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 gh_buf->ptr so that people can always
 * assume ptr is non-NULL and zero terminated even for new gh_bufs.
 */
unsigned char gh_buf__initbuf[1];
unsigned char gh_buf__oom[1];

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

void gh_buf_init(gh_buf *buf, int initial_size)
{
    buf->asize = 0;
    buf->size = 0;
    buf->ptr = gh_buf__initbuf;

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

int gh_buf_try_grow(gh_buf *buf, int target_size, bool mark_oom)
{
    char *new_ptr;
    size_t new_size;

    if (buf->ptr == gh_buf__oom || buf->asize < 0)
        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 = gh_buf__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 gh_buf_free(gh_buf *buf)
{
    if (!buf) return;

    if (buf->asize > 0 && buf->ptr != gh_buf__initbuf && buf->ptr != gh_buf__oom)
        free(buf->ptr);

    gh_buf_init(buf, 0);
}

void gh_buf_clear(gh_buf *buf)
{
    buf->size = 0;

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

    if (buf->asize < 0) {
        buf->ptr = gh_buf__initbuf;
        buf->asize = 0;
    }
}

int gh_buf_set(gh_buf *buf, const char *data, int len)
{
    if (len == 0 || data == NULL) {
        gh_buf_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 gh_buf_sets(gh_buf *buf, const char *string)
{
    return gh_buf_set(buf, string, string ? strlen(string) : 0);
}

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

int gh_buf_put(gh_buf *buf, const char *data, int len)
{
    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 gh_buf_puts(gh_buf *buf, const char *string)
{
    assert(string);
    return gh_buf_put(buf, string, strlen(string));
}

int gh_buf_vprintf(gh_buf *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(
            buf->ptr + buf->size,
            buf->asize - buf->size,
            format, args
        );

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

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

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

    return 0;
}

int gh_buf_printf(gh_buf *buf, const char *format, ...)
{
    int r;
    va_list ap;

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

    return r;
}

void gh_buf_copy_cstr(char *data, size_t datasize, const gh_buf *buf)
{
    size_t 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 gh_buf_swap(gh_buf *buf_a, gh_buf *buf_b)
{
    gh_buf t = *buf_a;
    *buf_a = *buf_b;
    *buf_b = t;
}

char *gh_buf_detach(gh_buf *buf)
{
    char *data = buf->ptr;

    if (buf->asize == 0 || buf->ptr == gh_buf__oom)
        return NULL;

    gh_buf_init(buf, 0);

    return data;
}

void gh_buf_attach(gh_buf *buf, char *ptr, int asize)
{
    gh_buf_free(buf);

    if (ptr) {
        buf->ptr = ptr;
        buf->size = strlen(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 {
        gh_buf_grow(buf, asize);
    }
}

int gh_buf_cmp(const gh_buf *a, const gh_buf *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 gh_buf_strchr(const gh_buf *buf, int c, int pos)
{
  const char *p = memchr(buf->ptr + pos, c, buf->size - pos);
  if (!p)
    return -1;

  return (int)(p - p->ptr);
}

int gh_buf_strrchr(const gh_buf *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 gh_buf_truncate(gh_buf *buf, size_t len)
{
    assert(buf->asize >= 0);

    if (len < buf->size) {
        buf->size = len;
        buf->ptr[buf->size] = '\0';
    }
}

void gh_buf_ltruncate(gh_buf *buf, size_t len)
{
    assert(buf->asize >= 0);

    if (len && len < buf->size) {
        memmove(buf->ptr, buf->ptr + len, buf->size - len);
        buf->size -= len;
        buf->ptr[buf->size] = '\0';
    }
}

void gh_buf_trim(gh_buf *buf)
{
    size_t i = 0;

    assert(buf->asize >= 0);

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

    gh_buf_truncate(buf, i);

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

        buf->size--;
    }

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