_RESULT_NEGATIVE(writer->write(&HEXADECIMAL_POINT, 1));
+      RET_IF_RESULT_NEGATIVE(writer->write(HEXADECIMAL_POINT));
     if (mant_digits > 1)
-      RET_IF_RESULT_NEGATIVE(writer->write(mant_buffer + 1, mant_digits - 1));
+      RET_IF_RESULT_NEGATIVE(
+          writer->write(cpp::string_view(mant_buffer + 1, mant_digits - 1)));
     if (trailing_zeroes > 0)
       RET_IF_RESULT_NEGATIVE(writer->write_chars('0', trailing_zeroes));
-    RET_IF_RESULT_NEGATIVE(writer->write(&exp_seperator, EXP_SEPERATOR_LEN));
-    RET_IF_RESULT_NEGATIVE(
-        writer->write(exp_buffer + exp_cur, EXP_LEN - exp_cur));
+    RET_IF_RESULT_NEGATIVE(writer->write(exp_seperator_str));
+    RET_IF_RESULT_NEGATIVE(writer->write(
+        cpp::string_view(exp_buffer + exp_cur, EXP_LEN - exp_cur)));
   }
   return WRITE_OK;
 }
diff --git a/libc/src/stdio/printf_core/float_inf_nan_converter.h b/libc/src/stdio/printf_core/float_inf_nan_converter.h
--- a/libc/src/stdio/printf_core/float_inf_nan_converter.h
+++ b/libc/src/stdio/printf_core/float_inf_nan_converter.h
@@ -62,11 +62,11 @@
     RET_IF_RESULT_NEGATIVE(writer->write_chars(' ', padding));
 
   if (sign_char)
-    RET_IF_RESULT_NEGATIVE(writer->write(&sign_char, 1));
+    RET_IF_RESULT_NEGATIVE(writer->write(cpp::string_view(&sign_char, 1)));
   if (mantissa == 0) { // inf
-    RET_IF_RESULT_NEGATIVE(writer->write((a == 'a' ? "inf" : "INF"), 3));
+    RET_IF_RESULT_NEGATIVE(writer->write(a == 'a' ? "inf" : "INF"));
   } else { // nan
-    RET_IF_RESULT_NEGATIVE(writer->write((a == 'a' ? "nan" : "NAN"), 3));
+    RET_IF_RESULT_NEGATIVE(writer->write(a == 'a' ? "nan" : "NAN"));
   }
 
   if (padding > 0 && ((to_conv.flags & FormatFlags::LEFT_JUSTIFIED) ==
diff --git a/libc/src/stdio/printf_core/int_converter.h b/libc/src/stdio/printf_core/int_converter.h
--- a/libc/src/stdio/printf_core/int_converter.h
+++ b/libc/src/stdio/printf_core/int_converter.h
@@ -141,11 +141,12 @@
   if ((flags & FormatFlags::LEFT_JUSTIFIED) == FormatFlags::LEFT_JUSTIFIED) {
     // If left justified it goes prefix zeroes digits spaces
     if (prefix_len != 0)
-      RET_IF_RESULT_NEGATIVE(writer->write(prefix, prefix_len));
+      RET_IF_RESULT_NEGATIVE(
+          writer->write(cpp::string_view(prefix, prefix_len)));
     if (zeroes > 0)
       RET_IF_RESULT_NEGATIVE(writer->write_chars('0', zeroes));
     if (digits_written > 0)
-      RET_IF_RESULT_NEGATIVE(writer->write(str->data(), digits_written));
+      RET_IF_RESULT_NEGATIVE(writer->write(*str));
     if (spaces > 0)
       RET_IF_RESULT_NEGATIVE(writer->write_chars(' ', spaces));
   } else {
@@ -153,11 +154,12 @@
     if (spaces > 0)
       RET_IF_RESULT_NEGATIVE(writer->write_chars(' ', spaces));
     if (prefix_len != 0)
-      RET_IF_RESULT_NEGATIVE(writer->write(prefix, prefix_len));
+      RET_IF_RESULT_NEGATIVE(
+          writer->write(cpp::string_view(prefix, prefix_len)));
     if (zeroes > 0)
       RET_IF_RESULT_NEGATIVE(writer->write_chars('0', zeroes));
     if (digits_written > 0)
-      RET_IF_RESULT_NEGATIVE(writer->write(str->data(), digits_written));
+      RET_IF_RESULT_NEGATIVE(writer->write(*str));
   }
   return WRITE_OK;
 }
diff --git a/libc/src/stdio/printf_core/parser.h b/libc/src/stdio/printf_core/parser.h
--- a/libc/src/stdio/printf_core/parser.h
+++ b/libc/src/stdio/printf_core/parser.h
@@ -12,7 +12,6 @@
 #include "src/__support/arg_list.h"
 #include "src/stdio/printf_core/core_structs.h"
 #include "src/stdio/printf_core/printf_config.h"
-#include "src/string/memory_utils/memset_implementations.h"
 
 #include <stddef.h>
 
diff --git a/libc/src/stdio/printf_core/parser.cpp b/libc/src/stdio/printf_core/parser.cpp
--- a/libc/src/stdio/printf_core/parser.cpp
+++ b/libc/src/stdio/printf_core/parser.cpp
@@ -13,6 +13,7 @@
 #include "src/__support/arg_list.h"
 
 #include "src/__support/CPP/bit.h"
+#include "src/__support/CPP/string_view.h"
 #include "src/__support/FPUtil/FPBits.h"
 #include "src/__support/ctype_utils.h"
 #include "src/__support/str_to_integer.h"
@@ -28,7 +29,6 @@
 
