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add SPNG_ENCODE_TO_BUFFER option

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Encoding to an internal buffer is no longer an implicit process.
This commit is contained in:
Randy 2021-09-25 15:50:55 +02:00
parent 7afcbe5178
commit cc04f6d08f
4 changed files with 67 additions and 39 deletions
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74
examples/example.c
View File

@ -5,7 +5,7 @@
int main(int argc, char **argv)
{
int r = 0;
int ret = 0;
FILE *png;
spng_ctx *ctx = NULL;
unsigned char *out = NULL;
@ -43,11 +43,11 @@ int main(int argc, char **argv)
spng_set_png_file(ctx, png); /* or _buffer(), _stream() */
struct spng_ihdr ihdr;
r = spng_get_ihdr(ctx, &ihdr);
ret = spng_get_ihdr(ctx, &ihdr);
if(r)
if(ret)
{
printf("spng_get_ihdr() error: %s\n", spng_strerror(r));
printf("spng_get_ihdr() error: %s\n", spng_strerror(ret));
goto error;
}
@ -75,15 +75,15 @@ int main(int argc, char **argv)
ihdr.interlace_method);
struct spng_plte plte = {0};
r = spng_get_plte(ctx, &plte);
ret = spng_get_plte(ctx, &plte);
if(r && r != SPNG_ECHUNKAVAIL)
if(ret && ret != SPNG_ECHUNKAVAIL)
{
printf("spng_get_plte() error: %s\n", spng_strerror(r));
printf("spng_get_plte() error: %s\n", spng_strerror(ret));
goto error;
}
if(!r) printf("palette entries: %" PRIu32 "\n", plte.n_entries);
if(!ret) printf("palette entries: %" PRIu32 "\n", plte.n_entries);
size_t out_size, out_width;
@ -98,18 +98,18 @@ int main(int argc, char **argv)
if you want to expand them pick another format */
if(ihdr.color_type == SPNG_COLOR_TYPE_INDEXED) fmt = SPNG_FMT_RGB8;
r = spng_decoded_image_size(ctx, fmt, &out_size);
ret = spng_decoded_image_size(ctx, fmt, &out_size);
if(r) goto error;
if(ret) goto error;
out = malloc(out_size);
if(out == NULL) goto error;
/* This is required to initialize for progressive decoding */
r = spng_decode_image(ctx, NULL, 0, fmt, SPNG_DECODE_PROGRESSIVE);
if(r)
ret = spng_decode_image(ctx, NULL, 0, fmt, SPNG_DECODE_PROGRESSIVE);
if(ret)
{
printf("progressive spng_decode_image() error: %s\n", spng_strerror(r));
printf("progressive spng_decode_image() error: %s\n", spng_strerror(ret));
goto error;
}
@ -120,16 +120,16 @@ int main(int argc, char **argv)
do
{
r = spng_get_row_info(ctx, &row_info);
if(r) break;
ret = spng_get_row_info(ctx, &row_info);
if(ret) break;
r = spng_decode_row(ctx, out + row_info.row_num * out_width, out_width);
ret = spng_decode_row(ctx, out + row_info.row_num * out_width, out_width);
}
while(!r);
while(!ret);
if(r != SPNG_EOI)
if(ret != SPNG_EOI)
{
printf("progressive decode error: %s\n", spng_strerror(r));
printf("progressive decode error: %s\n", spng_strerror(ret));
if(ihdr.interlace_method)
printf("last pass: %d, scanline: %" PRIu32 "\n", row_info.pass, row_info.scanline_idx);
@ -150,17 +150,17 @@ int main(int argc, char **argv)
struct spng_text *text = NULL;
uint32_t n_text;
r = spng_get_text(ctx, NULL, &n_text);
ret = spng_get_text(ctx, NULL, &n_text);
if(r == SPNG_ECHUNKAVAIL)
if(ret == SPNG_ECHUNKAVAIL)
{
r = 0;
ret = 0;
goto no_text; /* no text chunks found in file */
}
if(r)
if(ret)
{
printf("spng_get_text() error: %s\n", spng_strerror(r));
printf("spng_get_text() error: %s\n", spng_strerror(ret));
goto error;
}
@ -168,11 +168,11 @@ int main(int argc, char **argv)
if(text == NULL) goto error;
r = spng_get_text(ctx, text, &n_text);
ret = spng_get_text(ctx, text, &n_text);
if(r)
if(ret)
{
printf("spng_get_text() error: %s\n", spng_strerror(r));
printf("spng_get_text() error: %s\n", spng_strerror(ret));
goto no_text;
}
@ -200,7 +200,7 @@ int main(int argc, char **argv)
no_text:
free(text);
/* Formats other than SPNG_FMT_PNG are not yet supported */
/* The encoder supports all PNG formats but format conversion support is limited */
if(fmt != SPNG_FMT_PNG) goto skip_encode;
/* This example reencodes the decoded image */
@ -208,8 +208,10 @@ no_text:
/* Creating an encoder context requires a flag */
spng_ctx *enc = spng_ctx_new(SPNG_CTX_ENCODER);
/* The default behavior is to allocate and write the PNG to an internal buffer,
this can be overriden by calling spng_set_png_file() or spng_set_png_stream() */
/* Encode to internal buffer managed by the library */
spng_set_option(enc, SPNG_ENCODE_TO_BUFFER, 1);
/* Alternatively you can set an output FILE* or stream with spng_set_png_file() or spng_set_png_stream() */
/* In this case we're reencoding to the same PNG format */
spng_set_ihdr(enc, &ihdr);
@ -221,11 +223,11 @@ no_text:
fmt = SPNG_FMT_PNG;
/* SPNG_ENCODE_FINALIZE will finalize the PNG with the end-of-file marker */
r = spng_encode_image(enc, out, out_size, fmt, SPNG_ENCODE_FINALIZE);
ret = spng_encode_image(enc, out, out_size, fmt, SPNG_ENCODE_FINALIZE);
if(r)
if(ret)
{
printf("spng_encode_image() error: %s\n", spng_strerror(r));
printf("spng_encode_image() error: %s\n", spng_strerror(ret));
goto encode_error;
}
@ -233,11 +235,11 @@ no_text:
void *png_buf = NULL;
/* Get the internal buffer of the finished PNG */
png_buf = spng_get_png_buffer(enc, &png_size, &r);
png_buf = spng_get_png_buffer(enc, &png_size, &ret);
if(png_buf == NULL)
{
printf("spng_get_png_buffer() error: %s\n", spng_strerror(r));
printf("spng_get_png_buffer() error: %s\n", spng_strerror(ret));
}
/* User owns the buffer after a successful call */
@ -253,5 +255,5 @@ error:
spng_ctx_free(ctx);
free(out);
return r;
return ret;
}

