/* mbed Microcontroller Library * Copyright (c) 2017 ARM Limited * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #include "mbed_printf_implementation.h" #include #include #include #include /***************************/ /* MBED */ /***************************/ #if TARGET_LIKE_MBED #if MBED_CONF_PLATFORM_STDIO_CONVERT_NEWLINES static char mbed_stdio_out_prev = 0; #endif /***************************/ /* Linux */ /***************************/ #else /* Linux implementation is for debug only */ #define MBED_CONF_PLATFORM_MINIMAL_PRINTF_ENABLE_FLOATING_POINT 1 #define MBED_CONF_PLATFORM_MINIMAL_PRINTF_SET_FLOATING_POINT_MAX_DECIMALS 6 #define MBED_CONF_PLATFORM_MINIMAL_PRINTF_ENABLE_64_BIT 1 #endif #ifndef MBED_CONF_PLATFORM_MINIMAL_PRINTF_ENABLE_FLOATING_POINT #define MBED_CONF_PLATFORM_MINIMAL_PRINTF_ENABLE_FLOATING_POINT 0 #endif #ifndef MBED_CONF_PLATFORM_MINIMAL_PRINTF_SET_FLOATING_POINT_MAX_DECIMALS #define MBED_CONF_PLATFORM_MINIMAL_PRINTF_SET_FLOATING_POINT_MAX_DECIMALS 6 #endif #ifndef MBED_CONF_PLATFORM_MINIMAL_PRINTF_ENABLE_64_BIT #define MBED_CONF_PLATFORM_MINIMAL_PRINTF_ENABLE_64_BIT 1 #endif /** * Check architecture and choose storage data type. * On 32 bit machines, the default storage type is 32 bit wide * unless 64 bit integers are enabled in the configuration. */ #if INTPTR_MAX == INT32_MAX #define MBED_SIGNED_NATIVE_TYPE int32_t #define MBED_UNSIGNED_NATIVE_TYPE uint32_t #if MBED_CONF_PLATFORM_MINIMAL_PRINTF_ENABLE_64_BIT #define MBED_SIGNED_STORAGE int64_t #define MBED_UNSIGNED_STORAGE uint64_t #else #define MBED_SIGNED_STORAGE int32_t #define MBED_UNSIGNED_STORAGE uint32_t #endif #elif INTPTR_MAX == INT64_MAX #define MBED_SIGNED_NATIVE_TYPE int64_t #define MBED_UNSIGNED_NATIVE_TYPE uint64_t #define MBED_SIGNED_STORAGE int64_t #define MBED_UNSIGNED_STORAGE uint64_t #else #error unsupported architecture #endif /** * Precision defines */ #define PRECISION_DEFAULT (INT_MAX) /** * Enum for storing width modifier. */ typedef enum { LENGTH_NONE = 0x00, LENGTH_H = 0x11, LENGTH_L = 0x21, LENGTH_J = 0x31, LENGTH_Z = 0x41, LENGTH_T = 0x51, LENGTH_CAPITAL_L = 0x61, LENGTH_HH = 0x72, LENGTH_LL = 0x82 } length_t; /** * Prototypes */ static void mbed_minimal_formatted_string_signed(char *buffer, size_t length, int *result, MBED_SIGNED_STORAGE value, FILE *stream); static void mbed_minimal_formatted_string_unsigned(char *buffer, size_t length, int *result, MBED_UNSIGNED_STORAGE value, FILE *stream); static void mbed_minimal_formatted_string_hexadecimal(char *buffer, size_t length, int *result, MBED_UNSIGNED_STORAGE value, FILE *stream, bool upper); static void mbed_minimal_formatted_string_void_pointer(char *buffer, size_t length, int *result, const void *value, FILE *stream); static void mbed_minimal_formatted_string_character(char *buffer, size_t length, int *result, char character, FILE *stream); static void mbed_minimal_formatted_string_string(char *buffer, size_t length, int *result, const char *string, size_t precision, FILE *stream); /** * @brief Print a single character, checking for buffer and size overflows. * * @param buffer The buffer to store output (NULL for stdout). * @param[in] length The length of the buffer. * @param result The current output location. * @param[in] data The char to be printed. */ static void mbed_minimal_putchar(char *buffer, size_t length, int *result, char data, FILE *stream) { /* only continue if 'result' doesn't overflow */ if ((*result >= 0) && (*result <= INT_MAX - 1)) { /* write data only if there's enough space */ if ((size_t)*result < length) { if (buffer) { buffer[*result] = data; } else { fputc(data, stream); } } /* increment 'result' even if data was not written. This ensures that 'mbed_minimal_formatted_string' returns the correct value. */ *result += 1; } } /** * @brief Print signed integer. * * @param buffer The buffer