 FormatSection Parser::get_next_section() {
   FormatSection section;
-  section.raw_string = str + cur_pos;
   size_t starting_pos = cur_pos;
   if (str[cur_pos] == '%') {
     // format section
@@ -158,7 +158,8 @@
     while (str[cur_pos] != '%' && str[cur_pos] != '\0')
       ++cur_pos;
   }
-  section.raw_len = cur_pos - starting_pos;
+  section.raw_string =
+      cpp::string_view(str + starting_pos, cur_pos - starting_pos);
   return section;
 }
 
diff --git a/libc/src/stdio/printf_core/printf_main.cpp b/libc/src/stdio/printf_core/printf_main.cpp
--- a/libc/src/stdio/printf_core/printf_main.cpp
+++ b/libc/src/stdio/printf_core/printf_main.cpp
@@ -24,11 +24,12 @@
   Parser parser(str, args);
   int result = 0;
   for (FormatSection cur_section = parser.get_next_section();
-       cur_section.raw_len > 0; cur_section = parser.get_next_section()) {
+       !cur_section.raw_string.empty();
+       cur_section = parser.get_next_section()) {
     if (cur_section.has_conv)
       result = convert(writer, cur_section);
     else
-      result = writer->write(cur_section.raw_string, cur_section.raw_len);
+      result = writer->write(cur_section.raw_string);
 
     if (result < 0)
       return result;
diff --git a/libc/src/stdio/printf_core/ptr_converter.h b/libc/src/stdio/printf_core/ptr_converter.h
--- a/libc/src/stdio/printf_core/ptr_converter.h
+++ b/libc/src/stdio/printf_core/ptr_converter.h
@@ -9,6 +9,7 @@
 #ifndef LLVM_LIBC_SRC_STDIO_PRINTF_CORE_PTR_CONVERTER_H
 #define LLVM_LIBC_SRC_STDIO_PRINTF_CORE_PTR_CONVERTER_H
 
+#include "src/__support/CPP/string_view.h"
 #include "src/stdio/printf_core/converter_utils.h"
 #include "src/stdio/printf_core/core_structs.h"
 #include "src/stdio/printf_core/int_converter.h"
@@ -19,9 +20,7 @@
 
 int inline convert_pointer(Writer *writer, const FormatSection &to_conv) {
   if (to_conv.conv_val_ptr == (void *)(nullptr)) {
-    const char ZERO_STR[] = "(nullptr)";
-    // subtract 1 from sizeof to remove the null byte at the end.
-    RET_IF_RESULT_NEGATIVE(writer->write(ZERO_STR, sizeof(ZERO_STR) - 1));
+    RET_IF_RESULT_NEGATIVE(writer->write("(nullptr)"));
   } else {
     FormatSection hex_conv;
     hex_conv.has_conv = true;
diff --git a/libc/src/stdio/printf_core/string_converter.h b/libc/src/stdio/printf_core/string_converter.h
--- a/libc/src/stdio/printf_core/string_converter.h
+++ b/libc/src/stdio/printf_core/string_converter.h
@@ -9,6 +9,7 @@
 #ifndef LLVM_LIBC_SRC_STDIO_PRINTF_CORE_STRING_CONVERTER_H
 #define LLVM_LIBC_SRC_STDIO_PRINTF_CORE_STRING_CONVERTER_H
 
+#include "src/__support/CPP/string_view.h"
 #include "src/stdio/printf_core/converter_utils.h"
 #include "src/stdio/printf_core/core_structs.h"
 #include "src/stdio/printf_core/writer.h"
@@ -29,23 +30,24 @@
   if (to_conv.precision >= 0 && to_conv.precision < string_len)
     string_len = to_conv.precision;
 
-  if (to_conv.min_width > string_len) {
-    if ((to_conv.flags & FormatFlags::LEFT_JUSTIFIED) ==
-        FormatFlags::LEFT_JUSTIFIED) {
-      RET_IF_RESULT_NEGATIVE(writer->write(
-          reinterpret_cast<const char *>(to_conv.conv_val_ptr), string_len));
-      RET_IF_RESULT_NEGATIVE(
-          writer->write_chars(' ', to_conv.min_width - string_len));
-
-    } else {
-      RET_IF_RESULT_NEGATIVE(
-          writer->write_chars(' ', to_conv.min_width - string_len));
-      RET_IF_RESULT_NEGATIVE(writer->write(
-          reinterpret_cast<const char *>(to_conv.conv_val_ptr), string_len));
-    }
-  } else {
-    RET_IF_RESULT_NEGATIVE(writer->write(
-        reinterpret_cast<const char *>(to_conv.conv_val_ptr), string_len));
+  size_t padding_spaces =
+      to_conv.min_width > string_len ? to_conv.min_width - string_len : 0;
+
+  // If the padding is on the left side, write the spaces first.
+  if (padding_spaces > 0 &&
+      (to_conv.flags & FormatFlags::LEFT_JUSTIFIED) == 0) {
+    RET_IF_RESULT_NEGATIVE(
+        writer->write_chars(' ', to_conv.min_width - string_len));
+  }
+
+  RET_IF_RESULT_NEGATIVE(writer->write(cpp::string_view(
+      reinterpret_cast<const char *>(to_conv.conv_val_ptr), string_len)));
+
+  // If the padding is on the right side, write the spaces last.
+  if (padding_spaces > 0 &&
+      (to_conv.flags & FormatFlags::LEFT_JUSTIFIED) != 0) {
+    RET_IF_RESULT_NEGATIVE(
+        writer->write_chars(' ', to_conv.min_width - string_len));
   }
   return WRITE_OK;
 }
diff --git a/libc/src/stdio/printf_core/string_writer.h b/libc/src/stdio/printf_core/string_writer.h
--- a/libc/src/stdio/printf_core/string_writer.h
+++ b/libc/src/stdio/printf_core/string_writer.h
@@ -9,6 +9,7 @@
 #ifndef LLVM_LIBC_SRC_STDIO_PRINTF_CORE_STRING_WRITER_H
 #define LLVM_LIBC_SRC_STDIO_PRINTF_CORE_STRING_WRITER_H
 
+#include "src/__support/CPP/string_view.h"
 #include "src/string/memory_utils/memcpy_implementations.h"
 #include <stddef.h>
 
@@ -26,7 +27,8 @@
   StringWriter(char *__restrict buffer, size_t max_len = ~size_t(0))
       : cur_buffer(buffer), available_capacity(max_len) {}
 
-  void write(const char *__restrict to_write, size_t len);
+  void str_write(cpp::string_view new_string);
+  void chars_write(char new_char, size_t len);
 
