| /* |
| * The Minimal snprintf() implementation |
| * |
| * Copyright (c) 2013,2014 Michal Ludvig <michal@logix.cz> |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions are met: |
| * * Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * * Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * * Neither the name of the auhor nor the names of its contributors |
| * may be used to endorse or promote products derived from this software |
| * without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND |
| * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED |
| * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE |
| * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY |
| * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES |
| * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
| * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND |
| * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
| * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| * |
| * ---- |
| * |
| * This is a minimal snprintf() implementation optimised |
| * for embedded systems with a very limited program memory. |
| * mini_snprintf() doesn't support _all_ the formatting |
| * the glibc does but on the other hand is a lot smaller. |
| * Here are some numbers from my STM32 project (.bin file size): |
| * no snprintf(): 10768 bytes |
| * mini snprintf(): 11420 bytes (+ 652 bytes) |
| * glibc snprintf(): 34860 bytes (+24092 bytes) |
| * Wasting nearly 24kB of memory just for snprintf() on |
| * a chip with 32kB flash is crazy. Use mini_snprintf() instead. |
| * |
| */ |
| |
| #include "mini-printf.h" |
| |
| static unsigned int |
| mini_strlen(const char *s) |
| { |
| unsigned int len = 0; |
| while (s[len] != '\0') len++; |
| return len; |
| } |
| |
| static unsigned int |
| mini_itoa(int value, unsigned int radix, unsigned int uppercase, unsigned int unsig, |
| char *buffer, unsigned int zero_pad) |
| { |
| char *pbuffer = buffer; |
| int negative = 0; |
| unsigned int i, len; |
| |
| /* No support for unusual radixes. */ |
| if (radix > 16) |
| return 0; |
| |
| if (value < 0 && !unsig) { |
| negative = 1; |
| value = -value; |
| } |
| |
| /* This builds the string back to front ... */ |
| do { |
| int digit = value % radix; |
| *(pbuffer++) = (digit < 10 ? '0' + digit : (uppercase ? 'A' : 'a') + digit - 10); |
| value /= radix; |
| } while (value > 0); |
| |
| for (i = (pbuffer - buffer); i < zero_pad; i++) |
| *(pbuffer++) = '0'; |
| |
| if (negative) |
| *(pbuffer++) = '-'; |
| |
| *(pbuffer) = '\0'; |
| |
| /* ... now we reverse it (could do it recursively but will |
| * conserve the stack space) */ |
| len = (pbuffer - buffer); |
| for (i = 0; i < len / 2; i++) { |
| char j = buffer[i]; |
| buffer[i] = buffer[len-i-1]; |
| buffer[len-i-1] = j; |
| } |
| |
| return len; |
| } |
| |
| struct mini_buff { |
| char *buffer, *pbuffer; |
| unsigned int buffer_len; |
| }; |
| |
| static int |
| _putc(int ch, struct mini_buff *b) |
| { |
| if ((unsigned int)((b->pbuffer - b->buffer) + 1) >= b->buffer_len) |
| return 0; |
| *(b->pbuffer++) = ch; |
| *(b->pbuffer) = '\0'; |
| return 1; |
| } |
| |
| static int |
| _puts(char *s, unsigned int len, struct mini_buff *b) |
| { |
| unsigned int i; |
| |
| if (b->buffer_len - (b->pbuffer - b->buffer) - 1 < len) |
| len = b->buffer_len - (b->pbuffer - b->buffer) - 1; |
| |
| /* Copy to buffer */ |
| for (i = 0; i < len; i++) |
| *(b->pbuffer++) = s[i]; |
| *(b->pbuffer) = '\0'; |
| |
| return len; |
| } |
| |
| int |
| mini_vsnprintf(char *buffer, unsigned int buffer_len, const char *fmt, va_list va) |
| { |
| struct mini_buff b; |
| char bf[24]; |
| char ch; |
| |
| b.buffer = buffer; |
| b.pbuffer = buffer; |
| b.buffer_len = buffer_len; |
| |
| while ((ch=*(fmt++))) { |
| if ((unsigned int)((b.pbuffer - b.buffer) + 1) >= b.buffer_len) |
| break; |
| if (ch!='%') |
| _putc(ch, &b); |
| else { |
| char zero_pad = 0; |
| char *ptr; |
| unsigned int len; |
| |
| ch=*(fmt++); |
| |
| /* Zero padding requested */ |
| if (ch=='0') { |
| ch=*(fmt++); |
| if (ch == '\0') |
| goto end; |
| if (ch >= '0' && ch <= '9') |
| zero_pad = ch - '0'; |
| ch=*(fmt++); |
| } |
| |
| switch (ch) { |
| case 0: |
| goto end; |
| |
| case 'u': |
| case 'd': |
| len = mini_itoa(va_arg(va, unsigned int), 10, 0, (ch=='u'), bf, zero_pad); |
| _puts(bf, len, &b); |
| break; |
| |
| case 'x': |
| case 'X': |
| len = mini_itoa(va_arg(va, unsigned int), 16, (ch=='X'), 1, bf, zero_pad); |
| _puts(bf, len, &b); |
| break; |
| |
| case 'c' : |
| _putc((char)(va_arg(va, int)), &b); |
| break; |
| |
| case 's' : |
| ptr = va_arg(va, char*); |
| _puts(ptr, mini_strlen(ptr), &b); |
| break; |
| |
| default: |
| _putc(ch, &b); |
| break; |
| } |
| } |
| } |
| end: |
| return b.pbuffer - b.buffer; |
| } |
| |
| |
| int |
| mini_snprintf(char* buffer, unsigned int buffer_len, const char *fmt, ...) |
| { |
| int ret; |
| va_list va; |
| va_start(va, fmt); |
| ret = mini_vsnprintf(buffer, buffer_len, fmt, va); |
| va_end(va); |
| |
| return ret; |
| } |