#include "blob.h"

static const char *xd = "0123456789abcdefghijklmnopqrstuvwxyz";

static inline int dx(int c)
{
	if (likely(c >= '0' && c <= '9'))
		return c - '0';
	if (likely(c >= 'a' && c <= 'f'))
		return c - 'a' + 0xa;
	if (c >= 'A' && c <= 'F')
		return c - 'A' + 0xa;
	return -1;
}

char *blob_cstr_dup(blob_t b)
{
	char *p;

	if (blob_is_null(b))
		return NULL;

	p = malloc(b.len+1);
	if (p != NULL) {
		memcpy(p, b.ptr, b.len);
		p[b.len] = 0;
	}
	return p;
}

blob_t blob_dup(blob_t b)
{
	blob_t p;

	if (blob_is_null(b))
		return BLOB_NULL;

	p.ptr = malloc(b.len);
	if (p.ptr != NULL) {
		memcpy(p.ptr, b.ptr, b.len);
		p.len = b.len;
	} else {
		p.len = 0;
	}
	return p;
}

int blob_cmp(blob_t a, blob_t b)
{
	if (a.len != b.len)
		return a.len - b.len;
	return memcmp(a.ptr, b.ptr, a.len);
}

blob_t blob_pushed(blob_t buffer, blob_t left)
{
	if (buffer.ptr + buffer.len != left.ptr + left.len)
		return BLOB_NULL;
	return BLOB_PTR_LEN(buffer.ptr, left.ptr - buffer.ptr);
}

void blob_push(blob_t *b, blob_t d)
{
	if (b->len >= d.len) {
		memcpy(b->ptr, d.ptr, d.len);
		b->ptr += d.len;
		b->len -= d.len;
	} else {
		*b = BLOB_NULL;
	}
}

void blob_push_uint(blob_t *to, unsigned int value, int radix)
{
	char buf[64];
	char *ptr = &buf[sizeof(buf)-1];

	if (value == 0) {
		blob_push(to, BLOB_STR("0"));
		return;
	}

	while (value != 0) {
		*(ptr--) = xd[value % radix];
		value /= radix;
	}

	blob_push(to, BLOB_PTR_PTR(ptr+1, &buf[sizeof(buf)-1]));
}

void blob_push_hexdump(blob_t *to, blob_t binary)
{
	static const char *xd = "0123456789abcdef";
	char *d;
	int i;

	if (blob_is_null(*to))
		return;

	if (to->len < binary.len * 2) {
		*to = BLOB_NULL;
		return;
	}

	for (i = 0, d = to->ptr; i < binary.len; i++) {
		*(d++) = xd[(binary.ptr[i] >> 4) & 0xf];
		*(d++) = xd[binary.ptr[i] & 0xf];
	}
	to->ptr = d;
	to->len -= binary.len * 2;
}

void blob_push_urldecode(blob_t *to, blob_t url)
{
	blob_t b, orig = *to;

	do {
		blob_pull_matching(&url, BLOB_STR("/"));
		b = blob_pull_cspn(&url, BLOB_STR("/"));
		if (blob_is_null(url) && blob_is_null(b))
			break;

		if (blob_is_null(b) || blob_cmp(b, BLOB_STR(".")) == 0) {
			/* skip '.' or two consecutive / */
		} else if (blob_cmp(b, BLOB_STR("..")) == 0) {
			/* go up one path component */
			blob_shrink_tail(to, blob_pushed(orig, b), '/');
		} else {
			/* copy decoded; FIXME decode percent encoding */
			blob_push(to, BLOB_STR("/"));
			blob_push(to, b);
		}
	} while (1);
}

blob_t blob_pull(blob_t *b, int len)
{
	blob_t r;

	if (b->len >= len) {
		r = BLOB_PTR_LEN(b->ptr, len);
		b->ptr += len;
		b->len -= len;
		return r;
	}
	*b = BLOB_NULL;
	return BLOB_NULL;
}

void blob_pull_skip(blob_t *b, int len)
{
	if (b->len >= len) {
		b->ptr += len;
		b->len -= len;
	} else {
		*b = BLOB_NULL;
	}
}

int blob_pull_matching(blob_t *b, blob_t e)
{
	if (b->len < e.len)
		return 0;
	if (memcmp(b->ptr, e.ptr, e.len) != 0)
		return 0;
	b->ptr += e.len;
	b->len -= e.len;
	return 1;
}

unsigned int blob_pull_uint(blob_t *b, int radix)
{
	unsigned int val;
	int ch;

	val = 0;
	while (b->len && b->ptr[0] != 0) {
		ch = dx(b->ptr[0]);
		if (ch < 0 || ch >= radix)
			break;
		val *= radix;
		val += ch;

		b->ptr++;
		b->len--;
	}

	return val;
}

blob_t blob_pull_spn(blob_t *b, const blob_t reject)
{
	blob_t t = *b;
	int i;

	for (i = 0; i < t.len; i++) {
		if (memchr(reject.ptr, t.ptr[i], reject.len) == NULL) {
			*b = BLOB_PTR_LEN(t.ptr + i, t.len - i);
			return BLOB_PTR_LEN(t.ptr, i);
		}
	}

	*b = BLOB_NULL;
	return t;
}

blob_t blob_pull_cspn(blob_t *b, const blob_t reject)
{
	blob_t t = *b;
	int i;

	for (i = 0; i < t.len; i++) {
		if (memchr(reject.ptr, t.ptr[i], reject.len) != NULL) {
			*b = BLOB_PTR_LEN(t.ptr + i, t.len - i);
			return BLOB_PTR_LEN(t.ptr, i);
		}
	}

	*b = BLOB_NULL;
	return t;
}

blob_t blob_expand_head(blob_t *b, blob_t limits, unsigned char sep)
{
	blob_t t = *b;
	blob_t r;

	if (t.ptr < limits.ptr || t.ptr+t.len > limits.ptr+limits.len)
		return BLOB_NULL;
	while (t.ptr > limits.ptr && t.ptr[-1] == sep)
		t.ptr--, t.len++;

	r.ptr = t.ptr;
	r.len = 0;
	while (t.ptr > limits.ptr && t.ptr[-1] != sep) {
		t.ptr--, t.len++;
		r.ptr--, r.len++;
	}
	*b = t;
	return r;
}

blob_t blob_expand_tail(blob_t *b, blob_t limits, unsigned char sep)
{
	blob_t t = *b;
	blob_t r;

	if (t.ptr < limits.ptr || t.ptr+t.len > limits.ptr+limits.len)
		return BLOB_NULL;
	while (t.ptr + t.len < limits.ptr + limits.len && t.ptr[t.len] == sep)
		t.len++;

	r.ptr = t.ptr + t.len;
	r.len = 0;
	while (t.ptr + t.len < limits.ptr + limits.len && t.ptr[t.len] != sep) {
		t.len++;
		r.len++;
	}
	*b = t;
	return r;
}

blob_t blob_shrink_tail(blob_t *b, blob_t limits, unsigned char sep)
{
	blob_t t = *b;
	blob_t r;

	if (t.ptr <= limits.ptr || t.ptr+t.len > limits.ptr+limits.len)
		return BLOB_NULL;
	while (t.len && t.ptr[t.len-1] == sep)
		t.len--;

	r.ptr = t.ptr;
	r.len = 0;
	while (t.len && t.ptr[t.len-1] != sep) {
		t.len--;
		r.ptr--, r.len++;
	}
	*b = t;
	return r;
}