   // Terminate should only be called if the original max length passed to
   // snprintf was greater than 0. It writes a null byte to the end of the
@@ -34,10 +36,13 @@
   void terminate() { *cur_buffer = '\0'; }
 };
 
-// write_to_string treats raw_pointer as a StringWriter and calls its write
-// function.
-int write_to_string(void *raw_pointer, const char *__restrict to_write,
-                    size_t len);
+// write_str_to_string treats raw_pointer as a StringWriter and calls its write
+// function on new_string.
+int write_str_to_string(void *raw_pointer, cpp::string_view new_string);
+
+// write_chars_to_string treats raw_pointer as a StringWriter and calls its
+// write function on new_char and len.
+int write_chars_to_string(void *raw_pointer, char new_char, size_t len);
 
 } // namespace printf_core
 } // namespace __llvm_libc
diff --git a/libc/src/stdio/printf_core/string_writer.cpp b/libc/src/stdio/printf_core/string_writer.cpp
--- a/libc/src/stdio/printf_core/string_writer.cpp
+++ b/libc/src/stdio/printf_core/string_writer.cpp
@@ -7,28 +7,47 @@
 //===----------------------------------------------------------------------===//
 
 #include "src/stdio/printf_core/string_writer.h"
+#include "src/__support/CPP/string_view.h"
 #include "src/stdio/printf_core/core_structs.h"
 #include "src/string/memory_utils/memcpy_implementations.h"
+#include "src/string/memory_utils/memset_implementations.h"
 #include <stddef.h>
 
 namespace __llvm_libc {
 namespace printf_core {
 
-void StringWriter::write(const char *__restrict to_write, size_t len) {
+void StringWriter::str_write(cpp::string_view new_string) {
+  size_t len = new_string.size();
   if (len > available_capacity)
     len = available_capacity;
 
   if (len > 0) {
-    inline_memcpy(cur_buffer, to_write, len);
+    inline_memcpy(cur_buffer, new_string.data(), len);
     cur_buffer += len;
     available_capacity -= len;
   }
 }
 
-int write_to_string(void *raw_pointer, const char *__restrict to_write,
-                    size_t len) {
+void StringWriter::chars_write(char new_char, size_t len) {
+  if (len > available_capacity)
+    len = available_capacity;
+
+  if (len > 0) {
+    inline_memset(cur_buffer, new_char, len);
+    cur_buffer += len;
+    available_capacity -= len;
+  }
+}
+
+int write_str_to_string(void *raw_pointer, cpp::string_view new_string) {
+  StringWriter *string_writer = reinterpret_cast<StringWriter *>(raw_pointer);
+  string_writer->str_write(new_string);
+  return WRITE_OK;
+}
+
+int write_chars_to_string(void *raw_pointer, char new_char, size_t len) {
   StringWriter *string_writer = reinterpret_cast<StringWriter *>(raw_pointer);
-  string_writer->write(to_write, len);
+  string_writer->chars_write(new_char, len);
   return WRITE_OK;
 }
 
diff --git a/libc/src/stdio/printf_core/vfprintf_internal.cpp b/libc/src/stdio/printf_core/vfprintf_internal.cpp
--- a/libc/src/stdio/printf_core/vfprintf_internal.cpp
+++ b/libc/src/stdio/printf_core/vfprintf_internal.cpp
@@ -22,7 +22,8 @@
                       internal::ArgList &args) {
   FileWriter file_writer(stream);
   printf_core::Writer writer(reinterpret_cast<void *>(&file_writer),
-                             printf_core::write_to_file);
+                             printf_core::write_str_to_file,
+                             printf_core::write_chars_to_file);
   return printf_core::printf_main(&writer, format, args);
 }
 
diff --git a/libc/src/stdio/printf_core/writer.h b/libc/src/stdio/printf_core/writer.h
--- a/libc/src/stdio/printf_core/writer.h
+++ b/libc/src/stdio/printf_core/writer.h
@@ -9,12 +9,14 @@
 #ifndef LLVM_LIBC_SRC_STDIO_PRINTF_CORE_WRITER_H
 #define LLVM_LIBC_SRC_STDIO_PRINTF_CORE_WRITER_H
 
+#include "src/__support/CPP/string_view.h"
 #include <stddef.h>
 
 namespace __llvm_libc {
 namespace printf_core {
 
-using WriteFunc = int (*)(void *, const char *__restrict, size_t);
+using WriteStrFunc = int (*)(void *, cpp::string_view);
+using WriteCharsFunc = int (*)(void *, char, size_t);
 
 class Writer final {
   // output is a pointer to the string or file that the writer is meant to write
@@ -25,23 +27,26 @@
   // length, will copy the number of bytes equal to the length from the char*
   // onto the end of output. It should return a positive number or zero on
   // success, or a negative number on failure.
-  WriteFunc raw_write;
+  WriteStrFunc str_write;
+  WriteCharsFunc chars_write;
 
   int chars_written = 0;
 
 public:
-  Writer(void *init_output, WriteFunc init_raw_write)
-      : output(init_output), raw_write(init_raw_write) {}
-
-  // write will copy length bytes from new_string into output using
-  // raw_write. It increments chars_written by length always. It returns the
-  // result of raw_write.
-  int write(const char *new_string, size_t length);
-
-  // write_chars will copy length copies of new_char into output using the write
-  // function and a statically sized buffer. This is primarily used for padding.
-  // If write returns a negative value, this will return early with that value.
-  int write_chars(char new_char, size_t length);
+  Writer(void *init_output, WriteStrFunc init_str_write,
+         WriteCharsFunc init_chars_write)
+      : output(init_output), str_write(init_str_write),
+        chars_write(init_chars_write) {}
+
+  // write will copy new_string into output using str_write. It increments
+  // chars_written by the length of new_string. It returns the result of
+  // str_write.
+  int write(cpp::string_view new_string);
+
+  // write_chars will copy length copies of new_char into output using
+  // chars_write. This is primarily used for padding.  It returns the result of
+  // chars_write.
+  int write_chars(char new_char, size_t len);
 
   int get_chars_written() { return chars_written; }
 };
diff --git a/libc/src/stdio/printf_core/writer.cpp b/libc/src/stdio/printf_core/writer.cpp
--- a/libc/src/stdio/printf_core/writer.cpp
+++ b/libc/src/stdio/printf_core/writer.cpp
@@ -7,29 +7,20 @@
 //===----------------------------------------------------------------------===//
 