to store output (NULL for stdout). * @param[in] length The length of the buffer. * @param result The current output location. * @param[in] value The value to be printed. */ static void mbed_minimal_formatted_string_signed(char *buffer, size_t length, int *result, MBED_SIGNED_STORAGE value, FILE *stream) { MBED_UNSIGNED_STORAGE new_value = 0; /* if value is negative print sign and treat as positive number */ if (value < 0) { /* write sign */ mbed_minimal_putchar(buffer, length, result, '-', stream); /* get absolute value using two's complement */ new_value = ~((MBED_UNSIGNED_STORAGE) value) + 1; } else { new_value = value; } /* use unsigned long int function */ mbed_minimal_formatted_string_unsigned(buffer, length, result, new_value, stream); } /** * @brief Print unsigned integer. * * @param buffer The buffer to store output (NULL for stdout). * @param[in] length The length of the buffer. * @param result The current output location. * @param[in] value The value to be printed. */ static void mbed_minimal_formatted_string_unsigned(char *buffer, size_t length, int *result, MBED_UNSIGNED_STORAGE value, FILE *stream) { /* treat 0 as a corner case */ if (value == 0) { mbed_minimal_putchar(buffer, length, result, '0', stream); } else { /* allocate 3 digits per byte */ char scratch[sizeof(MBED_UNSIGNED_STORAGE) * 3] = { 0 }; size_t index = 0; /* write numbers in reverse order to scratch pad */ for (; value > 0; index++) { /* use '0' as base and add digit */ scratch[index] = '0' + (value % 10); /* shift value one decimal position */ value = value / 10; } /* write scratch pad to buffer or output */ for (; index > 0; index--) { mbed_minimal_putchar(buffer, length, result, scratch[index - 1], stream); } } } /** * @brief Print hexadecimal. * * @param buffer The buffer to store output (NULL for stdout). * @param[in] length The length of the buffer. * @param result The current output location. * @param[in] value The value to be printed. * @param upper Flag to print the hexadecimal in upper or lower case. */ static void mbed_minimal_formatted_string_hexadecimal(char *buffer, size_t length, int *result, MBED_UNSIGNED_STORAGE value, FILE *stream, bool upper) { bool print_leading_zero = false; for (int index = 7; index >= 0; index--) { /* get most significant byte */ uint8_t output = value >> (8 * index); /* only print leading zeros when set */ if (print_leading_zero || (output != 0) || (index == 0)) { unsigned int nibble_one = (output >> 4); unsigned int nibble_two = (output & 0x0F); const char int2hex_lower[16] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' }; const char int2hex_upper[16] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' }; const char *int2hex = upper ? int2hex_upper : int2hex_lower; if (print_leading_zero || nibble_one != 0) { mbed_minimal_putchar(buffer, length, result, int2hex[nibble_one], stream); } mbed_minimal_putchar(buffer, length, result, int2hex[nibble_two], stream); /* print zeroes after the first non-zero byte */ print_leading_zero = true; } } } /** * @brief Print pointer. * * @param buffer The buffer to store output (NULL for stdout). * @param[in] length The length of the buffer. * @param result The current output location. * @param[in] value The pointer to be printed. */ static void mbed_minimal_formatted_string_void_pointer(char *buffer, size_t length, int *result, const void *value, FILE *stream) { /* write leading 0x */ mbed_minimal_putchar(buffer, length, result, '0', stream); mbed_minimal_putchar(buffer, length, result, 'x', stream); /* write rest as a regular hexadecimal number */ mbed_minimal_formatted_string_hexadecimal(buffer, length, result, (ptrdiff_t) value, stream, true); } #if MBED_CONF_PLATFORM_MINIMAL_PRINTF_ENABLE_FLOATING_POINT /** * @brief Write double. * * @param buffer The buffer to store output (NULL for stdout). * @param[in] length