path: root/src/buffer.c

#include <stdarg.h>
#include <ctype.h>
#include <string.h>
#include <assert.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/param.h>

#include "buffer.h"

/* Used as default value for strbuf->ptr so that people can always
 * assume ptr is non-NULL and zero terminated even for new strbufs.
 */
unsigned char strbuf__initbuf[1];
unsigned char strbuf__oom[1];

#define ENSURE_SIZE(b, d)                   \
    if ((d) > buf->asize && strbuf_grow(b, (d)) < 0)    \
        return -1;

void strbuf_init(strbuf *buf, int initial_size)
{
    buf->asize = 0;
    buf->size = 0;
    buf->ptr = strbuf__initbuf;

    if (initial_size)
        strbuf_grow(buf, initial_size);
}

int strbuf_try_grow(strbuf *buf, int target_size, bool mark_oom)
{
    unsigned char *new_ptr;
    int new_size;

    if (buf->ptr == strbuf__oom)
        return -1;

    if (target_size <= buf->asize)
        return 0;

    if (buf->asize == 0) {
        new_size = target_size;
        new_ptr = NULL;
    } else {
        new_size = buf->asize;
        new_ptr = buf->ptr;
    }

    /* grow the buffer size by 1.5, until it's big enough
     * to fit our target size */
    while (new_size < target_size)
        new_size = (new_size << 1) - (new_size >> 1);

    /* round allocation up to multiple of 8 */
    new_size = (new_size + 7) & ~7;

    new_ptr = realloc(new_ptr, new_size);

    if (!new_ptr) {
        if (mark_oom)
            buf->ptr = strbuf__oom;
        return -1;
    }

    buf->asize = new_size;
    buf->ptr   = new_ptr;

    /* truncate the existing buffer size if necessary */
    if (buf->size >= buf->asize)
        buf->size = buf->asize - 1;
    buf->ptr[buf->size] = '\0';

    return 0;
}

void strbuf_free(strbuf *buf)
{
    if (!buf) return;

    if (buf->ptr != strbuf__initbuf && buf->ptr != strbuf__oom)
        free(buf->ptr);

    strbuf_init(buf, 0);
}

void strbuf_clear(strbuf *buf)
{
    buf->size = 0;

    if (buf->asize > 0)
        buf->ptr[0] = '\0';
}

int strbuf_set(strbuf *buf, const unsigned char *data, int len)
{
    if (len <= 0 || data == NULL) {
        strbuf_clear(buf);
    } else {
        if (data != buf->ptr) {
            ENSURE_SIZE(buf, len + 1);
            memmove(buf->ptr, data, len);
        }
        buf->size = len;
        buf->ptr[buf->size] = '\0';
    }
    return 0;
}

int strbuf_sets(strbuf *buf, const char *string)
{
    return strbuf_set(buf,
              (const unsigned char *)string,
              string ? strlen(string) : 0);
}

int strbuf_putc(strbuf *buf, int c)
{
    ENSURE_SIZE(buf, buf->size + 2);
    buf->ptr[buf->size++] = c;
    buf->ptr[buf->size] = '\0';
    return 0;
}

int strbuf_put(strbuf *buf, const unsigned char *data, int len)
{
    if (len <= 0)
        return 0;

    ENSURE_SIZE(buf, buf->size + len + 1);
    memmove(buf->ptr + buf->size, data, len);
    buf->size += len;
    buf->ptr[buf->size] = '\0';
    return 0;
}

int strbuf_puts(strbuf *buf, const char *string)
{
    return strbuf_put(buf, (const unsigned char *)string, strlen(string));
}

int strbuf_vprintf(strbuf *buf, const char *format, va_list ap)
{
    const int expected_size = buf->size + (strlen(format) * 2);
    int len;

    ENSURE_SIZE(buf, expected_size);

    while (1) {
        va_list args;
        va_copy(args, ap);

        len = vsnprintf(
            (char *)buf->ptr + buf->size,
            buf->asize - buf->size,
            format, args
            );

        if (len < 0) {
            free(buf->ptr);
            buf->ptr = strbuf__oom;
            return -1;
        }

        if (len + 1 <= buf->asize - buf->size) {
            buf->size += len;
            break;
        }