 #include "writer.h"
-#include "src/string/memory_utils/memset_implementations.h"
+#include "src/__support/CPP/string_view.h"
 #include <stddef.h>
 
 namespace __llvm_libc {
 namespace printf_core {
 
-int Writer::write(const char *new_string, size_t length) {
-  chars_written += length;
-  return raw_write(output, new_string, length);
+int Writer::write(cpp::string_view new_string) {
+  chars_written += new_string.size();
+  return str_write(output, new_string);
 }
 
 int Writer::write_chars(char new_char, size_t length) {
-  constexpr size_t BUFF_SIZE = 8;
-  char buff[BUFF_SIZE];
-  int result;
-  inline_memset(buff, new_char, BUFF_SIZE);
-  while (length > BUFF_SIZE) {
-    result = write(buff, BUFF_SIZE);
-    if (result < 0)
-      return result;
-    length -= BUFF_SIZE;
-  }
-  return write(buff, length);
+  chars_written += length;
+  return chars_write(output, new_char, length);
 }
 
 } // namespace printf_core
diff --git a/libc/src/stdio/snprintf.cpp b/libc/src/stdio/snprintf.cpp
--- a/libc/src/stdio/snprintf.cpp
+++ b/libc/src/stdio/snprintf.cpp
@@ -29,7 +29,8 @@
   va_end(vlist);
   printf_core::StringWriter str_writer(buffer, (buffsz > 0 ? buffsz - 1 : 0));
   printf_core::Writer writer(reinterpret_cast<void *>(&str_writer),
-                             printf_core::write_to_string);
+                             printf_core::write_str_to_string,
+                             printf_core::write_chars_to_string);
 
   int ret_val = printf_core::printf_main(&writer, format, args);
   if (buffsz > 0) // if the buffsz is 0 the buffer may be a null pointer.
diff --git a/libc/src/stdio/sprintf.cpp b/libc/src/stdio/sprintf.cpp
--- a/libc/src/stdio/sprintf.cpp
+++ b/libc/src/stdio/sprintf.cpp
@@ -28,7 +28,8 @@
   va_end(vlist);
   printf_core::StringWriter str_writer(buffer);
   printf_core::Writer writer(reinterpret_cast<void *>(&str_writer),
-                             printf_core::write_to_string);
+                             printf_core::write_str_to_string,
+                             printf_core::write_chars_to_string);
 
   int ret_val = printf_core::printf_main(&writer, format, args);
   str_writer.terminate();
diff --git a/libc/test/src/stdio/printf_core/CMakeLists.txt b/libc/test/src/stdio/printf_core/CMakeLists.txt
--- a/libc/test/src/stdio/printf_core/CMakeLists.txt
+++ b/libc/test/src/stdio/printf_core/CMakeLists.txt
@@ -9,6 +9,7 @@
   DEPENDS
     libc.src.stdio.printf_core.parser
     libc.src.stdio.printf_core.core_structs
+    libc.src.__support.CPP.string_view
     libc.src.__support.arg_list
 )
 
@@ -21,6 +22,7 @@
   DEPENDS
     libc.src.stdio.printf_core.writer
     libc.src.stdio.printf_core.string_writer
+    libc.src.__support.CPP.string_view
 )
 
 add_libc_unittest(
diff --git a/libc/test/src/stdio/printf_core/converter_test.cpp b/libc/test/src/stdio/printf_core/converter_test.cpp
--- a/libc/test/src/stdio/printf_core/converter_test.cpp
+++ b/libc/test/src/stdio/printf_core/converter_test.cpp
@@ -23,14 +23,14 @@
       __llvm_libc::printf_core::StringWriter(str);
   __llvm_libc::printf_core::Writer writer = __llvm_libc::printf_core::Writer(
       reinterpret_cast<void *>(&str_writer),
-      __llvm_libc::printf_core::write_to_string);
+      __llvm_libc::printf_core::write_str_to_string,
+      __llvm_libc::printf_core::write_chars_to_string);
 };
 
 TEST_F(LlvmLibcPrintfConverterTest, SimpleRawConversion) {
   __llvm_libc::printf_core::FormatSection raw_section;
   raw_section.has_conv = false;
   raw_section.raw_string = "abc";
-  raw_section.raw_len = 3;
 
   __llvm_libc::printf_core::convert(&writer, raw_section);
 
@@ -196,17 +196,10 @@
   ASSERT_EQ(writer.get_chars_written(), 5);
 }
 
-TEST(LlvmLibcPrintfConverterTest, HexConversion) {
-  char str[20];
-  __llvm_libc::printf_core::StringWriter str_writer(str);
-  __llvm_libc::printf_core::Writer writer(
-      reinterpret_cast<void *>(&str_writer),
-      __llvm_libc::printf_core::write_to_string);
-
+TEST_F(LlvmLibcPrintfConverterTest, HexConversion) {
   __llvm_libc::printf_core::FormatSection section;
   section.has_conv = true;
   section.raw_string = "%#018x";
-  section.raw_len = 6;
   section.conv_name = 'x';
   section.flags = static_cast<__llvm_libc::printf_core::FormatFlags>(
       __llvm_libc::printf_core::FormatFlags::ALTERNATE_FORM |
@@ -220,17 +213,11 @@
   ASSERT_EQ(writer.get_chars_written(), 18);
 }
 
-TEST(LlvmLibcPrintfConverterTest, PointerConversion) {
-  char str[20];
-  __llvm_libc::printf_core::StringWriter str_writer(str);
-  __llvm_libc::printf_core::Writer writer(
-      reinterpret_cast<void *>(&str_writer),
-      __llvm_libc::printf_core::write_to_string);
+TEST_F(LlvmLibcPrintfConverterTest, PointerConversion) {
 