26
spng/spng.c
View File

@ -259,6 +259,7 @@ struct spng_ctx
enum spng_state state;
unsigned streaming: 1;
unsigned internal_buffer: 1; /* encoding to internal buffer */
unsigned inflate: 1;
unsigned deflate: 1;
@ -777,6 +778,8 @@ static int require_bytes(spng_ctx *ctx, size_t bytes)
return 0;
}
if(!ctx->internal_buffer) return SPNG_ENODST;
size_t required = ctx->bytes_encoded + bytes;
if(required < bytes) return SPNG_EOVERFLOW;
@ -828,8 +831,7 @@ static int write_data(spng_ctx *ctx, const void *data, size_t bytes)
else
{
int ret = require_bytes(ctx, bytes);
if(ret) return encode_err(ctx, SPNG_EMEM);
if(ret) return encode_err(ctx, ret);
memcpy(ctx->write_ptr, data, bytes);
@ -5217,6 +5219,19 @@ int spng_set_option(spng_ctx *ctx, enum spng_option option, int value)
ctx->chunk_count_limit = value;
break;
}
case SPNG_ENCODE_TO_BUFFER:
{
if(value < 0) return 1;
if(!ctx->encode_only) return SPNG_ECTXTYPE;
if(ctx->state >= SPNG_STATE_OUTPUT) return SPNG_EOPSTATE;
if(!value) return 0;
ctx->internal_buffer = 1;
ctx->state = SPNG_STATE_OUTPUT;
break;
}
default: return 1;
}
@ -5284,6 +5299,13 @@ int spng_get_option(spng_ctx *ctx, enum spng_option option, int *value)
*value = ctx->chunk_count_limit;
break;
}
case SPNG_ENCODE_TO_BUFFER:
{
if(ctx->internal_buffer) *value = 1;
else *value = 0;
break;
}
default: return 1;
}

2
spng/spng.h
View File

@ -407,8 +407,8 @@ enum spng_option
SPNG_TEXT_COMPRESSION_STRATEGY,
SPNG_FILTER_CHOICE,
SPNG_CHUNK_COUNT_LIMIT,
SPNG_ENCODE_TO_BUFFER,
};
typedef void* SPNG_CDECL spng_malloc_fn(size_t size);

4
tests/testsuite.c
View File

@ -1172,6 +1172,8 @@ static int spngt_run_test(const char *filename, struct spngt_test_case *test_cas
dst = spng_ctx_new(SPNG_CTX_ENCODER);
spng_set_option(dst, SPNG_ENCODE_TO_BUFFER, 1);
ret = set_chunks(dst, &data);
if(ret) goto encode_cleanup;
@ -1431,6 +1433,8 @@ static int extended_tests(FILE *file, int fmt)
enc = spng_ctx_new(SPNG_CTX_ENCODER);
spng_set_option(enc, SPNG_ENCODE_TO_BUFFER, 1);
spng_set_ihdr(enc, &ihdr);
if(plte.n_entries) spng_set_plte(enc, &plte);