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#include "fitz-internal.h"
fz_buffer *
fz_new_buffer(fz_context *ctx, int size)
{
fz_buffer *b;
size = size > 1 ? size : 16;
b = fz_malloc_struct(ctx, fz_buffer);
b->refs = 1;
fz_try(ctx)
{
b->data = fz_malloc(ctx, size);
}
fz_catch(ctx)
{
fz_free(ctx, b);
fz_rethrow(ctx);
}
b->cap = size;
b->len = 0;
b->unused_bits = 0;
return b;
}
fz_buffer *
fz_keep_buffer(fz_context *ctx, fz_buffer *buf)
{
if (buf)
{
if (buf->refs == 1 && buf->cap > buf->len+1)
fz_resize_buffer(ctx, buf, buf->len);
buf->refs ++;
}
return buf;
}
void
fz_drop_buffer(fz_context *ctx, fz_buffer *buf)
{
if (!buf)
return;
if (--buf->refs == 0)
{
fz_free(ctx, buf->data);
fz_free(ctx, buf);
}
}
void
fz_resize_buffer(fz_context *ctx, fz_buffer *buf, int size)
{
buf->data = fz_resize_array(ctx, buf->data, size, 1);
buf->cap = size;
if (buf->len > buf->cap)
buf->len = buf->cap;
}
void
fz_grow_buffer(fz_context *ctx, fz_buffer *buf)
{
fz_resize_buffer(ctx, buf, (buf->cap * 3) / 2);
}
static void
fz_ensure_buffer(fz_context *ctx, fz_buffer *buf, int min)
{
int newsize = buf->cap;
while (newsize < min)
{
newsize = (newsize * 3) / 2;
}
fz_resize_buffer(ctx, buf, newsize);
}
void
fz_trim_buffer(fz_context *ctx, fz_buffer *buf)
{
if (buf->cap > buf->len+1)
fz_resize_buffer(ctx, buf, buf->len);
}
int
fz_buffer_storage(fz_context *ctx, fz_buffer *buf, unsigned char **datap)
{
if (datap)
*datap = (buf ? buf->data : NULL);
return (buf ? buf->len : 0);
}
void fz_write_buffer(fz_context *ctx, fz_buffer *buf, unsigned char *data, int len)
{
if (buf->len + len > buf->cap)
fz_ensure_buffer(ctx, buf, buf->len + len);
memcpy(buf->data + buf->len, data, len);
buf->len += len;
buf->unused_bits = 0;
}
void fz_write_buffer_byte(fz_context *ctx, fz_buffer *buf, int val)
{
if (buf->len > buf->cap)
fz_grow_buffer(ctx, buf);
buf->data[buf->len++] = val;
buf->unused_bits = 0;
}
void fz_write_buffer_bits(fz_context *ctx, fz_buffer *buf, int val, int bits)
{
int shift;
/* Throughout this code, the invariant is that we need to write the
* bottom 'bits' bits of 'val' into the stream. On entry we assume
* that val & ((1<<bits)-1) == val, but we do not rely on this after
* having written the first partial byte. */
if (bits == 0)
return;
/* buf->len always covers all the bits in the buffer, including
* any unused ones in the last byte, which will always be 0.
* buf->unused_bits = the number of unused bits in the last byte.
*/
/* Find the amount we need to shift val up by so that it will be in
* the correct position to be inserted into any existing data byte. */
shift = (buf->unused_bits - bits);
/* Extend the buffer as required before we start; that way we never
* fail part way during writing. If shift < 0, then we'll need -shift
* more bits. */
if (shift < 0)
{
int extra = (7-shift)>>3; /* Round up to bytes */
fz_ensure_buffer(ctx, buf, buf->len + extra);
}
/* Write any bits that will fit into the existing byte */
if (buf->unused_bits)
{
buf->data[buf->len-1] |= (shift >= 0 ? (((unsigned int)val)<<shift) : (((unsigned int)val)>>-shift));
if (shift >= 0)
{
/* If we were shifting up, we're done. */
buf->unused_bits -= bits;
return;
}
/* The number of bits left to write is the number that didn't
* fit in this first byte. */
bits = -shift;
}
/* Write any whole bytes */
while (bits >= 8)
{
bits -= 8;
buf->data[buf->len++] = val>>bits;
}
/* Write trailing bits (with 0's in unused bits) */
if (bits > 0)
{
bits = 8-bits;
buf->data[buf->len++] = val<<bits;
}
buf->unused_bits = bits;
}
void fz_write_buffer_pad(fz_context *ctx, fz_buffer *buf)
{
buf->unused_bits = 0;
}
void
fz_buffer_printf(fz_context *ctx, fz_buffer *buffer, char *fmt, ...)
{
va_list args;
va_start(args, fmt);
/* Caller guarantees not to generate more than 256 bytes per call */
while(buffer->cap - buffer->len < 256)
fz_grow_buffer(ctx, buffer);
buffer->len += vsprintf((char *)buffer->data + buffer->len, fmt, args);
va_end(args);
}
#ifdef TEST_BUFFER_WRITE
#define TEST_LEN 1024
void
fz_test_buffer_write(fz_context *ctx)
{
fz_buffer *master = fz_new_buffer(ctx, TEST_LEN);
fz_buffer *copy = fz_new_buffer(ctx, TEST_LEN);
fz_stream *stm;
int i, j, k;
/* Make us a dummy buffer */
for (i = 0; i < TEST_LEN; i++)
{
master->data[i] = rand();
}
master->len = TEST_LEN;
/* Now copy that buffer several times, checking it for validity */
stm = fz_open_buffer(ctx, master);
for (i = 0; i < 256; i++)
{
memset(copy->data, i, TEST_LEN);
copy->len = 0;
j = TEST_LEN * 8;
do
{
k = (rand() & 31)+1;
if (k > j)
k = j;
fz_write_buffer_bits(ctx, copy, fz_read_bits(stm, k), k);
j -= k;
}
while (j);
if (memcmp(copy->data, master->data, TEST_LEN) != 0)
fprintf(stderr, "Copied buffer is different!\n");
fz_seek(stm, 0, 0);
}
fz_close(stm);
fz_drop_buffer(ctx, master);
fz_drop_buffer(ctx, copy);
}
#endif
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