   __llvm_libc::printf_core::FormatSection section;
   section.has_conv = true;
   section.raw_string = "%p";
-  section.raw_len = 2;
   section.conv_name = 'p';
   section.conv_val_ptr = (void *)(0x123456ab);
   __llvm_libc::printf_core::convert(&writer, section);
@@ -240,17 +227,11 @@
   ASSERT_EQ(writer.get_chars_written(), 10);
 }
 
-TEST(LlvmLibcPrintfConverterTest, OctConversion) {
-  char str[20];
-  __llvm_libc::printf_core::StringWriter str_writer(str);
-  __llvm_libc::printf_core::Writer writer(
-      reinterpret_cast<void *>(&str_writer),
-      __llvm_libc::printf_core::write_to_string);
+TEST_F(LlvmLibcPrintfConverterTest, OctConversion) {
 
   __llvm_libc::printf_core::FormatSection section;
   section.has_conv = true;
   section.raw_string = "%o";
-  section.raw_len = 2;
   section.conv_name = 'o';
   section.conv_val_raw = 01234;
   __llvm_libc::printf_core::convert(&writer, section);
diff --git a/libc/test/src/stdio/printf_core/parser_test.cpp b/libc/test/src/stdio/printf_core/parser_test.cpp
--- a/libc/test/src/stdio/printf_core/parser_test.cpp
+++ b/libc/test/src/stdio/printf_core/parser_test.cpp
@@ -7,6 +7,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "src/__support/CPP/bit.h"
+#include "src/__support/CPP/string_view.h"
 #include "src/__support/arg_list.h"
 #include "src/stdio/printf_core/parser.h"
 
@@ -15,6 +16,8 @@
 #include "utils/UnitTest/PrintfMatcher.h"
 #include "utils/UnitTest/Test.h"
 
+using __llvm_libc::cpp::string_view;
+
 void init(const char *__restrict str, ...) {
   va_list vlist;
   va_start(vlist, str);
@@ -33,7 +36,8 @@
 
   __llvm_libc::printf_core::Parser parser(str, v);
 
-  for (auto cur_section = parser.get_next_section(); cur_section.raw_len > 0;
+  for (auto cur_section = parser.get_next_section();
+       !cur_section.raw_string.empty();
        cur_section = parser.get_next_section()) {
     *format_arr = cur_section;
     ++format_arr;
@@ -49,8 +53,8 @@
 
   __llvm_libc::printf_core::FormatSection expected;
   expected.has_conv = false;
-  expected.raw_len = 4;
-  expected.raw_string = str;
+
+  expected.raw_string = string_view(str, 4);
 
   ASSERT_FORMAT_EQ(expected, format_arr[0]);
   // TODO: add checks that the format_arr after the last one has length 0
@@ -63,21 +67,21 @@
 
   __llvm_libc::printf_core::FormatSection expected0, expected1, expected2;
   expected0.has_conv = false;
-  expected0.raw_len = 5;
-  expected0.raw_string = str;
+
+  expected0.raw_string = string_view(str, 5);
 
   ASSERT_FORMAT_EQ(expected0, format_arr[0]);
 
   expected1.has_conv = true;
-  expected1.raw_len = 2;
-  expected1.raw_string = str + 5;
+
+  expected1.raw_string = string_view(str + 5, 2);
   expected1.conv_name = '%';
 
   ASSERT_FORMAT_EQ(expected1, format_arr[1]);
 
   expected2.has_conv = false;
-  expected2.raw_len = 5;
-  expected2.raw_string = str + 7;
+
+  expected2.raw_string = string_view(str + 7, 5);
 
   ASSERT_FORMAT_EQ(expected2, format_arr[2]);
 }
@@ -90,8 +94,8 @@
 
   __llvm_libc::printf_core::FormatSection expected;
   expected.has_conv = true;
-  expected.raw_len = 2;
-  expected.raw_string = str;
+
+  expected.raw_string = string_view(str, 2);
   expected.conv_val_raw = arg1;
   expected.conv_name = 'd';
 
@@ -106,8 +110,8 @@
 
   __llvm_libc::printf_core::FormatSection expected;
   expected.has_conv = true;
-  expected.raw_len = 7;
-  expected.raw_string = str;
+
+  expected.raw_string = string_view(str, 7);
   expected.flags = static_cast<__llvm_libc::printf_core::FormatFlags>(
       __llvm_libc::printf_core::FormatFlags::FORCE_SIGN |
       __llvm_libc::printf_core::FormatFlags::LEFT_JUSTIFIED |
@@ -128,8 +132,8 @@
 
   __llvm_libc::printf_core::FormatSection expected;
   expected.has_conv = true;
-  expected.raw_len = 4;
-  expected.raw_string = str;
+
+  expected.raw_string = string_view(str, 4);
   expected.min_width = 12;
   expected.conv_val_raw = arg1;
   expected.conv_name = 'd';
@@ -145,8 +149,8 @@
 
   __llvm_libc::printf_core::FormatSection expected;
   expected.has_conv = true;
-  expected.raw_len = 5;
-  expected.raw_string = str;
+
+  expected.raw_string = string_view(str, 5);
   expected.precision = 34;
   expected.conv_val_raw = arg1;
   expected.conv_name = 'd';
@@ -162,8 +166,8 @@
 
   __llvm_libc::printf_core::FormatSection expected;
   expected.has_conv = true;
-  expected.raw_len = 3;
-  expected.raw_string = str;
+
+  expected.raw_string = string_view(str, 3);
   expected.precision = 0;
   expected.conv_val_raw = arg1;
   expected.conv_name = 'd';
@@ -179,8 +183,8 @@
 
   __llvm_libc::printf_core::FormatSection expected;
   expected.has_conv = true;
-  expected.raw_len = 3;
-  expected.raw_string = str;
+
+  expected.raw_string = string_view(str, 3);
   expected.length_modifier = __llvm_libc::printf_core::LengthModifier::h;
   expected.conv_val_raw = arg1;
   expected.conv_name = 'd';
@@ -196,8 +200,8 @@
 
