#include "cache.h"

/*
 * Used as the default ->buf value, so that people can always assume
 * buf is non NULL and ->buf is NUL terminated even for a freshly
 * initialized strbuf.
 */
char strbuf_slopbuf[1];

void strbuf_init(struct strbuf *sb, size_t hint)
{
        sb->alloc = sb->len = 0;
        sb->buf = strbuf_slopbuf;
        if (hint)
                strbuf_grow(sb, hint);
}

void strbuf_release(struct strbuf *sb)
{
        if (sb->alloc) {
                free(sb->buf);
                strbuf_init(sb, 0);
        }
}

char *strbuf_detach(struct strbuf *sb, size_t *sz)
{
        char *res = sb->alloc ? sb->buf : NULL;
        if (sz)
                *sz = sb->len;
        strbuf_init(sb, 0);
        return res;
}

void strbuf_attach(struct strbuf *sb, void *buf, size_t len, size_t alloc)
{
        strbuf_release(sb);
        sb->buf   = buf;
        sb->len   = len;
        sb->alloc = alloc;
        strbuf_grow(sb, 0);
        sb->buf[sb->len] = '\0';
}

void strbuf_grow(struct strbuf *sb, size_t extra)
{
        if (sb->len + extra + 1 <= sb->len)
                die("you want to use way too much memory");
        if (!sb->alloc)
                sb->buf = NULL;
        ALLOC_GROW(sb->buf, sb->len + extra + 1, sb->alloc);
}

void strbuf_rtrim(struct strbuf *sb)
{
        while (sb->len > 0 && isspace((unsigned char)sb->buf[sb->len - 1]))
                sb->len--;
        sb->buf[sb->len] = '\0';
}

int strbuf_cmp(struct strbuf *a, struct strbuf *b)
{
        int cmp;
        if (a->len < b->len) {
                cmp = memcmp(a->buf, b->buf, a->len);
                return cmp ? cmp : -1;
        } else {
                cmp = memcmp(a->buf, b->buf, b->len);
                return cmp ? cmp : a->len != b->len;
        }
}

void strbuf_splice(struct strbuf *sb, size_t pos, size_t len,
                                   const void *data, size_t dlen)
{
        if (pos + len < pos)
                die("you want to use way too much memory");
        if (pos > sb->len)
                die("`pos' is too far after the end of the buffer");
        if (pos + len > sb->len)
                die("`pos + len' is too far after the end of the buffer");

        if (dlen >= len)
                strbuf_grow(sb, dlen - len);
        memmove(sb->buf + pos + dlen,
                        sb->buf + pos + len,
                        sb->len - pos - len);
        memcpy(sb->buf + pos, data, dlen);
        strbuf_setlen(sb, sb->len + dlen - len);
}

void strbuf_insert(struct strbuf *sb, size_t pos, const void *data, size_t len)
{
        strbuf_splice(sb, pos, 0, data, len);
}

void strbuf_remove(struct strbuf *sb, size_t pos, size_t len)
{
        strbuf_splice(sb, pos, len, NULL, 0);
}

void strbuf_add(struct strbuf *sb, const void *data, size_t len)
{
        strbuf_grow(sb, len);
        memcpy(sb->buf + sb->len, data, len);
        strbuf_setlen(sb, sb->len + len);
}

void strbuf_addf(struct strbuf *sb, const char *fmt, ...)
{
        int len;
        va_list ap;

        va_start(ap, fmt);
        len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap);
        va_end(ap);
        if (len < 0) {
                len = 0;
        }
        if (len > strbuf_avail(sb)) {
                strbuf_grow(sb, len);
                va_start(ap, fmt);
                len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap);
                va_end(ap);
                if (len > strbuf_avail(sb)) {
                        die("this should not happen, your snprintf is broken");
                }
        }
        strbuf_setlen(sb, sb->len + len);
}

size_t strbuf_fread(struct strbuf *sb, size_t size, FILE *f)
{
        size_t res;

        strbuf_grow(sb, size);
        res = fread(sb->buf + sb->len, 1, size, f);
        if (res > 0) {
                strbuf_setlen(sb, sb->len + res);
        }
        return res;
}

ssize_t strbuf_read(struct strbuf *sb, int fd, size_t hint)
{
        size_t oldlen = sb->len;

        strbuf_grow(sb, hint ? hint : 8192);
        for (;;) {
                ssize_t cnt;

                cnt = xread(fd, sb->buf + sb->len, sb->alloc - sb->len - 1);
                if (cnt < 0) {
                        strbuf_setlen(sb, oldlen);
                        return -1;
                }
                if (!cnt)
                        break;
                sb->len += cnt;
                strbuf_grow(sb, 8192);
        }

        sb->buf[sb->len] = '\0';
        return sb->len - oldlen;
}

int strbuf_getline(struct strbuf *sb, FILE *fp, int term)
{
        int ch;

        strbuf_grow(sb, 0);
        if (feof(fp))
                return EOF;

        strbuf_reset(sb);
        while ((ch = fgetc(fp)) != EOF) {
                if (ch == term)
                        break;
                strbuf_grow(sb, 1);
                sb->buf[sb->len++] = ch;
        }
        if (ch == EOF && sb->len == 0)
                return EOF;

        sb->buf[sb->len] = '\0';
        return 0;
}

int strbuf_read_file(struct strbuf *sb, const char *path, size_t hint)
{
        int fd, len;

        fd = open(path, O_RDONLY);
        if (fd < 0)
                return -1;
        len = strbuf_read(sb, fd, hint);
        close(fd);
        if (len < 0)
                return -1;

        return len;
}