1 files changed, 266 insertions, 0 deletions
diff --git a/mozglue/misc/Printf.h b/mozglue/misc/Printf.h
new file mode 100644
index 0000000000..3f4fa2c1bb
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+++ b/mozglue/misc/Printf.h
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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: set ts=8 sts=2 et sw=2 tw=80:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* Printf-like functions, with canned variants that malloc their result.  */
+
+#ifndef mozilla_Printf_h
+#define mozilla_Printf_h
+
+/*
+** API for PR printf like routines.
+**
+** These exist partly for historical reasons -- initially they were in
+** NSPR, then forked in tree and modified in js/ -- but now the prime
+** motivation is both closer control over the exact formatting (with
+** one exception, see below) and also the ability to control where
+** exactly the generated results are sent.
+**
+** It might seem that this could all be dispensed with in favor of a
+** wrapper around |vsnprintf| -- except that this implementation
+** guarantees that the %s format will accept a NULL pointer, whereas
+** with standard functions this is undefined.
+**
+** This supports the following formats.  It implements a subset of the
+** standard formats; due to the use of MOZ_FORMAT_PRINTF, it is not
+** permissible to extend the standard, aside from relaxing undefined
+** behavior.
+**
+**      %d - decimal
+**      %u - unsigned decimal
+**      %x - unsigned hex
+**      %X - unsigned uppercase hex
+**      %o - unsigned octal
+**      %hd, %hu, %hx, %hX, %ho - "short" versions of above
+**      %ld, %lu, %lx, %lX, %lo - "long" versions of above
+**      %lld, %llu, %llx, %llX, %llo - "long long" versions of above
+**      %zd, %zo, %zu, %zx, %zX - size_t versions of above
+**      %Id, %Io, %Iu, %Ix, %IX - size_t versions of above (for Windows compat).
+**           Note that MSVC 2015 and newer supports the z length modifier so
+**           users should prefer using %z instead of %I. We are supporting %I in
+**           addition to %z in case third-party code that uses %I gets routed to
+**           use this printf implementation.
+**      %s - string
+**      %S, %ls - wide string, that is wchar_t*
+**      %c - character
+**      %p - pointer (deals with machine dependent pointer size)
+**      %f - float; note that this is actually formatted using the
+**           system's native printf, and so the results may vary
+**      %g - float; note that this is actually formatted using the
+**           system's native printf, and so the results may vary
+*/
+
+#include "mozilla/AllocPolicy.h"
+#include "mozilla/Assertions.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/IntegerPrintfMacros.h"
+#include "mozilla/Types.h"
+#include "mozilla/UniquePtr.h"
+
+#include <stdarg.h>
+#include <string.h>
+
+namespace mozilla {
+
+/*
+ * This class may be subclassed to provide a way to get the output of
+ * a printf-like call, as the output is generated.
+ */
+class PrintfTarget {
+ public:
+  /* The Printf-like interface.  */
+  bool MFBT_API print(const char* format, ...) MOZ_FORMAT_PRINTF(2, 3);
+
+  /* The Vprintf-like interface.  */
+  bool MFBT_API vprint(const char* fmt, va_list) MOZ_FORMAT_PRINTF(2, 0);
+
+  /* Fast paths for formatting integers as though by %d, %o, %u, or %x.
+     Since octal and hex formatting always treat numbers as unsigned, there
+     are no signed overloads for AppendInt{Oct,Hex}.  */
+  bool MFBT_API appendIntDec(int32_t);
+  bool MFBT_API appendIntDec(uint32_t);
+  bool MFBT_API appendIntOct(uint32_t);
+  bool MFBT_API appendIntHex(uint32_t);
+  bool MFBT_API appendIntDec(int64_t);
+  bool MFBT_API appendIntDec(uint64_t);
+  bool MFBT_API appendIntOct(uint64_t);
+  bool MFBT_API appendIntHex(uint64_t);
+
+  inline size_t emitted() { return mEmitted; }
+
+ protected:
+  MFBT_API PrintfTarget();
+  virtual ~PrintfTarget() = default;
+
+  /* Subclasses override this.  It is called when more output is
+     available.  It may be called with len==0.  This should return
+     true on success, or false on failure.  */
+  virtual bool append(const char* sp, size_t len) = 0;
+
+ private:
+  /* Number of bytes emitted so far.  */
+  size_t mEmitted;
+
+  /* The implementation calls this to emit bytes and update
+     mEmitted.  */
+  bool emit(const char* sp, size_t len) {
+    mEmitted += len;
+    return append(sp, len);
+  }
+
+  bool fill2(const char* src, int srclen, int width, int flags);
+  bool fill_n(const char* src, int srclen, int width, int prec, int type,
+              int flags);
+  bool cvt_l(long num, int width, int prec, int radix, int type, int flags,
+             const char* hexp);
+  bool cvt_ll(int64_t num, int width, int prec, int radix, int type, int flags,
+              const char* hexp);
+  bool cvt_f(double d, char c, int width, int prec, int flags);
+  bool cvt_s(const char* s, int width, int prec, int flags);
+};
+
+namespace detail {
+
+template <typename AllocPolicy = mozilla::MallocAllocPolicy>
+struct AllocPolicyBasedFreePolicy {
+  void operator()(const void* ptr) {
+    AllocPolicy policy;
+    policy.free_(const_cast<void*>(ptr));
+  }
+};
+
+}  // namespace detail
+
+// The type returned by Smprintf and friends.