   __llvm_libc::printf_core::FormatSection expected;
   expected.has_conv = true;
-  expected.raw_len = 4;
-  expected.raw_string = str;
+
+  expected.raw_string = string_view(str, 4);
   expected.length_modifier = __llvm_libc::printf_core::LengthModifier::ll;
   expected.conv_val_raw = arg1;
   expected.conv_name = 'd';
@@ -213,8 +217,8 @@
 
   __llvm_libc::printf_core::FormatSection expected;
   expected.has_conv = true;
-  expected.raw_len = 11;
-  expected.raw_string = str;
+
+  expected.raw_string = string_view(str, 11);
   expected.flags = static_cast<__llvm_libc::printf_core::FormatFlags>(
       __llvm_libc::printf_core::FormatFlags::LEFT_JUSTIFIED |
       __llvm_libc::printf_core::FormatFlags::LEADING_ZEROES |
@@ -238,24 +242,24 @@
 
   __llvm_libc::printf_core::FormatSection expected0, expected1, expected2;
   expected0.has_conv = true;
-  expected0.raw_len = 2;
-  expected0.raw_string = str;
+
+  expected0.raw_string = string_view(str, 2);
   expected0.conv_val_raw = arg1;
   expected0.conv_name = 'd';
 
   ASSERT_FORMAT_EQ(expected0, format_arr[0]);
 
   expected1.has_conv = true;
-  expected1.raw_len = 2;
-  expected1.raw_string = str + 2;
+
+  expected1.raw_string = string_view(str + 2, 2);
   expected1.conv_val_raw = __llvm_libc::cpp::bit_cast<uint64_t>(arg2);
   expected1.conv_name = 'f';
 
   ASSERT_FORMAT_EQ(expected1, format_arr[1]);
 
   expected2.has_conv = true;
-  expected2.raw_len = 2;
-  expected2.raw_string = str + 4;
+
+  expected2.raw_string = string_view(str + 4, 2);
   expected2.conv_val_ptr = const_cast<char *>(arg3);
   expected2.conv_name = 's';
 
@@ -272,8 +276,8 @@
 
   __llvm_libc::printf_core::FormatSection expected;
   expected.has_conv = true;
-  expected.raw_len = 4;
-  expected.raw_string = str;
+
+  expected.raw_string = string_view(str, 4);
   expected.conv_val_raw = arg1;
   expected.conv_name = 'd';
 
@@ -290,24 +294,24 @@
 
   __llvm_libc::printf_core::FormatSection expected0, expected1, expected2;
   expected0.has_conv = true;
-  expected0.raw_len = 4;
-  expected0.raw_string = str;
+
+  expected0.raw_string = string_view(str, 4);
   expected0.conv_val_raw = arg1;
   expected0.conv_name = 'd';
 
   ASSERT_FORMAT_EQ(expected0, format_arr[0]);
 
   expected1.has_conv = true;
-  expected1.raw_len = 4;
-  expected1.raw_string = str + 4;
+
+  expected1.raw_string = string_view(str + 4, 4);
   expected1.conv_val_raw = __llvm_libc::cpp::bit_cast<uint64_t>(arg2);
   expected1.conv_name = 'f';
 
   ASSERT_FORMAT_EQ(expected1, format_arr[1]);
 
   expected2.has_conv = true;
-  expected2.raw_len = 4;
-  expected2.raw_string = str + 8;
+
+  expected2.raw_string = string_view(str + 8, 4);
   expected2.conv_val_ptr = const_cast<char *>(arg3);
   expected2.conv_name = 's';
 
@@ -324,24 +328,24 @@
 
   __llvm_libc::printf_core::FormatSection expected0, expected1, expected2;
   expected0.has_conv = true;
-  expected0.raw_len = 4;
-  expected0.raw_string = str;
+
+  expected0.raw_string = string_view(str, 4);
   expected0.conv_val_raw = arg1;
   expected0.conv_name = 'd';
 
   ASSERT_FORMAT_EQ(expected0, format_arr[0]);
 
   expected1.has_conv = true;
-  expected1.raw_len = 4;
-  expected1.raw_string = str + 4;
+
+  expected1.raw_string = string_view(str + 4, 4);
   expected1.conv_val_raw = __llvm_libc::cpp::bit_cast<uint64_t>(arg2);
   expected1.conv_name = 'f';
 
   ASSERT_FORMAT_EQ(expected1, format_arr[1]);
 
   expected2.has_conv = true;
-  expected2.raw_len = 4;
-  expected2.raw_string = str + 8;
+
+  expected2.raw_string = string_view(str + 8, 4);
   expected2.conv_val_ptr = const_cast<char *>(arg3);
   expected2.conv_name = 's';
 
@@ -358,8 +362,8 @@
   for (size_t i = 0; i < 10; ++i) {
     __llvm_libc::printf_core::FormatSection expected;
     expected.has_conv = true;
-    expected.raw_len = 4 + (i >= 9 ? 1 : 0);
-    expected.raw_string = str + (4 * i);
+
+    expected.raw_string = string_view(str + (4 * i), 4 + (i >= 9 ? 1 : 0));
     expected.conv_val_raw = i + 1;
     expected.conv_name = 'd';
     EXPECT_FORMAT_EQ(expected, format_arr[i]);
@@ -380,14 +384,14 @@
       expected9;
 
   expected0.has_conv = false;
-  expected0.raw_len = 12;
-  expected0.raw_string = str;
+
+  expected0.raw_string = string_view(str, 12);
 
   EXPECT_FORMAT_EQ(expected0, format_arr[0]);
 
   expected1.has_conv = true;
-  expected1.raw_len = 6;
-  expected1.raw_string = str + 12;
+
+  expected1.raw_string = string_view(str + 12, 6);
   expected1.length_modifier = __llvm_libc::printf_core::LengthModifier::ll;
   expected1.conv_val_raw = arg3;
   expected1.conv_name = 'u';
@@ -395,27 +399,27 @@
   EXPECT_FORMAT_EQ(expected1, format_arr[1]);
 
   expected2.has_conv = false;
-  expected2.raw_len = 1;
-  expected2.raw_string = str + 18;
+
+  expected2.raw_string = string_view(str + 18, 1);
 
