/*
 * 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 int mini_strlen(const char *s) {
    int len = 0;
    while (s[len] != '\0') len++;
    return len;
}

static int mini_itoa(long value, unsigned int radix, int uppercase, int unsig, char *buffer) {
    char *pbuffer = buffer;
    int   negative = 0;
    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);

    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;
}

static int mini_pad(char *ptr, int len, char pad_char, int pad_to, char *buffer) {
    int   i;
    int   overflow = 0;
    char *pbuffer = buffer;
    if (pad_to == 0)
        pad_to = len;
    if (len > pad_to) {
        len = pad_to;
        overflow = 1;
    }
    for (i = pad_to - len; i > 0; i--) {
        *(pbuffer++) = pad_char;
    }
    for (i = len; i > 0; i--) {
        *(pbuffer++) = *(ptr++);
    }
    len = pbuffer - buffer;
    if (overflow) {
        for (i = 0; i < 3 && pbuffer > buffer; i++) {
            *(pbuffer-- - 1) = '*';
        }
    }
    return len;
}

struct mini_buff {
    char        *buffer, *pbuffer;
    unsigned int buffer_len;
};

static int _puts(char *s, int len, void *buf) {
    if (!buf)
        return len;
    struct mini_buff *b = buf;
    char             *p0 = b->buffer;
    int               i;
    /* Copy to buffer */
    for (i = 0; i < len; i++) {
        if (b->pbuffer == b->buffer + b->buffer_len - 1) {
            break;
        }
        *(b->pbuffer++) = s[i];
    }
    *(b->pbuffer) = 0;
    return b->pbuffer - p0;
}

#ifdef MINI_PRINTF_ENABLE_OBJECTS
static int (*mini_handler)(void *data, void *obj, int ch, int lhint, char **bf) = 0;
static void (*mini_handler_freeor)(void *data, void *) = 0;
static void *mini_handler_data = 0;

void mini_printf_set_handler(void *data, int (*handler)(void *data, void *obj, int ch, int len_hint, char **buf),
                             void (*freeor)(void *data, void *buf)) {
    mini_handler = handler;
    mini_handler_freeor = freeor;
    mini_handler_data = data;
}
#endif

int mini_vsnprintf(char *buffer, unsigned int buffer_len, const char *fmt, va_list va) {
    struct mini_buff b;
    b.buffer = buffer;
    b.pbuffer = buffer;
    b.buffer_len = buffer_len;
    if (buffer_len == 0)
        buffer = (void *)0;
    int n = mini_vpprintf(_puts, (buffer != (void *)0) ? &b : (void *)0, fmt, va);
    if (buffer == (void *)0) {
        return n;
    }
    return b.pbuffer - b.buffer;
}

int mini_vpprintf(int (*puts)(char *s, int len, void *buf), void *buf, const char *fmt, va_list va) {
    char bf[24];
    char bf2[24];
    char ch;
#ifdef MINI_PRINTF_ENABLE_OBJECTS
    void *obj;
#endif
    if (puts == (void *)0) {
        /* run puts in counting mode. */
        puts = _puts;
        buf = (void *)0;
    }
    int n = 0;
    while ((ch = *(fmt++))) {
        int len;
        if (ch != '%') {
            len = 1;
            len = puts(&ch, len, buf);
        } else {
            char  pad_char = ' ';
            int   pad_to = 0;
            char  l = 0;
            char *ptr;

            ch = *(fmt++);

            /* Zero padding requested */
            if (ch == '0')
                pad_char = '0';
            while (ch >= '0' && ch <= '9') {
                pad_to = pad_to * 10 + (ch - '0');
                ch = *(fmt++);
            }
            if (pad_to > (signed int)sizeof(bf)) {
                pad_to = sizeof(bf);
            }
            if (ch == 'l') {
                l = 1;
                ch = *(fmt++);
            }

            switch (ch) {
            case 0: goto end;
            case 'u':
            case 'd':
                if (l) {
                    len = mini_itoa(va_arg(va, unsigned long), 10, 0, (ch == 'u'), bf2);
                } else {
                    if (ch == 'u') {
                        len = mini_itoa((unsigned long)va_arg(va, unsigned int), 10, 0, 1, bf2);
                    } else {
                        len = mini_itoa((long)va_arg(va, int), 10, 0, 0, bf2);
                    }
                }
                len = mini_pad(bf2, len, pad_char, pad_to, bf);
                len = puts(bf, len, buf);
                break;

            case 'x':
            case 'X':
                if (l) {
                    len = mini_itoa(va_arg(va, unsigned long), 16, (ch == 'X'), 1, bf2);
                } else {
                    len = mini_itoa((unsigned long)va_arg(va, unsigned int), 16, (ch == 'X'), 1, bf2);
                }
                len = mini_pad(bf2, len, pad_char, pad_to, bf);
                len = puts(bf, len, buf);
                break;

            case 'c':
                ch = (char)(va_arg(va, int));
                len = mini_pad(&ch, 1, pad_char, pad_to, bf);
                len = puts(bf, len, buf);
                break;

            case 's':
                ptr = va_arg(va, char *);
                len = mini_strlen(ptr);
                if (pad_to > 0) {
                    len = mini_pad(ptr, len, pad_char, pad_to, bf);
                    len = puts(bf, len, buf);
                } else {
                    len = puts(ptr, len, buf);
                }
                break;
#ifdef MINI_PRINTF_ENABLE_OBJECTS
            case 'O': /* Object by content (e.g. str) */
            case 'R': /* Object by representation (e.g. repr)*/
                obj = va_arg(va, void *);
                len = mini_handler(mini_handler_data, obj, ch, pad_to, &ptr);
                if (pad_to > 0) {
                    len = mini_pad(ptr, len, pad_char, pad_to, bf);
                    len = puts(bf, len, buf);
                } else {
                    len = puts(ptr, len, buf);
                }
                mini_handler_freeor(mini_handler_data, ptr);
                break;
#endif
            default:
                len = 1;
                len = puts(&ch, len, buf);
                break;
            }
        }
        n = n + len;
    }
end:
    return n;
}

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;
}

int mini_pprintf(int (*puts)(char *s, int len, void *buf), void *buf, const char *fmt, ...) {
    int     ret;
    va_list va;
    va_start(va, fmt);
    ret = mini_vpprintf(puts, buf, fmt, va);
    va_end(va);

    return ret;
}