The length of the buffer. * @param result The current output location. * @param[in] value The value to be printed. */ static void mbed_minimal_formatted_string_double(char *buffer, size_t length, int *result, double value, FILE *stream) { /* get integer part */ MBED_SIGNED_STORAGE integer = value; /* write integer part */ mbed_minimal_formatted_string_signed(buffer, length, result, integer, stream); /* write decimal point */ mbed_minimal_formatted_string_character(buffer, length, result, '.', stream); /* get decimal part */ double precision = 1.0; for (size_t index = 0; index < MBED_CONF_PLATFORM_MINIMAL_PRINTF_SET_FLOATING_POINT_MAX_DECIMALS; index++) { precision *= 10; } value = (value - integer) * precision; /* convert to unsigned integer */ MBED_UNSIGNED_STORAGE decimal = 0; if (value < 0) { MBED_SIGNED_STORAGE temp = value; decimal = ~((MBED_UNSIGNED_STORAGE) temp) + 1; } else { decimal = value; } /* round up or down */ value -= decimal; if (!((value > -0.5) && (value < 0.5))) { decimal++; } /* convert precision to unsigned integer */ MBED_UNSIGNED_STORAGE precision_in_uint = precision; precision_in_uint /= 10; /* ensure that leading zeros are printed if decimal equals 0 */ MBED_UNSIGNED_STORAGE val = decimal ? decimal : decimal + 1; while (precision_in_uint > val) { /* print leading zeros */ mbed_minimal_putchar(buffer, length, result, '0', stream); precision_in_uint /= 10; } /* write decimal part */ mbed_minimal_formatted_string_unsigned(buffer, length, result, decimal, stream); } #endif /** * @brief Print character. * * @param buffer The buffer to store output (NULL for stdout). * @param[in] length The length of the buffer. * @param result The current output location. * @param[in] value The character to be printed. */ static void mbed_minimal_formatted_string_character(char *buffer, size_t length, int *result, char character, FILE *stream) { /* write character */ if (buffer) { mbed_minimal_putchar(buffer, length, result, character, stream); } else { /* convert \n to \r\n if enabled in platform configuration */ #if MBED_CONF_PLATFORM_STDIO_CONVERT_NEWLINES if (character == '\n' && mbed_stdio_out_prev != '\r') { mbed_minimal_putchar(buffer, length, result, '\r', stream); } /* cache character */ mbed_stdio_out_prev = character; #endif mbed_minimal_putchar(buffer, length, result, character, stream); } } /** * @brief Print string with precision. * * @param buffer The buffer to store output (NULL for stdout). * @param[in] length The length of the buffer. * @param result The current output location. * @param[in] value The string to be printed. * @param[in] precision The maximum number of characters to be printed. */ static void mbed_minimal_formatted_string_string(char *buffer, size_t length, int *result, const char *string, size_t precision, FILE *stream) { while ((*string != '\0') && (precision)) { mbed_minimal_putchar(buffer, length, result, *string, stream); string++; precision--; } } /** * @brief Parse formatted string and invoke write handlers based on type. * * @param buffer The buffer to write to, write to stdout if NULL. * @param[in] length The length of the buffer. * @param[in] format The formatted string. * @param[in] arguments The va_list arguments. * * @return Number of characters written. */ int mbed_minimal_formatted_string(char *buffer, size_t length, const char *format, va_list arguments, FILE *stream) { int result = 0; bool empty_buffer = false; /* ensure that function wasn't called with an empty buffer, or with or with a buffer size that is larger than the maximum 'int' value, or with a NULL format specifier */ if (format && length <= INT_MAX) { /* Make sure that there's always space for the NULL terminator */ if (length > 0) { length --; } else { /* the buffer is empty, there's no place to write the terminator */ empty_buffer = true; } /* parse