   EXPECT_FORMAT_EQ(expected2, format_arr[2]);
 
   expected3.has_conv = true;
-  expected3.raw_len = 2;
-  expected3.raw_string = str + 19;
+
+  expected3.raw_string = string_view(str + 19, 2);
   expected3.conv_name = '%';
 
   EXPECT_FORMAT_EQ(expected3, format_arr[3]);
 
   expected4.has_conv = false;
-  expected4.raw_len = 1;
-  expected4.raw_string = str + 21;
+
+  expected4.raw_string = string_view(str + 21, 1);
 
   EXPECT_FORMAT_EQ(expected4, format_arr[4]);
 
   expected5.has_conv = true;
-  expected5.raw_len = 8;
-  expected5.raw_string = str + 22;
+
+  expected5.raw_string = string_view(str + 22, 8);
   expected5.flags = __llvm_libc::printf_core::FormatFlags::SPACE_PREFIX;
   expected5.min_width = arg4;
   expected5.conv_val_raw = __llvm_libc::cpp::bit_cast<uint64_t>(arg2);
@@ -424,14 +428,14 @@
   EXPECT_FORMAT_EQ(expected5, format_arr[5]);
 
   expected6.has_conv = false;
-  expected6.raw_len = 1;
-  expected6.raw_string = str + 30;
+
+  expected6.raw_string = string_view(str + 30, 1);
 
   EXPECT_FORMAT_EQ(expected6, format_arr[6]);
 
   expected7.has_conv = true;
-  expected7.raw_len = 9;
-  expected7.raw_string = str + 31;
+
+  expected7.raw_string = string_view(str + 31, 9);
   expected7.flags = __llvm_libc::printf_core::FormatFlags::SPACE_PREFIX;
   expected7.precision = arg4;
   expected7.conv_val_raw = __llvm_libc::cpp::bit_cast<uint64_t>(arg2);
@@ -440,14 +444,14 @@
   EXPECT_FORMAT_EQ(expected7, format_arr[7]);
 
   expected8.has_conv = false;
-  expected8.raw_len = 1;
-  expected8.raw_string = str + 40;
+
+  expected8.raw_string = string_view(str + 40, 1);
 
   EXPECT_FORMAT_EQ(expected8, format_arr[8]);
 
   expected9.has_conv = true;
-  expected9.raw_len = 7;
-  expected9.raw_string = str + 41;
+
+  expected9.raw_string = string_view(str + 41, 7);
   expected9.min_width = 1;
   expected9.precision = 1;
   expected9.conv_val_raw = arg1;
diff --git a/libc/test/src/stdio/printf_core/string_writer_test.cpp b/libc/test/src/stdio/printf_core/string_writer_test.cpp
--- a/libc/test/src/stdio/printf_core/string_writer_test.cpp
+++ b/libc/test/src/stdio/printf_core/string_writer_test.cpp
@@ -6,17 +6,21 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "src/__support/CPP/string_view.h"
 #include "src/stdio/printf_core/string_writer.h"
 #include "src/stdio/printf_core/writer.h"
 
 #include "utils/UnitTest/Test.h"
 
+using __llvm_libc::cpp::string_view;
+
 TEST(LlvmLibcPrintfStringWriterTest, Constructor) {
   char str[10];
   __llvm_libc::printf_core::StringWriter str_writer(str);
   __llvm_libc::printf_core::Writer writer(
       reinterpret_cast<void *>(&str_writer),
-      __llvm_libc::printf_core::write_to_string);
+      __llvm_libc::printf_core::write_str_to_string,
+      __llvm_libc::printf_core::write_chars_to_string);
 }
 
 TEST(LlvmLibcPrintfStringWriterTest, Write) {
@@ -24,8 +28,9 @@
   __llvm_libc::printf_core::StringWriter str_writer(str);
   __llvm_libc::printf_core::Writer writer(
       reinterpret_cast<void *>(&str_writer),
-      __llvm_libc::printf_core::write_to_string);
-  writer.write("abc", 3);
+      __llvm_libc::printf_core::write_str_to_string,
+      __llvm_libc::printf_core::write_chars_to_string);
+  writer.write(string_view("abc", 3));
 
   EXPECT_EQ(str[3], 'G');
   // This null terminates the string. The writer has no indication when the
@@ -44,10 +49,11 @@
   __llvm_libc::printf_core::StringWriter str_writer(str);
   __llvm_libc::printf_core::Writer writer(
       reinterpret_cast<void *>(&str_writer),
-      __llvm_libc::printf_core::write_to_string);
-  writer.write("abc", 3);
-  writer.write("DEF", 3);
-  writer.write("1234", 3);
+      __llvm_libc::printf_core::write_str_to_string,
+      __llvm_libc::printf_core::write_chars_to_string);
+  writer.write(string_view("abc", 3));
+  writer.write(string_view("DEF", 3));
+  writer.write(string_view("1234", 3));
 
   str_writer.terminate();
 
@@ -60,7 +66,8 @@
   __llvm_libc::printf_core::StringWriter str_writer(str);
   __llvm_libc::printf_core::Writer writer(
       reinterpret_cast<void *>(&str_writer),
-      __llvm_libc::printf_core::write_to_string);
+      __llvm_libc::printf_core::write_str_to_string,
+      __llvm_libc::printf_core::write_chars_to_string);
   writer.write_chars('a', 3);
 
   EXPECT_EQ(str[3], 'G');
@@ -75,7 +82,8 @@
   __llvm_libc::printf_core::StringWriter str_writer(str);
   __llvm_libc::printf_core::Writer writer(
       reinterpret_cast<void *>(&str_writer),
-      __llvm_libc::printf_core::write_to_string);
+      __llvm_libc::printf_core::write_str_to_string,
+      __llvm_libc::printf_core::write_chars_to_string);
   writer.write_chars('a', 3);
   writer.write_chars('D', 3);
   writer.write_chars('1', 3);
@@ -91,7 +99,8 @@
   __llvm_libc::printf_core::StringWriter str_writer(str);
   __llvm_libc::printf_core::Writer writer(
       reinterpret_cast<void *>(&str_writer),
-      __llvm_libc::printf_core::write_to_string);
+      __llvm_libc::printf_core::write_str_to_string,
+      __llvm_libc::printf_core::write_chars_to_string);
   writer.write_chars('Z', 99);
 
   str_writer.terminate();
@@ -115,11 +124,12 @@
   __llvm_libc::printf_core::StringWriter str_writer(str);
   __llvm_libc::printf_core::Writer writer(
       reinterpret_cast<void *>(&str_writer),
-      __llvm_libc::printf_core::write_to_string);
+      __llvm_libc::printf_core::write_str_to_string,
+      __llvm_libc::printf_core::write_chars_to_string);
   writer.write_chars('a', 3);
-  writer.write("DEF", 3);
+  writer.write(string_view("DEF", 3));
   writer.write_chars('1', 3);
-  writer.write("456", 3);
+  writer.write(string_view("456", 3));
 
   str_writer.terminate();
 
