eBookReaderSwitch/mupdf/source/fitz/buffer.c

591 lines
12 KiB
C

#include "fitz-imp.h"
#include <string.h>
#include <stdarg.h>
fz_buffer *
fz_new_buffer(fz_context *ctx, size_t size)
{
fz_buffer *b;
size = size > 1 ? size : 16;
b = fz_malloc_struct(ctx, fz_buffer);
b->refs = 1;
fz_try(ctx)
{
b->data = Memento_label(fz_malloc(ctx, size), "fz_buffer_data");
}
fz_catch(ctx)
{
fz_free(ctx, b);
fz_rethrow(ctx);
}
b->cap = size;
b->len = 0;
b->unused_bits = 0;
return b;
}
/*
Create a new buffer with existing data.
data: Pointer to existing data.
size: Size of existing data.
Takes ownership of data. Does not make a copy. Calls fz_free on the
data when the buffer is deallocated. Do not use 'data' after passing
to this function.
Returns pointer to new buffer. Throws exception on allocation
failure.
*/
fz_buffer *
fz_new_buffer_from_data(fz_context *ctx, unsigned char *data, size_t size)
{
fz_buffer *b = NULL;
fz_try(ctx)
{
b = fz_malloc_struct(ctx, fz_buffer);
b->refs = 1;
b->data = data;
b->cap = size;
b->len = size;
b->unused_bits = 0;
}
fz_catch(ctx)
{
fz_free(ctx, data);
fz_rethrow(ctx);
}
return b;
}
/*
Like fz_new_buffer, but does not take ownership.
*/
fz_buffer *
fz_new_buffer_from_shared_data(fz_context *ctx, const unsigned char *data, size_t size)
{
fz_buffer *b;
b = fz_malloc_struct(ctx, fz_buffer);
b->refs = 1;
b->data = (unsigned char *)data; /* cast away const */
b->cap = size;
b->len = size;
b->unused_bits = 0;
b->shared = 1;
return b;
}
/*
Create a new buffer containing a copy of the passed data.
*/
fz_buffer *
fz_new_buffer_from_copied_data(fz_context *ctx, const unsigned char *data, size_t size)
{
fz_buffer *b = fz_new_buffer(ctx, size);
b->len = size;
memcpy(b->data, data, size);
return b;
}
/*
Create a new buffer with data decoded from a base64 input string.
*/
fz_buffer *
fz_new_buffer_from_base64(fz_context *ctx, const char *data, size_t size)
{
fz_buffer *buf = fz_new_buffer(ctx, size);
const char *end = data + (size > 0 ? size : strlen(data));
const char *s = data;
fz_try(ctx)
{
while (s < end)
{
int c = *s++;
if (c >= 'A' && c <= 'Z')
fz_append_bits(ctx, buf, c - 'A', 6);
else if (c >= 'a' && c <= 'z')
fz_append_bits(ctx, buf, c - 'a' + 26, 6);
else if (c >= '0' && c <= '9')
fz_append_bits(ctx, buf, c - '0' + 52, 6);
else if (c == '+')
fz_append_bits(ctx, buf, 62, 6);
else if (c == '/')
fz_append_bits(ctx, buf, 63, 6);
}
}
fz_catch(ctx)
{
fz_drop_buffer(ctx, buf);
fz_rethrow(ctx);
}
return buf;
}
fz_buffer *
fz_keep_buffer(fz_context *ctx, fz_buffer *buf)
{
return fz_keep_imp(ctx, buf, &buf->refs);
}
void
fz_drop_buffer(fz_context *ctx, fz_buffer *buf)
{
if (fz_drop_imp(ctx, buf, &buf->refs))
{
if (!buf->shared)
fz_free(ctx, buf->data);
fz_free(ctx, buf);
}
}
/*
Ensure that a buffer has a given capacity,
truncating data if required.
capacity: The desired capacity for the buffer. If the current size
of the buffer contents is smaller than capacity, it is truncated.