string */ for (size_t index = 0; format[index] != '\0'; index++) { /* format specifier begin */ if (format[index] == '%') { size_t next_index = index + 1; /************************************************************** * skip and ignore flags [-+(space)#0] *************************************************************/ if ((format[next_index] == '-') || (format[next_index] == '+') || (format[next_index] == ' ') || (format[next_index] == '#') || (format[next_index] == '0')) { /* skip to next character */ next_index++; } /************************************************************** * skip and ignore width [(number)*] *************************************************************/ if (format[next_index] == '*') { /* skip to next character */ next_index++; /* discard argument */ va_arg(arguments, MBED_SIGNED_NATIVE_TYPE); } else { while ((format[next_index] >= '0') && (format[next_index] <= '9')) { /* skip to next character */ next_index++; } } /************************************************************** * look for precision modifier *************************************************************/ int precision = PRECISION_DEFAULT; if ((format[next_index] == '.') && (format[next_index + 1] == '*')) { next_index += 2; /* read precision from argument list */ precision = va_arg(arguments, MBED_SIGNED_NATIVE_TYPE); } else if (format[next_index] == '.') { /* precision modifier found, reset default to 0 and increment index */ next_index++; precision = 0; /* parse precision until not a decimal */ size_t inner_index = 0; while ((format[next_index + inner_index] >= '0') && (format[next_index + inner_index] <= '9')) { precision = precision * 10 + (format[next_index + inner_index] - '0'); inner_index++; } /* move index forward to point at next character */ next_index += inner_index; } /************************************************************** * look for length modifier, default to NONE *************************************************************/ length_t length_modifier = LENGTH_NONE; /* look for two character length modifier */ if ((format[next_index] == 'h') && (format[next_index + 1] == 'h')) { length_modifier = LENGTH_HH; } else if ((format[next_index] == 'l') && (format[next_index + 1] == 'l')) { length_modifier = LENGTH_LL; } /* look for one character length modifier if two character search failed */ else if (format[next_index] == 'h') { length_modifier = LENGTH_H; } else if (format[next_index] == 'l') { length_modifier = LENGTH_L; } else if (format[next_index] == 'j') { length_modifier = LENGTH_J; } else if (format[next_index] == 'z') { length_modifier = LENGTH_Z; } else if (format[next_index] == 't') { length_modifier = LENGTH_T; } else if (format[next_index] == 'L') { length_modifier = LENGTH_CAPITAL_L; } /* increment index, length is encoded in modifier enum */ next_index += (length_modifier & 0x0F); /************************************************************** * read out character - this is a supported format character, * '\0', or a not suported character *************************************************************/ char next = format[next_index]; /* signed integer */ if ((next == 'd') || (next == 'i')) { MBED_SIGNED_STORAGE value = 0; #if MBED_CONF_PLATFORM_MINIMAL_PRINTF_ENABLE_64_BIT /* if 64 bit is enabled and the integer types are larger than the native type */ if (((length_modifier == LENGTH_LL) && (sizeof(long long int) > sizeof(MBED_SIGNED_NATIVE_TYPE))) || ((length_modifier == LENGTH_L) && (sizeof(long int) > sizeof(MBED_SIGNED_NATIVE_TYPE))) || ((length_modifier == LENGTH_NONE) && (sizeof(int) > sizeof(MBED_SIGNED_NATIVE_TYPE)))) { /* use 64 bit storage type for readout */ value = va_arg(arguments, MBED_SIGNED_STORAGE); } else #endif { /* use native storage type (which can be 32 or 64 bit) */ value = va_arg(arguments, MBED_SIGNED_NATIVE_TYPE); } /* constrict