Initial commit of libdynamic_depth

Dynamic depth is a standard for embedding depth maps and
other similar extensions into standard image files like JPEG.

Test: m libdynamic_depth
Bug: 109735087
Bug: 119211681
Change-Id: I0103b7d47e60dc8e3a3b277456903d76f727926f

1 files changed, 89 insertions, 0 deletions

diff --git a/internal/strings/ascii_ctype.h b/internal/strings/ascii_ctype.h
new file mode 100644
index 0000000..acc1fe5
--- /dev/null
+++ b/internal/strings/ascii_ctype.h
@@ -0,0 +1,89 @@
+// Character classification functions similar to standard <ctype.h>.
+// Some C++ implementations provide locale-sensitive implementations
+// of some <ctype.h> functions.  These ascii_* functions are
+// hard-wired for ASCII.  Hard-wired for ASCII is much faster.
+//
+// ascii_isalnum, ascii_isalpha, ascii_isascii, ascii_isblank,
+// ascii_iscntrl, ascii_isdigit, ascii_isgraph, ascii_islower,
+// ascii_isprint, ascii_ispunct, ascii_isspace, ascii_isupper,
+// ascii_isxdigit
+//   Similar to the <ctype.h> functions with similar names.
+//   Input parameter is an unsigned char.  Return value is a bool.
+//   If the input has a numerical value greater than 127
+//   then the output is "false".
+//
+// ascii_tolower, ascii_toupper
+//   Similar to the <ctype.h> functions with similar names.
+//   Input parameter is an unsigned char.  Return value is a char.
+//   If the input is not an ascii {lower,upper}-case letter
+//   (including numerical values greater than 127)
+//   then the output is the same as the input.
+
+#ifndef DYNAMIC_DEPTH_INTERNAL_STRINGS_ASCII_CTYPE_H_  // NOLINT
+#define DYNAMIC_DEPTH_INTERNAL_STRINGS_ASCII_CTYPE_H_  // NOLINT
+
+namespace dynamic_depth {
+
+// Array of character information.  This is an implementation detail.
+// The individual bits do not have names because the array definition is
+// already tightly coupled to these functions.  Names would just make it
+// harder to read and debug.
+
+extern const unsigned char kAsciiPropertyBits[256];
+
+// Public functions.
+
+static inline bool ascii_isalpha(unsigned char c) {
+  return (kAsciiPropertyBits[c] & 0x01) != 0;
+}
+
+static inline bool ascii_isalnum(unsigned char c) {
+  return (kAsciiPropertyBits[c] & 0x04) != 0;
+}
+
+static inline bool ascii_isspace(unsigned char c) {
+  return (kAsciiPropertyBits[c] & 0x08) != 0;
+}
+
+static inline bool ascii_ispunct(unsigned char c) {
+  return (kAsciiPropertyBits[c] & 0x10) != 0;
+}
+
+static inline bool ascii_isblank(unsigned char c) {
+  return (kAsciiPropertyBits[c] & 0x20) != 0;
+}
+
+static inline bool ascii_iscntrl(unsigned char c) {
+  return (kAsciiPropertyBits[c] & 0x40) != 0;
+}
+
+static inline bool ascii_isxdigit(unsigned char c) {
+  return (kAsciiPropertyBits[c] & 0x80) != 0;
+}
+
+static inline bool ascii_isdigit(unsigned char c) {
+  return c >= '0' && c <= '9';
+}
+
+static inline bool ascii_isprint(unsigned char c) { return c >= 32 && c < 127; }
+
+static inline bool ascii_isgraph(unsigned char c) { return c > 32 && c < 127; }
+
+static inline bool ascii_isupper(unsigned char c) {
+  return c >= 'A' && c <= 'Z';
+}
+
+static inline bool ascii_islower(unsigned char c) {
+  return c >= 'a' && c <= 'z';
+}
+
+static inline bool ascii_isascii(unsigned char c) { return c < 128; }
+
+extern const char kAsciiToLower[256];
+static inline char ascii_tolower(unsigned char c) { return kAsciiToLower[c]; }
+extern const char kAsciiToUpper[256];
+static inline char ascii_toupper(unsigned char c) { return kAsciiToUpper[c]; }
+
+}  // namespace dynamic_depth
+
+#endif  // DYNAMIC_DEPTH_INTERNAL_STRINGS_ASCII_CTYPE_H_  // NOLINT