        ENSURE_SIZE(buf, buf->size + len + 1);
    }

    return 0;
}

int strbuf_printf(strbuf *buf, const char *format, ...)
{
    int r;
    va_list ap;

    va_start(ap, format);
    r = strbuf_vprintf(buf, format, ap);
    va_end(ap);

    return r;
}

void strbuf_copy_cstr(char *data, int datasize, const strbuf *buf)
{
    int copylen;

    assert(data && datasize && buf);

    data[0] = '\0';

    if (buf->size == 0 || buf->asize <= 0)
        return;

    copylen = buf->size;
    if (copylen > datasize - 1)
        copylen = datasize - 1;
    memmove(data, buf->ptr, copylen);
    data[copylen] = '\0';
}

void strbuf_swap(strbuf *buf_a, strbuf *buf_b)
{
    strbuf t = *buf_a;
    *buf_a = *buf_b;
    *buf_b = t;
}

unsigned char *strbuf_detach(strbuf *buf)
{
    unsigned char *data = buf->ptr;

    if (buf->asize == 0 || buf->ptr == strbuf__oom) {
        /* return an empty string */
        return calloc(1, 1);
    }

    strbuf_init(buf, 0);
    return data;
}

void strbuf_attach(strbuf *buf, unsigned char *ptr, int asize)
{
    strbuf_free(buf);

    if (ptr) {
        buf->ptr = ptr;
        buf->size = strlen((char *)ptr);
        if (asize)
            buf->asize = (asize < buf->size) ? buf->size + 1 : asize;
        else /* pass 0 to fall back on strlen + 1 */
            buf->asize = buf->size + 1;
    } else {
        strbuf_grow(buf, asize);
    }
}

int strbuf_cmp(const strbuf *a, const strbuf *b)
{
    int result = memcmp(a->ptr, b->ptr, MIN(a->size, b->size));
    return (result != 0) ? result :
        (a->size < b->size) ? -1 : (a->size > b->size) ? 1 : 0;
}

int strbuf_strchr(const strbuf *buf, int c, int pos)
{
    const unsigned char *p = memchr(buf->ptr + pos, c, buf->size - pos);
    if (!p)
        return -1;

    return (int)(p - (const unsigned char *)buf->ptr);
}

int strbuf_strrchr(const strbuf *buf, int c, int pos)
{
    int i;

    for (i = pos; i >= 0; i--) {
        if (buf->ptr[i] == (unsigned char) c)
            return i;
    }

    return -1;
}

void strbuf_truncate(strbuf *buf, int len)
{
    if (len < buf->size) {
        buf->size = len;
        buf->ptr[buf->size] = '\0';
    }
}

void strbuf_drop(strbuf *buf, int n)
{
    if (n > 0) {
        buf->size = buf->size - n;
        if (buf->size)
            memmove(buf->ptr, buf->ptr + n, buf->size);

        buf->ptr[buf->size] = '\0';
    }
}

void strbuf_trim(strbuf *buf)
{
    int i = 0;

    if (!buf->size)
        return;

    while (i < buf->size && isspace(buf->ptr[i]))
        i++;

    strbuf_drop(buf, i);

    /* rtrim */
    while (buf->size > 0) {
        if (!isspace(buf->ptr[buf->size - 1]))
            break;

        buf->size--;
    }

    buf->ptr[buf->size] = '\0';
}

// Destructively modify string, collapsing consecutive
// space and newline characters into a single space.
void strbuf_normalize_whitespace(strbuf *s)
{
    bool last_char_was_space = false;
    int r, w;

    for (r = 0, w = 0; r < s->size; ++r) {
        switch (s->ptr[r]) {
        case ' ':
        case '\n':
            if (last_char_was_space)
                break;

            s->ptr[w++] = ' ';
            last_char_was_space = true;
            break;

        default:
            s->ptr[w++] = s->ptr[r];
            last_char_was_space = false;
        }
    }

    strbuf_truncate(s, w);
}

// Destructively unescape a string: remove backslashes before punctuation chars.
extern void strbuf_unescape(strbuf *buf)
{
    int r, w;

    for (r = 0, w = 0; r < buf->size; ++r) {
        if (buf->ptr[r] == '\\' && ispunct(buf->ptr[r + 1]))
            continue;

        buf->ptr[w++] = buf->ptr[r];
    }

    strbuf_truncate(buf, w);
}