@@ -132,8 +142,9 @@
   __llvm_libc::printf_core::StringWriter str_writer(str, 10);
   __llvm_libc::printf_core::Writer writer(
       reinterpret_cast<void *>(&str_writer),
-      __llvm_libc::printf_core::write_to_string);
-  writer.write("abcDEF123456", 12);
+      __llvm_libc::printf_core::write_str_to_string,
+      __llvm_libc::printf_core::write_chars_to_string);
+  writer.write(string_view("abcDEF123456", 12));
 
   str_writer.terminate();
 
@@ -146,7 +157,8 @@
   __llvm_libc::printf_core::StringWriter str_writer(str, 10);
   __llvm_libc::printf_core::Writer writer(
       reinterpret_cast<void *>(&str_writer),
-      __llvm_libc::printf_core::write_to_string);
+      __llvm_libc::printf_core::write_str_to_string,
+      __llvm_libc::printf_core::write_chars_to_string);
 
   writer.write_chars('1', 15);
 
@@ -161,11 +173,12 @@
   __llvm_libc::printf_core::StringWriter str_writer(str, 10);
   __llvm_libc::printf_core::Writer writer(
       reinterpret_cast<void *>(&str_writer),
-      __llvm_libc::printf_core::write_to_string);
+      __llvm_libc::printf_core::write_str_to_string,
+      __llvm_libc::printf_core::write_chars_to_string);
   writer.write_chars('a', 3);
-  writer.write("DEF", 3);
+  writer.write(string_view("DEF", 3));
   writer.write_chars('1', 3);
-  writer.write("456", 3);
+  writer.write(string_view("456", 3));
 
   str_writer.terminate();
 
@@ -178,13 +191,14 @@
   __llvm_libc::printf_core::StringWriter str_writer(str, 0);
   __llvm_libc::printf_core::Writer writer(
       reinterpret_cast<void *>(&str_writer),
-      __llvm_libc::printf_core::write_to_string);
+      __llvm_libc::printf_core::write_str_to_string,
+      __llvm_libc::printf_core::write_chars_to_string);
   // This is because the max length should be at most 1 less than the size of
   // the buffer it's writing to.
   writer.write_chars('a', 3);
-  writer.write("DEF", 3);
+  writer.write(string_view("DEF", 3));
   writer.write_chars('1', 3);
-  writer.write("456", 3);
+  writer.write(string_view("456", 3));
 
   str_writer.terminate();
 
@@ -196,11 +210,12 @@
   __llvm_libc::printf_core::StringWriter str_writer(nullptr, 0);
   __llvm_libc::printf_core::Writer writer(
       reinterpret_cast<void *>(&str_writer),
-      __llvm_libc::printf_core::write_to_string);
+      __llvm_libc::printf_core::write_str_to_string,
+      __llvm_libc::printf_core::write_chars_to_string);
   writer.write_chars('a', 3);
-  writer.write("DEF", 3);
+  writer.write(string_view("DEF", 3));
   writer.write_chars('1', 3);
-  writer.write("456", 3);
+  writer.write(string_view("456", 3));
 
   ASSERT_EQ(writer.get_chars_written(), 12);
 }
diff --git a/libc/utils/UnitTest/CMakeLists.txt b/libc/utils/UnitTest/CMakeLists.txt
--- a/libc/utils/UnitTest/CMakeLists.txt
+++ b/libc/utils/UnitTest/CMakeLists.txt
@@ -64,7 +64,7 @@
 add_dependencies(
   LibcPrintfHelpers
   LibcUnitTest
-  libc.src.__support.CPP.uint128
+  libc.src.__support.FPUtil.fputil #FPBits
   libc.src.stdio.printf_core.core_structs
   libc.utils.UnitTest.string_utils
 )
diff --git a/libc/utils/UnitTest/PrintfMatcher.cpp b/libc/utils/UnitTest/PrintfMatcher.cpp
--- a/libc/utils/UnitTest/PrintfMatcher.cpp
+++ b/libc/utils/UnitTest/PrintfMatcher.cpp
@@ -8,7 +8,7 @@
 
 #include "PrintfMatcher.h"
 
-#include "src/__support/CPP/UInt128.h"
+#include "src/__support/FPUtil/FPBits.h"
 #include "src/stdio/printf_core/core_structs.h"
 
 #include "utils/UnitTest/StringUtils.h"
@@ -37,8 +37,8 @@
     break
 
 void display(testutils::StreamWrapper &stream, FormatSection form) {
-  stream << "Raw String (len " << form.raw_len << "): \"";
-  for (size_t i = 0; i < form.raw_len; ++i) {
+  stream << "Raw String (len " << form.raw_string.size() << "): \"";
+  for (size_t i = 0; i < form.raw_string.size(); ++i) {
     stream << form.raw_string[i];
   }
   stream << "\"";
@@ -72,7 +72,10 @@
                     reinterpret_cast<uintptr_t>(form.conv_val_ptr))
              << "\n";
     else if (form.conv_name != '%')
-      stream << "\tvalue: " << int_to_hex<UInt128>(form.conv_val_raw) << "\n";
+      stream << "\tvalue: "
+             << int_to_hex<fputil::FPBits<long double>::UIntType>(
+                    form.conv_val_raw)
+             << "\n";
   }
 }
 } // anonymous namespace