*/
void
fz_resize_buffer(fz_context *ctx, fz_buffer *buf, size_t size)
{
if (buf->shared)
fz_throw(ctx, FZ_ERROR_GENERIC, "cannot resize a buffer with shared storage");
buf->data = fz_realloc(ctx, buf->data, size);
buf->cap = size;
if (buf->len > buf->cap)
buf->len = buf->cap;
}
/*
Make some space within a buffer (i.e. ensure that
capacity > size).
*/
void
fz_grow_buffer(fz_context *ctx, fz_buffer *buf)
{
size_t newsize = (buf->cap * 3) / 2;
if (newsize == 0)
newsize = 256;
fz_resize_buffer(ctx, buf, newsize);
}
static void
fz_ensure_buffer(fz_context *ctx, fz_buffer *buf, size_t min)
{
size_t newsize = buf->cap;
if (newsize < 16)
newsize = 16;
while (newsize < min)
{
newsize = (newsize * 3) / 2;
}
fz_resize_buffer(ctx, buf, newsize);
}
/*
Trim wasted capacity from a buffer by resizing internal memory.
*/
void
fz_trim_buffer(fz_context *ctx, fz_buffer *buf)
{
if (buf->cap > buf->len+1)
fz_resize_buffer(ctx, buf, buf->len);
}
void
fz_clear_buffer(fz_context *ctx, fz_buffer *buf)
{
buf->len = 0;
}
/*
Zero-terminate buffer in order to use as a C string.
This byte is invisible and does not affect the length of the buffer as returned by fz_buffer_storage.
The zero byte is written *after* the data, and subsequent writes will overwrite the terminating byte.
*/
void
fz_terminate_buffer(fz_context *ctx, fz_buffer *buf)
{
/* ensure that there is a zero-byte after the end of the data */
if (buf->len + 1 > buf->cap)
fz_grow_buffer(ctx, buf);
buf->data[buf->len] = 0;
}
/*
Retrieve internal memory of buffer.
datap: Output parameter that will be pointed to the data.
Returns the current size of the data in bytes.
*/
size_t
fz_buffer_storage(fz_context *ctx, fz_buffer *buf, unsigned char **datap)
{
if (datap)
*datap = (buf ? buf->data : NULL);
return (buf ? buf->len : 0);
}
/*
Ensure that a buffer's data ends in a
0 byte, and return a pointer to it.
*/
const char *
fz_string_from_buffer(fz_context *ctx, fz_buffer *buf)
{
if (!buf)
return "";
fz_terminate_buffer(ctx, buf);
return (const char *)buf->data;
}
/*
Take ownership of buffer contents.
Performs the same task as fz_buffer_storage, but ownership of
the data buffer returns with this call. The buffer is left
empty.
Note: Bad things may happen if this is called on a buffer with
multiple references that is being used from multiple threads.
data: Pointer to place to retrieve data pointer.
Returns length of stream.
*/
size_t
fz_buffer_extract(fz_context *ctx, fz_buffer *buf, unsigned char **datap)
{
size_t len = buf ? buf->len : 0;
*datap = (buf ? buf->data : NULL);
if (buf)
{
buf->data = NULL;
buf->len = 0;
}
return len;
}
void
fz_append_buffer(fz_context *ctx, fz_buffer *buf, fz_buffer *extra)
{
if (buf->cap - buf->len < extra->len)
{
buf->data = fz_realloc(ctx, buf->data, buf->len + extra->len);
buf->cap = buf->len + extra->len;
}
memcpy(buf->data + buf->len, extra->data, extra->len);
buf->len += extra->len;
}
/*
fz_append_*: Append data to a buffer.
fz_append_printf: Format and append data to buffer using printf-like formatting (see fz_vsnprintf).
fz_append_pdf_string: Append a string with PDF syntax quotes and escapes.
The buffer will automatically grow as required.