+template <typename AllocPolicy>
+using SmprintfPolicyPointer =
+    mozilla::UniquePtr<char, detail::AllocPolicyBasedFreePolicy<AllocPolicy>>;
+
+// The default type if no alloc policy is specified.
+typedef SmprintfPolicyPointer<mozilla::MallocAllocPolicy> SmprintfPointer;
+
+// Used in the implementation of Smprintf et al.
+template <typename AllocPolicy>
+class MOZ_STACK_CLASS SprintfState final : private mozilla::PrintfTarget,
+                                           private AllocPolicy {
+ public:
+  explicit SprintfState(char* base)
+      : mMaxlen(base ? strlen(base) : 0),
+        mBase(base),
+        mCur(base ? base + mMaxlen : 0) {}
+
+  ~SprintfState() { this->free_(mBase); }
+
+  bool vprint(const char* format, va_list ap_list) MOZ_FORMAT_PRINTF(2, 0) {
+    // The "" here has a single \0 character, which is what we're
+    // trying to append.
+    return mozilla::PrintfTarget::vprint(format, ap_list) && append("", 1);
+  }
+
+  SmprintfPolicyPointer<AllocPolicy> release() {
+    SmprintfPolicyPointer<AllocPolicy> result(mBase);
+    mBase = nullptr;
+    return result;
+  }
+
+ protected:
+  bool append(const char* sp, size_t len) override {
+    ptrdiff_t off;
+    char* newbase;
+    size_t newlen;
+
+    off = mCur - mBase;
+    if (off + len >= mMaxlen) {
+      /* Grow the buffer */
+      newlen = mMaxlen + ((len > 32) ? len : 32);
+      newbase = this->template maybe_pod_malloc<char>(newlen);
+      if (!newbase) {
+        /* Ran out of memory */
+        return false;
+      }
+      memcpy(newbase, mBase, mMaxlen);
+      this->free_(mBase);
+      mBase = newbase;
+      mMaxlen = newlen;
+      mCur = mBase + off;
+    }
+
+    /* Copy data */
+    memcpy(mCur, sp, len);
+    mCur += len;
+    MOZ_ASSERT(size_t(mCur - mBase) <= mMaxlen);
+    return true;
+  }
+
+ private:
+  size_t mMaxlen;
+  char* mBase;
+  char* mCur;
+};
+
+/*
+** sprintf into a malloc'd buffer. Return a pointer to the malloc'd
+** buffer on success, nullptr on failure. Call AllocPolicy::free_ to release
+** the memory returned.
+*/
+template <typename AllocPolicy = mozilla::MallocAllocPolicy>
+MOZ_FORMAT_PRINTF(1, 2)
+SmprintfPolicyPointer<AllocPolicy> Smprintf(const char* fmt, ...) {
+  SprintfState<AllocPolicy> ss(nullptr);
+  va_list ap;
+  va_start(ap, fmt);
+  bool r = ss.vprint(fmt, ap);
+  va_end(ap);
+  if (!r) {
+    return nullptr;
+  }
+  return ss.release();
+}
+
+/*
+** "append" sprintf into a malloc'd buffer. "last" is the last value of
+** the malloc'd buffer. sprintf will append data to the end of last,
+** growing it as necessary using realloc. If last is nullptr, SmprintfAppend
+** will allocate the initial string. The return value is the new value of
+** last for subsequent calls, or nullptr if there is a malloc failure.
+*/
+template <typename AllocPolicy = mozilla::MallocAllocPolicy>
+MOZ_FORMAT_PRINTF(2, 3)
+SmprintfPolicyPointer<AllocPolicy> SmprintfAppend(
+    SmprintfPolicyPointer<AllocPolicy>&& last, const char* fmt, ...) {
+  SprintfState<AllocPolicy> ss(last.release());
+  va_list ap;
+  va_start(ap, fmt);
+  bool r = ss.vprint(fmt, ap);
+  va_end(ap);
+  if (!r) {
+    return nullptr;
+  }
+  return ss.release();
+}
+
+/*
+** va_list forms of the above.
+*/
+template <typename AllocPolicy = mozilla::MallocAllocPolicy>
+MOZ_FORMAT_PRINTF(1, 0)
+SmprintfPolicyPointer<AllocPolicy> Vsmprintf(const char* fmt, va_list ap) {
+  SprintfState<AllocPolicy> ss(nullptr);
+  if (!ss.vprint(fmt, ap)) return nullptr;
+  return ss.release();
+}
+
+template <typename AllocPolicy = mozilla::MallocAllocPolicy>
+MOZ_FORMAT_PRINTF(2, 0)
+SmprintfPolicyPointer<AllocPolicy> VsmprintfAppend(
+    SmprintfPolicyPointer<AllocPolicy>&& last, const char* fmt, va_list ap) {
+  SprintfState<AllocPolicy> ss(last.release());
+  if (!ss.vprint(fmt, ap)) return nullptr;
+  return ss.release();
+}
+
+}  // namespace mozilla
+
+#endif /* mozilla_Printf_h */