png格式分析的代码

一个简单的png文件格式解析的代码，采用标准C来完成的。

#include <stdio.h>#include <string.h>void pngPrintHelp(void);int pngCheckExtention(char *filename);void pngParserFile(char *name, int flag);#define PARSER_FLAG_VERBOSE0x00000001int main(int argc, char **argv){int i, parserFlag = 0; /* when no argument, output help and exit */ if (argc <= 1) { pngPrintHelp(); return 0; } for(i=0; i<argc; i++){if(strcmp(argv[i], "--verbose")){parserFlag = PARSER_FLAG_VERBOSE;break;}}for(i=1; i<argc; i++){if(pngCheckExtention(argv[i]) == 0){pngParserFile(argv[i], parserFlag);continue;}}return 0;}void pngPrintHelp(void){printf("This is Png file format debuger.../n");printf("Please use this debuger as :/n");printf("./png xxx.png [xxx.png] :/n");}int pngCheckExtention(char *filename){int len = strlen(filename);return strcmp((char *)(filename+len-4), ".png");}//====================================================typedef struct _pngInfo{unsigned char signature[8];}pngInfo;void pngCheckChunkInfo(FILE *fPng, int flag){char chunkID[4], len[4];int offset = 0, address, size;fseek(fPng, 8, SEEK_SET);while(!feof(fPng)){fseek(fPng, offset, SEEK_CUR);address = ftell(fPng);fread(len, 4, 1, fPng);fread(chunkID, 4, 1, fPng);printf("%c%c%c%c/n", chunkID[0],chunkID[1],chunkID[2],chunkID[3]);printf("%08X: Chunk length: %02X %02X %02X %02X/n", address, len[0],len[1],len[2],len[3]);printf("%08X: Chunk ID: %02X %02X %02X %02X/n", address+4, chunkID[0],chunkID[1],chunkID[2],chunkID[3]);size = len[0];size <<= 8;size |= len[1];size <<= 8;size |= len[2];size <<= 8;size |= len[3];printf("size == %d/n", size);offset = size + 4;if((chunkID[0] == 'I')&&(chunkID[1] == 'E')&&(chunkID[2] == 'N')&&(chunkID[3] == 'D'))break;}}void pngParserFile(char *name, int flag){FILE *fPng;pngInfo info;fPng = fopen(name, "rb");fread(info.signature, 8, 1, fPng);printf("PNG signature:/n%02X %02X %02X %02X %02X %02X %02X %02X/n", info.signature[0],info.signature[1], info.signature[2], info.signature[3],info.signature[4],info.signature[5], info.signature[6], info.signature[7]);pngCheckChunkInfo(fPng, flag);fclose(fPng);}