*/
void
fz_append_data(fz_context *ctx, fz_buffer *buf, const void *data, size_t 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_append_string(fz_context *ctx, fz_buffer *buf, const char *data)
{
size_t len = strlen(data);
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_append_byte(fz_context *ctx, fz_buffer *buf, int val)
{
if (buf->len + 1 > buf->cap)
fz_grow_buffer(ctx, buf);
buf->data[buf->len++] = val;
buf->unused_bits = 0;
}
void
fz_append_rune(fz_context *ctx, fz_buffer *buf, int c)
{
char data[10];
int len = fz_runetochar(data, c);
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_append_int32_be(fz_context *ctx, fz_buffer *buf, int x)
{
fz_append_byte(ctx, buf, (x >> 24) & 0xFF);
fz_append_byte(ctx, buf, (x >> 16) & 0xFF);
fz_append_byte(ctx, buf, (x >> 8) & 0xFF);
fz_append_byte(ctx, buf, (x) & 0xFF);
}
void
fz_append_int16_be(fz_context *ctx, fz_buffer *buf, int x)
{
fz_append_byte(ctx, buf, (x >> 8) & 0xFF);
fz_append_byte(ctx, buf, (x) & 0xFF);
}
void
fz_append_int32_le(fz_context *ctx, fz_buffer *buf, int x)
{
fz_append_byte(ctx, buf, (x)&0xFF);
fz_append_byte(ctx, buf, (x>>8)&0xFF);
fz_append_byte(ctx, buf, (x>>16)&0xFF);
fz_append_byte(ctx, buf, (x>>24)&0xFF);
}
void
fz_append_int16_le(fz_context *ctx, fz_buffer *buf, int x)
{
fz_append_byte(ctx, buf, (x)&0xFF);
fz_append_byte(ctx, buf, (x>>8)&0xFF);
}
void
fz_append_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_append_bits_pad(fz_context *ctx, fz_buffer *buf)
{
buf->unused_bits = 0;
}
static void fz_append_emit(fz_context *ctx, void *buffer, int c)
{
fz_append_byte(ctx, buffer, c);
}
void
fz_append_printf(fz_context *ctx, fz_buffer *buffer, const char *fmt, ...)
{
va_list args;
va_start(args, fmt);
fz_format_string(ctx, buffer, fz_append_emit, fmt, args);
va_end(args);
}
void
fz_append_vprintf(fz_context *ctx, fz_buffer *buffer, const char *fmt, va_list args)
{
fz_format_string(ctx, buffer, fz_append_emit, fmt, args);
}
void
fz_append_pdf_string(fz_context *ctx, fz_buffer *buffer, const char *text)
{
size_t len = 2;
const char *s = text;
char *d;
char c;
while ((c = *s++) != 0)
{
switch (c)
{
case '\n':
case '\r':
case '\t':
case '\b':
case '\f':
case '(':
case ')':
case '\\':
len++;
break;
}
len++;
}
while(buffer->cap - buffer->len < len)
fz_grow_buffer(ctx, buffer);
s = text;
d = (char *)buffer->data + buffer->len;
*d++ = '(';
while ((c = *s++) != 0)
{
switch (c)
{
case '\n':
*d++ = '\\';
*d++ = 'n';
break;
case '\r':
*d++ = '\\';
*d++ = 'r';
break;
case '\t':
*d++ = '\\';
*d++ = 't';
break;
case '\b':
*d++ = '\\';
*d++ = 'b';
break;
case '\f':
*d++ = '\\';
*d++ = 'f';
break;
case '(':
*d++ = '\\';
*d++ = '(';
break;
case ')':
*d++ = '\\';
*d++ = ')';
break;
case '\\':
*d++ = '\\';
*d++ = '\\';
break;
default:
*d++ = c;
}
}
*d = ')';
buffer->len += len;
}
void
fz_md5_buffer(fz_context *ctx, fz_buffer *buffer, unsigned char digest[16])
{
fz_md5 state;
fz_md5_init(&state);
if (buffer)
fz_md5_update(&state, buffer->data, buffer->len);
fz_md5_final(&state, digest);
}
#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_append_bits(ctx, copy, fz_read_bits(ctx, 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_drop_stream(stm);
fz_drop_buffer(ctx, master);
fz_drop_buffer(ctx, copy);
}
#endif