value based on lenght modifier */ switch (length_modifier) { case LENGTH_NONE: value = (int) value; break; case LENGTH_HH: value = (signed char) value; break; case LENGTH_H: value = (short int) value; break; case LENGTH_L: value = (long int) value; break; case LENGTH_LL: value = (long long int) value; break; case LENGTH_J: value = (intmax_t) value; break; case LENGTH_T: value = (ptrdiff_t) value; break; default: break; } index = next_index; mbed_minimal_formatted_string_signed(buffer, length, &result, value, stream); } /* unsigned integer */ else if ((next == 'u') || (next == 'x') || (next == 'X')) { MBED_UNSIGNED_STORAGE value = 0; #if MBED_CONF_PLATFORM_MINIMAL_PRINTF_ENABLE_64_BIT /* if 64 bit is enabled and the integer types are larger than the native type */ if (((length_modifier == LENGTH_LL) && (sizeof(unsigned long long int) > sizeof(MBED_UNSIGNED_NATIVE_TYPE))) || ((length_modifier == LENGTH_L) && (sizeof(unsigned long int) > sizeof(MBED_UNSIGNED_NATIVE_TYPE))) || ((length_modifier == LENGTH_NONE) && (sizeof(unsigned int) > sizeof(MBED_UNSIGNED_NATIVE_TYPE)))) { /* use 64 bit storage type for readout */ value = va_arg(arguments, MBED_UNSIGNED_STORAGE); } else #endif { /* use native storage type (which can be 32 or 64 bit) */ value = va_arg(arguments, MBED_UNSIGNED_NATIVE_TYPE); } /* constrict value based on lenght modifier */ switch (length_modifier) { case LENGTH_NONE: value = (unsigned int) value; break; case LENGTH_HH: value = (unsigned char) value; break; case LENGTH_H: value = (unsigned short int) value; break; case LENGTH_L: value = (unsigned long int) value; break; case LENGTH_LL: value = (unsigned long long int) value; break; case LENGTH_J: value = (uintmax_t) value; break; case LENGTH_Z: value = (size_t) value; break; case LENGTH_T: value = (ptrdiff_t) value; break; default: break; } index = next_index; /* write unsigned or hexadecimal */ if (next == 'u') { mbed_minimal_formatted_string_unsigned(buffer, length, &result, value, stream); } else { mbed_minimal_formatted_string_hexadecimal(buffer, length, &result, value, stream, next == 'X'); } } #if MBED_CONF_PLATFORM_MINIMAL_PRINTF_ENABLE_FLOATING_POINT /* treat all floating points the same */ else if ((next == 'f') || (next == 'F') || (next == 'g') || (next == 'G')) { double value = va_arg(arguments, double); index = next_index; mbed_minimal_formatted_string_double(buffer, length, &result, value, stream); } #endif /* character */ else if (next == 'c') { char value = va_arg(arguments, MBED_SIGNED_NATIVE_TYPE); index = next_index; mbed_minimal_formatted_string_character(buffer, length, &result, value, stream); } /* string */ else if (next == 's') { char *value = va_arg(arguments, char *); index = next_index; mbed_minimal_formatted_string_string(buffer, length, &result, value, precision, stream); } /* pointer */ else if (next == 'p') { void *value = va_arg(arguments, void *); index = next_index; mbed_minimal_formatted_string_void_pointer(buffer, length, &result, value, stream); } else { // Unrecognised, or `%%`. Print the `%` that led us in. mbed_minimal_formatted_string_character(buffer, length, &result, '%', stream); if (next == '%') { // Continue printing loop after `%%` index = next_index; } // Otherwise we continue the printing loop after the leading `%`, so an // unrecognised thing like "Blah = %a" will just come out as "Blah = %a" } } else /* not a format specifier */ { /* write normal character */ mbed_minimal_formatted_string_character(buffer, length, &result, format[index], stream); } } if (buffer && !empty_buffer) { /* NULL-terminate the buffer no matter what. We use '<=' to compare instead of '<' because we know that we initially reserved space for '\0' by decrementing length */ if ((size_t)result <= length) { buffer[result] = '\0'; } else { buffer[length] = '\0'; } } } return result; }