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#include "mupdf/fitz.h"
#include <errno.h>
#include <stdio.h>
#include <string.h>
#include <time.h>
/* File stream - progressive reading to simulate http download */
typedef struct prog_state
{
FILE *file;
int64_t length;
int64_t available;
int bps;
clock_t start_time;
unsigned char buffer[4096];
} prog_state;
static int next_prog(fz_context *ctx, fz_stream *stm, size_t len)
{
prog_state *ps = (prog_state *)stm->state;
size_t n;
unsigned char *buf = ps->buffer;
if (len > sizeof(ps->buffer))
len = sizeof(ps->buffer);
/* Simulate more data having arrived */
if (ps->available < ps->length)
{
int64_t av = (int64_t)((float)(clock() - ps->start_time) * ps->bps / (CLOCKS_PER_SEC*8));
if (av > ps->length)
av = ps->length;
ps->available = av;
/* Limit any fetches to be within the data we have */
if (av < ps->length && len + stm->pos > (size_t)av)
{
len = av - stm->pos;
if (len <= 0)
fz_throw(ctx, FZ_ERROR_TRYLATER, "Not enough data yet");
}
}
n = (len > 0 ? fread(buf, 1, len, ps->file) : 0);
if (n < len && ferror(ps->file))
fz_throw(ctx, FZ_ERROR_GENERIC, "read error: %s", strerror(errno));
stm->rp = ps->buffer + stm->pos;
stm->wp = ps->buffer + stm->pos + n;
stm->pos += (int64_t)n;
if (n == 0)
return EOF;
return *stm->rp++;
}
static void seek_prog(fz_context *ctx, fz_stream *stm, int64_t offset, int whence)
{
prog_state *ps = (prog_state *)stm->state;
/* Simulate more data having arrived */
if (ps->available < ps->length)
{
int av = (int)((float)(clock() - ps->start_time) * ps->bps / (CLOCKS_PER_SEC*8));
if (av > ps->length)
av = ps->length;
ps->available = av;
}
if (ps->available < ps->length)
{
if (whence == SEEK_END)
fz_throw(ctx, FZ_ERROR_TRYLATER, "Not enough data to seek to end yet");
}
if (whence == SEEK_CUR)
{
whence = SEEK_SET;
offset += stm->pos;
if (offset > ps->available)
fz_throw(ctx, FZ_ERROR_TRYLATER, "Not enough data to seek (relatively) to offset yet");
}
if (whence == SEEK_SET)
{
if (offset > ps->available)
fz_throw(ctx, FZ_ERROR_TRYLATER, "Not enough data to seek to offset yet");
}
if (fseek(ps->file, offset, whence) != 0)
fz_throw(ctx, FZ_ERROR_GENERIC, "cannot seek: %s", strerror(errno));
stm->pos = offset;
stm->wp = stm->rp;
}
static void close_prog(fz_context *ctx, void *state)
{
prog_state *ps = (prog_state *)state;
fclose(ps->file);
fz_free(ctx, state);
}
static int meta_prog(fz_context *ctx, fz_stream *stm, int key, int size, void *ptr)
{
prog_state *ps = (prog_state *)stm->state;
switch(key)
{
case FZ_STREAM_META_PROGRESSIVE:
return 1;
break;
case FZ_STREAM_META_LENGTH:
return ps->length;
}
return -1;
}
static fz_stream *
fz_open_file_ptr_progressive(fz_context *ctx, FILE *file, int bps)
{
fz_stream *stm;
prog_state *state;
state = fz_malloc_struct(ctx, prog_state);
state->file = file;
state->bps = bps;
state->start_time = clock();
state->available = 0;
fseek(state->file, 0, SEEK_END);
state->length = ftell(state->file);
fseek(state->file, 0, SEEK_SET);
stm = fz_new_stream(ctx, state, next_prog, close_prog);
stm->seek = seek_prog;
stm->meta = meta_prog;
return stm;
}
fz_stream *
fz_open_file_progressive(fz_context *ctx, const char *name, int bps)
{
FILE *f;
#ifdef _WIN32
f = fz_fopen_utf8(name, "rb");
#else
f = fopen(name, "rb");
#endif
if (f == NULL)
fz_throw(ctx, FZ_ERROR_GENERIC, "cannot open %s", name);
return fz_open_file_ptr_progressive(ctx, f, bps);
}
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